Anand Veeravagu, MD, FAANS, FACS

All Publications

• Impact of Supine versus Prone Positioning on Segmental Lumbar Lordosis in Patients Undergoing ALIF Followed by PSF: A Comparative Study. Journal of clinical medicine Sadeghzadeh, S., Yoo, K. H., Lopez, I., Johnstone, T., Schonfeld, E., Haider, G., Marianayagam, N. J., Stienen, M. N., Veeravagu, A. 2024; 13 (12)

  Abstract

  Background: Anterior lumbar interbody fusion (ALIF) and posterior spinal fusion (PSF) play pivotal roles in restoring lumbar lordosis in spinal surgery. There is an ongoing debate between combined single-position surgery and traditional prone-position PSF for optimizing segmental lumbar lordosis. Methods: This retrospective study analyzed 59 patients who underwent ALIF in the supine position followed by PSF in the prone position at a single institution. Cobb angles were measured preoperatively, post-ALIF, and post-PSF using X-ray imaging. One-way repeated measures ANOVA and post-hoc analyses with Bonferroni adjustment were employed to compare mean Cobb angles at different time points. Cohen's d effect sizes were calculated to assess the magnitude of changes. Sample size calculations were performed to ensure statistical power. Results: The mean segmental Cobb angle significantly increased from preoperative (32.2 ± 13.8 degrees) to post-ALIF (42.2 ± 14.3 degrees, Cohen's d: -0.71, p < 0.0001) and post-PSF (43.6 ± 14.6 degrees, Cohen's d: -0.80, p < 0.0001). There was no significant difference between Cobb angles after ALIF and after PSF (Cohen's d: -0.10, p = 0.14). The findings remained consistent when Cobb angles were analyzed separately for single-screw and double-screw ALIF constructs. Conclusions: Both supine ALIF and prone PSF significantly increased segmental lumbar lordosis compared to preoperative measurements. The negligible difference between post-ALIF and post-PSF lordosis suggests that supine ALIF followed by prone PSF can be an effective approach, providing flexibility in surgical positioning without compromising lordosis improvement.

  View details for DOI 10.3390/jcm13123555

  View details for PubMedID 38930084

• Focal motor weakness and recovery following chronic subdural hematoma evacuation. Journal of neurosurgery Nisson, P. L., Francis, J., Michel, M., Patil, S., Uchikawa, H., Veeravagu, A., Bonda, D. 2024: 1-8

  Abstract

  The incidence of chronic subdural hematomas (cSDHs) is expected to climb precipitously in the coming decades because of the aging populous. Neurological weakness is one of the most common presenting neurological symptoms of cSDH. Yet, the recovery rates of motor strength recovery are seldom documented, as neurological outcomes have predominantly focused on broader functional assessment scores or mortality. In this study, the authors performed one of the first detailed analyses on functional motor weakness and recovery in patients who underwent cSDH evacuation.Patients who underwent evacuation of a cSDH at a tertiary academic medical center between November 2013 and December 2021 were retrospectively identified using ICD-9 and ICD-10 billing codes. The presence of focal motor weakness was subcategorized by location as upper extremity (UE) or lower extremity (LE). Postoperative improvement, worsening, or resolution of weakness was recorded at the time of discharge. Statistical analysis included univariate and backward stepwise multivariable logistic regression modeling.A total of 311 patients were included in the analysis. Patients were significantly more likely to experience UE weakness than LE weakness (29% vs 18%, p < 0.001). Forty-one percent (43/104) had both UE and LE weakness present. Risk factors for the development of focal motor weakness at the time of presentation were older age (OR 1.02, p = 0.03), increased cSDH size (OR 1.04, p = 0.02), and the presence of a unilateral cSDH (OR 2.32, p = 0.008). The majority of patients (68%, 71/104) experienced motor strength improvement following cSDH evacuation, with 58% (60/104) having complete resolution of weakness. Multivariable logistic regression analysis revealed that longer symptom duration was associated with lower rates of improvement (OR 0.96, p = 0.024). Older age was also associated with reduced resolution of weakness (OR 0.96, p = 0.02).This study represents one of the first in-depth analyses investigating the rates of motor strength weakness and recovery following cSDH evacuation. Nearly two-thirds of all patients had complete resolution of their weakness by the time of discharge, and more than three-quarters had partial improvement. Risk factors for impaired neurological recovery were longer symptom duration prior to treatment and older age.

  View details for DOI 10.3171/2024.4.JNS24121

  View details for PubMedID 38875718

• CyberKnife stereotactic radiosurgery for extramedullary plasmacytoma in the external auditory canal: illustrative case. Journal of neurosurgery. Case lessons Patil, S., Shaghaghian, E., Yuan, L., Shah, A., Marianayagam, N. J., Park, D. J., Soltys, S. G., Veeravagu, A., Gibbs, I. C., Li, G., Chang, S. D. 2024; 7 (19)

  Abstract

  Plasmacytoma, a rare plasma cell disorder, often presents as a solitary or multiple tumors within the bone marrow or soft tissues, typically associated with multiple myeloma. Extramedullary plasmacytomas (EMPs), particularly those located in the external auditory canal (EAC), are exceedingly rare and pose significant treatment challenges given their location, anatomical complexity, and high risk of recurrence.The authors report the case of a 72-year-old male with a history of multiple myeloma, presenting with recurrent left EAC plasmacytoma. After initial conventional radiotherapy for the lesion, a recurrence was documented in 7 years. The patient subsequently underwent stereotactic radiosurgery, which proved successful, leading to complete resolution of the lesion without any long-term adverse effects or radiation-related complications over a 45-month period.This case is a unique instance of utilizing stereotactic radiosurgery for recurrent EMP in the EAC, highlighting its potential as an effective approach in managing complex plasmacytomas.

  View details for DOI 10.3171/CASE2479

  View details for PubMedID 38710109

  View details for PubMedCentralID PMC11076403

• Experience with the utilization of new-generation shared-control robotic system for spinal instrumentation. Journal of neurosurgical sciences Haider, G., Shah, V., Lopez, I., Wagner, K. E., Stienen, M. N., Veeravagu, A. 2024

  Abstract

  Robotic assistance in spine surgery is emerging as an accurate, effective and enabling technology utilized in the treatment of patients with surgical spinal pathology. The safety and reproducibility of robotic assistance in the placement of pedicle screw instrumentation is still being investigated. The objective of this study was to present our experience of instrumented spinal fusion utilizing an intraoperative robotic guidance system.We retrospectively reviewed all cases of spinal instrumentation of the thoracic and lumbo-sacral spine using the Mazor X robotic system (Medtronic Inc, Minneapolis, MN, USA), performed at our institution by one surgeon between July 2017 and June 2020. Wilcoxon Rank test was used to compare time taken to place each screw during the first 20 cases and the cases thereafter.A total of 28 patients were included. A total of 159 screws were placed using the Mazor X robotic system. The overall mean time for screw placement was 7.8±2.3 minutes and there was a significant reduction in the mean time for screw placement after the 20th case or 120 screws (8.70 vs. 5.42 min, P=0.008). No postoperative neurologic deficit or new radiculopathy was noted to occur secondary to hardware placement. No revision surgery was required for replacement or removal of a mispositioned screw.From this single-center, single-surgeon series we conclude that robot-assisted spine surgery can be safely and efficiently integrated into the operating room workflow, which improves after a learning curve of approximately 20 operative interventions. We found robot-assisted spinal instrumentation to be reliable, safe, effective and highly precise.

  View details for DOI 10.23736/S0390-5616.24.06206-4

  View details for PubMedID 38619188

• Deep Learning Prediction of Cervical Spine Surgery Revision Outcomes Using Standard Laboratory and Operative Variables. World neurosurgery Schonfeld, E., Shah, A., Johnstone, T. M., Rodrigues, A., Morris, G. K., Stienen, M. N., Veeravagu, A. 2024

  Abstract

  INTRODUCTION: Cervical spine procedures represent a major proportion of all spine surgery. Mitigating the revision rate following cervical procedures requires careful patient selection. While complication risk has successfully been predicted, revision risk has proven more challenging. This is likely due to the absence of granular variables in claims databases. The objective of this study was to develop a state-of-the-art of revision prediction of cervical spine surgery using laboratory and operative variables.METHODS: Using the Stanford Research Repository, patients undergoing a cervical spine procedure between 2016-2022 were identified (N=3151) and recent laboratory values were collected. Patients were classified into separate cohorts by revision outcome and timeframe. Machine and deep learning models were trained to predict each revision outcome from laboratory and operative variables.RESULTS: Red blood cell count, Hemoglobin, Hematocrit, Mean Corpuscular Hemoglobin Concentration, Red Blood Cell Distribution Width, Platelet Count, CO2, Anion Gap, and Calcium were all significantly associated with one or more revision cohorts. For the prediction of 3-month revision, the deep neural network achieved AUC of 0.833. The model demonstrated increased performance for anterior than posterior and arthrodesis than decompression procedures.CONCLUSIONS: Our deep learning approach successfully predicted 3-month revision outcomes from demographic variables, standard laboratory values, and operative variables, in a cervical spine surgery cohort. This work introduces standard laboratory values and operative codes as meaningful predictive variables for revision outcome prediction. The increased performance on certain procedures evidences the need for careful development and validation of "one-size-fits-all" risk scores for spine procedures.

  View details for DOI 10.1016/j.wneu.2024.02.112

  View details for PubMedID 38408699

• Misplaced intraspinal venous stent causing cauda equina syndrome: illustrative case. Journal of neurosurgery. Case lessons Shah, V., Johnstone, T., Haider, G., Marianayagam, N. J., Stienen, M. N., Chandra, V., Veeravagu, A. 2024; 7 (7)

  Abstract

  Endovenous stents for deep venous thrombosis treatment can be unintentionally placed in the spinal canal, resulting in neurological deficit.The authors report the case of a patient presenting to our institution with intraspinal misplacement of an endovenous stent, resulting in cauda equina syndrome. The authors also performed a systematic literature review, evaluating the few previously reported cases. This review was performed according to the updated Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. In four of five cases describing stent misplacement into the spinal canal, the authors report that only anteroposterior monoplanar imaging modalities were utilized for venous localization and stent deployment. The anteroposterior plane cannot assess the relative depth of structures, nor can it distinguish between superimposed structures well. Therefore, the use of biplanar imaging should at least be considered before stent deployment, as intraspinal stent placement can lead to disastrous consequences.This report should serve as an impetus for the use of biplanar or three-dimensional imaging modalities for iliac venous stent placement. Additionally, this work should increase spine surgeons' awareness about management and operative techniques when faced with this complication.

  View details for DOI 10.3171/CASE23482

  View details for PubMedID 38346298

• Evaluating Computer Vision, Large Language, and Genome-Wide Association Models in a Limited Sized Patient Cohort for Pre-Operative Risk Stratification in Adult Spinal Deformity Surgery. Journal of clinical medicine Schonfeld, E., Pant, A., Shah, A., Sadeghzadeh, S., Pangal, D., Rodrigues, A., Yoo, K., Marianayagam, N., Haider, G., Veeravagu, A. 2024; 13 (3)

  Abstract

  Background: Adult spinal deformities (ASD) are varied spinal abnormalities, often necessitating surgical intervention when associated with pain, worsening deformity, or worsening function. Predicting post-operative complications and revision surgery is critical for surgical planning and patient counseling. Due to the relatively small number of cases of ASD surgery, machine learning applications have been limited to traditional models (e.g., logistic regression or standard neural networks) and coarse clinical variables. We present the novel application of advanced models (CNN, LLM, GWAS) using complex data types (radiographs, clinical notes, genomics) for ASD outcome prediction. Methods: We developed a CNN trained on 209 ASD patients (1549 radiographs) from the Stanford Research Repository, a CNN pre-trained on VinDr-SpineXR (10,468 spine radiographs), and an LLM using free-text clinical notes from the same 209 patients, trained via Gatortron. Additionally, we conducted a GWAS using the UK Biobank, contrasting 540 surgical ASD patients with 7355 non-surgical ASD patients. Results: The LLM notably outperformed the CNN in predicting pulmonary complications (F1: 0.545 vs. 0.2881), neurological complications (F1: 0.250 vs. 0.224), and sepsis (F1: 0.382 vs. 0.132). The pre-trained CNN showed improved sepsis prediction (AUC: 0.638 vs. 0.534) but reduced performance for neurological complication prediction (AUC: 0.545 vs. 0.619). The LLM demonstrated high specificity (0.946) and positive predictive value (0.467) for neurological complications. The GWAS identified 21 significant (p < 10-5) SNPs associated with ASD surgery risk (OR: mean: 3.17, SD: 1.92, median: 2.78), with the highest odds ratio (8.06) for the LDB2 gene, which is implicated in ectoderm differentiation. Conclusions: This study exemplifies the innovative application of cutting-edge models to forecast outcomes in ASD, underscoring the utility of complex data in outcome prediction for neurosurgical conditions. It demonstrates the promise of genetic models when identifying surgical risks and supports the integration of complex machine learning tools for informed surgical decision-making in ASD.

  View details for DOI 10.3390/jcm13030656

  View details for PubMedID 38337352

• Getting What You Pay For: Impact of Copayments on Physical Therapy and Opioid Initiation, Timing, and Continuation for Newly Diagnosed Low Back Pain. The spine journal : official journal of the North American Spine Society Jin, M. C., Jensen, M., Barros Guinle, M. I., Ren, A., Zhou, Z., Zygourakis, C. C., Desai, A. M., Veeravagu, A., Ratliff, J. K. 2024

  Abstract

  Physical therapy (PT) is an important component of low back pain (LBP) management. Despite established guidelines, heterogeneity in medical management remains common.We sought to understand how copayments impact timing and utilization of PT in newly diagnosed LBP.The IBM Watson Health MarketScan claims database was utilized in a longitudinal setting.Adult patients with LBP.The primary outcomes-of-interest were timing and overall utilization of PT services. Additional outcomes-of-interest included timing of opioid prescribing.Actual and inferred copayments based on non-PCP visit claims were used to evaluate the relationship between PT copayment and incidence of PT initiation. Multivariable regression models were used to evaluate factors influencing PT usage.Overall, 2,467,389 patients were included. PT initiation, among those with at ≥1 PT service during the year after LBP diagnosis (30.6%), occurred at a median of 8 days post-diagnosis (IQR 1-55). Among those with at least one PT encounter, incidence of subsequent PT visits was significantly lower for those with high initial PT copayments. High initial PT copayments, while inversely correlated with PT utilization, were directly correlated with subsequent opioid use (0.77 prescriptions/patient [$0 PT copayment] vs 1.07 prescriptions/patient [$50-74 PT copayment]; 1.15 prescriptions/patient [$75+ PT copayment]). Among patients with known opioid and PT copayments, higher PT copayments were correlated with faster opioid use while higher opioid copayments were correlated with faster PT use (Spearman p < 0.05). For multivariable whole-cohort analyses, incidence of PT initiation among patients with inferred copayments in the 50-75th and 75th-100th percentiles was significantly lower than those below the 50th percentile (HR=0.893 [95%CI 0.887-0.899] and HR=0.905 [95%CI 0.899-0.912], respectively).Higher PT copayments correlated with reduced PT utilization; higher PT copayments and lower opioid copayments were independent contributors to delayed PT initiation and higher opioid use. In patients covered by plans charging high PT copayments, opioid use was significantly higher. Co-pays may impact long-term adherence to PT.

  View details for DOI 10.1016/j.spinee.2024.01.008

  View details for PubMedID 38262499

• Machine Learning in Neurosurgery: Toward Complex Inputs, Actionable Predictions, and Generalizable Translations CUREUS JOURNAL OF MEDICAL SCIENCE Schonfeld, E., Mordekai, N., Berg, A., Johnstone, T., Shah, A., Shah, V., Haider, G., Marianayagam, N. J., Veeravagu, A. 2024; 16 (1)

  View details for DOI 10.7759/cureus.51963

  View details for Web of Science ID 001153117000002

• An Integrated 3-Dimentional Navigation System Increases the Accuracy, Efficiency, and Safety of Percutaneous Thoracolumbar Pedicle Screw Placement in Minimally Invasive Approaches: A Randomized Cadaveric Study. Global spine journal Lakomkin, N., Eastlack, R. K., Uribe, J. S., Park, P., Ryu, S. I., Kretzer, R., Mimran, R. I., Holman, P., Veeravagu, A., Hassanzadeh, H., Johnson, M. M., Sullivan, L., Clark, A., Mundis, G. M. 2024: 21925682231224394

  Abstract

  STUDY DESIGN: Cadaveric study.OBJECTIVES: The purpose of this study was to compare a novel, integrated 3D navigational system (NAV) and conventional fluoroscopy in the accuracy, efficiency, and radiation exposure of thoracolumbar percutaneous pedicle screw (PPS) placement.METHODS: Twelve skeletally mature cadaveric specimens were obtained for twelve individual surgeons. Each participant placed bilateral PS at 11 segments, from T8 to S1. Prior to insertion, surgeons were randomized to the sequence of techniques and the side (left or right). Following placement, a CT scan of the spine was obtained for each cadaver, and an independent reviewer assessed the accuracy of screw placement using the Gertzbein grading system. Outcome metrics of interest included a comparison of breach incidence/severity, screw placement time, total procedure time, and radiation exposure between the techniques. Bivariate statistics were employed to compare outcomes at each level.RESULTS: A total of 262 screws (131 using each technique) were placed. The incidence of cortical breaches was significantly lower with NAV compared to FG (9% vs 18%; P = .048). Of breaches with NAV, 25% were graded as moderate or severe compared to 39% in the FG subgroup (P = .034). Median time for screw placement was significantly lower with NAV (2.7 vs 4.1 min/screw; P = .012), exclusive of registration time. Cumulative radiation exposure to the surgeon was significantly lower for NAV-guided placement (9.4 vs 134 muGy, P = .02).CONCLUSIONS: The use of NAV significantly decreased the incidence of cortical breaches, the severity of screw breeches, screw placement time, and radiation exposure to the surgeon when compared to traditional FG.

  View details for DOI 10.1177/21925682231224394

  View details for PubMedID 38165219

• Machine Learning in Neurosurgery: Toward Complex Inputs, Actionable Predictions, and Generalizable Translations. Cureus Schonfeld, E., Mordekai, N., Berg, A., Johnstone, T., Shah, A., Shah, V., Haider, G., Marianayagam, N. J., Veeravagu, A. 2024; 16 (1): e51963

  Abstract

  Machine learning can predict neurosurgical diagnosis and outcomes, power imaging analysis, and perform robotic navigation and tumor labeling. State-of-the-art models can reconstruct and generate images, predict surgical events from video, and assist in intraoperative decision-making. In this review, we will detail the neurosurgical applications of machine learning, ranging from simple to advanced models, and their potential to transform patient care. As machine learning techniques, outputs, and methods become increasingly complex, their performance is often more impactful yet increasingly difficult to evaluate. We aim to introduce these advancements to the neurosurgical audience while suggesting major potential roadblocks to their safe and effective translation. Unlike the previous generation of machine learning in neurosurgery, the safe translation of recent advancements will be contingent on neurosurgeons' involvement in model development and validation.

  View details for DOI 10.7759/cureus.51963

  View details for PubMedID 38333513

  View details for PubMedCentralID PMC10851045

• Intradural cystic schwannomas of the spine: A case-based systematic review of an unusual tumor BRAIN AND SPINE Terrapon, A., Stienen, M. N., Veeravagu, A., Fehlings, M., Bozinov, O., Hejrati, N. 2024; 4

  View details for DOI 10.1016/j.bas.2024.102843

  View details for Web of Science ID 001252019100001

• Stanford University School of Medicine: Our Neurosurgical Heritage. Neurosurgery Veeravagu, A., Kim, L. H., Rao, V. L., Lim, M., Shuer, L. M., Harris, O. A., Steinberg, G. K. 2023

  Abstract

  The legacy of Stanford University's Department of Neurosurgery began in 1858, with the establishment of a new medical school on the West Coast. Stanford Neurosurgery instilled an atmosphere of dedication to neurosurgical care, scientific research, education, and innovation. We highlight key historical events leading to the formation of the medical school and neurosurgical department, the individuals who shaped the department's vision and expansion, as well as pioneering advances in research and clinical care. The residency program was started in 1961, establishing the basis of the current education model with a strong emphasis on training future leaders, and the Moyamoya Center, founded in 1991, became the largest Moyamoya referral center in the United States. The opening of Stanford Stroke Center (1992) and seminal clinical trials resulted in a significant impact on cerebrovascular disease by expanding the treatment window of IV thrombolysis and intra-arterial thrombectomy. The invention and implementation of CyberKnife® (1994) marks another important event that revolutionized the field of radiosurgery, and the development of Stanford's innovative Brain Computer Interface program is pushing the boundaries of this specialty. The more recent launch of the Neurosurgery Virtual Reality and Simulation Center (2017) exemplifies how Stanford is continuing to evolve in this ever-changing field. The department also became a model for diversity within the school as well as nationwide. The growth of Stanford Neurosurgery from one of the youngest neurosurgery departments in the country to a prominent comprehensive neurosurgery center mirrors the history of neurosurgery itself: young, innovative, and willing to overcome challenges.

  View details for DOI 10.1227/neu.0000000000002799

  View details for PubMedID 38095422

• Type II Odontoid Fractures in the Elderly Presenting to the Emergency Department: An Assessment of Factors Affecting In-Hospital Mortality and Discharge to Skilled Nursing Facilities. The spine journal : official journal of the North American Spine Society Johnstone, T., Shah, V., Schonfeld, E., Sadeghzadeh, S., Haider, G., Stienen, M., Marianayagam, N. J., Veeravagu, A. 2023

  Abstract

  Type II odontoid fractures (OF) are among the most common cervical spine injuries in the geriatric population. However, there is a paucity of literature regarding their epidemiology. Additionally, the optimal management of these injuries remains controversial, and no study has evaluated the short-term outcomes of geriatric patients presenting to emergency departments (ED).This study aims to document the epidemiology of geriatric patients presenting to EDs with type II OFs and determine whether surgical management was associated with early adverse outcomes such as in-hospital mortality and discharge to skilled nursing facilities (SNF).This is a retrospective cohort study.Data was used from the 2016-2020 Nationwide Emergency Department Sample. Patient encounters corresponding to type II OFs were identified. Patients younger than 65 at the time of presentation to the ED and those with concomitant spinal pathology were excluded.The association between the surgical management of geriatric type II OFs and outcomes such as in-hospital mortality and discharge to SNFs.Patient, fracture, and surgical management characteristics were recorded. A propensity score matched cohort was constructed to reduce differences in age, comorbidities, and injury severity between patients undergoing operative and nonoperative management. Additionally, to develop a positive control for the analysis of geriatric patients with type II OFs and no other concomitant spinal pathology, a cohort of patients that had been excluded due to the presence of a concomitant spinal cord injury (SCI) was also constructed. Multivariate regressions were then performed on both the matched and unmatched cohorts to ascertain the associations between surgical treatment and in-hospital mortality, inpatient length of stay, encounter charges, and discharge to SNFs.11,325 encounters were included. The mean total charge per encounter was $60,221. 634 (5.6%) patients passed away during their encounters. 1,005 (8.9%) patients were managed surgically. Surgical management of type II OFs was associated with a 316% increase in visit charge (95% CI: 291%-341%, p<0.001), increased inpatient length of stay (IRR: 2.87, 95% CI: 2.62-3.12, p<0.001), and increased likelihood of discharge to SNFs (OR = 2.62, 95% CI: 2.26-3.05, p <0.001), but decreased in-hospital mortality (OR = 0.32, CI: 0.21-0.45, p<0.001). The propensity score matched cohort consisted of 2,010 patients, matching each of the 1,005 that underwent surgery to 1,005 that did not. These cohorts were well balanced across age (78.24 vs. 77.91 years), Elixhauser Comorbidity Index (3.68 vs. 3.71), and Injury Severity Score (30.15 vs 28.93). This matching did not meaningfully alter the associations determined between surgical management and in-hospital mortality (OR = 0.34, CI = 0.21-0.55, p<0.001) or SNF discharge (OR = 2.59, CI = 2.13-3.16, p<0.001). Lastly, the positive control cohort of patients with concurrent SCI had higher rates of SNF discharge (50.0% vs. 42.6%, p<0.001), surgical management (32.3% vs. 9.7%, p<0.001), and in-hospital mortality (28.9% vs. 5.6%, p<0.001).This study lends insight into the epidemiology of geriatric type II OFs and quantifies risk factors influencing adverse outcomes. Patient informed consent should include a discussion of the protective association between definitive surgical management and in-hospital mortality against potential operative morbidity, increased lengths of hospital stay, and increased likelihood of discharge to SNFs. This information may impact patient treatment selection and decision making.

  View details for DOI 10.1016/j.spinee.2023.11.023

  View details for PubMedID 38101547

• Accuracy of predicted postoperative segmental lumbar lordosis in spinal fusion using an intraoperative robotic planning and guidance system. Journal of neurosurgical sciences Haider, G., Shah, V., Johnstone, T., Maldaner, N., Stienen, M., Veeravagu, A. 2023

  Abstract

  Restoring lumbar lordosis is one of the main goals in lumbar spinal fusion surgery. The Mazor X-AlignTM software allows for the prediction of postoperative segmental lumbar lordosis based on preoperative imaging. There is limited data on the accuracy of this preoperative prediction, especially in patients undergoing short segment lumbar fusion. The objective of our study was to determine the accuracy of predicted postoperative segmental lumbar lordosis using the Mazor X-AlignTM software in patients requiring short segmental fusion.Retrospective analysis of adult patients undergoing pedicle screw spinal instrumentation of not more than four levels using the Mazor XTM Robot (Medtronic Inc., Minneapolis, MN, USA) between July 2017 to June 2020. The robotic guidance software, Mazor X-AlignTM (Medtronic Inc., Minneapolis, MN, USA) was used to calculate the predicted segmental lumbar lordosis based on preoperative CT-imaging and the plan was executed under intraoperative robotic guidance. Predicted segmental lumbar lordosis was compared to achieved segmental lumbar lordosis on 1-month postoperative x-rays using the Cobb angle methodology.A total of 15 patients (46.6% female) with a mean age of 61.5±10.9 years were included. All patients underwent posterior lumbo-sacral spinal fusion with the Mazor XTM robotic system with 11 patients (73.3%) undergoing anterior column reconstruction prior to posterior fixation. Instrumentation was performed across a mean of 2.6 levels per case. Preoperative, the mean segmental lumbar lordosis was 30.2±13.6 degrees. The mean planned segmental lumbar lordosis was 35.5±17.0 degrees while the mean achieved segmental lumbar lordosis was 35.8±16.7 degrees. There was no significant mean difference between the planned and achieved segmental lumbar lordosis (P=0.334).The Mazor XTM intraoperative robotic planning and guidance is accurate in predicting postoperative segmental lumbar lordosis after short segmental fusion. Our findings may assure surgical decision making and planning.

  View details for DOI 10.23736/S0390-5616.23.06142-8

  View details for PubMedID 37997323

• Spinal metastases of pineal region glioblastoma with primitive neuroectodermal features highlighting the importance of molecular diagnoses: illustrative case. Journal of neurosurgery. Case lessons Shah, A., Marianayagam, N. J., Zamarud, A., Park, D. J., Persad, A. R., Soltys, S. G., Chang, S. D., Veeravagu, A. 2023; 6 (20)

  Abstract

  Glioblastoma (GBM) is the most common primary brain tumor with poor patient prognosis. Spinal leptomeningeal metastasis has been rarely reported, with long intervals between the initial discovery of the primary tumor in the brain and eventual spine metastasis.Here, the authors present the case of a 51-year-old male presenting with 7 days of severe headache, nausea, and vomiting. Magnetic resonance imaging of the brain and spine demonstrated a contrast-enhancing mass in the pineal region, along with spinal metastases to T8, T12, and L5. Initial frozen-section diagnosis led to the treatment strategy for medulloblastoma, but further molecular analysis revealed characteristics of isocitrate dehydrogenase-wild type, grade 4 GBM.Glioblastoma has the potential to show metastatic spread at the time of diagnosis. Spinal imaging should be considered in patients with clinical suspicion of leptomeningeal spread. Furthermore, molecular analysis should be confirmed following pathological diagnosis to fine-tune treatment strategies.

  View details for DOI 10.3171/CASE23536

  View details for PubMedID 37956418

• STEREOTACTIC RADIOSURGERY FOR RESIDUAL, RECURRENT, AND METASTATIC HEMANGIOPERICYTOMAS: A SINGLE INSTITUTION EXPERIENCE Yoo, K., Park, D., Veeravagu, A., Lee, M., Marianayagam, N., Zamarud, A., Gu, X., Pollom, E., Soltys, S., Chang, S., Meola, A. OXFORD UNIV PRESS INC. 2023

  View details for Web of Science ID 001115245400225

• Socio-economic disparities influence likelihood of post-operative radiation to resection cavities of metastatic brain tumors ACTA NEUROCHIRURGICA Haider, G., Dadey, D. A., Rodrigues, A., Pollom, E. L., Adler, J. R., Veeravagu, A. 2023

  View details for DOI 10.1007/s00701-023-05826

  View details for Web of Science ID 001087777900004

• Socio-economic disparities influence likelihood of post-operative radiation to resection cavities of metastatic brain tumors. Acta neurochirurgica Haider, G., Dadey, D. Y., Rodrigues, A., Pollom, E. L., Adler, J. R., Veeravagu, A. 2023

  Abstract

  PURPOSE: Irradiating the surgical bed of resected brain metastases improves local and distant disease control. Over time, stereotactic radiosurgery (SRS) has replaced whole brain radiotherapy (WBRT) as the treatment standard of care because it minimizes long-term damage to neuro-cognition. Despite this data and growing adoption, socio-economic disparities in clinical access can result in sub-standard care for some patient populations. We aimed to analyze the clinical and socio-economic characteristics of patients who did not receive radiation after surgical resection of brain metastasis.METHODS: Our sample was obtained from Clinformatics Data Mart Database and included all patients from 2004 to 2021 who did or did not receive radiation treatment within sixty days after resection of tumors metastatic to the brain. Regression analysis was done to identify factors responsible for loss to adjuvant radiation treatment.RESULTS: Of 8362 patients identified who had undergone craniotomy for resection of metastatic brain tumors, 3430 (41%) patients did not receive any radiation treatment. Compared to patients who did receive some form of radiation treatment (SRS or WBRT), patients who did not get any form of radiation were more likely to be older (p = 0.0189) and non-white (p = 0.008). Patients with Elixhauser Comorbidity Index ≥3 were less likely to receive radiation treatment (p < 0.01). Fewer patients with household income ≥ $75,000 did not receive radiation treatment (p < 0.01).CONCLUSION: Age, race, household income, and comorbidity status were associated with differential likelihood to receive post-operative radiation treatment.

  View details for DOI 10.1007/s00701-023-05826-w

  View details for PubMedID 37816918

• Sigma-1 receptor expression in a subpopulation of lumbar spinal cord microglia in response to peripheral nerve injury. Scientific reports Schonfeld, E., Johnstone, T. M., Haider, G., Shah, A., Marianayagam, N. J., Biswal, S., Veeravagu, A. 2023; 13 (1): 14762

  Abstract

  Sigma-1 Receptor has been shown to localize to sites of peripheral nerve injury and back pain. Radioligand probes have been developed to localize Sigma-1 Receptor and thus image pain source. However, in non-pain conditions, Sigma-1 Receptor expression has also been demonstrated in the central nervous system and dorsal root ganglion. This work aimed to study Sigma-1 Receptor expression in a microglial cell population in the lumbar spine following peripheral nerve injury. A publicly available transcriptomic dataset of 102,691 L4/5 mouse microglial cells from a sciatic-sural nerve spared nerve injury model and 93,027 age and sex matched cells from a sham model was used. At each of three time points-postoperative day 3, postoperative day 14, and postoperative month 5-gene expression data was recorded for both spared nerve injury and Sham cell groups. For all cells, 27,998 genes were sequenced. All cells were clustered into 12 distinct subclusters and gene set enrichment pathway analysis was performed. For both the spared nerve injury and Sham groups, Sigma-1 Receptor expression significantly decreased at each time point following surgery. At the 5-month postoperative time point, only one of twelve subclusters showed significantly increased Sigma-1 Receptor expression in spared nerve injury cells as compared to Sham cells (p = 0.0064). Pathway analysis of this cluster showed a significantly increased expression of the inflammatory response pathway in the spared nerve injury cells relative to Sham cells at the 5-month time point (p = 6.74e-05). A distinct subcluster of L4/5 microglia was identified which overexpress Sigma-1 Receptor following peripheral nerve injury consistent with neuropathic pain inflammatory response functioning. This indicates that upregulated Sigma-1 Receptor in the central nervous system characterizes post-acute peripheral nerve injury and may be further developed for clinical use in the differentiation between low back pain secondary to peripheral nerve injury and low back pain not associated with peripheral nerve injury in cases where the pain cannot be localized.

  View details for DOI 10.1038/s41598-023-42063-8

  View details for PubMedID 37679500

  View details for PubMedCentralID PMC10484902

• Demonstrating the successful application of synthetic learning in spine surgery for training multi-center models with increased patient privacy. Scientific reports Schonfeld, E., Veeravagu, A. 2023; 13 (1): 12481

  Abstract

  From real-time tumor classification to operative outcome prediction, applications of machine learning to neurosurgery are powerful. However, the translation of many of these applications are restricted by the lack of "big data" in neurosurgery. Important restrictions in patient privacy and sharing of imaging data reduce the diversity of the datasets used to train resulting models and therefore limit generalizability. Synthetic learning is a recent development in machine learning that generates synthetic data from real data and uses the synthetic data to train downstream models while preserving patient privacy. Such an approach has yet to be successfully demonstrated in the spine surgery domain. Spine radiographs were collected from the VinDR-SpineXR dataset, with 1470 labeled as abnormal and 2303 labeled as normal. A conditional generative adversarial network (GAN) was trained on the radiographs to generate a spine radiograph and normal/abnormal label. A modified conditional GAN (SpineGAN) was trained on the same task. A convolutional neural network (CNN) was trained using the real data to label abnormal radiographs. A CNN was trained to label abnormal radiographs using synthetic images from the GAN and in a separate experiment from SpineGAN. Using the real radiographs, an AUC of 0.856 was achieved in abnormality classification. Training on synthetic data generated by the standard GAN (AUC of 0.814) and synthetic data generated by our SpineGAN (AUC of 0.830) resulted in similar classifier performance. SpineGAN generated images with higher FID and lower precision scores, but with higher recall and increased performance when used for synthetic learning. The successful application of synthetic learning was demonstrated in the spine surgery domain for the classification of spine radiographs as abnormal or normal. A modified domain-relevant GAN is introduced for the generation of spine images, evidencing the importance of domain-relevant generation techniques in synthetic learning. Synthetic learning can allow neurosurgery to use larger and more diverse patient imaging sets to train more generalizable algorithms with greater patient privacy.

  View details for DOI 10.1038/s41598-023-39458-y

  View details for PubMedID 37528216

  View details for PubMedCentralID 9099011

• Progression to fusion after lumbar laminectomy for degenerative lumbar spondylolisthesis: Rate and risk-factors. A national database study. Clinical neurology and neurosurgery Haider, G., Varshneya, K., Rodrigues, A., Marianayagam, N., Stienen, M. N., Veeravagu, A. 2023; 233: 107919

  Abstract

  Lumbar laminectomy is often utilized in the treatment of degenerative lumbar spondylolisthesis. Risk factors that contribute to reoperation rates, in particular to progression to fusion, are poorly understood. We aimed to identify rate and risk factors of lumbar fusion surgery following lumbar laminectomy for the treatment of degenerative lumbar spinal spondylolisthesis.Our sample was obtained from the national MarketScan Commercial Claims and Encounters Database. We reviewed patients undergoing lumbar laminectomy for stable degenerative lumbar spondylolisthesis (Grade-1) at one or two levels between January 2007 and December 2016.A total of 33,681 patients were included. By 2 years after the index operation, 2.48 % of patients had required lumbar fusion surgery. Female sex was associated with lower odds (OR 0.8, 95 %CI 0.7-0.9) of reoperation for fusion. Diabetes (OR 1.2, 95 %CI 1.1-1.4), rheumatoid arthritis (OR 1.5, 95 %CI 1.2-1.7) and clinical presentation with LBP (OR 2.1, 95 %CI 1.6-2.9), lower extremity weakness (OR 1.4, 95 %CI 1.1-1.5), as well as occurrence of a postoperative neurological complications (OR 2.0, 95 %CI 1.1-3.4) increased the odds ratio for requiring fusion surgery within two years after lumbar laminectomy.In this large cross-sectional sample of a national claims database consisting of lumbar laminectomy patients for the treatment of spondylolisthesis, approximately 2.5 % required subsequent lumbar fusion. Several modifiable risk factors for fusion progression were identified, which may guide clinicians in shared decision-making and to help identify patients with elevated post-operative risk providing potential leverage point for prevention.

  View details for DOI 10.1016/j.clineuro.2023.107919

  View details for PubMedID 37536253

• Artificial Intelligence in Neurosurgery: A State-of-the-Art Review from Past to Future. Diagnostics (Basel, Switzerland) Tangsrivimol, J. A., Schonfeld, E., Zhang, M., Veeravagu, A., Smith, T. R., Härtl, R., Lawton, M. T., El-Sherbini, A. H., Prevedello, D. M., Glicksberg, B. S., Krittanawong, C. 2023; 13 (14)

  Abstract

  In recent years, there has been a significant surge in discussions surrounding artificial intelligence (AI), along with a corresponding increase in its practical applications in various facets of everyday life, including the medical industry. Notably, even in the highly specialized realm of neurosurgery, AI has been utilized for differential diagnosis, pre-operative evaluation, and improving surgical precision. Many of these applications have begun to mitigate risks of intraoperative and postoperative complications and post-operative care. This article aims to present an overview of the principal published papers on the significant themes of tumor, spine, epilepsy, and vascular issues, wherein AI has been applied to assess its potential applications within neurosurgery. The method involved identifying high-cited seminal papers using PubMed and Google Scholar, conducting a comprehensive review of various study types, and summarizing machine learning applications to enhance understanding among clinicians for future utilization. Recent studies demonstrate that machine learning (ML) holds significant potential in neuro-oncological care, spine surgery, epilepsy management, and other neurosurgical applications. ML techniques have proven effective in tumor identification, surgical outcomes prediction, seizure outcome prediction, aneurysm prediction, and more, highlighting its broad impact and potential in improving patient management and outcomes in neurosurgery. This review will encompass the current state of research, as well as predictions for the future of AI within neurosurgery.

  View details for DOI 10.3390/diagnostics13142429

  View details for PubMedID 37510174

• Contemporary Trends in Minimally Invasive Sacroiliac Joint Fusion Utilization in the Medicare Population by Specialty. Neurosurgery Hersh, A. M., Jimenez, A. E., Pellot, K. I., Gong, J. H., Jiang, K., Khalifeh, J. M., Ahmed, A. K., Raad, M., Veeravagu, A., Ratliff, J. K., Jain, A., Lubelski, D., Bydon, A., Witham, T. F., Theodore, N., Azad, T. D. 2023

  Abstract

  Sacroiliac (SI) joint dysfunction constitutes a leading cause of pain and disability. Although surgical arthrodesis is traditionally performed under open approaches, the past decade has seen a rise in minimally invasive surgical (MIS) techniques and new federally approved devices for MIS approaches. In addition to neurosurgeons and orthopedic surgeons, proceduralists from nonsurgical specialties are performing MIS procedures for SI pathology. Here, we analyze trends in SI joint fusions performed by different provider groups, along with trends in the charges billed and reimbursement provided by Medicare.We review yearly Physician/Supplier Procedure Summary data from 2015 to 2020 from the Centers for Medicare and Medicaid Services for all SI joint fusions. Patients were stratified as undergoing MIS or open procedures. Utilization was adjusted per million Medicare beneficiaries and weighted averages for charges and reimbursements were calculated, controlling for inflation. Reimbursement-to-charge (RCR) ratios were calculated, reflecting the proportion of provider billed amounts reimbursed by Medicare.A total of 12 978 SI joint fusion procedures were performed, with the majority (76.5%) being MIS procedures. Most MIS procedures were performed by nonsurgical specialists (52.1%) while most open fusions were performed by spine surgeons (71%). Rapid growth in MIS procedures was noted for all specialty categories, along with an increased number of procedures offered in the outpatient setting and ambulatory surgical centers. The overall RCR increased over time and was ultimately similar between spine surgeons (RCR = 0.26) and nonsurgeon specialists (RCR = 0.27) performing MIS procedures.Substantial growth in MIS procedures for SI pathology has occurred in recent years in the Medicare population. This growth can largely be attributed to adoption by nonsurgical specialists, whose reimbursement and RCR increased for MIS procedures. Future studies are warranted to better understand the impact of these trends on patient outcomes and costs.

  View details for DOI 10.1227/neu.0000000000002564

  View details for PubMedID 37306413

• Clinical Outcomes and Cost Profiles for Cage and Allograft Anterior Cervical Discectomy and Fusion Procedures in the Adult Population: A Propensity Score-Matched Study ASIAN SPINE JOURNAL Rodrigues, A., Varshneya, K., Stienen, M., Schonfeld, E., Than, K., Veeravagu, A. 2023

  View details for DOI 10.31616/asj.2022.0261

  View details for Web of Science ID 001005859400001

• The Impact of Preoperative Myelopathy on Postoperative Outcomes among Anterior Cervical Discectomy and Fusion Procedures in the Nonelderly Adult Population: A Propensity-Score Matched Study. Asian spine journal Rodrigues, A. J., Schonfeld, E., Varshneya, K., Stienen, M. N., Veeravagu, A. 2023

  Abstract

  Retrospective cohort study.Anterior cervical discectomy and fusion (ACDF) is a common surgical intervention for patients diagnosed with cervical degenerative diseases with or without myelopathy. A thorough understanding of outcomes in patients with and without myelopathy undergoing ACDF is required because of the widespread utilization of ACDF for these indications.Non-ACDF approaches achieved inferior outcomes in certain myelopathic cases. Studies have compared patient outcomes across procedures, but few have compared outcomes concerning myelopathic versus nonmyelopathic cohorts.The MarketScan database was queried from 2007 to 2016 to identify adult patients who were ≤65 years old, and underwent ACDF using the international classification of diseases 9th version and current procedural terminology codes. Nearest neighbor propensity-score matching was employed to balance patient demographics and operative characteristics between myelopathic and nonmyelopathic cohorts.Of 107,480 patients who met the inclusion criteria, 29,152 (27.1%) were diagnosed with myelopathy. At baseline, the median age of patients with myelopathy was higher (52 years vs. 50 years, p <0.001), and they had a higher comorbidity burden (mean Charlson comorbidity index, 1.92 vs. 1.58; p <0.001) than patients without myelopathy. Patients with myelopathy were more likely to undergo surgical revision at 2 years (odds ratio [OR], 1.63; 95% confidence interval [CI], 1.54-1.73) or are readmitted within 90 days (OR, 1.27; 95% CI, 1.20-1.34). After patient cohorts were matched, patients with myelopathy remained at elevated risk for reoperation at 2 years (OR, 1.55; 95% CI, 1.44-1.67) and postoperative dysphagia (2.78% vs. 1.68%, p <0.001) compared to patients without myelopathy.We found inferior postoperative outcomes at baseline for patients with myelopathy undergoing ACDF compared to patients without myelopathy. Patients with myelopathy remained at significantly greater risk for reoperation and readmission after balancing potential confounding variables across cohorts, and these differences in outcomes were largely driven by patients with myelopathy undergoing 1-2 level fusions.

  View details for DOI 10.31616/asj.2022.0347

  View details for PubMedID 37226379

• Clinical Outcomes and Cost Profiles for Cage and Allograft Anterior Cervical Discectomy and Fusion Procedures in the Adult Population: A Propensity Score-Matched Study. Asian spine journal Rodrigues, A. J., Varshneya, K., Stienen, M. N., Schonfeld, E., Than, K. D., Veeravagu, A. 2023

  Abstract

  Retrospective cohort study.To characterize the postoperative outcomes and economic costs of anterior cervical discectomy and fusion (ACDF) procedures using synthetic biomechanical intervertebral cage (BC) and structural allograft (SA) implants.ACDF is a common spine procedure that typically uses an SA or BC for the cervical fusion. Previous studies that compared the outcomes between the two implants were limited by small sample sizes, short-term postoperative outcomes, and procedures with single-level fusion.Adult patients who underwent an ACDF procedure in 2007-2016 were included. Patient records were extracted from MarketScan, a national registry that captures person-specific clinical utilization, expenditures, and enrollments across millions of inpatient, outpatient, and prescription drug services. Propensity-score matching (PSM) was employed to match the patient cohorts across demographic characteristics, comorbidities, and treatments.Of 110,911 patients, 65,151 (58.7%) received BC implants while 45,760 (41.3%) received SA implants. Patients who underwent BC surgeries had slightly higher reoperation rates within 1 year after the index ACDF procedure (3.3% vs. 3.0%, p=0.004), higher postoperative complication rates (4.9% vs. 4.6%, p=0.022), and higher 90-day readmission rates (4.9% vs. 4.4%, p =0.001). After PSM, the postoperative complication rates did not vary between the two cohorts (4.8% vs. 4.6%, p=0.369), although dysphagia (2.2% vs. 1.8%, p<0.001) and infection (0.3% vs. 0.2%, p=0.007) rates remained higher for the BC group. Other outcome differences, including readmission and reoperation, decreased. Physician's fees remained high for BC implantation procedures.We found marginal differences in clinical outcomes between BC and SA ACDF interventions in the largest published database cohort of adult ACDF surgeries. After adjusting for group-level differences in comorbidity burden and demographic characteristics, BC and SA ACDF surgeries showed similar clinical outcomes. Physician's fees, however, were higher for BC implantation procedures.

  View details for DOI 10.31616/asj.2022-0261

  View details for PubMedID 37226385

• Clinical outcomes and cost differences between patients undergoing primary anterior cervical discectomy and fusion procedures with private or Medicare insurance: a propensity score matched study. World neurosurgery Shah, V., Rodrigues, A. J., Malhotra, S., Johnstone, T., Varshneya, K., Haider, G., Stienen, M. N., Veeravagu, A. 2023

  Abstract

  To assess whether insurance type reflects a patient's quality of care following an ACDF procedure, by comparing differences in post-operative complications, readmission rates, reoperation rates, length of hospital stay, and cost of treatment between patients with Medicare versus private insurance.Propensity score matching (PSM) was employed to match patient cohorts insured by Medicare and private insurance in the MarketScan Commercial Claims and Encounters Database (2007-2016). Age, sex, year of operation, geographic region, comorbidities, and operative factors were used to match cohorts of patients undergoing an ACDF procedure.A total of 110,911 patients met the inclusion criteria, of which 97,543 patients (87.9%) were privately insured and 13,368 patients (12.1%) were insured by Medicare. The PSM algorithm matched 7,026 privately insured patients to 7,026 Medicare patients. After matching, there was no significant difference in 90-day post-operative complication rates, length of stay, or reoperation rates between the Medicare and privately insured cohorts. The Medicare group had lower post-operative readmission rates for all time points: 30 days (1.8% vs. 4.6%; p < 0.001), 60 days (2.5% vs. 6.3%; p < 0.001), and 90 days (4.2% vs. 7.7%; p < 0.001). The median payments to physicians were significantly lower for the Medicare group ($3,885 vs. $5,601; p < 0.001).In this study, propensity score matched patients covered by Medicare and private insurance that underwent an ACDF procedure were found to have similar treatment outcomes.

  View details for DOI 10.1016/j.wneu.2023.02.129

  View details for PubMedID 36871653

• Commentary: Technique for Validation of Intraoperative Navigation in Minimally Invasive Spine Surgery. Operative neurosurgery (Hagerstown, Md.) Haider, G., Veeravagu, A. 2023

  View details for DOI 10.1227/ons.0000000000000639

  View details for PubMedID 36805416

• Neurosurgical Utilization, Charges, and Reimbursement After the Affordable Care Act: Trends From 2011 to 2019. Neurosurgery Hersh, A. M., Dedrickson, T., Gong, J. H., Jimenez, A. E., Materi, J., Veeravagu, A., Ratliff, J. K., Azad, T. D. 2023

  Abstract

  BACKGROUND: An estimated 50 million Americans receive Medicare health care coverage. Prior studies have established a downward trend in Medicare reimbursement for commonly billed surgical procedures, but it is unclear whether these trends hold true across all neurosurgical procedures.OBJECTIVE: To assess trends in utilization, charges, and reimbursement by Medicare for neurosurgical procedures after passage of the Affordable Care Act in 2010.METHODS: We review yearly Physician/Supplier Procedure Summary datasets from the Centers for Medicare and Medicaid Services for all procedures billed by neurosurgeons to Medicare Part B between 2011 and 2019. Procedural coding was categorized into cranial, spine, vascular, peripheral nerve, and radiosurgery cases. Weighted averages for charges and reimbursements adjusted for inflation were calculated. The ratio of the weighted mean reimbursement to weighted mean charge was calculated as the reimbursement-to-charge ratio, representing the proportion of charges reimbursed by Medicare.RESULTS: Overall enrollment-adjusted utilization decreased by 12.1%. Utilization decreased by 24.0% in the inpatient setting but increased by 639% at ambulatory surgery centers and 80.2% in the outpatient setting. Inflation-adjusted, weighted mean charges decreased by 4.0% while reimbursement decreased by 4.6%. Procedure groups that saw increases in reimbursement included cervical spine surgery, cranial functional and epilepsy procedures, cranial pain procedures, and endovascular procedures. Ambulatory surgery centers saw the greatest increase in charges and reimbursements.CONCLUSION: Although overall reimbursement declined across the study period, substantial differences emerged across procedural categories. We further find a notable shift in utilization and reimbursement for neurosurgical procedures done in non-inpatient care settings.

  View details for DOI 10.1227/neu.0000000000002306

  View details for PubMedID 36700751

• Telehealth in Neurosurgery: 2021 Council of State Neurosurgical Societies National Survey Results. World neurosurgery Xu, J. C., Haider, S. A., Sharma, A., Blumenfeld, K., Cheng, J., Mazzola, C. A., Orrico, K. O., Rosenow, J., Stacy, J., Stroink, A., Tomei, K., Tumialan, L., Veeravagu, A., Linskey, M. E., Schwalb, J. 2022

  Abstract

  OBJECTIVE: Telehealth was rapidly adopted during the COVID-19 pandemic. A survey was distributed to neurosurgeons in the United States (US) to understand its use within neurosurgery, what barriers exist, unique issues related to neurosurgery, and opportunities for improvement.METHODS: A survey was distributed via email and used the SurveyMonkey platform. The survey was sent to 3,828 practicing neurosurgeons within the US 404 responses were collected between Oct. 30, 2021, through Dec. 4, 2021.RESULTS: During the pandemic, telehealth was used multiple times per week by 60.65% and used daily by an additional 12.78% of respondents. A supermajority (89.84%) of respondents felt that evaluating patients across state lines with telemedicine is beneficial. Most respondents (95.81%) believed that telehealth improves patient access to care. The major criticism of telehealth was the inability to perform a neurological exam.CONCLUSIONS: Telehealth has been widely implemented within the field of neurosurgery during the COVID-19 pandemic and has increased access to care. It has allowed patients to be evaluated remotely, including across state lines. While certain aspects of the neurological exam are suited for video evaluation, sensation and reflexes cannot be adequately assessed. Neurosurgeons believe that telehealth adds value to their ability to deliver care.

  View details for DOI 10.1016/j.wneu.2022.09.126

  View details for PubMedID 36202339

• Comparison of Deep Learning and Classical Machine Learning Algorithms to Predict Post-operative Outcomes for Anterior Cervical Discectomy and Fusion Procedures with State-of-the-art Performance. Spine Rodrigues, A. J., Schonfeld, E., Varshneya, K., Stienen, M. N., Staartjes, V. E., Jin, M. C., Veeravagu, A. 2022

  Abstract

  STUDY DESIGN: Retrospective cohort.OBJECTIVE: Due to Anterior cervical discectomy and fusion (ACDF) popularity, it is important to predict post-operative complications, unfavorable 90-day readmissions, and 2-year re-operations to improve surgical decision making, prognostication and planning.SUMMARY OF BACKGROUND DATA: Machine learning has been applied to predict post-operative complications for ACDF; however, studies were limited by sample size and model type. These studies achieved 0.70 AUC. Further approaches, not limited to ACDF, focused on specific complication types, and resulted in AUC between 0.70-0.76.METHODS: The IBM MarketScan Commercial Claims and Encounters Database and Medicare Supplement were queried from 2007-2016 to identify adult patients who underwent an ACDF procedure (N=176,816). Traditional machine learning algorithms, logistic regression, support vector machines, were compared with deep neural networks to predict: 90-day post-operative complications, 90-day readmission, and 2-year reoperation. We further generated random deep learning model architectures and trained them on the 90-day complication task to approximate an upper bound. Lastly, using deep learning, we investigated the importance of each input variable for the prediction of 90-day post-operative complications in ACDF.RESULTS: For the prediction of 90-day complication, 90-day readmission, and 2-year reoperation, the deep neural network-based models achieved area under the curve (AUC) of 0.832, 0.713, and 0.671. Logistic regression achieved AUCs of 0.820, 0.712, and 0.671. SVM approaches were significantly lower. The upper bound of deep learning performance was approximated as 0.832. Myelopathy, age, HIV, previous myocardial infarctions, obesity, and documentary weakness were found to be the strongest variable to predict 90-day post-operative complications.CONCLUSIONS: The deep neural network may be used to predict complications for clinical applications after multi-center validation. The results suggest limited added knowledge exists in interactions between the input variables used for this task. Future work should identify novel variables to increase predictive power.

  View details for DOI 10.1097/BRS.0000000000004481

  View details for PubMedID 36149852

• Utilization Trends, Cost, and Payments for Adult Spinal Deformity Surgery in Commercial and Medicare-Insured Populations. Neurosurgery Wadhwa, H., Leung, C., Sklar, M., Ames, C. P., Veeravagu, A., Desai, A., Ratliff, J., Zygourakis, C. C. 2022

  Abstract

  BACKGROUND: Previous studies have characterized utilization rates and cost of adult spinal deformity (ASD) surgery, but the differences between these factors in commercially insured and Medicare populations are not well studied.OBJECTIVE: To identify predictors of increased payments for ASD surgery in commercially insured and Medicare populations.METHODS: We identified adult patients who underwent fusion for ASD, 2007 to 2015, in 20% Medicare inpatient file (n = 21614) and MarketScan commercial insurance database (n = 38789). Patient age, sex, race, insurance type, geographical region, Charlson Comorbidity Index, and length of stay were collected. Outcomes included predictors of increased payments, surgical utilization rates, total cost (calculated using Medicare charges and hospital-specific charge-to-cost ratios), and total Medicare and commercial payments for ASD.RESULTS: Rates of fusion increased from 9.0 to 8.4 per 10000 in 2007 to 20.7 and 18.2 per 10000 in 2015 in commercial and Medicare populations, respectively. The Medicare median total charges increased from $88106 to $144367 (compound annual growth rate, CAGR: 5.6%), and the median total cost increased from $31846 to $39852 (CAGR: 2.5%). Commercial median total payments increased from $58164 in 2007 to $64634 in 2015 (CAGR: 1.2%) while Medicare median total payments decreased from $31415 in 2007 to $25959 in 2015 (CAGR: -2.1%). The Northeast and Western regions were associated with higher payments in both populations, but there is substantial state-level variation.CONCLUSION: Rate of ASD surgery increased from 2007 to 2015 among commercial and Medicare beneficiaries. Despite increasing costs, Medicare payments decreased. Age, length of stay, and BMP usage were associated with increased payments for ASD surgery in both populations.

  View details for DOI 10.1227/neu.0000000000002140

  View details for PubMedID 36136402

• Chronic opioid use prior to ACDF surgery is associated with inferior post-operative outcomes: a propensity-matched study of 17,443 chronic opioid users. World neurosurgery Rodrigues, A. J., Varshneya, K., Schonfeld, E., Malhotra, S., Stienen, M. N., Veeravagu, A. 2022

  Abstract

  STUDY DESIGN: Retrospective cohort OBJECTIVE: Candidates for anterior cervical discectomy and fusion (ACDF) have a higher rate of opioid use than does the public, but studies on pre-operative opioid use have not been conducted. We aimed to understand how pre-operative opioid use affects post-ACDF outcomes.METHODS: The MarketScan Database was queried from 2007-2015 to identify adult patients who underwent an ACDF. Patients were classified into separate cohorts based on the number of separate opioid prescriptions in the year before their ACDF. 90-day post-operative complications, post-operative readmission, re-operation, and total inpatient costs were compared between opioid strata. Propensity-score matching (PSM) matched patient cohorts across observed comorbidities.RESULTS: Of 81,671 ACDF patients, 31,312 (38.3%) were non-users, 30,302 (37.1%) were mild users, and 20,057 (24.6%) were chronic users. Chronic opioid users had a higher comorbidity burden, on average, than patients with less frequent opioid use (p<0.001). Chronic opioid users had higher rates of post-operative complications (9.1%) than mild opioid users (6.0%) and non-users (5.3%) (p<0.001), and higher rates of readmission and reoperation. After balancing opioid non-users vs. chronic opioid users along demographic, pre-operative comorbidity, and operative characteristics, post-operative complications remained elevated for chronic opioid users relative to opioid non-users (8.6% vs. 5.7%; p<0.001), as did rates of readmission and reoperation.CONCLUSIONS: Chronic opioid users had more comorbidities than opioid non-users and mild opioid users, longer hospitalizations, and higher rates of post-operative complication, readmission, and reoperation. After balancing patients across covariates, the outcome differences persisted, suggesting a durable association between pre-operative opioid use and negative post-operative outcomes.

  View details for DOI 10.1016/j.wneu.2022.07.002

  View details for PubMedID 35809840

• Health Care Resource Utilization in Management of Opioid-Naive Patients With Newly Diagnosed Neck Pain. JAMA network open Jin, M. C., Jensen, M., Zhou, Z., Rodrigues, A., Ren, A., Barros Guinle, M. I., Veeravagu, A., Zygourakis, C. C., Desai, A. M., Ratliff, J. K. 2022; 5 (7): e2222062

  Abstract

  Importance: Research has uncovered heterogeneity and inefficiencies in the management of idiopathic low back pain, but few studies have examined longitudinal care patterns following newly diagnosed neck pain.Objective: To understand health care utilization in patients with new-onset idiopathic neck pain.Design, Setting, and Participants: This cross-sectional study used nationally sourced longitudinal data from the IBM Watson Health MarketScan claims database (2007-2016). Participants included adult patients with newly diagnosed neck pain, no recent opioid use, and at least 1 year of continuous postdiagnosis follow-up. Exclusion criteria included prior or concomitant diagnosis of traumatic cervical disc dislocation, vertebral fractures, myelopathy, and/or cancer. Only patients with at least 1 year of prediagnosis lookback were included. Data analysis was performed from January 2021 to January 2022.Main Outcomes and Measures: The primary outcome of interest was 1-year postdiagnosis health care expenditures, including costs, opioid use, and health care service utilization. Early services were those received within 30 days of diagnosis. Multivariable regression models and regression-adjusted statistics were used.Results: In total, 679 030 patients (310 665 men [45.6%]) met the inclusion criteria, of whom 7858 (1.2%) underwent surgery within 1 year of diagnosis. The mean (SD) age was 44.62 (14.87) years among nonsurgical patients and 49.69 (9.53) years among surgical patients. Adjusting for demographics and comorbidities, 1-year regression-adjusted health care costs were $24 267.55 per surgical patient and $515.69 per nonsurgical patient. Across all health care services, $95 379 949 was accounted for by nonsurgical patients undergoing early imaging who did not receive any additional conservative therapy or epidural steroid injections, for a mean (SD) of $477.53 ($1375.60) per patient and median (IQR) of $120.60 ($20.70-$452.37) per patient. On average, patients not undergoing surgery, physical therapy, chiropractic manipulative therapy, or epidural steroid injection, who underwent either early advanced imaging (magnetic resonance imaging or computed tomography) or both early advanced and radiographic imaging, accumulated significantly elevated health care costs ($850.69 and $1181.67, respectively). Early conservative therapy was independently associated with 24.8% (95% CI, 23.5%-26.2%) lower health care costs.Conclusions and Relevance: In this cross-sectional study, early imaging without subsequent intervention was associated with significantly increased health care spending among patients with newly diagnosed idiopathic neck pain. Early conservative therapy was associated with lower costs, even with increased frequency of therapeutic services, and may have reduced long-term care inefficiency.

  View details for DOI 10.1001/jamanetworkopen.2022.22062

  View details for PubMedID 35816312

• Utilization of lateral anterior lumbar interbody fusion for revision of failed prior TLIF: illustrative case. Journal of neurosurgery. Case lessons Haider, G., Wagner, K. E., Chandra, V., Cheng, I., Stienen, M. N., Veeravagu, A. 2022; 3 (23): CASE2296

  Abstract

  BACKGROUND: The use of the lateral decubitus approach for L5-S1 anterior lumbar interbody fusion (LALIF) is a recent advancement capable of facilitating single-position surgery, revision operations, and anterior column reconstruction. To the authors' knowledge, this is the first description of the use of LALIF at L5-S1 for failed prior transforaminal lumbar interbody fusion (TLIF) and anterior column reconstruction. Using an illustrative case, the authors discuss their experience using LALIF at L5-S1 for the revision of pseudoarthrosis and TLIF failure.OBSERVATIONS: The patient had prior attempted L2 to S1 fusion with TLIF but suffered from hardware failure and pseudoarthrosis at the L5-S1 level. LALIF was used to facilitate same-position revision at L5-S1 in addition to further anterior column revision and reconstruction by lateral lumbar interbody fusion at the L1-2 level. Robotic posterior T10-S2 fusion was then added to provide stability to the construct and address the patient's scoliotic deformity. No complications were noted, and the patient was followed until 1 year after the operation with a favorable clinical and radiological result.LESSONS: Revision of a prior failed L5-S1 TLIF with an LALIF approach has technical challenges but may be advantageous for single position anterior column reconstruction under certain conditions.

  View details for DOI 10.3171/CASE2296

  View details for PubMedID 35733821

• Impact of socio-economic factors on radiation treatment after resection of metastatic brain tumors: trends from a private insurance database. Journal of neuro-oncology Dadey, D. Y., Rodrigues, A., Haider, G., Pollom, E. L., Adler, J. R., Veeravagu, A. 2022

  Abstract

  BACKGROUND: Stereotactic radiosurgery (SRS) to the surgical bed of resected brain metastases is now considered the standard of care due to its advantages over whole brain radiation therapy (WBRT). Despite the upward trend in SRS adoption since the 2000s, disparities have been reported suggesting that socio-economic factors can influence SRS utilization.OBJECTIVE: To analyze recent trends in SRS use and identify factors that influence treatment.METHODS: We conducted a retrospective cohort study with the Optum Commercial Claims and Encounters Database and included all patients from 2004 to 2021 who received SRS or WBRT within 60days after resection of tumors metastatic to the brain.RESULTS: A total of 3495 patients met the inclusion and exclusion criteria. There were 1998 patients in the SRS group and 1497 patients in the WBRT group. SRS use now supersedes WBRT by a wide margin. Lung, breast and colon were the most common sites of primary tumor. Although we found no significant differences based on race among the treatment groups, patients with annual household income greater than $75,000 and those with some college or higher education are significantly more likely to receive SRS (OR 1.44 and 1.30; 95% CI 1.18-1.76 and 1.08-1.56; P=0.001 and 0.005, respective). Patients with Elixhauser Comorbidity Index of three or more were significantly more likely to receive SRS treatment.CONCLUSION: The use of post-surgical SRS for brain metastasis has increased significantly over time, however education and income were associated with differential SRS utilization.

  View details for DOI 10.1007/s11060-022-04031-6

  View details for PubMedID 35596873

• Factors Which Predict Adverse Outcomes in Anterior Cervical Discectomy and Fusion Procedures in the Nonelderly Adult Population. Clinical spine surgery Rodrigues, A. J., Jokhai, R., Varshneya, K., Stienen, M. N., Veeravagu, A. 2022

  Abstract

  STUDY DESIGN: Retrospective cohort.OBJECTIVE: The largest published cohort of anterior cervical discectomy and fusion (ACDF) patients was queried to better characterize demographic and operative factors that predict 90-day complication and 2-year reoperation risk.SUMMARY OF BACKGROUND DATA: The MarketScan Database was queried from 2007 to 2016 to identify adult patients until 65 years, who underwent an ACDF procedure using International Classification of Diseases 9th Version (ICD-9) and Current Procedural Terminology (CPT) codes. MarketScan is a national insurance claims database that contains millions of patient records across all 50 states.METHODS: Multivariate logistic regression was used to identify factors associated with complications until 90 days and reoperations until 2 years.RESULTS: Of 138,839 ACDF procedures, 8500 patients (6.1%) experienced a complication within 90 days of the ACDF, and 7433 (5.4%) underwent surgical revision by 2 years. While the use of anterior cervical plating did not predict 2-year reoperation, it was associated with dramatically reduced 90-day complication risk (adjusted odds ratio [aOR]: 0.32; 95% confidence interval [CI]: 0.30-0.34;P<0.001). Upon multivariate analysis, female sex (aOR: 0.83; 95% CI: 0.79-0.87;P<0.001) was associated with decreased risk of 2-year reoperation, while depression predicted a 50% increase in reoperation risk (aOR: 1.51; 95% CI: 1.43-1.59;P<0.001). The single largest factor associated with reoperation risk, however, was the presence of a 90-day postoperative complication (aOR: 1.79; 95% CI: 1.66-1.94;P<0.001).CONCLUSION: Increased patient comorbidities and the use of bone morphogenic protein were found to increase the risk for postoperative complications, while cervical plating was associated with a strong decline in this risk. In addition, poor patient mental health outweighed the adverse of impact of other comorbidities on 2-year revision risk. The presence of a postoperative complication was the key modifiable risk factor associated with reoperation risk. Conclusions from this study may help surgeons better identify high-risk ACDF patients for more careful patient selection, counseling, informed consent, and management.

  View details for DOI 10.1097/BSD.0000000000001326

  View details for PubMedID 35385403

• Commentary: Robotic Nerve Sheath Tumor Resection With Intraoperative Neuromonitoring: Case Series and Systematic Review. Operative neurosurgery (Hagerstown, Md.) Wagner, K. E., Haider, G., Veeravagu, A. 2022

  View details for DOI 10.1227/ons.0000000000000164

  View details for PubMedID 35316253

• Vertebrae segmentation in reduced radiation CT imaging for augmented reality applications. International journal of computer assisted radiology and surgery Schonfeld, E., de Lotbiniere-Bassett, M., Jansen, T., Anthony, D., Veeravagu, A. 1800

  Abstract

  PURPOSE: There is growing evidence for the use of augmented reality (AR) navigation in spinal surgery to increase surgical accuracy and improve clinical outcomes. Recent research has employed AR techniques to create accurate auto-segmentations, the basis of patient registration, using reduced radiation dose intraoperative computed tomography images. In this study, we aimed to determine if spinal surgery AR applications can employ reduced radiation dose preoperative computed tomography (pCT) images.METHODS: We methodically decreased the imaging dose, with the addition of Gaussian noise, that was introduced into pCT images to determine the image quality threshold that was required for auto-segmentation. The Gaussian distribution's standard deviation determined noise level, such that a scalar multiplier (L: [0.00, 0.45], with steps of 0.03) simulated lower doses as L increased. We then enhanced the images with denoising algorithms to evaluate the effect on the segmentation.RESULTS: The pCT radiation dose was decreased to below the current lowest clinical threshold and the resulting images produced segmentations that were appropriate for input into AR applications. This held true at simulated dose L=0.06 (estimated 144 mAs) but not at L=0.09 (estimated 136 mAs). The application of denoising algorithms to the images resulted in increased artifacts and decreased bone density.CONCLUSIONS: The pCT image quality that is required for AR auto-segmentation is lower than that which is currently employed in spinal surgery. We recommend a reduced radiation dose protocol of approximately 140 mAs. This has the potential to reduce the radiation experienced by patients in comparison to procedures without AR support. Future research is required to identify the specific, clinically relevant radiation dose thresholds required for surgical navigation.

  View details for DOI 10.1007/s11548-022-02561-y

  View details for PubMedID 35025073

• A Discussion of Machine Learning Approaches for Clinical Prediction Modeling. Acta neurochirurgica. Supplement Jin, M. C., Rodrigues, A. J., Jensen, M., Veeravagu, A. 2022; 134: 65-73

  Abstract

  While machine learning has occupied a niche in clinical medicine for decades, continued method development and increased accessibility of medical data have led to broad diversification of approaches. These range from humble regression-based models to more complex artificial neural networks; yet, despite heterogeneity in foundational principles and architecture, the spectrum of machine learning approaches to clinical prediction modeling have invariably led to the development of algorithms advancing our ability to provide optimal care for our patients. In this chapter, we briefly review early machine learning approaches in medicine before delving into common approaches being applied for clinical prediction modeling today. For each, we offer a brief introduction into theory and application with accompanying examples from the medical literature. In doing so, we present a summarized image of the current state of machine learning and some of its many forms in medical predictive modeling.

  View details for DOI 10.1007/978-3-030-85292-4_9

  View details for PubMedID 34862529

• Commentary: Loss of Relativity: The Physician Fee Schedule, the Neurosurgeon, and the Trojan Horse NEUROSURGERY Tumialan, L. M., Veeravagu, A., Ratliff, J. K. 2021; 89 (6): E323-E324

  View details for Web of Science ID 000776491500009

• Do Epidural Steroid Injections Affect Outcomes and Costs in Cervical Degenerative Disease? A Retrospective MarketScan Database Analysis. Global spine journal Wadhwa, H., Varshneya, K., Stienen, M. N., Veeravagu, A. 2021: 21925682211050320

  Abstract

  STUDY DESIGN: Retrospective cohort study.OBJECTIVE: To investigate the effect of preoperative epidural steroid injection (ESI) on quality outcomes and costs in patients undergoing surgery for cervical degenerative disease.METHODS: We queried the MarketScan database, a national administrative claims dataset, to identify patients who underwent cervical degenerative surgery from 2007 to 2016. Patients under 18 and patients with history of tumor or trauma were excluded. Patients were stratified by ESI use at 3, 6, 12, 18, and 24 or more months preoperative. Propensity score matched controls for these groups were obtained. Baseline demographics, postoperative complications, reoperations, readmissions, and costs were compared via univariate and multivariate analysis.RESULTS: 97117 patients underwent cervical degenerative surgery, of which 29963 (30.7%) had ESI use at any time preoperatively. Overall, 90-day complication rate was not significantly different between groups. The ESI cohorts had shorter length of stay, but higher 90-day readmission and reoperation rates. ESI use was associated with higher total payments through the 2-year follow-up period. Among patients who received preoperative ESI, male sex, history of cancer, obesity, PVD, rheumatoid arthritis, nonsmokers, cervical myelopathy, BMP use, anterior approach, 90-day complication, 90-day reoperation, and 90-day readmission were independently associated with increased 90-day total cost.CONCLUSION: ESI can offer pain relief in some patients refractory to other conservative management techniques, but those who eventually undergo surgery have greater healthcare resource utilization. Certain characteristics can predispose patients who receive preoperative ESI to incur higher healthcare costs.

  View details for DOI 10.1177/21925682211050320

  View details for PubMedID 34686085

• The impact of osteoporosis on adult deformity surgery outcomes in Medicare patients. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society Varshneya, K., Bhattacharjya, A., Jokhai, R. T., Fatemi, P., Medress, Z. A., Stienen, M. N., Ho, A. L., Ratliff, J. K., Veeravagu, A. 2021

  Abstract

  OBJECTIVE: To identify the impact of osteoporosis (OS) on postoperative outcomes in Medicare patients undergoing ASD surgery.BACKGROUND: Patients with OP and advanced age experience higher than average rates of ASD. However, poor bone density could undermine the durability of a deformity correction.METHODS: We queried the MarketScan Medicare Supplemental database to identify patients Medicare patients who underwent ASD surgery from 2007 to 2016.RESULTS: A total of 2564 patients met the inclusion criteria of this study, of whom n=971 (61.0%) were diagnosed with osteoporosis. Patients with OP had a similar 90-day postoperative complication rates (OP: 54.6% vs. non-OP: 49.2%, p=0.0076, not significant after multivariate regression correction). This was primarily driven by posthemorrhagic anemia (37.6% in OP, vs. 33.1% in non-OP). Rates of revision surgery were similar at 90days (non-OP 15.0%, OP 16.8%), but by 2years, OP patients had a significantly higher reoperation rate (30.4% vs. 22.9%, p<0.0001). In multivariate regression analysis, OP increased odds for revision surgery at 1year (OR 1.4) and 2years (OR 1.5) following surgery (all p<0.05). OP was also an independent predictor of readmission at all time points (90days, OR 1.3, p<0.005).CONCLUSION: Medicare patients with OP had elevated rates of complications, reoperations, and outpatient costs after undergoing primary ASD surgery.

  View details for DOI 10.1007/s00586-021-06985-z

  View details for PubMedID 34655336

• Commentary: Loss of Relativity: The Physician Fee Schedule, the Neurosurgeon, and the Trojan Horse. Neurosurgery Tumialan, L. M., Veeravagu, A., Ratliff, J. K. 2021

  View details for DOI 10.1093/neuros/nyab339

  View details for PubMedID 34498695

• Outcome Measures of Medicare Patients With Diabetes Mellitus Undergoing Thoracolumbar Deformity Surgery. Clinical spine surgery Varshneya, K., Bhattacharjya, A., Sharma, J., Stienen, M. N., Medress, Z. A., Ratliff, J. K., Veeravagu, A. 2021

  Abstract

  STUDY DESIGN: This was a retrospective study.OBJECTIVE: The objective of this study was to identify the impact of diabetes on postoperative outcomes in Medicare patients undergoing adult spinal deformity (ASD) surgery.METHODS: We queried the MarketScan Medicare database to identify patients who underwent ASD surgery from 2007 to 2016. Patients were then stratified based on diabetes status at the time of the index operation. Patients not enrolled in the Medicare dataset and those with any prior history of trauma or tumor were excluded from this study.RESULTS: A total of 2564 patients met the inclusion criteria of this study, of which n=746 (29.1.%) were diabetic. Patients with diabetes had a higher rate of postoperative infection than nondiabetic patients (3.1% vs. 1.7%, P<0.05) within 90 days. Renal complications were also more elevated in the diabetic cohort (3.2% vs. 1.3%, P<0.05). Readmission rates were significantly higher in the diabetes cohort through of 60 days (15.2% vs. 11.8%, P<0.05) and 90 days (17.0% vs. 13.4%, P<0.05). When looking specifically at the outpatient payments, patients with diabetes did have a higher financial burden at 60 days ($8147 vs. $6956, P<0.05) and 90 days ($10,126 vs. $8376, P<0.05).CONCLUSIONS: In this study, diabetic patients who underwent ASD surgery had elevated rates of postoperative infection, outpatient costs, and rates of readmissions within 90 days. Further research should investigate the role of poor glycemic control on spine surgery outcomes.

  View details for DOI 10.1097/BSD.0000000000001229

  View details for PubMedID 34183547

• Surgical Outcomes of Human Immunodeficiency Virus-positive Patients Undergoing Lumbar Degenerative Surgery. Clinical spine surgery Varshneya, K., Wadhwa, H., Ho, A. L., Medress, Z. A., Stienen, M. N., Desai, A., Ratliff, J. K., Veeravagu, A. 2021

  Abstract

  STUDY DESIGN: This was a retrospective cohort studying using a national administrative database.OBJECTIVE: The objective of this study was to determine the postoperative complications and quality outcomes of the human immunodeficiency virus (HIV)-positive patients undergoing surgical management for lumbar degenerative disease (LDD).METHODS: This study identified patients with who underwent surgery for LDD between 2007 and 2016. Patients were stratified based on whether they were HIV positive at the time of surgery. Multivariate regression was utilized to reduce the confounding of baseline covariates. Patients who underwent 3 or more levels of surgical correction were under the age of 18 years, or those with any prior history of trauma or tumor were excluded from this study. Baseline comorbidities, postoperative complication rates, and reoperation rates were determined.RESULTS: A total of 120,167 patients underwent primary lumbar degenerative surgery, of which 309 (0.26%) were HIV positive. In multivariate regression analysis, the HIV-positive cohort was more likely to be readmitted at 30 days [odds ratio (OR)=1.9, 95% confidence interval (CI): 1.2-2.8], 60 days (OR=1.7, 95% CI: 1.2-2.5), and 90 days (OR=1.5, 95% CI: 1.0-2.2). The HIV-positive cohort was also more likely to experience any postoperative complication (OR=1.7, 95% CI: 1.2-2.3). Of the major drivers identified, HIV-positive patients had significantly greater odds of cerebrovascular disease and postoperative neurological complications (OR=3.8, 95% CI: 1.8-6.9) and acute kidney injury (OR=3.4, 95% CI: 1.3-7.1). Costs of index hospitalization were not significantly different between the 2 cohorts ($30,056 vs. $29,720, P=0.6853). The total costs were also similar throughout the 2-year follow-up period.CONCLUSION: Patients who are HIV positive at the time of LDD surgery are at a higher risk for postoperative central nervous system and renal complications and unplanned readmissions.

  View details for DOI 10.1097/BSD.0000000000001221

  View details for PubMedID 34183544

• External validation of a predictive model of adverse events following spine surgery. The spine journal : official journal of the North American Spine Society Fatemi, P., Zhang, Y., Han, S. S., Purington, N., Zygourakis, C. C., Veeravagu, A., Desai, A., Park, J., Shuer, L. M., Ratliff, J. K. 2021

  Abstract

  BACKGROUND CONTEXT: We lack models that reliably predict 30-day postoperative adverse events (AEs) following spine surgery.PURPOSE: We externally validated a previously developed predictive model for common 30-day adverse events (AEs) after spine surgery.STUDY DESIGN/SETTING: This prospective cohort study utilizes inpatient and outpatient data from a tertiary academic medical center.PATIENT SAMPLE: We assessed a prospective cohort of all 276 adult patients undergoing spine surgery in the Department of Neurosurgery at a tertiary academic institution between April 1, 2018 and October 31, 2018. No exclusion criteria were applied.OUTCOME MEASURES: Incidence of observed AEs was compared with predicted incidence of AEs. Fifteen assessed AEs included: pulmonary complications, congestive heart failure, neurological complications, pneumonia, cardiac dysrhythmia, renal failure, myocardial infarction, wound infection, pulmonary embolus, deep venous thrombosis, wound hematoma, other wound complication, urinary tract infection, delirium, and other infection.METHODS: Our group previously developed the Risk Assessment Tool for Adverse Events after Spine Surgery (RAT-Spine), a predictive model of AEs within 30 days following spine surgery using a cohort of approximately one million patients from combined Medicare and MarketScan databases. We applied RAT-Spine to the single academic institution prospective cohort by entering each patient's preoperative medical and demographic characteristics and surgical type. The model generated a patient-specific overall risk score ranging from 0 to 1 representing the probability of occurrence of any AE. The predicted risks are presented as absolute percent risk and divided into low (<17%), medium (17-28%), and high (>28%).RESULTS: Among the 276 patients followed prospectively, 76 experienced at least one 30-day postoperative AE. Slightly more than half of the cohort were women (53.3%). The median age was slightly lower in the non-AE cohort (63 vs 66.5 years old). Patients with Medicaid comprised 2.5% of the non-AE cohort and 6.6% of the AE cohort. Spinal fusion was performed in 59.1% of cases, which was comparable across cohorts. There was good agreement between the predicted AE and observed AE rates, Area Under the Curve (AUC) 0.64 (95% CI 0.56-0.710). The incidence of observed AEs in the prospective cohort was 17.8% among the low-risk group, 23.0% in the medium-risk group, and 38.4% in the high risk group (p = 0.003).CONCLUSIONS: We externally validated a model for postoperative AEs following spine surgery (RAT-Spine). The results are presented as low-, moderate-, and high-risk designations.

  View details for DOI 10.1016/j.spinee.2021.06.006

  View details for PubMedID 34116215

• Factors which predict adverse events following surgery in adults with cervical spinal deformity BONE & JOINT JOURNAL Varshneya, K., Jokhai, R., Medress, Z. A., Stienen, M. N., Ho, A., Fatemi, P., Ratliff, J. K., Veeravagu, A. 2021; 103B (4): 734–38

  View details for Web of Science ID 000636935700020

• Factors which predict adverse events following surgery in adults with cervical spinal deformity. The bone & joint journal Varshneya, K., Jokhai, R., Medress, Z. A., Stienen, M. N., Ho, A., Fatemi, P., Ratliff, J. K., Veeravagu, A. 2021; 103-B (4): 734–38

  Abstract

  AIMS: The aim of this study was to identify the risk factors for adverse events following the surgical correction of cervical spinal deformities in adults.METHODS: We identified adult patients who underwent corrective cervical spinal surgery between 1 January 2007 and 31 December 2015 from the MarketScan database. The baseline comorbidities and characteristics of the operation were recorded. Adverse events were defined as the development of a complication, an unanticipated deleterious postoperative event, or further surgery. Patients aged < 18 years and those with a previous history of tumour or trauma were excluded from the study.RESULTS: A total of 13,549 adults in the database underwent primary corrective surgery for a cervical spinal deformity during the study period. A total of 3,785 (27.9%) had a complication within 90 days of the procedure, and 3,893 (28.7%) required further surgery within two years. In multivariate analysis, male sex (odds ratio (OR) 0.90 (95% confidence interval (CI) 0.8 to 0.9); p = 0.019) and a posterior approach (compared with a combined surgical approach, OR 0.66 (95% CI 0.5 to 0.8); p < 0.001) significantly decreased the risk of complications. Osteoporosis (OR 1.41 (95% CI 1.3 to 1.6); p < 0.001), dyspnoea (OR 1.48 (95% CI 1.3 to 1.6); p < 0.001), cerebrovascular accident (OR 1.81 (95% CI 1.6 to 2.0); p < 0.001), a posterior approach (compared with an anterior approach, OR 1.23 (95% CI 1.1 to 1.4); p < 0.001), and the use of bone morphogenic protein (BMP) (OR 1.22 (95% CI 1.1 to 1.4); p = 0.003) significantly increased the risks of 90-day complications. In multivariate regression analysis, preoperative dyspnoea (OR 1.50 (95% CI 1.3 to 1.7); p < 0.001), a posterior approach (compared with an anterior approach, OR 2.80 (95% CI 2.4 to 3.2; p < 0.001), and postoperative dysphagia (OR 2.50 (95% CI 1.8 to 3.4); p < 0.001) were associated with a significantly increased risk of further surgery two years postoperatively. A posterior approach (compared with a combined approach, OR 0.32 (95% CI 0.3 to 0.4); p < 0.001), the use of BMP (OR 0.48 (95% CI 0.4 to 0.5); p < 0.001) were associated with a significantly decreased risk of further surgery at this time.CONCLUSION: The surgical approach and intraoperative use of BMP strongly influence the risk of further surgery, whereas the comorbidity burden and the characteristics of the operation influence the rates of early complications in adult patients undergoing corrective cervical spinal surgery. These data may aid surgeons in patient selection and surgical planning. Cite this article: Bone Joint J2021;103-B(4):734-738.

  View details for DOI 10.1302/0301-620X.103B4.BJJ-2020-0845.R2

  View details for PubMedID 33789479

• Risk Factors for Revision Surgery After Primary Adult Thoracolumbar Deformity Surgery. Clinical spine surgery Varshneya, K., Stienen, M. N., Medress, Z. A., Fatemi, P., Pendharkar, A. V., Ratliff, J. K., Veeravagu, A. 2021

  Abstract

  STUDY DESIGN: This is a retrospective cohort study.OBJECTIVE: The aim was to identify the risk factors for revision surgery within 2 years of patients undergoing primary adult spinal deformity (ASD) surgery.SUMMARY OF BACKGROUND DATA: Previous literature reports estimate 20% of patients undergoing thoracolumbar ASD correction undergo reoperation within 2 years. There is limited published data regarding specific risk factors for reoperation in ASD surgery in the short term and long term.METHODS: The authors queried the MarketScan database in order to identify patients who were diagnosed with a spinal deformity and underwent ASD surgery from 2007 to 2015. Patient-level factors and revision risk were investigated during 2 years after primary ASD surgery. Patients under the age of 18 years and those with any prior history of trauma or tumor were excluded from this study.RESULTS: A total 7422 patients underwent ASD surgery during 2007-2015 in the data set. Revision rates were 13.1% at 90 days, 14.5% at 6 months, 16.7% at 1 year, and 19.3% at 2 years. In multivariate multiple logistic regression analysis, obesity [adjusted odds ratio (OR): 1.58, P<0.001] and tobacco use (adjusted OR: 1.38, P=0.0011) were associated with increased odds of reoperation within 2 years. Patients with a combined anterior-posterior approach had lower odds of reoperation compared with those with posterior only approach (adjusted OR: 0.66, P=0.0117).CONCLUSIONS: Obesity and tobacco are associated with increased odds of revision surgery within 2 years of index ASD surgery. Male sex and combined surgical approach are associated with decreased odds of revision surgery.

  View details for DOI 10.1097/BSD.0000000000001124

  View details for PubMedID 33443943

• Advanced Age Does Not Impact Outcomes After 1-level or 2-level Lateral Lumbar Interbody Fusion. Clinical spine surgery Wadhwa, H., Oquendo, Y. A., Tigchelaar, S. S., Warren, S. I., Koltsov, J. C., Desai, A., Veeravagu, A., Alamin, T. F., Ratliff, J. K., Hu, S. S., Cheng, I. 2021

  Abstract

  This was a retrospective comparative study.The objective of this study was to assess the effect of increased age on perioperative and postoperative complication rates, reoperation rates, and patient-reported pain and disability scores after lateral lumbar interbody fusion (LLIF).LLIF was developed to minimize soft tissue trauma and reduce the risk of vascular injury; however, there is little evidence regarding the effect of advanced age on outcomes of LLIF.Patients who underwent LLIF from 2009 to 2019 at one institution with a minimum 6-month follow-up were retrospectively reviewed. Patients less than 18 years old with musculoskeletal tumor or trauma were excluded. The primary outcome was the preoperative to postoperative change in the Numeric Pain Rating Scale (NPRS) for back pain. Operative time, estimated blood loss, length of stay, perioperative and 90-day complications, unplanned readmissions, reoperations, and change in Oswestry Disability Index were also evaluated. Relationships with age were assessed both with age as a continuous variable and segmenting by age below 70 versus 70+.In total, 279 patients were included. The median age was 65±13 years and 159 (57%) were female. Age was not related to improvements in back NPRS and Oswestry Disability Index. Operative time, estimated blood loss, length of stay, perioperative and 90-day complications, unplanned readmissions, reoperations, and radiographic fusion rate also were not related to age. After multivariable risk adjustment, increasing age was associated with greater improvements in back NPRS. The decrease in back NPRS was 0.68 (95% confidence interval: 0.14, 1.22; P=0.014) points greater for every 10-year increase in age. Age was not associated with rates of complication, readmission, or reoperation.LLIF is a safe and effective procedure in the elderly population. Advanced age is associated with larger improvements in preoperative back pain. Surgeons should consider the benefits of LLIF and other minimally invasive techniques when evaluating elderly candidates for lumbar fusion.Level III.

  View details for DOI 10.1097/BSD.0000000000001270

  View details for PubMedID 34724454

• Defining and Describing Treatment Heterogeneity in New-Onset Idiopathic Lower Back and Extremity Pain Through Reconstruction of Longitudinal Care Sequences. The spine journal : official journal of the North American Spine Society Jin, M. C., Azad, T. D., Fatemi, P., Ho, A. L., Vail, D., Zhang, Y., Feng, A. Y., Kim, L. H., Bentley, J. P., Stienen, M. N., Li, G., Desai, A. M., Veeravagu, A., Ratliff, J. K. 2021

  Abstract

  Despite established guidelines, long-term management of surgically-treated low back pain (LBP) and lower extremity pain (LEP) remains heterogeneous. Understanding care heterogeneity could inform future approaches for standardization of practices.To describe treatment heterogeneity in surgically-managed LBP and LEP.Retrospective study of a nationwide commercial database spanning inpatient and outpatient encounters for enrollees of eligible employer-supplied healthcare plans (2007-2016).A population-based sample of opioid-naïve adult patients with newly-diagnosed LBP or LEP were identified. Inclusion required at least 12-months of pre-diagnosis and post-diagnosis continuous follow-up.Included treatments/evaluations include conservative management (chiropractic manipulative therapy, physical therapy, epidural steroid injections), imaging (x-ray, MRI, CT), pharmaceuticals (opioids, benzodiazepines), and spine surgery (decompression, fusion).Primary outcomes-of-interest were 12-month net healthcare expenditures (inpatient and outpatient) and 12-month opioid usage.Analyses include interrogation of care sequence heterogeneity and temporal trends in sequence-initiating services. Comparisons were conducted in the framework of sequence-specific treatment sequences, which reflect the personalized order of healthcare services pursued by each patient. Outlier sequences characterized by high opioid use and costs were identified from frequently observed surgical treatment sequences using Mahalanobis distance.A total of 2,496,908 opioid-naïve adult patients with newly-diagnosed LBP or LEP were included (29,519 surgical). In the matched setting, increased care sequence heterogeneity was observed in surgical patients (0.51 vs 0.12 previously-unused interventions/studies pursued per month). Early opioid and MRI use has decreased between 2008 and 2015 but is matched by increases in early benzodiazepine and x-ray use. Outlier sequences, characterized by increased opioid use and costs, were found in 5.8% of surgical patients. Use of imaging prior to conservative management was common in patients pursuing outlier sequences compared to non-outlier sequences (96.5% vs 63.8%, p<0.001). Non-outlier sequences were more frequently characterized by early conservative interventions (31.9% vs 7.4%, p<0.001).Surgically-managed LBP and LEP care sequences demonstrate high heterogeneity despite established practice guidelines. Outlier sequences associated with high opioid usage and costs can be identified and are characterized by increased early imaging and decreased early conservative management. Elements that may portend suboptimal longitudinal management could provide opportunities for standardization of patient care.

  View details for DOI 10.1016/j.spinee.2021.05.019

  View details for PubMedID 34033933

• Anterior Cervical Discectomy and Fusion vs. Laminoplasty for Multilevel Cervical Spondylotic Myelopathy: A National Administrative Database Analysis. World neurosurgery Wadhwa, H., Sharma, J., Varshneya, K., Fatemi, P., Nathan, J., Medress, Z. A., Stienen, M. N., Ratliff, J. K., Veeravagu, A. 2021

  Abstract

  Anterior cervical discectomy and fusion (ACDF) is effective for treatment of single level cervical spondylotic myelopathy (CSM), but data surrounding multilevel CSM remains controversial. One alternative is laminoplasty, though evidence comparing these strategies remains sparce. In this paper, we retrospectively review readmission and reoperation rates among patients undergoing ACDF or laminoplasty for multilevel CSM from a national longitudinal administrative claims database.We queried the MarketScan Commercial Claims and Encounters database to identify patients who underwent ACDF or laminoplasty for multilevel CSM from 2007-2016. Patients were stratified by operation type. Patients younger than 18 years of age, with a history of tumor or trauma, or underwent an anterior-posterior approach were excluded from this study.A total of 5,445 patients were included, of which 1,521 underwent laminoplasty. A matched cohort who underwent ACDF was identified. The overall 90-day postoperative complication rate was higher in the laminoplasty cohort (OR 1.48 (95% CI 1.18 - 1.86); p < 0.0001). Mean length of stay and 90-day rates of readmission were higher in the laminoplasty cohort. Hospital and total costs of the index hospitalization were higher in the ACDF cohort, as were total payments up to 2 years after the index hospitalization.In this administrative claims database study, there was no difference in reoperation rate between ACDF and laminoplasty. ACDF had fewer complications and readmissions than laminoplasty but was associated with higher costs. Further, prospective research should investigate the factors driving the higher cost of ACDF in this population, and long-term clinical outcomes.

  View details for DOI 10.1016/j.wneu.2021.06.064

  View details for PubMedID 34153482

• Obesity in Patients Undergoing Lumbar Degenerative Surgery-A Retrospective Cohort Study of Postoperative Outcomes. Spine Varshneya, K., Wadhwa, H., Stienen, M. N., Ho, A. L., Medress, Z. A., Aikin, J., Li, G., Desai, A., Ratliff, J. K., Veeravagu, A. 2021; 46 (17): 1191-1196

  Abstract

  Retrospective cohort studying using a national, administrative database.The aim of this study was to determine the postoperative complications and quality outcomes of patients with and without obesity undergoing surgical management for lumbar degenerative disease (LDD).Obesity is a global epidemic that negatively impacts health outcomes. Characterizing the effect of obesity on LDD surgery is important given the growing elderly obese population.This study identified patients with who underwent surgery for LDD between 2007 and 2016. Patients were stratified based on whether the patient had a concurrent diagnosis of obesity at time of surgery. Propensity score matching (PSM) was then utilized to mitigate intergroup differences between patients with and without obesity. Patients who underwent three or more levels surgical correction, were under the age of 18 years, or those with any previous history of trauma or tumor were excluded from this study. Baseline comorbidities, postoperative complication rates, and reoperation rates were determined.A total of 67,215 patients underwent primary lumbar degenerative surgery, of which 22,405 (33%) were obese. After propensity score matching, baseline covariates of the two cohorts were similar. The complication rate was 8.3% in the nonobese cohort and 10.4% in the obese cohort (P < 0.0001). Patients with obesity also had longer lengths of stay (2.7 days vs. 2.4 days, P < 0.05), and higher rates of reoperation and readmission at all time-points through the study follow-up period to their nonobese counterparts (P < 0.05). Including payments after discharge, lumbar degenerative surgery in patients with obesity was associated with higher payments throughout the 2-year follow-up period ($68,061 vs. $59,068 P < 0.05).Patients with a diagnosis of obesity at time of LDD surgery are at a higher risk for postoperative complications, reoperation, and readmission.Level of Evidence: 4.

  View details for DOI 10.1097/BRS.0000000000004001

  View details for PubMedID 34384097

• Single vs Multistage Surgical Management of Single and Two-Level Lumbar Degenerative Disease. World neurosurgery Varshneya, K., Wadhwa, H., Stienen, M. N., Ho, A. L., Medress, Z. A., Herrick, D. B., Desai, A., Ratliff, J. K., Veeravagu, A. 2021

  Abstract

  Retrospective cohort studying using a national, administrative database.To determine the postoperative complications and quality outcomes of single and multi-stage surgical management for lumbar degenerative disease (LDD).This study identified patients with who underwent surgery for LDD between 2007 - 2016. Patients were stratified based on whether their surgeon choose to correct their LDD in a single or multistage manner, and these cohorts were mutually exclusive. Propensity score matching (PSM) was then utilized to mitigate intergroup differences between single and multi-stage patients. Patients who underwent three or more levels surgical correction, were under the age of 18 years, or those with any prior history of trauma or tumor were excluded from this study. Baseline comorbidities, postoperative complication rates, and reoperation rates were determined.A total of 47,190 patients underwent primary surgery for LDD, of which 9,438 (20%) underwent multi-stage surgery. After propensity score matching, baseline covariates of the two cohorts were similar. The complication rate was 6.1% in the single stage cohort and 11.0% in the multistage cohort. Rates of post-hemorrhagic anemia, infection, wound complication, DVT, and hematoma were all higher in the multistage cohort. Lengths of stay, revision, and readmission rates were also significantly higher in the multi-stage cohort. Through 2-years of follow up, multi-stage surgery was associated with higher payments throughout the 2-year follow-up period ($57,036 vs $39,318, p < 0.05).Single stage surgery for lumbar degenerative disc disease demonstrates improved outcomes and lower healthcare utilization. Spine surgeons should carefully consider single-stage surgery when treating patients with less than three-level LDD.

  View details for DOI 10.1016/j.wneu.2021.05.115

  View details for PubMedID 34087456

• Global adoption of robotic technology into neurosurgical practice and research. Neurosurgical review Stumpo, V., Staartjes, V. E., Klukowska, A. M., Golahmadi, A. K., Gadjradj, P. S., Schroder, M. L., Veeravagu, A., Stienen, M. N., Serra, C., Regli, L. 2020

  Abstract

  Recent technological advancements have led to the development and implementation of robotic surgery in several specialties, including neurosurgery. Our aim was to carry out a worldwide survey among neurosurgeons to assess the adoption of and attitude toward robotic technology in the neurosurgical operating room and to identify factors associated with use of robotic technology. The online survey was made up of nine or ten compulsory questions and was distributed via the European Association of the Neurosurgical Societies (EANS) and the Congress of Neurological Surgeons (CNS) in February and March 2018. From a total of 7280 neurosurgeons who were sent the survey, we received 406 answers, corresponding to a response rate of 5.6%, mostly from Europe and North America. Overall, 197 neurosurgeons (48.5%) reported having used robotic technology in clinical practice. The highest rates of adoption of robotics were observed for Europe (54%) and North America (51%). Apart from geographical region, only age under 30, female gender, and absence of a non-academic setting were significantly associated with clinical use of robotics. The Mazor family (32%) and ROSA (26%) robots were most commonly reported among robot users. Our study provides a worldwide overview of neurosurgical adoption of robotic technology. Almost half of the surveyed neurosurgeons reported having clinical experience with at least one robotic system. Ongoing and future trials should aim to clarify superiority or non-inferiority of neurosurgical robotic applications and balance these potential benefits with considerations on acquisition and maintenance costs.

  View details for DOI 10.1007/s10143-020-01445-6

  View details for PubMedID 33252717

• Commentary: The Enforceability of Noncompete Clauses in the Medical Profession: A Review by the Workforce Committee and the Medico-legal Committee of the Council of State Neurosurgical Societies. Neurosurgery Veeravagu, A., Medress, Z. A., Ratliff, J. 2020

  View details for DOI 10.1093/neuros/nyaa481

  View details for PubMedID 33231255

• Adult spinal deformity surgery: is there a need for a second attending? Response JOURNAL OF NEUROSURGERY-SPINE Medress, Z. A., Khormaee, S., Stienen, M. N., Veeravagu, A., Cheng, I. 2020; 33 (5): 558–59

  View details for DOI 10.3171/2020.4.SPINE20512

  View details for Web of Science ID 000585215400003

• Medical malpractice in spine surgery: a review NEUROSURGICAL FOCUS Medress, Z. A., Jin, M. C., Feng, A., Varshneya, K., Veeravagu, A. 2020; 49 (5): E16

  Abstract

  Medical malpractice is an important but often underappreciated topic within neurosurgery, particularly for surgeons in the early phases of practice. The practice of spinal neurosurgery involves substantial risk for litigation, as both the natural history of the conditions being treated and the operations being performed almost always carry the risk of permanent damage to the spinal cord or nerve roots, a cardiopulmonary event, death, or other dire outcomes. In this review, the authors discuss important topics related to medical malpractice in spine surgery, including tort reform, trends and frequency of litigation claims in spine surgery, wrong-level and wrong-site surgery, catastrophic outcomes including spinal cord injury and death, and ethical considerations.

  View details for DOI 10.3171/2020.8.FOCUS20602

  View details for Web of Science ID 000585759900016

  View details for PubMedID 33130625

• Fostering Reproducibility and Generalizability in Machine Learning for Clinical Prediction Modeling in Spine Surgery. The spine journal : official journal of the North American Spine Society Azad, T. D., Ehresman, J., Ahmed, A. K., Staartjes, V. E., Lubelski, D., Stienen, M. N., Veeravagu, A., Ratliff, J. K. 2020

  Abstract

  As the use of machine learning algorithms in the development of clinical prediction models has increased, researchers are becoming more aware of the deleterious that stem from the lack of reporting standards. One of the most obvious consequences is the insufficient reproducibility found in current prediction models. In an attempt to characterize methods to improve reproducibility and to allow for better clinical performance, we utilize a previously proposed taxonomy that separates reproducibility into three components: technical, statistical, and conceptual reproducibility. By following this framework, we discuss common errors that lead to poor reproducibility, highlight the importance of generalizability when evaluating a ML model's performance, and provide suggestions to optimize generalizability to ensure adequate performance. These efforts are a necessity before such models are applied to patient care.

  View details for DOI 10.1016/j.spinee.2020.10.006

  View details for PubMedID 33065274

• Predictive Modeling of Long-Term Opioid and Benzodiazepine Use after Intradural Tumor Resection. The spine journal : official journal of the North American Spine Society Jin, M. C., Ho, A. L., Feng, A. Y., Zhang, Y., Staartjes, V. E., Stienen, M. N., Han, S. S., Veeravagu, A., Ratliff, J. K., Desai, A. M. 2020

  Abstract

  INTRODUCTION: Despite increased awareness of the ongoing opioid epidemic, opioid and benzodiazepine use remain high after spine surgery. In particular, long-term co-prescription of opioids and benzodiazepines have been linked to high risk of overdose-associated death. Tumor patients represent a unique subset of spine surgery patients and few studies have attempted to develop predictive models to anticipate long-term opioid and benzodiazepine use after spinal tumor resection.METHODS: The IBM Watson Health MarketScan Database and Medicare Supplement were assessed to identify admissions for intradural tumor resection between 2007 and 2015. Adult patients were required to have at least 6-months of continuous pre-admission baseline data and 12-months of continuous post-discharge follow-up. Primary outcomes were long-term opioid and benzodiazepine use, defined as at least 6 prescriptions within 12 months. Secondary outcomes were durations of opioid and benzodiazepine prescribing. Logistic regression models, with and without regularization, were trained on an 80% training sample and validated on the withheld 20%.RESULTS: A total of 1,942 patients were identified. The majority of tumors were extramedullary (74.8%) and benign (62.5%). A minority of patients received arthrodesis (9.2%) and most patients were discharged to home (79.1%). Factors associated with post-discharge opioid use duration include tumor malignancy (vs benign, B=19.8 prescribed-days/year, 95% CI 1.1 to 38.5) and intramedullary compartment (vs extramedullary, B=18.1 prescribed-days/year, 95% CI 3.3 to 32.9). Pre- and peri-operative use of prescribed NSAIDs and gabapentin/pregabalin were associated with shorter and longer duration opioid use, respectively. History of opioid and history of benzodiazepine use were both associated with increased post-discharge opioid and benzodiazepine use. Intramedullary location was associated with longer duration post-discharge benzodiazepine use (B=10.3 prescribed-days/year, 95% CI 1.5 to 19.1). Among assessed models, elastic net regularization demonstrated best predictive performance in the withheld validation cohort when assessing both long-term opioid use (AUC=0.748) and long-term benzodiazepine use (AUC=0.704). Applying our model to the validation set, patients scored as low-risk demonstrated a 4.8% and 2.4% risk of long-term opioid and benzodiazepine use, respectively, compared to 35.2% and 11.1% of high-risk patients.CONCLUSIONS: We developed and validated a parsimonious, predictive model to anticipate long-term opioid and benzodiazepine use early after intradural tumor resection, providing physicians opportunities to consider alternative pain management strategies.

  View details for DOI 10.1016/j.spinee.2020.10.010

  View details for PubMedID 33065272

• Machine learning in neurosurgery: a global survey. Acta neurochirurgica Staartjes, V. E., Stumpo, V., Kernbach, J. M., Klukowska, A. M., Gadjradj, P. S., Schroder, M. L., Veeravagu, A., Stienen, M. N., van Niftrik, C. H., Serra, C., Regli, L. 2020

  Abstract

  BACKGROUND: Recent technological advances have led to the development and implementation of machine learning (ML) in various disciplines, including neurosurgery. Our goal was to conduct a comprehensive survey of neurosurgeons to assess the acceptance of and attitudes toward ML in neurosurgical practice and to identify factors associated with its use.METHODS: The online survey consisted of nine or ten mandatory questions and was distributed in February and March 2019 through the European Association of Neurosurgical Societies (EANS) and the Congress of Neurosurgeons (CNS).RESULTS: Out of 7280 neurosurgeons who received the survey, we received 362 responses, with a response rate of 5%, mainly in Europe and North America. In total, 103 neurosurgeons (28.5%) reported using ML in their clinical practice, and 31.1% in research. Adoption rates of ML were relatively evenly distributed, with 25.6% for North America, 30.9% for Europe, 33.3% for Latin America and the Middle East, 44.4% for Asia and Pacific and 100% for Africa with only two responses. No predictors of clinical ML use were identified, although academic settings and subspecialties neuro-oncology, functional, trauma and epilepsy predicted use of ML in research. The most common applications were for predicting outcomes and complications, as well as interpretation of imaging.CONCLUSIONS: This report provides a global overview of the neurosurgical applications of ML. A relevant proportion of the surveyed neurosurgeons reported clinical experience with ML algorithms. Future studies should aim to clarify the role and potential benefits of ML in neurosurgery and to reconcile these potential advantages with bioethical considerations.

  View details for DOI 10.1007/s00701-020-04532-1

  View details for PubMedID 32812067

• Predictors of 2-year reoperation in Medicare patients undergoing primary thoracolumbar deformity surgery. Journal of neurosurgery. Spine Varshneya, K., Jokhai, R. T., Fatemi, P., Stienen, M. N., Medress, Z. A., Ho, A. L., Ratliff, J. K., Veeravagu, A. 2020: 1–5

  Abstract

  OBJECTIVE: This was a retrospective cohort study in which the authors used a nationally representative administrative database. Their goal was to identify the risk factors for reoperation in Medicare patients undergoing primary thoracolumbar adult spinal deformity (ASD) surgery. Previous literature reports estimate that 20% of patients undergoing thoracolumbar ASD correction undergo revision surgery within 2 years. Most published data discuss risk factors for revision surgery in the general population, but these have not been explored specifically in the Medicare population.METHODS: Using the MarketScan Medicare Supplemental database, the authors identified patients who were diagnosed with a spinal deformity and underwent ASD surgery between 2007 and 2015. The interactions of patient demographics, surgical factors, and medical factors with revision surgery were investigated during the 2 years following primary ASD surgery. The authors excluded patients without Medicare insurance and those with any prior history of trauma or tumor.RESULTS: Included in the data set were 2564 patients enrolled in Medicare who underwent ASD surgery between 2007 and 2015. The mean age at diagnosis with spinal deformity was 71.5 years. A majority of patients (68.5%) were female. Within 2 years of follow-up, 661 (25.8%) patients underwent reoperation. Preoperative osteoporosis (OR 1.58, p < 0.0001), congestive heart failure (OR 1.35, p = 0.0161), and paraplegia (OR 2.41, p < 0.0001) independently increased odds of revision surgery. The use of intraoperative bone morphogenetic protein was protective against reoperation (OR 0.71, p = 0.0371). Among 90-day postoperative complications, a wound complication was the strongest predictor of undergoing repeat surgery (OR 2.85, p = 0.0061). The development of a pulmonary embolism also increased the odds of repeat surgery (OR 1.84, p = 0.0435).CONCLUSIONS: Approximately one-quarter of Medicare patients with ASD who underwent surgery required an additional spinal surgery within 2 years. Baseline comorbidities such as osteoporosis, congestive heart failure, and paraplegia, as well as short-term complications such as pulmonary embolism and wound complications significantly increased the odds of repeat surgery.

  View details for DOI 10.3171/2020.5.SPINE191425

  View details for PubMedID 32707541

• A Comparative Analysis of Patients Undergoing Fusion for Adult Cervical Deformity by Approach Type. Global spine journal Varshneya, K., Medress, Z. A., Stienen, M. N., Nathan, J., Ho, A., Pendharkar, A. V., Loo, S., Aikin, J., Li, G., Desai, A., Ratliff, J. K., Veeravagu, A. 2020: 2192568220915717

  Abstract

  Retrospective cohort study.To provide insight into postoperative complications, short-term quality outcomes, and costs of the surgical approaches of adult cervical deformity (ACD).A national database was queried from 2007 to 2016 to identify patients who underwent cervical fusion for ACD. Patients were stratified by approach type-anterior, posterior, or circumferential. Patients undergoing anterior and posterior approach surgeries were additionally compared using propensity score matching.A total of 6575 patients underwent multilevel cervical fusion for ACD correction. Circumferential fusion had the highest postoperative complication rate (46.9% vs posterior: 36.7% vs anterior: 18.5%, P < .0001). Anterior fusion patients more commonly required reoperation compared with posterior fusion patients (P < .0001), and 90-day readmission rate was highest for patients undergoing circumferential fusion (P < .0001). After propensity score matching, the complication rate remained higher in the posterior, as compared to the anterior fusion group (P < .0001). Readmission rate also remained higher in the posterior fusion group; however, anterior fusion patients were more likely to require reoperation. At index hospitalization, posterior fusion led to 1.5× higher costs, and total payments at 90 days were 1.6× higher than their anterior fusion counterparts.Patients who undergo posterior fusion for ACD have higher complication rates, readmission rates, and higher cost burden than patients who undergo anterior fusion; however, posterior correction of ACD is associated with a lower rate of reoperation.

  View details for DOI 10.1177/2192568220915717

  View details for PubMedID 32875897

• A Comparative Analysis of Patients Undergoing Fusion for Adult Cervical Deformity by Approach Type GLOBAL SPINE JOURNAL Varshneya, K., Medress, Z. A., Stienen, M. N., Nathan, J., Ho, A., Pendharkar, A. V., Loo, S., Aikin, J., Li, G., Desai, A., Ratliff, J. K., Veeravagu, A. 2020

  View details for DOI 10.1177/2192568220915717

  View details for Web of Science ID 000527642400001

• Objective activity tracking in spine surgery: a prospective feasibility study with a low-cost consumer grade wearable accelerometer. Scientific reports Stienen, M. N., Rezaii, P. G., Ho, A. L., Veeravagu, A., Zygourakis, C. C., Tomkins-Lane, C., Park, J., Ratliff, J. K., Desai, A. M. 2020; 10 (1): 4939

  Abstract

  Patient-reported outcome measures (PROMs) are commonly used to estimate disability of patients with spinal degenerative disease. Emerging technological advances present an opportunity to provide objective measurements of activity. In a prospective, observational study we utilized a low-cost consumer grade wearable accelerometer (LCA) to determine patient activity (steps per day) preoperatively (baseline) and up to one year (Y1) after cervical and lumbar spine surgery. We studied 30 patients (46.7% male; mean age 57 years; 70% Caucasian) with a baseline activity level of 5624 steps per day. The activity level decreased by 71% in the 1st postoperative week (p<0.001) and remained 37% lower in the 2nd (p<0.001) and 23% lower in the 4th week (p=0.015). At no time point until Y1 did patients increase their activity level, compared to baseline. Activity was greater in patients with cervical, as compared to patients with lumbar spine disease. Age, sex, ethnic group, anesthesia risk score and fusion were variables associated with activity. There was no correlation between activity and PROMs, but a strong correlation with depression. Determining activity using LCAs provides real-time and longitudinal information about patient mobility and return of function. Recovery took place over the first eight postoperative weeks, with subtle improvement afterwards.

  View details for DOI 10.1038/s41598-020-61893-4

  View details for PubMedID 32188895

• Postoperative Complication Burden, Revision Risk, and Health Care Use in Obese Patients Undergoing Primary Adult Thoracolumbar Deformity Surgery GLOBAL SPINE JOURNAL Varshneya, K., Pangal, D. J., Stienen, M. N., Ho, A. L., Fatemi, P., Medress, Z. A., Herrick, D. B., Desai, A., Ratliff, J. K., Veeravagu, A. 2020

  View details for DOI 10.1177/2192568220904341

  View details for Web of Science ID 000517915400001

• Postoperative Complication Burden, Revision Risk, and Health Care Use in Obese Patients Undergoing Primary Adult Thoracolumbar Deformity Surgery. Global spine journal Varshneya, K., Pangal, D. J., Stienen, M. N., Ho, A. L., Fatemi, P., Medress, Z. A., Herrick, D. B., Desai, A., Ratliff, J. K., Veeravagu, A. 2020: 2192568220904341

  Abstract

  This is a retrospective cohort study using a nationally representative administrative database.To identify the impact of obesity on postoperative outcomes in patients undergoing thoracolumbar adult spinal deformity (ASD) surgery.The obesity rate in the United States remains staggering, with approximately one-third of all Americans being overweight or obese. However, the impact of elevated body mass index on spine surgery outcomes remains unclear.We queried the MarketScan database to identify patients who were diagnosed with a spinal deformity and underwent ASD surgery from 2007 to 2016. Patients were then stratified by whether or not they were diagnosed as obese at index surgical admission. Propensity score matching (PSM) was then utilized to mitigate intergroup differences between obese and nonobese patients. Patients <18 years and those with any prior history of trauma or tumor were excluded from this study. Baseline demographics and comorbidities, postoperative complication rates, and short- and long-term reoperation rates were determined.A total of 7423 patients met the inclusion criteria of this study, of whom 597 (8.0%) were obese. Initially, patients with obesity had a higher 90-day postoperative complication rate than nonobese patients (46.1% vs 40.8%, P < .05); however, this difference did not remain after PSM. Revision surgery rates after 2 years were similar across the 2 groups following primary surgery (obese, 21.4%, vs nonobese, 22.0%; P = .7588). Health care use occurred at a higher rate among obese patients through 2 years of long-term follow-up (obese, $152 930, vs nonobese, $140 550; P < .05).Patients diagnosed with obesity who underwent ASD surgery did not demonstrate increased rates of complications, reoperations, or readmissions. However, overall health care use through 2 years of follow-up after index surgery was higher in the obesity cohort.

  View details for DOI 10.1177/2192568220904341

  View details for PubMedID 32875891

• Lumboperitoneal and Ventriculoperitoneal Shunting for Idiopathic Intracranial Hypertension Demonstrate Comparable Failure and Complication Rates NEUROSURGERY Azad, T. D., Zhang, Y., Varshneya, K., Veeravagu, A., Ratliff, J. K., Li, G. 2020; 86 (2): 272–80

  View details for DOI 10.1093/neuros/nyz080

  View details for Web of Science ID 000515122000068

• Cervical osteochondroma: surgical planning. Spinal cord series and cases Fowler, J. n., Takayanagi, A. n., Siddiqi, I. n., Ghanchi, H. n., Siddiqi, J. n., Veeravagu, A. n., Desai, A. n., Vrionis, F. n., Hariri, O. R. 2020; 6 (1): 44

  Abstract

  Osteochondromas are benign bone tumors which occur as solitary lesions or as part of the syndrome multiple hereditary exostoses. While most osteochondromas occur in the appendicular skeleton, they can also occur in the spine. Most lesions are asymptomatic however some may encroach on the spinal cord or the nerve roots causing neurological symptoms. While most patients with osteochondromas undergo laminectomy without fusion, laminectomy with fusion is indicated in appropriately selected cases of spinal decompression.We present a case of a 32-year-old male with history of multiple hereditary exostoses who presented with symptoms of bilateral upper extremity numbness and complaints of gait imbalance and multiple falls. He reported rapid progression of his symptoms during the 10 days before presentation. Computed tomography of the cervical spine revealed a lobulated bony tumor along the inner margin of the cervical 4 lamina. He underwent cervical 3 and 4 laminectomies, partial cervical 2 and 5 laminectomies and cervical 3-5 mass screw placement. Pathology was consistent with osteochondroma. The patient's symptoms had markedly improved at follow-up.According to our literature review, osteochondromas most commonly occur at cervical 2 and cervical 5. We present a case of an osteochondroma at a less common level, cervical 4. While most osteochondromas are addressed with laminectomy without arthrodesis, the decision of whether arthrodesis is necessary should be considered in all patients with osteochondroma as with any cervical decompression.

  View details for DOI 10.1038/s41394-020-0292-7

  View details for PubMedID 32467563

• A Predictive-Modeling Based Screening Tool for Prolonged Opioid Use after Surgical Management of Low Back and Lower Extremity Pain. The spine journal : official journal of the North American Spine Society Zhang, Y. n., Fatemi, P. n., Medress, Z. n., Azad, T. D., Veeravagu, A. n., Desai, A. n., Ratliff, J. K. 2020

  Abstract

  Outpatient postoperative pain management in spine patients, specifically involving the use of opioids, demonstrates significant variability.Using preoperative risk factors and 30-day postoperative opioid prescribing patterns, we developed models for predicting long-term opioid use in patients after elective spine surgery.This retrospective cohort study utilizes inpatient, outpatient, and pharmaceutical data from MarketScan databases (Truven Health).In all, 19,317 patients who were newly diagnosed with low back or lower extremity pain (LBP or LEP) between 2008 and 2015 and underwent thoracic or lumbar surgery within one year after diagnosis were enrolled. Some patients initiated opioids after diagnosis but all patients were opioid-naïve prior to the diagnosis.Long-term opioid use was defined as filling ≥180 days of opioids within one year after surgery.Using demographic variables, medical and psychiatric comorbidities, preoperative opioid use, and 30-day postoperative opioid use, we generated seven models on 80% of the dataset and tested the models on the remaining 20%. We used three regression-based models (full logistic regression, stepwise logistic regression, least absolute shrinkage and selection operator [LASSO]), support vector machine, two tree-based models (random forest, stochastic gradient boosting), and time-varying convolutional neural network. Area under the curve (AUC), Brier index, sensitivity, and calibration curves were used to assess the discrimination and calibration of the models.We identified 903 (4.6%) of patients who met criteria for long-term opioid use. The regression-based models demonstrated the highest AUC, ranging from 0.835 to 0.847, and relatively high sensitivities, predicting between 74.9-76.5% of the long-term opioid use patients in the test dataset. The three strongest positive predictors of long-term opioid use were high preoperative opioid use (OR 2.70; 95% CI 2.27-3.22), number of days with active opioid prescription between postoperative days 15-30 (OR 1.10; 95% CI 1.07-1.12), and number of dosage increases between postoperative day 15-30 (OR 1.71, 95% CI 1.41-2.08). The strongest negative predictors were number of dosage decreases in the 30-day postoperative period.We evaluated several predictive models for postoperative long-term opioid use in a large cohort of patients with LBP or LEP who underwent surgery. A regression-based model with high sensitivity and AUC is provided online to screen patients for high risk of long-term opioid use based on preoperative risk factors and opioid prescription patterns in the first 30 days after surgery. It is hoped that this work will improve identification of patients at high risk of prolonged opioid use and enable early intervention and counseling.

  View details for DOI 10.1016/j.spinee.2020.05.098

  View details for PubMedID 32445803

• Costs and Complications Associated with Resection of Supratentorial Tumors with and without the Operative Microscope in the United States. World neurosurgery Zhang, Y. n., Zhang, M. n., Lin, M. n., Gephart, M. H., Veeravagu, A. n., Ratliff, J. K., Li, G. n. 2020

  Abstract

  The operative microscope, a commonly used tool in neurosurgery, is critical in many supratentorial tumor cases. However, use of operating microscope for supratentorial tumor varies by surgeon.To assess complication rates, readmissions, and costs associated with operative microscope use in supratentorial resections.A retrospective analysis was conducted using a national administrative database to identify patients with glioma or brain metastases who underwent supratentorial resection between 2007 and 2016. Univariate and multivariate analyses were used to assess 30-day complications, readmissions and costs between patients who underwent resection with and without use of microscope.The cohort included 12058 glioma patients and 5433 metastasis patients. Rates of microscope use varied by state from 19.0% to 68.6%. Microscope use was associated with $5228.9 in additional costs of index hospitalization among glioma patients (p < 0.001), and $2824.0 among metastasis patients (p < 0.001). Rates of intraoperative cerebral edema were lower among the microscope cohort than among the non-microscope cohort (p < 0.027). Microscope use was associated with a slight reduction in 30-day rates of neurological complications (14.7% vs. 16.7%, p = 0.048), specifically in nonspecific cerebrovascular complications. There were no differences in rates of other complications, readmissions, or 30-day postoperative costs.Use of operative microscope for supratentorial resections varies by state and is associated with higher cost of surgery. Microscope use may be associated with lower rates of intraoperative cerebral edema and some cerebrovascular complications, but is not associated with significant differences in other complications, readmissions, or 30-day costs.

  View details for DOI 10.1016/j.wneu.2020.03.021

  View details for PubMedID 32171932

• Complications, Costs, and Quality Outcomes of Patients Undergoing Cervical Deformity Surgery with Intraoperative BMP Use. Spine Varshneya, K. n., Wadhwa, H. n., Pendharkar, A. V., Medress, Z. A., Stienen, M. N., Ratliff, J. K., Veeravagu, A. n. 2020

  Abstract

  An epidemiological study using national administrative data from the MarketScan database.To identify the impact of bone morphogenetic protein (BMP) on postoperative outcomes in patients undergoing adult cervical deformity (ACD) surgery.BMP has been shown to stimulate bone growth and improve fusion rates in spine surgery. However, the impact of BMP on reoperation rates and postoperative complication rate is controversial.We queried the MarketScan database to identify patients who underwent ACD surgery from 2007-2015. Patients were stratified by BMP use in the index operation. Patients under 18 and those with any history of tumor or trauma were excluded. Baseline demographics and comorbidities, postoperative complication rates and reoperation rates were analyzed.A total of 13,549 patients underwent primary ACD surgery, of which 1155 (8.5%) had intraoperative BMP use. The overall 90-day complication rate was 27.6% in the non-BMP cohort and 31.1% in the BMP cohort (p < 0.05). Patients in the BMP cohort had longer average length of stay (4.0 days vs 3.7 days, p < 0.05) but lower revision surgery rates at 90-days (14.5% vs 28.3%, p < 0.05), 6 months (14.9% vs 28.6%, p < 0.05), 1 year (15.7% vs 29.2%, p < 0.05), and 2 years (16.5% vs 29.9%, p < 0.05) postoperatively. BMP use was associated with higher payments throughout the 2-year follow-up period ($107,975 vs $97,620, p < 0.05). When controlling for baseline group differences, BMP use independently increased the odds of postoperative complication (OR 1.22, 95% CI 1.1 - 1.4) and reduced the odds of reoperation throughout 2-years of follow-up (OR 0.49, 95% CI 0.4 - 0.6).Intraoperative BMP use has benefits for fusion integrity in ACD surgery but is associated with increased postoperative complication rate. Spine surgeons should weigh these benefits and drawbacks to identify optimal candidates for BMP use in ACD surgery.3.

  View details for DOI 10.1097/BRS.0000000000003629

  View details for PubMedID 32756275

• Opioid Prescribing Patterns for Low Back Pain Among Commercially-Insured Children. Spine Azad, T. D., Harries, M. D., Veeravagu, A. n., Ratliff, J. K. 2020

  View details for DOI 10.1097/BRS.0000000000003657

  View details for PubMedID 32858745

• Adult Spinal Deformity Surgery in Patients With Movement Disorders: A Propensity-matched Analysis of Outcomes and Cost. Spine Varshneya, K. n., Azad, T. D., Pendharkar, A. V., Desai, A. n., Cheng, I. n., Karikari, I. n., Ratliff, J. K., Veeravagu, A. n. 2020; 45 (5): E288–E295

  Abstract

  This was a retrospective study using national administrative data from the MarketScan database.To investigate the complication rates, quality outcomes, and costs in a nationwide cohort of patients with movement disorders (MD) who undergo spinal deformity surgery.Patients with MD often present with spinal deformities, but their tolerance for surgical intervention is unknown.The MarketScan administrative claims database was queried to identify adult patients with MD who underwent spinal deformity surgery. A propensity-score match was conducted to create two uniform cohorts and mitigate interpopulation confounders. Perioperative complication rates, 90-day postoperative outcomes, and total costs were compared between patients with MD and controls.A total of 316 patients with MD (1.7%) were identified from the 18,970 undergoing spinal deformity surgery. The complication rate for MD patients was 44.6% and for the controls 35.6% (P = 0.009). The two most common perioperative complications were more likely to occur in MD patients, acute-posthemorrhagic anemia (26.9% vs. 20.8%, P < 0.05) and deficiency anemia (15.5% vs. 8.5%, P < 0.05). At 90 days, MD patients were more likely to be readmitted (17.4% vs. 13.2%, P < 0.05) and have a higher total cost ($94,672 vs. $85,190, P < 0.05). After propensity-score match, the overall complication rate remained higher in the MD group (44.6% vs. 37.6%, P < 0.05). 90-day readmissions and costs also remained significantly higher in the MD cohort. Multivariate modeling revealed MD was an independent predictor of postoperative complication and inpatient readmission. Subgroup analysis revealed that Parkinson disease was an independent predictor of inpatient readmission, reoperation, and increased length of stay.Patients with MD who undergo spinal deformity surgery may be at risk of higher rate of perioperative complications and 90-day readmissions compared with patients without these disorders.3.

  View details for DOI 10.1097/BRS.0000000000003251

  View details for PubMedID 32045403

• Commentary: Predictors of the Best Outcomes Following Minimally Invasive Surgery for Grade 1 Degenerative Lumbar Spondylolisthesis. Neurosurgery Medress, Z. A., Veeravagu, A. n. 2020

  View details for DOI 10.1093/neuros/nyaa288

  View details for PubMedID 32687591

• Conventional Versus Stereotactic Image Guided Pedicle Screw Placement During Spinal Deformity Correction: A Retrospective Propensity Score-Matched Study of a National Longitudinal Database. The International journal of neuroscience Rezaii, P. G., Pendharkar, A. V., Ho, A. L., Sussman, E. S., Veeravagu, A. n., Ratliff, J. K., Desai, A. M. 2020: 1–13

  Abstract

  Purpose/aim: To compare complications, readmissions, revisions, and payments between navigated and conventional pedicle screw fixation for treatment of spine deformity.Methods: The Thomson Reuters MarketScan national longitudinal database was used to identify patients undergoing osteotomy, posterior instrumentation, and fusion for treatment of spinal deformity with or without image-guided navigation between 2007-2016. Conventional and navigated groups were propensity-matched (1:1) to normalize differences between demographics, comorbidities, and surgical characteristics. Clinical outcomes and charges were compared between matched groups using bivariate analyses.Results: A total of 4,604 patients were identified as having undergone deformity correction, of which 286 (6.2%) were navigated. Propensity-matching resulted in a total of 572 well-matched patients for subsequent analyses, of which half were navigated. Rate of mechanical instrumentation-related complications was found to be significantly lower for navigated procedures (p = 0.0371). Navigation was also associated with lower rates of 90-day unplanned readmissions (p = 0.0295), as well as 30- and 90-day postoperative revisions (30-day: p = 0.0304, 90-day: p = 0.0059). Hospital, physician, and total payments favored the conventional group for initial admission (p = 0.0481, 0.0001, 0.0019, respectively); however, when taking into account costs of readmissions, hospital payments became insignificantly different between the two groups.Conclusions: Procedures involving image-guided navigation resulted in decreased instrumentation-related complications, unplanned readmissions, and postoperative revisions, highlighting its potential utility for the treatment of spine deformity. Future advances in navigation technologies and methodologies can continue to improve clinical outcomes, decrease costs, and facilitate widespread adoption of navigation for deformity correction.

  View details for DOI 10.1080/00207454.2020.1763343

  View details for PubMedID 32364414

• Association between Physician Industry Payments and Cost of Anterior Cervical Discectomy and Fusion in Medicare Beneficiaries. World neurosurgery Liu, C. n., Ahmed, K. n., Chen, C. L., Dudley, R. A., Gonzales, R. n., Orrico, K. n., Yerneni, K. n., Stienen, M. N., Veeravagu, A. n., Desai, A. n., Park, J. n., Ratliff, J. K., Zygourakis, C. C. 2020

  Abstract

  Neurosurgical spine specialists receive considerable amounts of industry support which may impact the cost of care. The aim of this study was to evaluate the association between industry payments received by spine surgeons and the total hospital and operating room (OR) costs of an anterior cervical discectomy and fusion (ACDF) procedure among Medicare beneficiaries.All ACDF cases were identified among the Medicare Carrier Files, from January 1, 2013, to December 31, 2014, and matched to the Medicare Inpatient Baseline File. The total hospital and OR charges were obtained for these cases. Charges were converted to cost using year-specific cost-to-charge ratios. Surgeons were identified among Open Payments database, which is used to quantify industry support. Analyses was performed to examine the association between industry payments received and ACDF costs.Matching resulting in the inclusion of 2,209 ACDF claims from 2013-2014. In 2013 and 2014, the mean total cost for an ACDF was $21,798 and $21,008, respectively; mean OR cost was $5,878 and $6,064, respectively. Mann-Whitney U test demonstrated no significant differences in the mean total or OR cost for an ACDF based on quartile of general industry payment received (p=0.21 and p=0.54), and linear regression found no association between industry general payments, research support, or investments on the total hospital cost (p=0.41, p=0.13, and p=0.25), or OR cost for an ACDF (p=0.35, p=0.24, and p=0.40).This study suggests that spine surgeons performing ACDF surgeries may receive industry support without impacting the cost of care.

  View details for DOI 10.1016/j.wneu.2020.08.023

  View details for PubMedID 32791230

• Adverse Events and Bundled Costs after Cranial Neurosurgical Procedures: Validation of the LACE Index Across 40,431 Admissions and Development of the LACE-Cranial Index. World neurosurgery Jin, M. C., Wu, A. n., Medress, Z. A., Parker, J. J., Desai, A. n., Veeravagu, A. n., Grant, G. A., Li, G. n., Ratliff, J. K. 2020

  Abstract

  Anticipating post-discharge complications following neurosurgery remains difficult. The LACE index, based on four hospitalization descriptors, stratifies patients by risk of 30-day post-discharge adverse events but has not been validated in a procedure-specific manner in neurosurgery. Our study sought to explore the utility of the LACE index in cranial neurosurgery population and to develop an enhanced model, LACE-Cranial.The Optum Clinformatics Database was used to identify cranial neurosurgery admissions (2004-2017). Procedures were grouped as trauma/hematoma/ICP, open vascular, functional/pain, skull base, tumor, or endovascular. Adverse events were defined as post-discharge death/readmission. LACE-Cranial was developed using a logistic regression framework incorporating an expanded feature set in addition to the original LACE components.A total of 40,431 admissions were included. Predictions of 30-day readmissions was best for skull-base (AUC=0.636) and tumor (AUC=0.63) admissions but was generally poor. Predictive ability of 30-day mortality was best for functional/pain admissions (AUC=0.957) and poorest for trauma/hematoma/ICP admissions (AUC=0.613). Across procedure types except for functional/pain, a high-risk LACE score was associated with higher post-discharge bundled payment costs. Incorporating features identified to contribute independent predictive value, the LACE-Cranial model achieved procedure-specific 30-day mortality AUCs ranging from 0.904 to 0.98. Prediction of 30-day and 90-day readmissions was also improved, with tumor and skull base cases achieving 90-day readmission AUCs of 0.718 and 0.717, respectively.While the unmodified LACE index demonstrates inconsistent classification performance, the enhanced LACE-Cranial model offers excellent prediction of short-term post-discharge mortality across procedure groups and significantly improved anticipation of short-term post-discharge readmissions.

  View details for DOI 10.1016/j.wneu.2020.10.103

  View details for PubMedID 33127572

• Opioid Use in Adults with Low Back or Lower Extremity Pain who Undergo Spine Surgical Treatment within One Year of Diagnosis. Spine Fatemi, P. n., Zhang, Y. n., Ho, A. n., Lama, R. n., Jin, M. n., Veeravagu, A. n., Desai, A. n., Ratliff, J. K. 2020

  Abstract

  Retrospective longitudinal cohort.We investigated opioid prescribing patterns amongst adults in the United States diagnosed with low back or lower extremity pain (LBP/LEP) who underwent spine surgery.Opioid-based treatment of LBP/LEP and postsurgical pain have separately been associated with chronic opioid use, but a combined and large-scale cohort study is missing.This study utilizes commercial inpatient, outpatient, and pharmaceutical insurance claims. Between 2008 and 2015, patients without prior prescription opioids with a new diagnosis of LBP/LEP who underwent surgery within one year after diagnosis were enrolled. Opioid prescribing patterns after LBP/LEP diagnosis and after surgery were evaluated. All patients had one-year postoperative follow-up. Low and high frequency (≥6 refills in 12 months) opioid prescription groups were identified.25,506 patients without prior prescription opioids were diagnosed with LBP/LEP and underwent surgery within one year of diagnosis. After LBP/LEP diagnosis, 18,219 (71.4%) were prescribed opioids while 7,287 (28.6%) were not. After surgery, 2,952 (11.6%) were prescribed opioids with high frequency and 22,554 (88.4%) with low frequency. Among patients prescribed opioids prior to surgery, those with high frequency prescriptions were more likely to continue this pattern postoperatively than those with low frequency prescriptions preoperatively (OR:2.15, 95% CI:1.97-2.34). For those prescribed opioids preoperatively, average daily morphine milligram equivalent (MME) decreased after surgery (by 2.62 in decompression alone cohort and 0.25 in arthrodesis cohort, p < 0.001). Postoperative low-frequency patients were more likely than high-frequency patients to discontinue opioids one-year after surgery (OR:3.78, 95% CI:3.59-3.99). Postoperative high-frequency patients incurred higher cost than low-frequency patients. Postoperative high-frequency prescribing varied widely across states (4.3%-20%).A stepwise association exists between opioid use after LEP or LBP diagnosis and frequency and duration of opioid prescriptions after surgery. Simultaneously, the strength of prescriptions as measured by MME decreased following surgery.3.

  View details for DOI 10.1097/BRS.0000000000003663

  View details for PubMedID 32833930

• Evaluating the Impact of Spinal Osteotomy on Surgical Outcomes of Thoracolumbar Deformity Correction. World neurosurgery Varshneya, K. n., Stienen, M. N., Ho, A. L., Medress, Z. A., Fatemi, P. n., Pendharkar, A. V., Ratliff, J. K., Veeravagu, A. n. 2020

  Abstract

  In cases of adult spinal deformity (ASD) with severe sagittal malalignment, the use of osteotomies may be necessary in addition to posterior fusion. However, little data exists describing the impact of osteotomies on complications and quality outcomes during ASD surgery.We queried the MarketScan database to identify patients who underwent ASD surgery from 2007-2016. Patients were stratified into whether or not an osteotomy was used in the index operation. Propensity score matching (PSM) was then utilized to mitigate intergroup differences between osteotomy and non-osteotomy patients. Patients under the age of 18 years and those with any prior history of trauma or tumor were excluded from this study.7423 patients met the inclusion criteria of this study, of which n = 2700 (36.4%) received an osteotomy. After PSM, baseline comorbidities and approach type were similar between cohorts. The overall 90-day complication rate was 43.2% in non-osteotomy patients and 52.8% in osteotomy patients (p < 0.0001). The osteotomy cohort also had significantly higher rates of revision surgeries through 2 years (21.1% vs 18.0%, p < 0.05) following index surgery. Three-column osteotomy patients had the highest procedural payments, costing $155,885 through 90-days and $167,161 through 1 year following surgery.This analysis confirms high costs as well as complication, readmission and reoperation rates until two years after ASD surgery in general, which are even higher in cases where an osteotomy is required. Further research should explore strategies for optimizing patient outcomes following osteotomy.

  View details for DOI 10.1016/j.wneu.2020.09.072

  View details for PubMedID 32956883

• Single- versus dual-attending strategy for spinal deformity surgery: 2-year experience and systematic review of the literature. Journal of neurosurgery. Spine Cheng, I. n., Stienen, M. N., Medress, Z. A., Varshneya, K. n., Ho, A. L., Ratliff, J. K., Veeravagu, A. n. 2020: 1–12

  Abstract

  Adult spinal deformity (ASD) surgery is complex and associated with high morbidity and complication rates. There is growing evidence in the literature for the beneficial effects of an approach to surgery in which two attending physicians rather than a single attending physician perform surgery for and oversee the surgical care of a single patient in a dual-attending care model. The authors developed a dual-attending care collaboration in August 2017 in which a neurosurgeon and an orthopedic surgeon mutually operated on patients with ASD.The authors recorded data for 2 years of experience with ASD patients operated on by dual attending surgeons. Analyses included estimated blood loss (EBL), transfusions, length of stay (LOS), discharge disposition, complication rates, emergency room visits and readmissions, subjective health status improvement, and disability (Oswestry Disability Index [ODI] score) and pain (visual analog scale [VAS] score) at last follow-up. In addition, the pertinent literature for dual-attending spinal deformity correction was systematically reviewed.The study group comprised 19 of 254 (7.5%) consecutively operated patients who underwent thoracolumbar fusion during the period from January 2017 to June 2019 (68.4% female; mean patient age 65.1 years, ODI score 44.5, VAS pain score 6.8). The study patients were matched by age, sex, anesthesia risk, BMI, smoking status, ODI score, VAS pain score, prior spine surgeries, and basic operative characteristics (type of interbody implants, instrumented segments, pelvic fixation) to 19 control patients (all p > 0.05). There was a trend toward less EBL (mean 763 vs 1524 ml, p = 0.059), fewer intraoperative red blood cell transfusions (mean 0.5 vs 2.3, p = 0.079), and fewer 90-day readmissions (0% vs 15.8%, p = 0.071) in the dual-attending group. LOS and discharge disposition were similar, as were the rates of any < 30-day postsurgery complications, < 90-day postsurgery emergency room visits, and reoperations, and ODI and VAS pain scores at last follow-up (all p > 0.05). At last follow-up, 94.7% vs 68.4% of patients in the dual- versus single-attending group stated their health status had improved (p = 0.036). In the authors' literature search of prior articles on spinal deformity correction, 5 of 8 (62.5%) articles reported lower EBL and 6 of 8 (75%) articles reported significantly lower operation duration in dual-attending cases. The literature contained differing results with regard to complication- or reoperation-sparing effects associated with dual-attending cases. Similar clinical outcomes of dual- versus single-attending cases were reported.Establishing a dual-attending care management platform for ASD correction was feasible at the authors' institution. Results of the use of a dual-attending strategy at the authors' institution were favorable. Positive safety and outcome profiles were found in articles on this topic identified by a systematic literature review.

  View details for DOI 10.3171/2020.3.SPINE2016

  View details for PubMedID 32650315

• Evaluating Shunt Survival Following Ventriculoperitoneal Shunting with and without Stereotactic Navigation in Previously Shunt-Naïve Patients. World neurosurgery Jin, M. C., Wu, A. n., Azad, T. D., Feng, A. n., Prolo, L. M., Veeravagu, A. n., Grant, G. A., Ratliff, J. n., Li, G. n. 2020

  View details for DOI 10.1016/j.wneu.2020.01.138

  View details for PubMedID 31996335

• Timing of Adjuvant Radiation Therapy and Risk of Wound-Related Complications Among Patients With Spinal Metastatic Disease. Global spine journal Azad, T. D., Varshneya, K., Herrick, D. B., Pendharkar, A. V., Ho, A. L., Stienen, M., Zygourakis, C., Bagshaw, H. P., Veeravagu, A., Ratliff, J. K., Desai, A. 2019: 2192568219889363

  Abstract

  This was an epidemiological study using national administrative data from the MarketScan database.To investigate the impact of early versus delayed adjuvant radiotherapy (RT) on wound healing following surgical resection for spinal metastatic disease.We queried the MarketScan database (2007-2016), identifying patients with a diagnosis of spinal metastasis who also underwent RT within 8 weeks of surgery. Patients were categorized into "Early RT" if they received RT within 4 weeks of surgery and as "Late RT" if they received RT between 4 and 8 weeks after surgery. Descriptive statistics and hypothesis testing were used to compare baseline characteristics and wound complication outcomes.A total of 540 patients met the inclusion criteria: 307 (56.9%) received RT within 4 weeks (Early RT) and 233 (43.1%) received RT within 4 to 8 weeks (Late RT) of surgery. Mean days to RT for the Early RT cohort was 18.5 (SD, 6.9) and 39.7 (SD, 7.6) for the Late RT cohort. In a 90-day surveillance period, n = 9 (2.9%) of Early RT and n = 8 (3.4%) of Late RT patients developed wound complications (P = .574).When comparing patients who received RT early versus delayed following surgery, there were no significant differences in the rates of wound complications. Further prospective studies should aim to identify optimal patient criteria for early postoperative RT for spinal metastases.

  View details for DOI 10.1177/2192568219889363

  View details for PubMedID 32875859

• Timing of Adjuvant Radiation Therapy and Risk of Wound-Related Complications Among Patients With Spinal Metastatic Disease GLOBAL SPINE JOURNAL Azad, T. D., Varshneya, K., Herrick, D. B., Pendharkar, A., Ho, A. L., Stienen, M., Zygourakis, C., Bagshaw, H. P., Veeravagu, A., Ratliff, J. K., Desai, A. 2019

  View details for DOI 10.1177/2192568219889363

  View details for Web of Science ID 000498682300001

• Patterns of Opioid and Benzodiazepine Use in Opioid-Naive Patients with Newly Diagnosed Low Back and Lower Extremity Pain. Journal of general internal medicine Azad, T. D., Zhang, Y., Stienen, M. N., Vail, D., Bentley, J. P., Ho, A. L., Fatemi, P., Herrick, D., Kim, L. H., Feng, A., Varshneya, K., Jin, M., Veeravagu, A., Bhattacharya, J., Desai, M., Lembke, A., Ratliff, J. K. 2019

  Abstract

  BACKGROUND: The morbidity and mortality associated with opioid and benzodiazepine co-prescription is a pressing national concern. Little is known about patterns of opioid and benzodiazepine use in patients with acute low back pain or lower extremity pain.OBJECTIVE: To characterize patterns of opioid and benzodiazepine prescribing among opioid-naive, newly diagnosed low back pain (LBP) or lower extremity pain (LEP) patients and to investigate the relationship between benzodiazepine prescribing and long-term opioid use.DESIGN/SETTING: We performed a retrospective analysis of a commercial database containing claims for more than 75 million enrollees in the USA.PARTICIPANTS: Participants were adult patients newly diagnosed with LBP or LEP between 2008 and 2015 who did not have a red flag diagnosis, had not received an opioid prescription in the 6months prior to diagnosis, and had 12months of continuous enrollment after diagnosis.MAIN OUTCOMES AND MEASURES: Among patients receiving at least one opioid prescription within 12months of diagnosis, we defined discrete patterns of benzodiazepine prescribing-continued use, new use, stopped use, and never use. We tested the association of these prescription patterns with long-term opioid use, defined as six or more fills within 12months.RESULTS: We identified 2,497,653 opioid-naive patients with newly diagnosed LBP or LEP. Between 2008 and 2015, 31.9% and 11.5% of these patients received opioid and benzodiazepine prescriptions, respectively, within 12months of diagnosis. Rates of opioid prescription decreased from 34.8% in 2008 to 27.0% in 2015 (P<0.001); however, prescribing of benzodiazepines only decreased from 11.6% in 2008 to 10.8% in 2015. Patients with continued or new benzodiazepine use consistently used more opioids than patients who never used or stopped using benzodiazepines during the study period (one-way ANOVA, P<0.001). For patients with continued and new benzodiazepine use, the odds ratio of long-term opioid use compared with those never prescribed a benzodiazepine was 2.99 (95% CI, 2.89-3.08) and 2.68 (95% CI, 2.62-2.75), respectively.LIMITATIONS: This study used administrative claims analyses, which rely on accuracy and completeness of diagnostic, procedural, and prescription codes.CONCLUSION: Overall opioid prescribing for low back pain or lower extremity pain decreased substantially during the study period, indicating a shift in management within the medical community. Rates of benzodiazepine prescribing, however, remained at approximately 11%. Concurrent prescriptions of benzodiazepines and opioids after LBP or LEP diagnosis were associated with increased risk of long-term opioid use.

  View details for DOI 10.1007/s11606-019-05549-8

  View details for PubMedID 31720966

• Propensity-matched Comparison of Outcomes and Costs After Macroscopic and Microscopic Anterior Cervical Corpectomy Using a National Longitudinal Database. Spine Ho, A. L., Rezaii, P. G., Pendharkar, A. V., Sussman, E. S., Veeravagu, A., Ratliff, J. K., Desai, A. M. 2019; 44 (21): E1281–E1288

  Abstract

  STUDY DESIGN: A retrospective analysis of national longitudinal database.OBJECTIVE: The aim of this study was to examine the outcomes and cost-effectiveness of operating microscope utilization in anterior cervical corpectomy (ACC).SUMMARY OF BACKGROUND DATA: The operating microscope allows for superior visualization and facilitates ACC with less manipulation of tissue and improved decompression of neural elements. However, many groups report no difference in outcomes with increased cost associated with microscope utilization.METHODS: A longitudinal database (MarketScan) was utilized to identify patients undergoing ACC with or without microscope between 2007 and 2016. Propensity matching was performed to normalize differences between the two cohorts. Outcomes and costs were subsequently compared.RESULTS: A total of 11,590 patients were identified for the "macroscopic" group, while 4299 patients were identified for the "microscopic" group. For the propensity-matched analysis, 4298 patients in either cohort were successfully matched according to preoperative characteristics. Hospital length of stay was found to be significantly longer in the macroscopic group than the microscopic group (1.86 nights vs. 1.56 nights, P < 0.0001). Macroscopic ACC patients had an overall higher rate of readmissions [30-day: 4.2% vs. 3.2%, odds ratio (OR) = 0.76 (0.61-0.96), P = 0.0223; 90-day: 7.0% vs. 5.9%, OR = 0.82 (0.69-0.98), P = 0.0223]. Microscopic ACC patients had a higher rate of discharge to home [86.6% vs. 92.5%, OR = 1.91 (1.65-2.21), P < 0.0001] and lower rates of new referrals to pain management [1.0% vs. 0.4%, OR = 0.42 (0.23-0.74), P = 0.0018] compared with macroscopic ACC. Postoperative complication rate was not found to be significantly different between the groups. Finally, total initial admission charges were not significantly different between the macroscopic and microscopic groups ($30,175 vs. $29,827, P = 0.9880).CONCLUSION: The present study suggests that the use of the operating microscope for ACC is associated with decreased length of stay, readmissions, and new referrals to pain management, as well as higher rate of discharge to home.LEVEL OF EVIDENCE: 3.

  View details for DOI 10.1097/BRS.0000000000003147

  View details for PubMedID 31634304

• Risks, costs, and outcomes of cerebrospinal fluid leaks after pediatric skull fractures: a MarketScan analysis between 2007 and 2015 NEUROSURGICAL FOCUS Varshneya, K., Rodrigues, A. J., Medress, Z. A., Stienen, M. N., Grant, G. A., Ratliff, J. K., Veeravagu, A. 2019; 47 (5): E10

  Abstract

  Skull fractures are common after blunt pediatric head trauma. CSF leaks are a rare but serious complication of skull fractures; however, little evidence exists on the risk of developing a CSF leak following skull fracture in the pediatric population. In this epidemiological study, the authors investigated the risk factors of CSF leaks and their impact on pediatric skull fracture outcomes.The authors queried the MarketScan database (2007-2015), identifying pediatric patients (age < 18 years) with a diagnosis of skull fracture and CSF leak. Skull fractures were disaggregated by location (base, vault, facial) and severity (open, closed, multiple, concomitant cerebral or vascular injury). Descriptive statistics and hypothesis testing were used to compare baseline characteristics, complications, quality metrics, and costs.The authors identified 13,861 pediatric patients admitted with a skull fracture, of whom 1.46% (n = 202) developed a CSF leak. Among patients with a skull fracture and a CSF leak, 118 (58.4%) presented with otorrhea and 84 (41.6%) presented with rhinorrhea. Patients who developed CSF leaks were older (10.4 years vs 8.7 years, p < 0.0001) and more commonly had skull base (n = 183) and multiple (n = 22) skull fractures (p < 0.05). These patients also more frequently underwent a neurosurgical intervention (24.8% vs 9.6%, p < 0.0001). Compared with the non-CSF leak population, patients with a CSF leak had longer average hospitalizations (9.6 days vs 3.7 days, p < 0.0001) and higher rates of neurological deficits (5.0% vs 0.7%, p < 0.0001; OR 7.0; 95% CI 3.6-13.6), meningitis (5.5% vs 0.3%, p < 0.0001; OR 22.4; 95% CI 11.2-44.9), nonroutine discharge (6.9% vs 2.5%, p < 0.0001; OR 2.9; 95% CI 1.7-5.0), and readmission (24.7% vs 8.5%, p < 0.0001; OR 3.4; 95% CI 2.5-4.7). Total costs at 90 days for patients with a CSF leak averaged $81,206, compared with $32,831 for patients without a CSF leak (p < 0.0001).The authors found that CSF leaks occurred in 1.46% of pediatric patients with skull fractures and that skull fractures were associated with significantly increased rates of neurosurgical intervention and risks of meningitis, hospital readmission, and neurological deficits at 90 days. Pediatric patients with skull fractures also experienced longer average hospitalizations and greater healthcare costs at presentation and at 90 days.

  View details for DOI 10.3171/2019.8.FOCUS19543

  View details for Web of Science ID 000493985900010

  View details for PubMedID 31675705

• Conventional Versus Stereotactic Image-guided Pedicle Screw Placement During Posterior Lumbar Fusions: A Retrospective Propensity Score-matched Study of a National Longitudinal Database. Spine Pendharkar, A. V., Rezaii, P. G., Ho, A. L., Sussman, E. S., Veeravagu, A., Ratliff, J. K., Desai, A. M. 2019; 44 (21): E1272–E1280

  Abstract

  STUDY DESIGN: Retrospective 1:1 propensity score-matched analysis on a national longitudinal database between 2007 and 2016.OBJECTIVE: The aim of this study was to compare complication rates, revision rates, and payment differences between navigated and conventional posterior lumbar fusion (PLF) procedures with instrumentation.SUMMARY OF BACKGROUND DATA: Stereotactic navigation techniques for spinal instrumentation have been widely demonstrated to improve screw placement accuracies and decrease perforation rates when compared to conventional fluoroscopic and free-hand techniques. However, the clinical utility of navigation for instrumented PLF remains controversial.METHODS: Patients who underwent elective laminectomy and instrumented PLF were stratified into "single level" and "3- to 6-level" cohorts. Navigation and conventional groups within each cohort were balanced using 1:1 propensity score matching, resulting in 1786 navigated and conventional patients in the single-level cohort and 2060 in the 3 to 6 level cohort. Outcomes were compared using bivariate analysis.RESULTS: For the single-level cohort, there were no significant differences in rates of complications, readmissions, revisions, and length of stay between the navigation and conventional groups. For the 3- to 6-level cohort, length of stay was significantly longer in the navigation group (P < 0.0001). Rates of readmissions were, however, greater for the conventional group (30-day: P = 0.0239; 90-day: P = 0.0449). Overall complications were also greater for the conventional group (P = 0.0338), whereas revision rate was not significantly different between the 2 groups. Total payments were significantly greater for the navigation group in both the single level and 3- to 6-level cohorts (P < 0.0001).CONCLUSION: Although use of navigation for 3- to 6-level instrumented PLF was associated with increased length of stay and payments, the concurrent decreased overall complication and readmission rates alluded to its potential clinical utility. However, for single-level instrumented PLF, no differences in outcomes were found between groups, suggesting that the value in navigation may lie in more complex procedures.LEVEL OF EVIDENCE: 3.

  View details for DOI 10.1097/BRS.0000000000003130

  View details for PubMedID 31634303

• Trends in Anterior Lumbar Interbody Fusion in the United States: A MarketScan Study From 2007 to 2014. Clinical spine surgery Varshneya, K., Medress, Z. A., Jensen, M., Azad, T. D., Rodrigues, A., Stienen, M. N., Desai, A., Ratliff, J. K., Veeravagu, A. 2019

  Abstract

  BACKGROUND: Although the incidence of spinal fusions has increased significantly in the United States over the last quarter century, national trends of anterior lumbar interbody fusion (ALIF) utilization are not known.PURPOSE: The objective of this study was to characterize trends, clinical characteristics, risk factors associated with, and outcomes of ALIF in the United States.STUDY DESIGN: This was an epidemiological study using national administrative data from the MarketScan database.METHODS: Using a large administrative database, we identified adults who underwent ALIF in the United States from 2007 to 2014. The incidence of ALIF was studied longitudinally over time and across geographic regions in the United States. Data related to postoperative complications, length of stay, readmission, and cost were collected.RESULTS: We identified 49,945 patients that underwent ALIF in the United States between 2007 and 2014. The total number of ALIF procedures increased from 3650 in 2007 to 6151 in 2014, accounting for an average increase of 24.07% annually. The Southern United States performed the highest number of ALIFs. The most common conditions treated were degenerative disc disease and spondylolisthesis. Over one third of patients (34.6%) underwent multilevel fusion. The most common complications were iron deficiency anemia, urinary tract infections, and pulmonary complications. Hospital and physician pay increased significantly during the study period.CONCLUSIONS: For the first time in our knowledge, we identified national trends in ALIF utilization, outcomes, and cost using a large administrative database. Our study reaffirms prior work that has demonstrated low rates of complications, mortality, and readmission following ALIF.LEVEL OF EVIDENCE: Level III.

  View details for DOI 10.1097/BSD.0000000000000904

  View details for PubMedID 31609798

• A Descriptive Analysis of Spinal Cord Arteriovenous Malformations: Clinical Features, Outcomes, and Trends in Management. World neurosurgery Varshneya, K., Pendharkar, A. V., Azad, T. D., Ratliff, J. K., Veeravagu, A. 2019

  Abstract

  BACKGROUND: Spinal arteriovenous malformations (AVM) are an abnormal interconnection of vasculature in the spine than can lead to significant neurological deficit if left untreated.OBJECTIVE: The objective of this study was to characterize how spinal AVM patients initially presented, what treatment options were utilized, and their overall outcomes on a national scale.METHODS: The MarketScan database was queried to identify adult patients diagnosed with a spinal AVM from 2007 - 2015. Trends in management, postoperative complication rates, and costs were determined.RESULTS: 976 patients were identified with having a diagnosis of a spinal AVM. Patients were more commonly treated with an open incision than an embolization (40.1% vs 15.4%). The overall complication rate was 33.61%. Spinal AVM admissions have been stable over the past decade and mean cost of hospitalization has risen from of $48,700 in 2007 to $71,292 in 2015. Patients who underwent open surgery had a higher complication rate than those treated with embolization (31.15% vs 18.25%, p < 0.005); however, this may be strongly influenced by complexity of spinal AVM pathology and not treatment modality.CONCLUSIONS: Costs of spinal AVM management continue to rise, even when treatment modalities have reduced length of stay significantly. Open surgery may lead to more postoperative complications and a higher length of stay than endovascular approaches. Further studies should look to identify the efficacy of endovascular approaches for spinal cord AVMs, particularly in complex spinal AVM traditionally treated with open surgery and to isolate factors leading to the elevated hospitalization costs.LEVEL OF EVIDENCE: III.

  View details for DOI 10.1016/j.wneu.2019.08.010

  View details for PubMedID 31404690

• Laminectomy versus Corpectomy for Spinal Metastatic Disease-Complications, Costs, and Quality Outcomes. World neurosurgery Azad, T. D., Varshneya, K., Ho, A. L., Veeravagu, A., Sciubba, D. M., Ratliff, J. K. 2019

  View details for DOI 10.1016/j.wneu.2019.07.206

  View details for PubMedID 31404695

• Grade II Spondylolisthesis: Reverse Bohlman Procedure with Trans-Discal S1-L5 and S2Ai Screws Placed with Robotic Guidance. World neurosurgery Ho, A. L., Varshneya, K., Medress, Z. A., Pendharkar, A. V., Sussman, E. S., Cheng, I., Veeravagu, A. 2019

  Abstract

  STUDY DESIGN: Technical Report with two illustrative cases.OBJECTIVE: Grade II spondylolisthesis remains a complex surgical pathology for which there is no consensus regarding optimal surgical strategies. Surgical strategies vary regarding extent of reduction, utilization of instrumentation/interbody support, and anterior versus posterior approaches with or without decompression. The objective of this study is to provide the first report on the efficacy of robotic spinal surgery systems in supporting the treatment of grade II spondylolisthesis.METHODS: Utilizing two illustrative cases, we provide a technical report of how a robotic spinal surgery platform can be utilized to treatment grade II spondylolisthesis with a novel instrumentation strategy.RESULTS: We describe how utilization of the "Reverse Bohlman" technique to achieve a large anterior fusion construct spanning the pathologic level and buttressed by the adjacent level above, coupled with a novel, high fidelity posterior fixation scheme with transdiscal S1-L5 and S2Ai screws placed in a minimally invasive fashion with robot guidance allows for the best chance of fusion in situ.CONCLUSIONS: The "Reverse Bohlman" technique coupled with transdiscal S1-L5 and S2Ai screw fixation accomplishes the surgical goals of creating a solid fusion construct, avoiding neurologic injury with aggressive reduction, and halting the progression of anterolisthesis. Utilization of robot guidance allows for efficient placement of these difficult screw trajectories in a minimally invasive fashion.

  View details for DOI 10.1016/j.wneu.2019.07.229

  View details for PubMedID 31398524

• Objective measures of functional impairment for degenerative diseases of the lumbar spine: a systematic review of the literature SPINE JOURNAL Stienen, M. N., Ho, A. L., Staartjes, V. E., Maldaner, N., Veeravagu, A., Desai, A., Gautschi, O. P., Bellut, D., Regli, L., Ratliff, J. K., Park, J. 2019; 19 (7): 1276–93

  View details for DOI 10.1016/j.spinee.2019.02.014

  View details for Web of Science ID 000471904100017

• Expenditures and Health Care Utilization Among Adults With Newly Diagnosed LowBack and Lower Extremity Pain JAMA NETWORK OPEN Kim, L. H., Vail, D., Azad, T. D., Bentley, J. P., Zhang, Y., Ho, A. L., Fatemi, P., Feng, A., Varshneya, K., Desai, M., Veeravagu, A., Ratliff, J. K. 2019; 2 (5)

  View details for DOI 10.1001/jamanetworkopen.2019.3676

  View details for Web of Science ID 000476806200041

• Patient Satisfaction and Press Ganey Scores for Spine Versus Nonspine Neurosurgery Clinics. Clinical spine surgery Chen, Y., Johnson, E., Montalvo, C., Stratford, S., Veeravagu, A., Tharin, S., Desai, A., Ratliff, J., Shuer, L., Park, J. 2019

  Abstract

  STUDY DESIGN: Retrospective survey review.OBJECTIVE: We seek to evaluate satisfaction scores in patients seen in neurosurgical spine versus neurosurgical nonspine clinics.SUMMARY OF BACKGROUND DATA: The Press Ganey survey is a well-established metric for measuring hospital performance and patient satisfaction. These measures have important implications in setting hospital policy and guiding interventions to improve patient perceptions of care.METHODS: Retrospective Press Ganey survey review was performed to identify patient demographics and patient visit characteristics from January 1st, 2012 to October 10th, 2017 at Stanford Medical Center. A total of 40 questions from the Press Ganey survey were investigated and grouped in categories addressing physician and nursing care, personal concerns, admission, room, meal, operating room, treatment and discharge conditions, visitor accommodations and overall clinic assessment. Raw ordinal scores were converted to continuous scores of 100 for unpaired student t test analysis. We identified 578 neurosurgical spine clinic patients and 1048 neurosurgical nonspine clinic patients.RESULTS: Spine clinic patients reported lower satisfaction scores in aggregate (88.2 vs. 90.1; P=0.0014), physician (89.5 vs. 92.6; P=0.0002) and nurse care (91.3 vs. 93.4; P=0.0038), personal concerns (88.2 vs. 90.9; P=0.0009), room (81.0 vs. 83.1; P=0.0164), admission (90.8 vs. 92.6; P=0.0154) and visitor conditions (87.0 vs. 89.2; P=0.0148), and overall clinic assessment (92.9 vs. 95.5; P=0.005).CONCLUSIONS: This study is the first to evaluate the relationship between neurosurgical spine versus nonspine clinic with regards to patient satisfaction. The spine clinic cohort reported less satisfaction than the nonspine cohort in all significant questions on the Press Ganey survey. Our findings suggest that efforts should be made to further study and improve patient satisfaction in spine clinics.LEVEL OF EVIDENCE: Level III.

  View details for DOI 10.1097/BSD.0000000000000825

  View details for PubMedID 30969193

• Socioeconomic Predictors of Surgical Resection and Survival for Patients With Osseous Spinal Neoplasms CLINICAL SPINE SURGERY Deb, S., Brewster, R., Pendharkar, A., Veeravagu, A., Ratliff, J., Desai, A. 2019; 32 (3): 125–31

  View details for DOI 10.1097/BSD.0000000000000738

  View details for Web of Science ID 000464982800008

• Stem cell therapies for acute spinal cord injury in humans: a review NEUROSURGICAL FOCUS Jin, M. C., Medress, Z. A., Azad, T. D., Doulames, V. M., Veeravagu, A. 2019; 46 (3): E10

  Abstract

  Recent advances in stem cell biology present significant opportunities to advance clinical applications of stem cell-based therapies for spinal cord injury (SCI). In this review, the authors critically analyze the basic science and translational evidence that supports the use of various stem cell sources, including induced pluripotent stem cells, oligodendrocyte precursor cells, and mesenchymal stem cells. They subsequently explore recent advances in stem cell biology and discuss ongoing clinical translation efforts, including combinatorial strategies utilizing scaffolds, biogels, and growth factors to augment stem cell survival, function, and engraftment. Finally, the authors discuss the evolution of stem cell therapies for SCI by providing an overview of completed (n = 18) and ongoing (n = 9) clinical trials.

  View details for DOI 10.3171/2018.12.FOCUS18602

  View details for Web of Science ID 000460130200010

  View details for PubMedID 30835679

• Objective measures of functional impairment for degenerative diseases of the lumbar spine: a systematic review of the literature. The spine journal : official journal of the North American Spine Society Stienen, M. N., Ho, A. L., Staartjes, V. E., Maldaner, N., Veeravagu, A., Desai, A., Gautschi, O. P., Bellut, D., Regli, L., Ratliff, J. K., Park, J. 2019

  Abstract

  BACKGROUND CONTEXT: The accurate determination of a patient's functional status is necessary for therapeutic decision-making and to critically appraise treatment efficacy. Current subjective patient-reported outcome measure (PROM)-based assessments have limitations and can be complimented by objective measures of function.PURPOSE: To systematically review the literature and provide an overview on the available objective measures of function for patients with degenerative diseases of the lumbar spine.STUDY DESIGN/SETTING: Systematic review of the literature.METHODS: The PRISMA guidelines were followed. Two reviewers independently searched the PubMed, Web of Science, EMBASE and SCOPUS databases for permutations of the words "objective", "assessment", "function", "lumbar" and "spine", including articles on human subjects with degenerative diseases of the lumbar spine that reported on objective measures of function, published until September 2018. No funding was received. The authors report no conflicts of interest.RESULTS: Of 2389 identified articles, 82 were included in the final analysis. There was a significant increase of 0.12 per year in the number of publications dealing with objective measures of function since 1989 (95% CI 0.08-0.16, p<0.001). Some publications studied multiple diagnoses and objective measures. The US was the leading nation in terms of scientific output for objective outcome measures (n=21; 25.6%), followed by Switzerland (n=17; 20.7%), Canada, Germany and the United Kingdom (each n=6; 7.3%). Our search revealed 21 different types of objective measures, predominantly applied to patients with lumbar spinal stenosis (n=67 publications; 81.7%), chronic/unspecific low back pain (n=28; 34.2%) and lumbar disc herniation (n=22; 26.8%). The Timed-Up-and-Go (TUG) test was the most frequently applied measure (n=26 publications; 31.7%; cumulative number of reported subjects: 5181), followed by the Motorized Treadmill Test (MTT; n=25 publications; 30.5%, 1499 subjects) and with each n=9 publications (11.0%) the Five-Repetition Sit-To-Stand test (5R-STS; 955 subjects), as well as accelerometry analyses (336 subjects). The reliability and validity of many of the less-applied objective measures was uncertain. There was profound heterogeneity in their application and interpretation of results. Risk of bias was not assessed.CONCLUSIONS: Clinical studies on patients with lumbar degenerative diseases increasingly employ objective measures of function, which offer high potential for improving the quality of outcome measurement in patient-care and research. This review provides an overview on available options. Our findings call for an agreement and standardization in terms of test selection, conduction and analysis to facilitate comparison of results across cohorts.

  View details for PubMedID 30831316

• Initial Provider Specialty Is Associated With Long-term Opiate Use in Patients With Newly Diagnosed Low Back and Lower Extremity Pain SPINE Azad, T. D., Vail, D., Bentley, J., Han, S. S., Suarez, P., Varshneya, K., Mittal, V., Veeravagu, A., Desai, M., Bhattacharya, J., Ratliff, J. K. 2019; 44 (3): 211–18

  View details for DOI 10.1097/BRS.0000000000002840

  View details for Web of Science ID 000467734800018

• Outcomes and costs following Ommaya placement with thrombocytopenia among US cancer patients. World neurosurgery Zhang, M. n., Zhang, Y. n., Zheng, E. n., Gephart, M. H., Veeravagu, A. n., Desai, A. n., Ratliff, J. K., Li, G. n. 2019

  Abstract

  Placement of Ommaya reservoirs for administration of intrathecal chemotherapy may be complicated by comorbid thrombocytopenia among patients with hematologic or leptomeningeal disease. Aggregated data on risks of Ommaya placement among thrombocytopenic patients is lacking. This study assesses complications, revision rates, and costs associated with Ommaya placement among patients with thrombocytopenia in a large population sample.Using a national administrative database, this retrospective study identifies a cohort of adult cancer patients who underwent Ommaya placement between 2007 and 2016. Preoperative thrombocytopenia was defined as diagnosis of secondary thrombocytopenia, bleeding event, procedure to control bleeding, or platelet transfusion, within 30 days prior to index admission. Univariate and multivariate analyses were performed to assess costs, 30-day complications, readmissions, and revisions among patients with and without preoperative thrombocytopenia.The analytic cohort included 1652 patients, of whom 29.3% met criteria for preoperative thrombocytopenia. In-hospital mortality rates were 7.7% among thrombocytopenic patients vs. 1.2% among non-thrombocytopenic patients (p < 0.001). Preoperative thrombocytopenia was associated with 14.5 times greater hazard of intracranial hemorrhage within 30 days following Ommaya placement, occurring in 25.6% vs. 2.0% of thrombocytopenic and non-thrombocytopenic patients, respectively (p < 0.014). Revision rates did not differ significantly between thrombocytopenic and non-thrombocytopenic patients. Thrombocytopenia was associated with longer length of stay (7.4 vs 13.9 days, p < 0.001) and additional $10,000 per patient in costs of index hospitalization (p < 0.001).This is the largest study to date documenting costs and complication rates of Ommaya placement in patients with and without thrombocytopenia.

  View details for DOI 10.1016/j.wneu.2019.12.063

  View details for PubMedID 31866457

• Randomized Controlled Trials in Functional Neurosurgery-Association of Device Approval Status and Trial Quality. Neuromodulation : journal of the International Neuromodulation Society Azad, T. D., Feng, A. Y., Mehta, S. n., Bak, A. B., Johnson, E. n., Mittal, V. n., Esparza, R. n., Veeravagu, A. n., Halpern, C. H., Grant, G. A. 2019

  Abstract

  Randomized controlled trials (RCTs) have been critical in evaluating the safety and efficacy of functional neurosurgery interventions. Given this, we sought to systematically assess the quality of functional neurosurgery RCTs.We used a database of neurosurgical RCTs (trials published from 1961 to 2016) to identify studies of functional neurosurgical procedures (N = 48). We extracted data on the design and quality of these RCTs and quantified the quality of trials using Jadad scores. We categorized RCTs based on the device approval status at the time of the trial and tested the association of device approval status with trial design and quality parameters.Of the 48 analyzed functional neurosurgery RCTs, the median trial size was 34.5 patients with a median age of 51. The most common indications were Parkinson's disease (N = 20), epilepsy (N = 10), obsessive-compulsive disorder (N = 4), and pain (N = 4). Most trials reported inclusion and exclusion criteria (95.8%), sample size per arm (97.9%), and baseline characteristics of the patients being studied (97.9%). However, reporting of allocation concealment (29.2%), randomization mode (66.7%), and power calculations (54.2%) were markedly less common. We observed that trial quality has improved over time (Spearman r, 0.49). We observed that trials studying devices with humanitarian device exemption (HDE) and experimental indications (EI) tended to be of higher quality than trials of FDA-approved devices (p = 0.011). A key distinguishing quality characteristic was the proportion of HDE and EI trials that were double-blinded, compared to trials of FDA-approved devices (HDE, 83.3%; EI, 69.2%; FDA-approved, 35.3%). Although more than one-third of functional neurosurgery RCTs reported funding from industry, no significant association was identified between funding source and trial quality or outcome.The quality of RCTs in functional neurosurgery has improved over time but reporting of specific metrics such as power calculations and allocation concealment requires further improvement. Device approval status but not funding source was associated with trial quality.

  View details for DOI 10.1111/ner.13083

  View details for PubMedID 31828896

• Reliability of the 6-minute walking test smartphone application. Journal of neurosurgery. Spine Stienen, M. N., Gautschi, O. P., Staartjes, V. E., Maldaner, N. n., Sosnova, M. n., Ho, A. L., Veeravagu, A. n., Desai, A. n., Zygourakis, C. C., Park, J. n., Regli, L. n., Ratliff, J. K. 2019: 1–8

  Abstract

  Objective functional measures such as the 6-minute walking test (6WT) are increasingly applied to evaluate patients with degenerative diseases of the lumbar spine before and after (surgical) treatment. However, the traditional 6WT is cumbersome to apply, as it requires specialized in-hospital infrastructure and personnel. The authors set out to compare 6-minute walking distance (6WD) measurements obtained with a newly developed smartphone application (app) and those obtained with the gold-standard distance wheel (DW).The authors developed a free iOS- and Android-based smartphone app that allows patients to measure the 6WD in their home environment using global positioning system (GPS) coordinates. In a laboratory setting, the authors obtained 6WD measurements over a range of smartphone models, testing environments, and walking patterns and speeds. The main outcome was the relative measurement error (rME; in percent of 6WD), with |rME| < 7.5% defined as reliable. The intraclass correlation coefficient (ICC) for agreement between app- and DW-based 6WD was calculated.Measurements (n = 406) were reliable with all smartphone types in neighborhood, nature, and city environments (without high buildings), as well as with unspecified, straight, continuous, and stop-and-go walking patterns (ICC = 0.97, 95% CI 0.97-0.98, p < 0.001). Measurements were unreliable indoors, in city areas with high buildings, and for predominantly rectangular walking courses. Walking speed had an influence on the ME, with worse accuracy (2% higher rME) for every kilometer per hour slower walking pace (95% CI 1.4%-2.5%, p < 0.001). Mathematical adjustment of the app-based 6WD for velocity-dependent error mitigated the rME (p < 0.011), attenuated velocity dependence (p = 0.362), and had a positive effect on accuracy (ICC = 0.98, 95% CI 0.98-0.99, p < 0.001).The new, free, spine-specific 6WT smartphone app measures the 6WD conveniently by using GPS coordinates, empowering patients to independently determine their functional status before and after (surgical) treatment. Measurements of 6WD obtained for the target population under the recommended circumstances are highly reliable.

  View details for DOI 10.3171/2019.6.SPINE19559

  View details for PubMedID 31518975

• Robotic-Assisted Spine Surgery: History, Efficacy, Cost, And Future Trends. Robotic surgery (Auckland) D'Souza, M. n., Gendreau, J. n., Feng, A. n., Kim, L. H., Ho, A. L., Veeravagu, A. n. 2019; 6: 9–23

  Abstract

  Robot-assisted spine surgery has recently emerged as a viable tool to enable less invasive and higher precision surgery. The first-ever spine robot, the SpineAssist (Mazor Robotics Ltd., Caesarea, Israel), gained FDA approval in 2004. With its ability to provide real-time intraoperative navigation and rigid stereotaxy, robotic-assisted surgery has the potential to increase accuracy while decreasing radiation exposure, complication rates, operative time, and recovery time. Currently, robotic assistance is mainly restricted to spinal fusion and instrumentation procedures, but recent studies have demonstrated its use in increasingly complex procedures such as spinal tumor resections and ablations, vertebroplasties, and deformity correction. However, robots do require high initial costs and training, and thus, require justification for their incorporation into common practice. In this review, we discuss the history of spinal robots along as well as currently available systems. We then examine the literature to evaluate accuracy, operative time, complications, radiation exposure, and costs - comparing robotic-assisted to traditional fluoroscopy-assisted freehand approaches. Finally, we consider future applications for robots in spine surgery.

  View details for DOI 10.2147/RSRR.S190720

  View details for PubMedID 31807602

  View details for PubMedCentralID PMC6844237

• Lumboperitoneal and Ventriculoperitoneal Shunting for Idiopathic Intracranial Hypertension Demonstrate Comparable Failure and Complication Rates. Neurosurgery Azad, T. D., Zhang, Y. n., Varshneya, K. n., Veeravagu, A. n., Ratliff, J. K., Li, G. n. 2019

  Abstract

  Idiopathic intracranial hypertension results in increased intracranial pressure leading to headache and visual loss. This disease frequently requires surgical intervention through lumboperitoneal (LP) or ventriculoperitoneal (VP) shunting.To compare postoperative outcomes between LP and VP shunts, including failure and complication rates.A retrospective analysis was conducted using a national administrative database (MarketScan) to identify idiopathic intracranial hypertension (IIH) patients who underwent LP or VP shunting from 2007 to 2014. Multivariate logistic and Cox regressions were performed to compare rates of shunt failure and time to shunt failure between LP and VP shunts while controlling for demographics and comorbidities.The analytic cohort included 1082 IIH patients, 347 of whom underwent LP shunt placement at index hospitalization and 735 of whom underwent VP shunt placement. Rates of shunt failure were similar among patients with LP and VP shunt (34.6% vs 31.7%; P = .382). Among patients who experienced shunt failure, the mean number of shunt failures was 2.1 ± 1.6 and was similar between LP and VP cohorts. Ninety-day readmission rates, complication rates, and costs did not differ significantly between LP and VP shunts. Patients who experienced more than two shunt failures tended to have an earlier time to first shunt failure (hazard ratio 1.41; 95% confidence interval 1.08-1.85; P = .013).These findings suggest that LP and VP shunts may have comparable rates of shunt failure and complication. Regardless of shunt type, earlier time to first shunt failure may be associated with multiple shunt failures.

  View details for PubMedID 30937428

• Analysis of Outcomes and Cost of Inpatient and Ambulatory Anterior Cervical Disk Replacement Using a State-level Database. Clinical spine surgery Purger, D. A., Pendharkar, A. V., Ho, A. L., Sussman, E. S., Veeravagu, A. n., Ratliff, J. K., Desai, A. M. 2019

  Abstract

  Outpatient cervical artificial disk replacement (ADR) is a promising candidate for cost reduction. Several studies have demonstrated low overall complications and minimal readmission in anterior cervical procedures.The objective of this study was to compare clinical outcomes and cost associated between inpatient and ambulatory setting ADR.Outcomes and cost were retrospectively analyzed for patients undergoing elective ADR in California, Florida, and New York from 2009 to 2011 in State Inpatient and Ambulatory Databases.A total of 1789 index ADR procedures were identified in the inpatient database (State Inpatient Databases) compared with 370 procedures in the ambulatory cohort (State Ambulatory Surgery and Services Databases). Ambulatory patients presented to the emergency department 19 times (5.14%) within 30 days of the index procedure compared with 4.2% of inpatients. Four unique patients underwent readmission within 30 days in the ambulatory ADR cohort (1% total) compared with 2.2% in the inpatient ADR group. No ambulatory ADR patients underwent a reoperation within 30 days. Of the inpatient ADR group, 6 unique patients underwent reoperation within 30 days (0.34%, Charlson Comorbidity Index zero=0.28%, Charlson Comorbidity Index>0=0.6%). There was no significant difference in emergency department visit rate, inpatient readmission rate, or reoperation rates within 30 days of the index procedure between outpatient or inpatient ADR. Outpatient ADR is noninferior to inpatient ADR in all clinical outcomes. The direct cost was significantly lower in the outpatient ADR group ($11,059 vs. 17,033; P<0.001). The 90-day cumulative charges were significantly lower in the outpatient ADR group (mean $46,404.03 vs. $80,055; P<0.0001).ADR can be performed in an ambulatory setting with comparable morbidity, readmission rates, and lower costs, to inpatient ADR.

  View details for DOI 10.1097/BSD.0000000000000840

  View details for PubMedID 31180992

• Spine. Operative neurosurgery (Hagerstown, Md.) Ahmad, F. U., Bisson, E. F., Burks, S. S., Chang, J. J., Chugh, A. J., Côté, I. n., Frerich, J. M., Gersey, Z. C., Hendricks, B. K., Karsy, M. n., Kasliwal, M. n., Krause, K. L., Manzano, G. R., Morgan, C. D., Snyder, L. A., Swinney, C. C., Than, K. D., Theodotou, C. B., Veeravagu, A. n., Ventura, J. n. 2019

  View details for DOI 10.1093/ons/opz073

  View details for PubMedID 31099842

• Expenditures and Health Care Utilization Among Adults With Newly Diagnosed Low Back and Lower Extremity Pain. JAMA network open Kim, L. H., Vail, D. n., Azad, T. D., Bentley, J. P., Zhang, Y. n., Ho, A. L., Fatemi, P. n., Feng, A. n., Varshneya, K. n., Desai, M. n., Veeravagu, A. n., Ratliff, J. K. 2019; 2 (5): e193676

  Abstract

  Low back pain (LBP) with or without lower extremity pain (LEP) is one of the most common reasons for seeking medical care. Previous studies investigating costs in this population targeted patients receiving surgery. Little is known about health care utilization among patients who do not undergo surgery.To assess use of health care resources for LBP and LEP management and analyze associated costs.This cohort study used a retrospective analysis of a commercial database containing inpatient and outpatient data for more than 75 million individuals. Participants were US adults who were newly diagnosed with LBP or LEP between 2008 and 2015, did not have a red-flag diagnosis, and were opiate naive prior to diagnosis. Dates of analysis were October 6, 2018, to March 7, 2019.Newly diagnosed LBP or LEP.The primary outcome was total cost of care within the first 6 and 12 months following diagnosis, stratified by whether patients received spinal surgery. An assessment was performed to determine whether patients who did not undergo surgery received care in accordance with proposed guidelines for conservative LBP and LEP management. Costs resulting from use of different health care services were estimated.A total of 2 498 013 adult patients with a new LBP or LEP diagnosis (median [interquartile range] age, 47 [36-58] years; 1 373 076 [55.0%] female) were identified. More than half (55.7%) received no intervention. Only 1.2% of patients received surgery, but they accounted for 29.3% of total 12-month costs ($784 million). Total costs of care among the 98.8% of patients who did not receive surgery were $1.8 billion. Patients who did not undergo surgery frequently received care that was inconsistent with clinical guidelines for LBP and LEP: 32.3% of these patients received imaging within 30 days of diagnosis and 35.3% received imaging without a trial of physical therapy.The findings suggest that surgery is rare among patients with newly diagnosed LBP and LEP but remains a significant driver of spending. Early imaging in patients who do not undergo surgery was also a major driver of increased health care expenditures. Avoidable costs among patients with typically self-limited conditions result in considerable economic burden to the US health care system.

  View details for PubMedID 31074820

• Utility of cervical collars following cervical fusion surgery; does it improve fusion rates or outcomes? A systematic review. World neurosurgery Karikari, I., Ghogawala, Z., Ropper, A., Yavin, D., Gabr, M., Goodwin, C. R., Abd-El-Barr, M., Veeravagu, A., Wang, M. C. 2018

  View details for PubMedID 30593959

• Socioeconomic Predictors of Surgical Resection and Survival for Patients With Osseous Spinal Neoplasms. Clinical spine surgery Deb, S., Brewster, R., Pendharkar, A. V., Veeravagu, A., Ratliff, J., Desai, A. 2018

  Abstract

  OF BACKGROUND DATA: Primary osseous spinal neoplasms (POSNs) include locally aggressive tumors such as osteosarcoma, chondrosarcoma, Ewing sarcoma, and chordoma. For such tumors, surgical resection is associated with improved survival for patients. Socioeconomic predictors of receiving surgery, however, have not been studied.OBJECTIVE: To examine the independent effect of race on receiving surgery and survival probability in patients with POSN.STUDY DESIGN: A total of 1904 patients from the SEER program at the National Cancer Institute database, all diagnosed with POSN of the spinal cord, vertebral column, pelvis, or sacrum from 2003 through 2012 were included in the study. Race was reported as white or nonwhite. Treatment included receiving surgery and no surgery.MATERIALS AND METHODS: Multivariable logistic regression was used to determine odds of receiving surgery based on race. Survival probability based on and race and surgery status was analyzed by Cox proportional hazards model and Kaplan-Meir curves. Results were adjusted for age at diagnosis, sex, socioeconomic status (composite index), tumor size, and tumor grade. Data were analyzed with SAS version 9.4.RESULTS: The study found that white patients were significantly more likely to receive surgery (odds ratio=3.076, P<0.01). Furthermore, nonwhite race was associated with significantly shorter survival time [hazard ratio (HR)=1.744, P<0.05]. Receiving surgery was associated with improved overall survival (HR=2.486, P<0.01). After adjusting for receiving surgery, white race remained significantly associated with higher survival probability (HR=2.061, P<0.05).CONCLUSIONS: This national study of patients with typically aggressive POSN found a significant correlation between race and the likelihood of receiving surgery. The study also found race to be a significant predictor of overall survival, regardless of receiving surgical treatment. These findings suggest an effect of race on receiving treatment and survival in patients with POSN, regardless of socioeconomic status. Further studies are required to understand reasons underlying these findings, and how they may be addressed.

  View details for PubMedID 30531357

• Intraoperative analgesic regimens and surgical duration after spine surgery Response NEUROSURGICAL FOCUS O'Connell, C., Sun, E., Ratliff, J. K., Veeravagu, A. 2018; 45 (3)

  View details for DOI 10.3171/2018.4.FOCUS18136

  View details for Web of Science ID 000443301900013

• Outpatient spine surgery: defining the outcomes, value, and barriers to implementation. Neurosurgical focus Pendharkar, A. V., Shahin, M. N., Ho, A. L., Sussman, E. S., Purger, D. A., Veeravagu, A., Ratliff, J. K., Desai, A. M. 2018; 44 (5): E11

  Abstract

  Spine surgery is a key target for cost reduction within the United States health care system. One possible strategy involves the transition of inpatient surgeries to the ambulatory setting. Lumbar laminectomy with or without discectomy, lumbar fusion, anterior cervical discectomy and fusion, and cervical disc arthroplasty all represent promising candidates for outpatient surgeries in select populations. In this focused review, the authors clarify the different definitions used in studies describing outpatient spine surgery. They also discuss the body of evidence supporting each of these procedures and summarize the proposed cost savings. Finally, they examine several patient- and surgeon-specific considerations to highlight the barriers in translating outpatient spine surgery into actual practice.

  View details for PubMedID 29712520

• Propensity-matched comparison of outcomes and cost after macroscopic and microscopic lumbar discectomy using a national longitudinal database. Neurosurgical focus Pendharkar, A. V., Rezaii, P. G., Ho, A. L., Sussman, E. S., Purger, D. A., Veeravagu, A., Ratliff, J. K., Desai, A. M. 2018; 44 (5): E12

  Abstract

  OBJECTIVE There has been considerable debate about the utility of the operating microscope in lumbar discectomy and its effect on outcomes and cost. METHODS A commercially available longitudinal database was used to identify patients undergoing discectomy with or without use of a microscope between 2007 and 2015. Propensity matching was performed to normalize differences between demographics and comorbidities in the 2 cohorts. Outcomes, complications, and cost were subsequently analyzed using bivariate analysis. RESULTS A total of 42,025 patients were identified for the "macroscopic" group, while 11,172 patients were identified for the "microscopic" group. For the propensity-matched analysis, the 11,172 patients in the microscopic discectomy group were compared with a group of 22,340 matched patients who underwent macroscopic discectomy. There were no significant differences in postoperative complications between the groups other than a higher proportion of deep vein thrombosis (DVT) in the macroscopic discectomy cohort versus the microscopic discectomy group (0.4% vs 0.2%, matched OR 0.48 [95% CI 0.26-0.82], p = 0.0045). Length of stay was significantly longer in the macroscopic group compared to the microscopic group (mean 2.13 vs 1.83 days, p < 0.0001). Macroscopic discectomy patients had a higher rate of revision surgery when compared to microscopic discectomy patients (OR 0.92 [95% CI 0.84-1.00], p = 0.0366). Hospital charges were higher in the macroscopic discectomy group (mean $19,490 vs $14,921, p < 0.0001). CONCLUSIONS The present study suggests that the use of the operating microscope in lumbar discectomy is associated with decreased length of stay, lower DVT rate, lower reoperation rate, and decreased overall hospital costs.

  View details for PubMedID 29712527

• Geographic variation in the surgical management of lumbar spondylolisthesis: characterizing practice patterns and outcomes. The spine journal : official journal of the North American Spine Society Azad, T. D., Vail, D. n., O'Connell, C. n., Han, S. S., Veeravagu, A. n., Ratliff, J. K. 2018

  Abstract

  The role of arthrodesis in the surgical management of lumbar spondylolisthesis remains controversial. We hypothesized that practice patterns and outcomes for this patient population may vary widely.To characterize geographic variation in surgical practices and outcomes for patients with lumbar spondylolisthesis.Retrospective analysis on a national longitudinal database between 2007 and 2014.We calculated arthrodesis rates, inpatient and long term costs, and key quality indicators (e.g. reoperation rates). Using linear and logistic regression models, we then calculated expected quality indicator values, adjusting for patient-level demographic factors, and compared these values to the observed values, to assess quality variation apart from differences in patient populations.We identified a cohort of 67,077 patients (60.7% female, mean age of 59.8 years (SD, 12.0) with lumbar spondylolisthesis who received either laminectomy or laminectomy with arthrodesis. The majority of patients received arthrodesis (91.8%). Actual rates of arthrodesis varied from 97.5% in South Dakota to 81.5% in Oregon. Geography remained a significant predictor of arthrodesis even after adjusting for demographic factors (p<0.001). Marked geographic variation was also observed in initial costs ($32,485 in Alabama to $78,433 in Colorado), two-year post-operative costs ($15,612 in Arkansas to $34,096 in New Jersey), length of hospital stay (2.6 days in Arkansas to 4.5 in Washington, D.C.), 30-day complication rates (9.5% in South Dakota to 22.4% in Maryland), 30-day readmission rates (2.5% in South Dakota to 13.6% in Connecticut), and reoperation rates (1.8% in Maine to 12.7% in Alabama).There is marked geographic variation in the rates of arthrodesis in treatment of spondylolisthesis within the United States. This variation remains pronounced after accounting for patient-level demographic differences. Costs of surgery and quality outcomes also vary widely. Further study is necessary to understand the drivers of this variation.

  View details for PubMedID 29746964

• Surgical outcomes of pediatric spinal cord astrocytomas: systematic review and meta-analysis. Journal of neurosurgery. Pediatrics Azad, T. D., Pendharkar, A. V., Pan, J. n., Huang, Y. n., Li, A. n., Esparza, R. n., Mehta, S. n., Connolly, I. D., Veeravagu, A. n., Campen, C. J., Cheshier, S. H., Edwards, M. S., Fisher, P. G., Grant, G. A. 2018: 1–7

  Abstract

  OBJECTIVE Pediatric spinal astrocytomas are rare spinal lesions that pose unique management challenges. Therapeutic options include gross-total resection (GTR), subtotal resection (STR), and adjuvant chemotherapy or radiation therapy. With no randomized controlled trials, the optimal management approach for children with spinal astrocytomas remains unclear. The aim of this study was to conduct a systematic review and meta-analysis on pediatric spinal astrocytomas. METHODS The authors performed a systematic review of the PubMed/MEDLINE electronic database to investigate the impact of histological grade and extent of resection on overall survival among patients with spinal cord astrocytomas. They retained publications in which the majority of reported cases included astrocytoma histology. RESULTS Twenty-nine previously published studies met the eligibility criteria, totaling 578 patients with spinal cord astrocytomas. The spinal level of intramedullary spinal cord tumors was predominantly cervical (53.8%), followed by thoracic (40.8%). Overall, resection was more common than biopsy, and GTR was slightly more commonly achieved than STR (39.7% vs 37.0%). The reported rates of GTR and STR rose markedly from 1984 to 2015. Patients with high-grade astrocytomas had markedly worse 5-year overall survival than patients with low-grade tumors. Patients receiving GTR may have better 5-year overall survival than those receiving STR. CONCLUSIONS The authors describe trends in the management of pediatric spinal cord astrocytomas and suggest a benefit of GTR over STR for 5-year overall survival.

  View details for PubMedID 30028275

• Initial Provider Specialty is Associated with Long-term Opiate Use in Patients with Newly Diagnosed Low Back and Lower Extremity Pain. Spine Azad, T. n., Vail, D. n., Bentley, J. n., Han, S. n., Suarez, P. n., Varshneya, K. n., Mittal, V. n., Veeravagu, A. n., Desai, M. n., Bhattacharya, J. n., Ratliff, J. n. 2018

  Abstract

  Retrospective longitudinal cohort analysis of patients diagnosed in 2010, with continuous enrollment six months prior to and 12 months following the initial visit.To determine whether provider specialty influences patterns of opiate utilization long after initial diagnosis.Patients with low back pain present to a variety of providers and receive a spectrum of treatments, including opiate medications. The impact of initial provider type on opiate use in this population is uncertain.We performed a retrospective analysis of opiate-naïve adult patients in the United States with newly diagnosed low back or lower extremity pain. We estimated the risk of early opiate prescription (≤ 14 days from diagnosis) and long-term opiate use (≥ six prescriptions in 12 months) based on the provider type at initial diagnosis using multivariable logistic regression, adjusting for patient demographics and comorbidities.We identified 478,981 newly diagnosed opiate-naïve patients. Of these, 40.4% received an opiate prescription within one year and 4.0% met criteria for long-term use. The most common initial provider type was family practice, associated with a 24.4% risk of early opiate prescription (95% CI, 24.1-24.6) and a 2.0% risk of long-term opiate use (95% CI, 2.0-2.1). Risk of receiving an early opiate prescription was higher among patients initially diagnosed by emergency medicine (43.1%; 95% CI, 41.6-44.5) or at an urgent care facility (40.8%; 95% CI, 39.4-42.3). Risk of long-term opiate use was highest for patients initially diagnosed by pain management/anesthesia (6.7%; 95% CI, 6.0-7.3) or physical medicine and rehabilitation (3.4%; 95% CI, 3.1-3.8) providers.Initial provider type influences early opiate prescription and long-term opiate use among opiate-naïve patients with newly diagnosed low back and lower extremity pain.3.

  View details for PubMedID 30095796

• Stabilization of the Craniocervical Junction Following Resection of Chordomas and Chondrosarcomas of the Skull Base and Spine CHORDOMAS AND CHONDROSARCOMAS OF THE SKULL BASE AND SPINE, 2ND EDITION Azad, T. D., Veeravagu, A., Ravikumar, V., Ratliff, J. K., Harsh, G. R., VazGuimaraes, F. 2018: 271–78

  View details for DOI 10.1016/B978-0-12-804257-1.00023-2

  View details for Web of Science ID 000426245100025

• Long-Term Effectiveness of Gross-Total Resection for Symptomatic Spinal Cord Cavernous Malformations. Neurosurgery Azad, T. D., Veeravagu, A. n., Li, A. n., Zhang, M. n., Madhugiri, V. n., Steinberg, G. K. 2018

  Abstract

  Intramedullary spinal cord cavernous malformations (CMs) account for 5% of all CMs in the central nervous system and 5% to 12% of all spinal cord vascular lesions, yet their optimal management is controversial.To identify factors associated with the clinical progression of spinal cord CMs and quantify the range of surgical outcomes.Retrospective observational cohort study of 32 patients who underwent open surgical resection for spinal CMs, the majority of which presented to a dorsal or lateral pial surface, from 1996 to 2017 at a single institution. We evaluated outcomes as clinically improved, worsened, or unchanged against preoperative baseline; Frankel and Aminoff-Logue disability grades were also calculated.Mean age at presentation was 44.2 (range, 0.5-77 yr). Symptoms included sensory deficits (n = 26, 81%), loss of strength/coordination (n = 16, 50%), pain (n = 16, 50%), and bladder/bowel dysfunction (n = 6, 19%). Thoracic (n = 16, 50%) and cervical CMs (n = 16, 50%) were equally common, with overall mean size of 7.1 mm (range, 1-20 mm). Functional outcomes at last follow-up, compared to preoperative status for patients with >6 mo of follow-up, were improved in 6 (23%), unchanged in 19 (73%), and worsened in 1 (4%) patients. Preoperative Frankel grade and improved Frankel grade immediately following resection were strongly associated with improvement from baseline at long-term followup (P < .01).Gross total resection of symptomatic spinal cord CMs can prevent further neurological decline. Our experience suggests excellent long-term outcomes and minimal surgical morbidity following resection.

  View details for PubMedID 29425323

• Preoperative depression, lumbar fusion, and opioid use: an assessment of postoperative prescription, quality, and economic outcomes. Neurosurgical focus O'Connell, C. n., Azad, T. D., Mittal, V. n., Vail, D. n., Johnson, E. n., Desai, A. n., Sun, E. n., Ratliff, J. K., Veeravagu, A. n. 2018; 44 (1): E5

  Abstract

  OBJECTIVE Preoperative depression has been linked to a variety of adverse outcomes following lumbar fusion, including increased pain, disability, and 30-day readmission rates. The goal of the present study was to determine whether preoperative depression is associated with increased narcotic use following lumbar fusion. Moreover, the authors examined the association between preoperative depression and a variety of secondary quality indicator and economic outcomes, including complications, 30-day readmissions, revision surgeries, likelihood of discharge home, and 1- and 2-year costs. METHODS A retrospective analysis was conducted using a national longitudinal administrative database (MarketScan) containing diagnostic and reimbursement data on patients with a variety of private insurance providers and Medicare for the period from 2007 to 2014. Multivariable logistic and negative binomial regressions were performed to assess the relationship between preoperative depression and the primary postoperative opioid use outcomes while controlling for demographic, comorbidity, and preoperative prescription drug-use variables. Logistic and log-linear regressions were also used to evaluate the association between depression and the secondary outcomes of complications, 30-day readmissions, revisions, likelihood of discharge home, and 1- and 2-year costs. RESULTS The authors identified 60,597 patients who had undergone lumbar fusion and met the study inclusion criteria, 4985 of whom also had a preoperative diagnosis of depression and 21,905 of whom had a diagnosis of spondylolisthesis at the time of surgery. A preoperative depression diagnosis was associated with increased cumulative opioid use (β = 0.25, p < 0.001), an increased risk of chronic use (OR 1.28, 95% CI 1.17-1.40), and a decreased probability of opioid cessation (OR 0.96, 95% CI 0.95-0.98) following lumbar fusion. In terms of secondary outcomes, preoperative depression was also associated with a slightly increased risk of complications (OR 1.14, 95% CI 1.03-1.25), revision fusions (OR 1.15, 95% CI 1.05-1.26), and 30-day readmissions (OR 1.19, 95% CI 1.04-1.36), although it was not significantly associated with the probability of discharge to home (OR 0.92, 95% CI 0.84-1.01). Preoperative depression also resulted in increased costs at 1 (β = 0.06, p < 0.001) and 2 (β = 0.09, p < 0.001) years postoperatively. CONCLUSIONS Although these findings must be interpreted in the context of the limitations inherent to retrospective studies utilizing administrative data, they provide additional evidence for the link between a preoperative diagnosis of depression and adverse outcomes, particularly increased opioid use, following lumbar fusion.

  View details for DOI 10.3171/2017.10.FOCUS17563

  View details for PubMedID 29290135

• Impact of Inpatient Venous Thromboembolism Continues After Discharge: Retrospective Propensity Scored Analysis in a Longitudinal Database CLINICAL SPINE SURGERY Li, A. Y., Azad, T. D., Veeravagu, A., Bhatti, I., Li, A., Cole, T., Desai, A., Ratliff, J. K. 2017; 30 (10): E1392–E1398

  View details for DOI 10.1097/BSD.0000000000000437

  View details for Web of Science ID 000416241600010

• Endoscope-Assisted Abscess Drainage Secondary to Endoscope-Assisted Transforaminal Lumbar Interbody Fusion: 1-Year Follow-Up WORLD NEUROSURGERY Madhavan, K., Burks, S., Chieng, L., Veeravagu, A., Wang, M. Y. 2017; 107: 511–14

  Abstract

  Endoscopic discectomy and fusions have been gaining popularity in the recent past and are noted to be safe for their application in elderly population. The procedure involves ultra-small incision for discectomy followed by placement of percutaneous screws in awake patients. Treatment of advanced spinal pathology with endoscope-assisted techniques is challenging. Although not common with the endoscopic approach, postoperative infection can be problematic, as there are no established guidelines on its management.A 76-year-old female patient underwent lumbar 4-5 endoscopic-assisted transforaminal lumbar interbody fusion for severe degenerative changes leading to back and radicular leg pain. She did well postoperatively and was discharged home the following day. She presented to the outside hospital with new onset of severe back pain, sepsis, and positive methicillin-susceptible Staphylococcus aureus with blood culture and demonstrated no improvement while on antibiotics.Initial magnetic resonance imaging revealed postoperative changes only. With positive blood culture and localized pain, she was then offered to undergo a percutaneous drainage of the abscess. Under local anesthesia and intravenous sedation, a small pocket of collection was found along the endoscopic trajectory from previous surgery. After evacuation of the collection, the interbody device was irrigated with vancomycin through endoscope. Postoperatively, immediate symptomatic improvement was noted in back pain. She was discharged home on oxacillin and continues to do well at 12 months' follow-up with excellent fusion.The present case illustrates the successful treatment of a surgical-site infection after endoscope-assisted transforaminal lumbar interbody fusion via a repeat percutaneous endoscopic approach.

  View details for PubMedID 28735135

• Surgeon Procedure Volume and Complication Rates in Anterior Cervical Discectomy and Fusions: Analysis of a National Longitudinal Database. Clinical spine surgery Cole, T., Veeravagu, A., Zhang, M., Ratliff, J. K. 2017; 30 (5): E633-E639

  Abstract

  Retrospective study using the MarketScan longitudinal database (2006-2010).Compare complication rates between groups of patients undergoing anterior cervical discectomy and fusion (ACDF) procedures performed by surgeons with high versus low mean annual ACDF volume.Over the past decade the volume of ACDFs performed has increased, concurrent with greater appreciation of potential for associated complications. The effect of surgeon procedure volume on adverse events occurrence in the postoperative period has not been described.We evaluated the relationship between surgeon procedure volume and postoperative incidence of any complication using a multivariate logistic regression model. A total of 24,461 patients undergoing single and multiple level ACDFs were identified in the MarketScan database by Current Procedural Terminology coding. Annual surgeon volume was determined by tracking of anonymized surgeon identification numbers, with high-volume surgeons defined as those performing an average of at least 30 ACDF procedures annually.Over 50% of unique surgeon identifiers reported <9 ACDF operations per year, whereas the highest decile reported a range of 44-101. High surgeon volume was protective for any complication [odds ratio (OR), 72; 95% confidence interval, 0.65-0.81; P<0.0001], with an adjusted number needed to harm of 44. Patients treated by high-volume physicians specifically had lower odds of dysphagia (2.22% vs. 3.08%; OR, 0.71; P<0.0013), neurological complications (0.33% vs. 0.64%; OR, 0.52; P<0.0107), new diagnosis of chronic pain (0.48% vs. 0.82%; OR, 0.58; P<0.0119), pulmonary complications (1.10% vs. 1.58%; OR, 0.69; P<0.0138), and other wound complications (0.06% vs. 0.22%; OR, 0.28; P<0.0242).We demonstrate a possible association between higher surgeon procedure volume and decreased postoperative complications after ACDF. There was no difference observed in need for revision surgery or readmission rates.

  View details for DOI 10.1097/BSD.0000000000000238

  View details for PubMedID 28525490

• Cranioplasty Complications and Costs: A National Population-Level Analysis Using the MarketScan Longitudinal Database. World neurosurgery Li, A., Azad, T. D., Veeravagu, A., Bhatti, I., Long, C., Ratliff, J. K., Li, G. 2017; 102: 209-220

  Abstract

  To characterize cranioplasty complications and costs at a population level using a longitudinal national claims database.We identified cranioplasty patients between 2007-2014 in the MarketScan national database. We evaluated age, autograft usage, cranioplasty size, and cranioplasty timing on postoperative outcomes. We further analyzed associated costs. A subset analysis of adult cranioplasty patients with emergent indications, including stroke and trauma, was also performed.We identified 8,275 patients (mean 44.0±20.0 years, 45.2% male) consisting of 13.8% pediatric (<18 years), 76.0% adults (18-64 years), and 10.2% elderly adults (>65 years). Overall complication rate was 36.6%, mortality rate 0.5%, and 30-day readmission rate 12.0%. Elderly patients had the highest complication rate (p<0.0001). Overall, large cranioplasties (>5 cm) saw higher complication rates than small cranioplasties (≤5 cm, p=0.047). In those with emergent indications only(N=1,282), size did not influence complications-though large cranioplasties showed higher infection risk (p=0.02). Overall, autograft use did not affect outcomes, but was associated with higher complication risk-including infections-in the subset with only emergent indications (p<0.001, p=0.001). Late (>90 days) cranioplasty timing had higher complication rates in both the overall cohort and subset with emergent indications (p<0.001, p<0.001). Index costs of care were mainly driven by hospital payments in both the overall cohort and those with emergent indications.We found a high complication rate associated with cranioplasty in the U.S.A. Older age, large cranioplasties, and delayed cranioplasties increased complication risk overall. Among those with only emergent indications, complications were associated with a delayed time to cranioplasty and autograft usage.

  View details for DOI 10.1016/j.wneu.2017.03.022

  View details for PubMedID 28315803

• Outpatient vs Inpatient Anterior Cervical Discectomy and Fusion: A Population-Level Analysis of Outcomes and Cost. Neurosurgery Purger, D. A., Pendharkar, A. V., Ho, A. L., Sussman, E. S., Yang, L., Desai, M., Veeravagu, A., Ratliff, J. K., Desai, A. 2017

  Abstract

  Outpatient anterior cervical discectomy and fusion (ACDF) is a promising candidate for US healthcare cost reduction as several studies have demonstrated that overall complications are relatively low and early discharge can preserve high patient satisfaction, low morbidity, and minimal readmission.To compare clinical outcomes and associated costs between inpatient and ambulatory setting ACDF.Demographics, comorbidities, emergency department (ED) visits, readmissions, reoperation rates, and 90-d charges were retrospectively analyzed for patients undergoing elective ACDF in California, Florida, and New York from 2009 to 2011 in State Inpatient and Ambulatory Databases.A total of 3135 ambulatory and 46 996 inpatient ACDFs were performed. Mean Charlson comorbidity index, length of stay, and mortality were 0.2, 0.4 d, and 0% in the ambulatory cohort and 0.4, 1.8 d, and 0.04% for inpatients ( P < .0001). Ambulatory patients were younger (48.0 vs 53.1) and more likely to be Caucasian. One hundred sixty-eight ambulatory patients (5.4%) presented to the ED within 30 d (mean 11.3 d), 51 (1.6%) were readmitted, and 5 (0.2%) underwent reoperation. Among inpatient surgeries, 2607 patients (5.5%) presented to the ED within 30 d (mean 9.7 d), 1778 (3.8%) were readmitted (mean 6.3 d), and 200 (0.4%) underwent reoperation. Higher Charlson comorbidity index increased rate of ED visits (ambulatory operating room [OR] 1.285, P < .05; inpatient OR 1.289, P < .0001) and readmission (ambulatory OR 1.746, P < .0001; inpatient OR 1.685, P < .0001). Overall charges were significantly lower for ambulatory ACDFs ($33 362.51 vs $74 667.04; P < .0001).ACDF can be performed in an ambulatory setting with comparable morbidity and readmission rates, and lower costs, to those performed in an inpatient setting.

  View details for DOI 10.1093/neuros/nyx215

  View details for PubMedID 28498922

• Predicting complication risk in spine surgery: a prospective analysis of a novel risk assessment tool. Journal of neurosurgery. Spine Veeravagu, A., Li, A., Swinney, C., Tian, L., Moraff, A., Azad, T. D., Cheng, I., Alamin, T., Hu, S. S., Anderson, R. L., Shuer, L., Desai, A., Park, J., Olshen, R. A., Ratliff, J. K. 2017: 1-11

  Abstract

  OBJECTIVE The ability to assess the risk of adverse events based on known patient factors and comorbidities would provide more effective preoperative risk stratification. Present risk assessment in spine surgery is limited. An adverse event prediction tool was developed to predict the risk of complications after spine surgery and tested on a prospective patient cohort. METHODS The spinal Risk Assessment Tool (RAT), a novel instrument for the assessment of risk for patients undergoing spine surgery that was developed based on an administrative claims database, was prospectively applied to 246 patients undergoing 257 spinal procedures over a 3-month period. Prospectively collected data were used to compare the RAT to the Charlson Comorbidity Index (CCI) and the American College of Surgeons National Surgery Quality Improvement Program (ACS NSQIP) Surgical Risk Calculator. Study end point was occurrence and type of complication after spine surgery. RESULTS The authors identified 69 patients (73 procedures) who experienced a complication over the prospective study period. Cardiac complications were most common (10.2%). Receiver operating characteristic (ROC) curves were calculated to compare complication outcomes using the different assessment tools. Area under the curve (AUC) analysis showed comparable predictive accuracy between the RAT and the ACS NSQIP calculator (0.670 [95% CI 0.60-0.74] in RAT, 0.669 [95% CI 0.60-0.74] in NSQIP). The CCI was not accurate in predicting complication occurrence (0.55 [95% CI 0.48-0.62]). The RAT produced mean probabilities of 34.6% for patients who had a complication and 24% for patients who did not (p = 0.0003). The generated predicted values were stratified into low, medium, and high rates. For the RAT, the predicted complication rate was 10.1% in the low-risk group (observed rate 12.8%), 21.9% in the medium-risk group (observed 31.8%), and 49.7% in the high-risk group (observed 41.2%). The ACS NSQIP calculator consistently produced complication predictions that underestimated complication occurrence: 3.4% in the low-risk group (observed 12.6%), 5.9% in the medium-risk group (observed 34.5%), and 12.5% in the high-risk group (observed 38.8%). The RAT was more accurate than the ACS NSQIP calculator (p = 0.0018). CONCLUSIONS While the RAT and ACS NSQIP calculator were both able to identify patients more likely to experience complications following spine surgery, both have substantial room for improvement. Risk stratification is feasible in spine surgery procedures; currently used measures have low accuracy.

  View details for DOI 10.3171/2016.12.SPINE16969

  View details for PubMedID 28430052

• An assessment of data and methodology of online surgeon scorecards JOURNAL OF NEUROSURGERY-SPINE Xu, L. W., Li, A., Swinney, C., Babu, M., Veeravagu, A., Wolfe, S. Q., Nahed, B. V., Ratliff, J. K. 2017; 26 (2): 235-242

  Abstract

  OBJECTIVE Recently, 2 surgeon rating websites (Consumers' Checkbook and ProPublica) were published to allow the public to compare surgeons through identifying surgeon volume and complication rates. Among neurosurgeons and orthopedic surgeons, only cervical and lumbar spine, hip, and knee procedures were included in this assessment. METHODS The authors examined the methodology of each website to assess potential sources of inaccuracy. Each online tool was queried for reports on neurosurgeons specializing in spine surgery and orthopedic surgeons specializing in spine, hip, or knee surgery. Surgeons were chosen from top-ranked hospitals in the US, as recorded by a national consumer publication ranking system, within the fields of neurosurgery and orthopedic surgery. The results were compared for accuracy and surgeon representation, and the results of the 2 websites were also compared. RESULTS The methodology of each site was found to have opportunities for bias and limited risk adjustment. The end points assessed by each site were actually not complications, but proxies of complication occurrence. A search of 510 surgeons (401 orthopedic surgeons [79%] and 109 neurosurgeons [21%]) showed that only 28% and 56% of surgeons had data represented on Consumers' Checkbook and ProPublica, respectively. There was a significantly higher chance of finding surgeon data on ProPublica (p < 0.001). Of the surgeons from top-ranked programs with data available, 17% were quoted to have high complication rates, 13% with lower volume than other surgeons, and 79% had a 3-star out of 5-star rating. There was no significant correlation found between the number of stars a surgeon received on Consumers' Checkbook and his or her adjusted complication rate on ProPublica. CONCLUSIONS Both the Consumers' Checkbook and ProPublica websites have significant methodological issues. Neither site assessed complication occurrence, but rather readmissions or prolonged length of stay. Risk adjustment was limited or nonexistent. A substantial number of neurosurgeons and orthopedic surgeons from top-ranked hospitals have no ratings on either site, or have data that suggests they are low-volume surgeons or have higher complication rates. Consumers' Checkbook and ProPublica produced different results with little correlation between the 2 websites in how surgeons were graded. Given the significant methodological issues, incomplete data, and lack of appropriate risk stratification of patients, the featured websites may provide erroneous information to the public.

  View details for DOI 10.3171/2016.7.SPINE16183

  View details for Web of Science ID 000393088900015

• Biopsy versus resection for themanagement of low-grade gliomas COCHRANE DATABASE OF SYSTEMATIC REVIEWS Jiang, B., Chaichana, K., Veeravagu, A., Chang, S. D., Black, K. L., Patil, C. G. 2017

  Abstract

  This is an updated version of the original Cochrane review published in 2013, Issue 4.Low-grade gliomas (LGG) constitute a class of slow-growing primary brain neoplasms. Patients with clinically and radiographically suspected LGG have two initial surgical options, biopsy or resection. Biopsy can provide a histological diagnosis with minimal risk but does not offer a direct treatment. Resection may have additional benefits such as increasing survival and delaying recurrence, but is associated with a higher risk for surgical morbidity. There remains controversy about the role of biopsy versus resection and the relative clinical outcomes for the management of LGG.To assess the clinical effectiveness of biopsy compared to surgical resection in patients with a new lesion suspected to be a LGG.The following electronic databases were searched in 2012 for the first version of the review: Cochrane Central Register of Controlled Trials (CENTRAL) (2012, Issue 11), MEDLINE (1950 to November week 3 2012), Embase (1980 to Week 46 2012). For this updated version, the following electronic databases were searched: Cochrane Central Register of Controlled Trials (CENTRAL) (2016, Issue 5), MEDLINE (Nov 2012 to June week 3 2016), Embase (Nov 2012 to 2016 week 26). All relevant articles were identified on PubMed and by using the 'related articles' feature. We also searched unpublished and grey literature including ISRCTN-metaRegister of Controled Trials, Physicians Data Query and ClinicalTrials.gov for ongoing trials.We planned to include patients of any age with a suspected intracranial LGG receiving biopsy or resection within a randomized clinical trial (RCT) or controlled clinical trial (CCT). Patients with prior resections, radiation therapy, or chemotherapy for LGG were excluded. Outcome measures included overall survival (OS), progression-free survival (PFS), functionally independent survival (FIS), adverse events, symptom control, and quality of life (QoL).A total of 1375 updated citations were searched and critically analyzed for relevance. This was undertaken independently by two review authors. The original electronic database searches yielded a total of 2764 citations. In total, 4139 citations have been critically analyzed for this updated review.No new RCTs of biopsy or resection for LGG were identified. No additional ineligible non-randomized studies (NRS) were included in this updated review. Twenty other ineligible studies were previously retrieved for further analysis despite not meeting the pre-specified criteria. Ten studies were retrospective or were literature reviews. Three studies were prospective, however they were limited to tumor recurrence and volumetric analysis and extent of resection. One study was a population-based parallel cohort in Norway, but not an RCT. Four studies were RCTs, however patients were randomized with respect to varying radiotherapy regimens to assess timing and dose of radiation. One RCT was on high-grade gliomas (HGGs) and not LGG. Finally, one RCT evaluated diffusion tensor imaging (DTI)-based neuro-navigation for surgical resection.Since the last version of this review, no new studies have been identified for inclusion and currently there are no RCTs or CCTs available on which to base definitive clinical decisions. Therefore, physicians must approach each case individually and weigh the risks and benefits of each intervention until further evidence is available. Some retrospective studies and non-randomized prospective studies do seem to suggest improved OS and seizure control correlating to higher extent of resection. Future research could focus on RCTs to determine outcomes benefits for biopsy versus resection.

  View details for DOI 10.1002/14651858.CD009319.pub3

  View details for Web of Science ID 000400759700029

  View details for PubMedID 28447767

• Endoscopic vs. Microscopic Resection of Sellar Lesions-A Matched Analysis of Clinical and Socioeconomic Outcomes. Frontiers in surgery Azad, T. D., Lee, Y. J., Vail, D. n., Veeravagu, A. n., Hwang, P. H., Ratliff, J. K., Li, G. n. 2017; 4: 33

  Abstract

  Direct comparisons of microscopic and endoscopic resection of sellar lesions are scarce, with conflicting reports of cost and clinical outcome advantages.To determine if the proposed benefits of endoscopic resection are realized on a population level.We performed a matched cohort study of 9,670 adult patients in the MarketScan database who underwent either endoscopic or microscopic surgery for sellar lesions. Coarsened matching was applied to estimate the effects of surgical approach on complication rates, length of stay (LOS), costs, and likelihood of postoperative radiation.We found that LOS, readmission, and revision rates did not differ significantly between approaches. The overall complication rate was higher for endoscopy (47% compared to 39%, OR 1.37, 95% CI 1.22-1.53). Endoscopic approach was associated with greater risk of neurological complications (OR 1.32, 95% CI 1.11-1.55), diabetes insipidus (OR 1.65, 95% CI 1.37-2.00), and cerebrospinal fluid rhinorrhea (OR 1.83, 95% CI 1.07-3.13) compared to the microscopic approach. Although the total index payment was higher for patients receiving endoscopic resection ($32,959 compared to $29,977 for microscopic resection), there was no difference in long-term payments. Endoscopic surgery was associated with decreased likelihood of receiving post-resection stereotactic radiosurgery (OR 0.67, 95% CI 0.49-0.90) and intensity-modulated radiation therapy (OR 0.78, 95% CI 0.65-0.93).Our results suggest that the transition from a microscopic to endoscopic approach to sellar lesions must be subject to careful evaluation. Although there are evident advantages to transsphenoidal endoscopy, our analysis suggests that the benefits of the endoscopic approach are yet to be materialized.

  View details for PubMedID 28691009

• Microsurgical vs. Endoscopic Excision of Colloid Cysts: An Analysis of Complications and Costs Using a Longitudinal Administrative Database. Frontiers in neurology Connolly, I. D., Johnson, E. n., Lamsam, L. n., Veeravagu, A. n., Ratliff, J. n., Li, G. n. 2017; 8: 259

  Abstract

  Open microsurgical and endoscopic approaches are the two main surgical options for excision of colloid cysts. Controversy remains as to which is superior. Previous studies consist of small cohort sizes. This topic has not been investigated using national administrative claims data which benefits from larger patient numbers.Current Procedural Terminology (CPT) and International Classification of Disease version 9 (ICD-9) coding at inpatient visit was used to select for index surgical procedures corresponding to microsurgical or endoscopic excision of colloid cysts. Comorbidities, costs, and complications were collected.We identified a total of 483 patients. In all, 240 were from the microsurgical cohort and 243 were from the endoscopic cohort. The two groups displayed similar demographic and comorbidity profiles. Thirty-day post-operative complications were also similar between groups with the exception of seizures and thirty-day readmissions, both higher in the open surgical cohort. The seizure rates were 14.7 and 5.4% in the microsurgical and endoscopic cohorts, respectively (p = 0.0011). The thirty-day readmission rates were 17.3 and 9.6% in the microsurgical and endoscopic cohorts, respectively (p = 0.0149). Index admission costs and 90-day post discharge payments were higher in patients receiving microsurgical excision.An analysis of administrative claims data revealed few differences in surgical complications following colloid cyst excision via microsurgical and endoscopic approaches. Post-operative seizures and thirty-day readmissions were seen at higher frequency in patients who underwent microsurgical resection. Despite similar complication profiles, patients undergoing microsurgical excision experienced higher index admission costs and 90-day aggregated costs suggesting that complications may have been more severe in this group.

  View details for PubMedID 28649225

• Outcomes of cervical laminoplasty-Population-level analysis of a national longitudinal database. Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia Veeravagu, A. n., Azad, T. D., Zhang, M. n., Li, A. n., Pendharkar, A. V., Ratliff, J. K., Shuer, L. M. 2017

  Abstract

  Cervical laminoplasty is an important alternative to laminectomy in decompressing of the cervical spine. Further evidence to assess the utility of laminoplasty is required. We examine outcomes of cervical laminoplasty via a population level analysis in the United States.We performed a population-level analysis using the national MarketScan longitudinal database to analyze outcomes and costs of cervical laminoplasty between 2007 and 2014. Outcomes included postoperative complications, revision rates, and functional outcomes.Using a national administrative database, we identified 2613 patients (65.6% male, mean 58.5 years) who underwent cervical laminoplasty. Mean length of stay was 3.1 ± 2.8 days and mean follow-up was 795.5 ± 670.6 days. The overall complication rate was 22.5% (N = 587), 30-day readmission rate was 7.5% (N = 195), and mortality rate was 0.08% (N = 2, elderly patients only). The complication rate was significantly increased in elderly patients (age >65 years) compared to non-elderly patients (OR 0.751, p < .01). The use of intraoperative neuromonitoring (IONM) during the cervical laminoplasty procedure did not significantly impact outcomes. The overall re-operation rate after the initial procedure was 10.9%. Total costs of cervical laminoplasty were mainly driven by hospital charges with physician-related payments comprising a small amount.Our national analysis of cervical laminoplasty found the procedure to be clinically effective with low complication rates and postoperative symptomatic improvement.

  View details for PubMedID 29153782

• Postoperative Opioid Use, Complications, and Costs in Surgical Management of Lumbar Spondylolisthesis. Spine Vail, D. n., Azad, T. D., O'Connell, C. n., Han, S. S., Veeravagu, A. n., Ratliff, J. K. 2017

  Abstract

  Retrospective analysis on a national longitudinal database (2007-2014).To determine the association between arthrodesis and complication rates, costs, surgical revision, and postoperative opioid prescription.Arthrodesis in patients receiving laminectomy for lumbar spondylolisthesis remains controversial. However, population-level evidence to support the use of arthrodesis remains limited.We identified 73,176 patient records and used coarsened exact matching to create comparable populations of patients who received laminectomy or laminectomy with arthrodesis. We use linear and logistic regression models to analyze the relationship between arthrodesis and postoperative complications, length of stay, costs, readmissions, surgical revisions, and postoperative opioid prescribing.Patients who underwent arthrodesis spent one more day in the hospital on average (p < 0.01), and had higher costs of care at their index visit ($24,126, p < 0.01), which were partially offset by lower costs of care over the two years following their procedure ($14,667 less in arthrodesis patients, p = 0.01). Patients with arthrodesis were less likely to have a surgical revision (OR = 0.66, p < 0.01). Patients with arthrodesis used more opioids in the first two months following their procedure, but had comparable opioid use to patients undergoing laminectomy without arthrodesis in all other post-operative months over the next two years, and were not more or less likely to convert to chronic opioid use. Postoperative opioid prescription varied dramatically across states (p < 0.01); geographic variation in opioid use is substantially greater than differences in opioid use based on procedure performed.Arthrodesis is associated with reduced likelihood of surgical revision and increased use of opioids in the first two months following surgery, but not associated with greater or lesser opioid use beyond the initial two postoperative months. Geographic variation in opioid use is substantial even after accounting for patient characteristics and for whether patients underwent arthrodesis.3.

  View details for PubMedID 29215492

• Diagnostic Utility of Intraoperative Neurophysiological Monitoring for Intramedullary Spinal Cord Tumors: Systematic Review and Meta-Analysis. Clinical spine surgery Azad, T. D., Pendharkar, A. V., Nguyen, V. n., Pan, J. n., Connolly, I. D., Veeravagu, A. n., Popat, R. n., Ratliff, J. K., Grant, G. A. 2017

  Abstract

  Systematic review and meta-analysis.The aim of this study was to systematically evaluate the diagnostic utility of intraoperative neurophysiological monitoring (IONM) for detecting postoperative injury in resection of intramedullary spinal cord tumors (IMSCT).Surgical management of IMSCT can involve key neurological and vascular structures. IONM aims to assess the functional integrity of susceptible elements in real time. The diagnostic value of IONM for ISMCT has not been systematically evaluated.We performed a systematic review of the PubMed and MEDLINE databases for studies investigating the use of IONM for IMSCT and conducted a meta-analysis of diagnostic capability.Our search produced 257 citations. After application of exclusion criteria, 21 studies remained, 10 American Academy of Neurology grade III and 11 American Academy of Neurology grade IV. We found that a strong pooled mean sensitivity of 90% [95% confidence interval (CI), 84-94] and a weaker pooled mean specificity of 82% (95% CI, 70-90) for motor-evoked potential (MEP) recording changes. Somatosensory-evoked potential (SSEP) recording changes yielded pooled sensitivity of 85% (95% CI, 75-91) and pooled specificity of 72% (95% CI, 57-83). The pooled diagnostic odds ratio for MEP was 55.7 (95% CI, 26.3-119.1) and 14.3 (95% CI, 5.47-37.3) for SSEP. Bivariate analysis yielded summary receiver operative characteristic curves with area under the curve of 91.8% for MEPs and 86.3% for SSEPs.MEPs and SSEPs appear to be more sensitive than specific for detection of postoperative injury. Patients with perioperative neurological deficits are 56 times more likely to have had changes in MEPs during the procedure. We observed considerable variability in alarm criteria and interventions in response to IONM changes, indicating the need for prospective studies capable of defining standardized alarm criteria and responses.

  View details for PubMedID 28650882

• Spontaneous Intrauterine Depressed Skull Fractures: Report of Two Cases Requiring Neurosurgical Intervention and Literature Review. World neurosurgery Veeravagu, A. n., Azad, T. D., Jiang, B. n., Edwards, M. S. 2017

  Abstract

  Spontaneous intrauterine depressed skull fractures (IDSF) are rare fractures that often require neurosurgical evaluation and therapy. The majority of reported congenital depressions are secondary to maternal abdominal trauma or instrumentation during delivery. Spontaneous IDSF occur in the setting of uneventful normal spontaneous vaginal delivery (NSVD) or cesarean section, without obvious predisposing risk factors. The etiology and optimal management of spontaneous IDSF remain controversial.We describe 2 cases of spontaneous IDSF that underwent cranioplasty at our institution using an absorbable mesh, as well as review the current state of knowledge regarding the diagnosis and management of spontaneous IDSF. The 2 neonates, 1 male and 1 female, presented at Lucile Packard Children's Hospital with spontaneous IDSF after uneventful NSVDs. The fractures were located in the left frontal and right parieto-temporal calvarium, respectively. Both patients underwent open craniotomy and elevation of their IDSF with mesh cranioplasty. At last follow-up, both patients were normocephalic and neurologically intact.Neurosurgery consultation is necessary for initial evaluation of spontaneous IDSF. Surgical intervention is indicated for larger defects and/or intracranial involvement. Expectant management and negative-pressure elevation have also been shown to be effective.

  View details for DOI 10.1016/j.wneu.2017.10.029

  View details for PubMedID 29051109

• Neurosurgical Randomized Controlled Trials-Distance Travelled. Neurosurgery Azad, T. D., Veeravagu, A. n., Mittal, V. n., Esparza, R. n., Johnson, E. n., Ioannidis, J. P., Grant, G. A. 2017

  Abstract

  The evidence base for many neurosurgical procedures has been limited. We performed a comprehensive and systematic analysis of study design, quality of reporting, and trial results of neurosurgical randomized controlled trials (RCTs).To systematically assess the design and quality characteristics of neurosurgical RCTs.From January 1961 to June 2016, RCTs with >5 patients assessing any 1 neurosurgical procedure against another procedure, nonsurgical treatment, or no treatment were retrieved from MEDLINE, Scopus, and Cochrane Library.The median sample size in the 401 eligible RCTs was 73 patients with a mean patient age of 49.6. Only 111 trials (27.1%) described allocation concealment, 140 (34.6%) provided power calculations, and 117 (28.9%) were adequately powered. Significant efficacy or trend for efficacy was claimed in 226 reports (56.4%), no difference between the procedures was found in 166 trials (41.4%), and significant harm was reported in 9 trials (2.2%). Trials with a larger sample size were more likely to report randomization mode, specify allocation concealment, and power calculations (all P < .001). Government funding was associated with better specification of power calculations ( P = .008) and of allocation concealment ( P = .026), while industry funding was associated with reporting significant efficacy ( P = .02). Reporting of funding, specification of randomization mode and primary outcomes, and mention of power calculations improved significantly (all, P < .05) over time.Several aspects of the design and reporting of RCTs on neurosurgical procedures have improved over time. Better powered and accurately reported trials are needed in neurosurgery to deliver evidence-based care and achieve optimal outcomes.

  View details for PubMedID 28645203

• CyberKnife stereotactic radiosurgery for the treatment of symptomatic vertebral hemangiomas: a single-institution experience NEUROSURGICAL FOCUS Zhang, M., Chen, Y., Chang, S. D., Veeravagu, A. 2017; 42 (1)

  Abstract

  OBJECTIVE Symptomatic vertebral hemangiomas (SVHs) are a very rare pathology that can present with persistent pain or neurological deficits that warrant surgical intervention. Given the relative rarity and difficulty in assessment, the authors sought to present a dedicated series of SVHs treated using stereotactic radiosurgery (SRS) to provide insight into clinical decision making. METHODS A retrospective review of a single institution's experience with hypofractionated radiosurgery for SVH from 2004 to 2011 was conducted to determine the clinical and radiographic outcomes following SRS treatment. The authors report and analyze the treatment course of 5 patients with 7 lesions, 2 of which were treated primarily by SRS. RESULTS Of the 5 patients studied, 4 presented with a chief complaint of pain refractory to conservative measures. Three patients reported dysesthesias, and 2 reported upper-extremity weakness. Following radiosurgery, 4 of 5 patients exhibited improvement in their primary symptoms (3 for pain and 1 for weakness), achieving a clinical response after a mean period of 1 year. In 2 cases there was 20%-40% reduction in lesion size in the most responsive dimension as noted on images. All treatments were well tolerated. CONCLUSIONS SRS for SVH is a safe and feasible treatment strategy, comparable to prior radiotherapy studies, and in select cases may successfully confer delayed decompressive effects. Additional investigation will determine future patient selection and how conformal SRS treatment can best be administered.

  View details for DOI 10.3171/2016.9.FOCUS16372

  View details for Web of Science ID 000392113200013

  View details for PubMedID 28041316

• Cervical Osteochondroma Causing Myelopathy in Adults: Management Considerations and Literature Review WORLD NEUROSURGERY Veeravagu, A., Li, A., Shuer, L. M., Desai, A. M. 2017; 97

  Abstract

  Osteochondromas are the most frequent benign bone tumors but only rarely occur along the spinal column and even more rarely induce symptoms from spinal cord compression.We report 2 adult patients, both with a history of hereditary multiple exostoses, who presented with cervical myelopathy secondary to osteochondromas. The first patient is a 22-year-old man with numbness and weakness of his right upper limb and neck pain. Radiologic images showed a bony tumor arising from the C3 lamina with evidence of severe spinal cord compression. The second patient is a 20-year-old woman with weakness of her left upper and lower limbs and progressive numbness of the left hand, as well as neck and back pain. Radiologic images showed a bony tumor arising from the C4 lamina with evidence of significant spinal cord compression and cord signal abnormality. Both patients underwent surgical excision of the epidural mass and pathology confirmed a diagnosis of osteochondroma.We discuss the role of surgical intervention, management, and postoperative follow-up in adult patients with cervical osteochondromas. Recommended management includes radiographic imaging and surgical intervention, particularly when evidence of spinal cord impingement occurs. Consistent postoperative follow-up is necessary to ensure appropriate recovery of neurologic function. Surgical management of cervical osteochondromas typically results in excellent and stable clinical outcomes with rare recurrence.

  View details for DOI 10.1016/j.wneu.2016.10.061

  View details for Web of Science ID 000396449400122

• Optimization of tumor resection with intra-operative magnetic resonance imaging JOURNAL OF CLINICAL NEUROSCIENCE Swinney, C., Li, A., Bhatti, I., Veeravagu, A. 2016; 34: 11-14

  Abstract

  Intra-operative MRI (ioMRI) may be used to optimize tumor resection. Utilization of this technology allows for the removal of residual tumor mass following initial tumor removal, maximizing the extent of resection. This, in turn, has been shown to lead to improved outcomes. Individual studies have examined the impact of ioMRI on the rate of extended resection, but a comprehensive review of this topic is needed. A literature review of the MEDLINE, EMBASE, CENTRAL, and Google Scholar databases revealed 12 eligible studies. This included 804 primary operations and 238 extended resections based on ioMRI findings. Use of ioMRI led to extended tumor resection in 13.3-54.8% of patients (mean 37.3%). Stratification by tumor type showed additional resection occurred, on average, in 39.1% of glioma resections (range 13.3-70.0%), 23.5% of pituitary tumor resections (range 13.3-33.7%), and 35.0% of nonspecific tumor resections (range 17.5-40%). Tumor type (glioma vs. pituitary) did not significantly influence the rate of further excision following ioMRI (p=0.309). There was no difference in secondary resection rate between studies limited to pediatric patients and those including adults (p=0.646). Thus, the use of intra-operative MRI frequently results in further resection of tumors. It is primarily used for the resection of gliomas and pituitary tumors. Tumor type does not appear to be a significant contributing factor to the rate of secondary tumor removal. Limited evidence suggests that extended resection may translate into improved clinical outcomes and mortality rates. However, results have not been unanimous, while clinical effect sizes have often been modest.

  View details for DOI 10.1016/j.jocn.2016.05.030

  View details for Web of Science ID 000389093300003

  View details for PubMedID 27469412

• Neuroregeneration: North America's First Human Stem Cell Trial for Stroke NEUROSURGERY Chang, H., Veeravagu, A., Wang, M. Y. 2016; 79 (6): N21–N22

  View details for DOI 10.1227/01.neu.0000508607.84436.6d

  View details for Web of Science ID 000392614700013

  View details for PubMedID 27861413

• Cervical Fracture/Subluxation in a Patient with a Prior C2-Sacrum Fusion: Case Report and Review of Literature. Cureus Chen, Y., Chan, A. Y., Kumar, K. K., Veeravagu, A. 2016; 8 (11)

  Abstract

  Traumatic injury to an adjacent segment of a previously fused spine is a rare complication of scoliosis surgery. The adjacent spinal segments may be more vulnerable to traumatic fracture or dislocation due to increased strain. We present a patient with prior C2 to sacrum fusion who suffered a C2 fracture/dislocation after falling. A 52-year-old female with a previous C2 to the sacrum fusion for idiopathic scoliosis presented with severe and progressively worsening neck pain after multiple falls. Imaging showed anterior displacement of the C2 vertebral body, fracture of C2, and anterior subluxation of the C1-2 complex on C3. The patient underwent posterior occiput to cervical fusion and reduction of the C1-C2 complex. Our case describes a potential complication of long-segment fusion. Adjacent segments may be more prone to fracture-dislocation because of increased intradiscal pressure and strain. Clinicians should have a high suspicion of fractures in patients with prior spinal fusions in the setting of trauma.

  View details for DOI 10.7759/cureus.888

  View details for PubMedID 28018758

  View details for PubMedCentralID PMC5179249

• Cervical Osteochondroma Causing Myelopathy in Adults: Management Considerations and Literature Review. World neurosurgery Veeravagu, A., Li, A., Shuer, L. M., Desai, A. M. 2016

  Abstract

  Osteochondromas are the most frequent benign bone tumors but only rarely occur along the spinal column and even more rarely induce symptoms from spinal cord compression.We report 2 adult patients, both with a history of hereditary multiple exostoses, who presented with cervical myelopathy secondary to osteochondromas. The first patient is a 22-year-old man with numbness and weakness of his right upper limb and neck pain. Radiologic images showed a bony tumor arising from the C3 lamina with evidence of severe spinal cord compression. The second patient is a 20-year-old woman with weakness of her left upper and lower limbs and progressive numbness of the left hand, as well as neck and back pain. Radiologic images showed a bony tumor arising from the C4 lamina with evidence of significant spinal cord compression and cord signal abnormality. Both patients underwent surgical excision of the epidural mass and pathology confirmed a diagnosis of osteochondroma.We discuss the role of surgical intervention, management, and postoperative follow-up in adult patients with cervical osteochondromas. Recommended management includes radiographic imaging and surgical intervention, particularly when evidence of spinal cord impingement occurs. Consistent postoperative follow-up is necessary to ensure appropriate recovery of neurologic function. Surgical management of cervical osteochondromas typically results in excellent and stable clinical outcomes with rare recurrence.

  View details for DOI 10.1016/j.wneu.2016.10.061

  View details for PubMedID 27777159

• Impact of Inpatient Venous Thromboembolism Continues After Discharge: Retrospective Propensity Scored Analysis in a Longitudinal Database. Clinical spine surgery Li, A. Y., Azad, T. D., Veeravagu, A., Bhatti, I., Li, A., Cole, T., Desai, A., Ratliff, J. K. 2016: -?

  Abstract

  Propensity score matched retrospective study using a nationwide longitudinal database.To quantify the longitudinal economic impact of venous thromboembolism (VTE) complications in spinal fusion patients.VTE is a rare and serious complication that may occur after spine surgery. The long-term socioeconomic impact understanding of these events has been limited by small sample sizes and a lack of longitudinal follow-up. We provide a comparative economic outcomes analysis of these complications.We identified 204,308 patients undergoing spinal fusion procedures in a national billing claims database (MarketScan) between 2006 and 2010. Cohorts were balanced using 50:1 propensity score matching and outcome measures compared at 6, 12, and 18 months postoperation.A total of 1196 (0.6%) patients developed postoperative VTE, predominantly occurring following lumbar fusion (69.7%). Postoperative VTE patients demonstrated an increase in hospital length of stay (7.8 vs. 3.3 d, P<0.001) and a decreased likelihood of being discharged home (71% vs. 85%, P<0.001). A $26,306 increase in total hospital payments (P<0.001) was observed, with a disproportionate increase seen in hospital payments ($22,103, P<0.001), relative to physician payments ($1766, P=0.001).At 6, 12, and 18 months postfusion, increased rates of readmission and follow-up clinic visits were observed. Delayed readmissions were associated with decreased length of stay (3.6 vs. 4.6 d, P<0.001), but increased total payments, averaging at $21,270 per readmission. VTE patients generated greater cumulative outpatient service payments, costing $8075, $11,134, and $13,202 more at 6, 12, and 18 months (P<0.001).VTEs are associated with longer hospitalizations, a decreased likelihood of being discharged home, and overall increases of hospital resource utilization and cost in inpatient and outpatient settings. VTE patients generate greater charges in the outpatient setting and are more likely to become readmitted at 6, 12, and 18 months after surgery, demonstrating a significant socioeconomic impact long after occurrence.Level III-therapeutic.

  View details for PubMedID 27750270

• An assessment of data and methodology of online surgeon scorecards. Journal of neurosurgery. Spine Xu, L. W., Li, A., Swinney, C., Babu, M., Veeravagu, A., Wolfe, S. Q., Nahed, B. V., Ratliff, J. K. 2016: 1-8

  Abstract

  OBJECTIVE Recently, 2 surgeon rating websites (Consumers' Checkbook and ProPublica) were published to allow the public to compare surgeons through identifying surgeon volume and complication rates. Among neurosurgeons and orthopedic surgeons, only cervical and lumbar spine, hip, and knee procedures were included in this assessment. METHODS The authors examined the methodology of each website to assess potential sources of inaccuracy. Each online tool was queried for reports on neurosurgeons specializing in spine surgery and orthopedic surgeons specializing in spine, hip, or knee surgery. Surgeons were chosen from top-ranked hospitals in the US, as recorded by a national consumer publication ranking system, within the fields of neurosurgery and orthopedic surgery. The results were compared for accuracy and surgeon representation, and the results of the 2 websites were also compared. RESULTS The methodology of each site was found to have opportunities for bias and limited risk adjustment. The end points assessed by each site were actually not complications, but proxies of complication occurrence. A search of 510 surgeons (401 orthopedic surgeons [79%] and 109 neurosurgeons [21%]) showed that only 28% and 56% of surgeons had data represented on Consumers' Checkbook and ProPublica, respectively. There was a significantly higher chance of finding surgeon data on ProPublica (p < 0.001). Of the surgeons from top-ranked programs with data available, 17% were quoted to have high complication rates, 13% with lower volume than other surgeons, and 79% had a 3-star out of 5-star rating. There was no significant correlation found between the number of stars a surgeon received on Consumers' Checkbook and his or her adjusted complication rate on ProPublica. CONCLUSIONS Both the Consumers' Checkbook and ProPublica websites have significant methodological issues. Neither site assessed complication occurrence, but rather readmissions or prolonged length of stay. Risk adjustment was limited or nonexistent. A substantial number of neurosurgeons and orthopedic surgeons from top-ranked hospitals have no ratings on either site, or have data that suggests they are low-volume surgeons or have higher complication rates. Consumers' Checkbook and ProPublica produced different results with little correlation between the 2 websites in how surgeons were graded. Given the significant methodological issues, incomplete data, and lack of appropriate risk stratification of patients, the featured websites may provide erroneous information to the public.

  View details for PubMedID 27661563

• Complications, Readmissions, and Revisions for Spine Procedures Performed by Orthopedic Surgeons Versus Neurosurgeons: A Retrospective, Longitudinal Study. Clinical spine surgery Mabud, T., Norden, J., Veeravagu, A., Swinney, C., Cole, T., McCutcheon, B. A., Ratliff, J. 2016: -?

  Abstract

  Retrospective database analysis.To examine the impact of training pathway, either neurosurgical or orthopedic, on complications, readmissions, and revisions in spine surgery.Training pathway has been shown to have an impact on outcomes in various surgical subspecialties. Although training pathway has not been shown to have a significant impact on spine surgery outcomes in the perioperative period, long-term results are unknown.A retrospective analysis of 197,682 patients receiving 1 of 3 common spine surgeries [lumbar laminectomy, lumbar fusion, and anterior cervical discectomy and fusion (ACDF)] between 2006 and 2010 was conducted. Patient data were obtained from a large claims database. Postoperative adverse effects, all-cause readmission, revision surgery rates, and intermediary payments in these cohorts of patients were compared between spine surgeons with either neurosurgical or orthopedic backgrounds.Patient demographics, hospital-stay characteristics, and medical comorbidities were similar between neurosurgeons and orthopedic surgeons. The risks of surgical complications, all-cause readmission, and revision surgery were also similar between neurosurgeons and orthopedic surgeons across all procedure types assessed, with several minor exceptions: neurosurgeons had marginally higher odds of any complication for lumbar fusions [odds ratio (OR) 1.14; 95% confidence interval (CI), 1.09-1.20] and ACDFs (OR, 1.09; 95% CI, 1.04-1.15). Neurosurgeons also had slightly higher rates of revision surgery for concurrent lumbar laminectomy with fusion (OR, 1.14; 95% CI, 1.08-1.22), and ACDFs (OR, 1.20; 95% CI, 1.14-1.28). No associations between surgeon type and any particular complication were consistently observed for all procedure groups. There were also no associations between surgeon type and 30-day all-cause readmission. Median total intermediary payments were somewhat higher for neurosurgery patients for all procedure groups assessed.Few significant associations between surgeon type and patient outcomes exist in the context of spine surgery. Those which do are small and unlikely to be clinically meaningful.Level 3.

  View details for PubMedID 27623297

• Surgeon Procedure Volume and Complication Rates in Anterior Cervical Discectomy and Fusions: Analysis of a National Longitudinal Database. Clinical spine surgery Cole, T., Veeravagu, A., Zhang, M., Ratliff, J. K. 2016: -?

  Abstract

  Retrospective study using the MarketScan longitudinal database (2006-2010).Compare complication rates between groups of patients undergoing anterior cervical discectomy and fusion (ACDF) procedures performed by surgeons with high versus low mean annual ACDF volume.Over the past decade the volume of ACDFs performed has increased, concurrent with greater appreciation of potential for associated complications. The effect of surgeon procedure volume on adverse events occurrence in the post-operative period has not been described.We evaluated the relationship between surgeon procedure volume and post-operative incidence of any complication using a multivariate logistic regression model. 24,461 patients undergoing single and multiple level ACDFs were identified in the MarketScan database by Current Procedural Terminology coding. Annual surgeon volume was determined by tracking of anonymized surgeon identification numbers, with high-volume surgeons defined as those performing an average of at least 30 ACDF procedures annually.Over 50% of unique surgeon identifiers reported less than 9 ACDF operations per year, while the highest decile reported a range of 44 to 101. High surgeon volume was protective for any complication (OR.72, 95% CI 0.65-0.81 P<0.0001), with an adjusted number needed to harm of 44. Patients treated by high-volume physicians specifically had lower odds of dysphagia (2.22% vs. 3.08%, OR 0.71, P<0.0013), neurological complications (0.33% vs. 0.64%, OR 0.52, P<0.0107), new diagnosis of chronic pain (0.48% vs. 0.82%, OR 0.58, P<0.0119), pulmonary complications (1.10% vs. 1.58%, OR 0.69, P<0.0138), and other wound complications (0.06% vs. 0.22%, OR 0.28, P<0.0242).We demonstrate a possible association between higher surgeon procedure volume and decreased post-operative complications following anterior cervical discectomy and fusion. There was no difference observed in need for revision surgery or readmission rates.

  View details for PubMedID 25551324

• Delayed Presentation of Sciatic Nerve Injury after Total Hip Arthroplasty: Neurosurgical Considerations, Diagnosis, and Management. Journal of neurological surgery reports Xu, L. W., Veeravagu, A., Azad, T. D., Harraher, C., Ratliff, J. K. 2016; 77 (3): e134-8

  Abstract

  Total hip arthroplasty (THA) is an established treatment for end-stage arthritis, congenital deformity, and trauma with good long-term clinical and functional outcomes. Delayed sciatic nerve injury is a rare complication after THA that requires prompt diagnosis and management.We present a case of sciatic nerve motor and sensory deficit in a 52-year-old patient 2 years after index left THA. Electromyography (EMG) results and imaging with radiographs and CT of the affected hip demonstrated an aberrant acetabular cup screw in the posterior-inferior quadrant adjacent to the sciatic nerve.The patient underwent surgical exploration that revealed injury to the peroneal division of the sciatic nerve due to direct injury from screw impingement. A literature review identified 11 patients with late-onset neuropathy after THA. Ten patients underwent surgical exploration and pain often resolved after surgery with 56% of patients recovering sensory function and 25% experiencing full recovery of motor function.Delayed neuropathy of the sciatic nerve is a rare complication after THA that is most often due to hardware irritation, component failure, or wear-related pseudotumor formation. Operative intervention is often pursued to explore and directly visualize the nerve with limited results in the literature showing modest relief of pain and sensory symptoms and poor restoration of motor function.

  View details for DOI 10.1055/s-0035-1568134

  View details for PubMedID 27602309

  View details for PubMedCentralID PMC5011454

• Surgical outcomes of cervical spondylotic myelopathy: an analysis of a national, administrative, longitudinal database. Neurosurgical focus Veeravagu, A., Connolly, I. D., Lamsam, L., Li, A., Swinney, C., Azad, T. D., Desai, A., Ratliff, J. K. 2016; 40 (6): E11-?

  Abstract

  OBJECTIVE The authors performed a population-based analysis of national trends, costs, and outcomes associated with cervical spondylotic myelopathy (CSM) in the United States. They assessed postoperative complications, resource utilization, and predictors of costs, in this surgically treated CSM population. METHODS MarketScan data (2006-2010) were used to retrospectively analyze the complications and costs of different spine surgeries for CSM. The authors determined outcomes following anterior cervical discectomy and fusion (ACDF), posterior fusion, combined anterior/posterior fusion, and laminoplasty procedures. RESULTS The authors identified 35,962 CSM patients, comprising 5154 elderly (age ≥ 65 years) patients (mean 72.2 years, 54.9% male) and 30,808 nonelderly patients (mean 51.1 years, 49.3% male). They found an overall complication rate of 15.6% after ACDF, 29.2% after posterior fusion, 41.1% after combined anterior and posterior fusion, and 22.4% after laminoplasty. Following ACDF and posterior fusion, a significantly higher risk of complication was seen in the elderly compared with the nonelderly (reference group). The fusion level and comorbidity-adjusted ORs with 95% CIs for these groups were 1.54 (1.40-1.68) and 1.25 (1.06-1.46), respectively. In contrast, the elderly population had lower 30-day readmission rates in all 4 surgical cohorts (ACDF, 2.6%; posterior fusion, 5.3%; anterior/posterior fusion, 3.4%; and laminoplasty, 3.6%). The fusion level and comorbidity-adjusted odds ratios for 30-day readmissions for ACDF, posterior fusion, combined anterior and posterior fusion, and laminoplasty were 0.54 (0.44-0.68), 0.32 (0.24-0.44), 0.17 (0.08-0.38), and 0.39 (0.18-0.85), respectively. CONCLUSIONS The authors' analysis of the MarketScan database suggests a higher complication rate in the surgical treatment of CSM than previous national estimates. They found that elderly age (≥ 65 years) significantly increased complication risk following ACDF and posterior fusion. Elderly patients were less likely to experience a readmission within 30 days of surgery. Postoperative complication occurrence, and 30-day readmission were significant drivers of total cost within 90 days of the index surgical procedure.

  View details for DOI 10.3171/2016.3.FOCUS1669

  View details for PubMedID 27246481

• Predicting Occurrence of Spine Surgery Complications Using "Big Data" Modeling of an Administrative Claims Database JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME Ratliff, J. K., Balise, R., Veeravagu, A., Cole, T. S., Cheng, I., Olshen, R. A., Tian, L. 2016; 98 (10): 824-834

  Abstract

  Postoperative metrics are increasingly important in determining standards of quality for physicians and hospitals. Although complications following spinal surgery have been described, procedural and patient variables have yet to be incorporated into a predictive model of adverse-event occurrence. We sought to develop a predictive model of complication occurrence after spine surgery.We used longitudinal prospective data from a national claims database and developed a predictive model incorporating complication type and frequency of occurrence following spine surgery procedures. We structured our model to assess the impact of features such as preoperative diagnosis, patient comorbidities, location in the spine, anterior versus posterior approach, whether fusion had been performed, whether instrumentation had been used, number of levels, and use of bone morphogenetic protein (BMP). We assessed a variety of adverse events. Prediction models were built using logistic regression with additive main effects and logistic regression with main effects as well as all 2 and 3-factor interactions. Least absolute shrinkage and selection operator (LASSO) regularization was used to select features. Competing approaches included boosted additive trees and the classification and regression trees (CART) algorithm. The final prediction performance was evaluated by estimating the area under a receiver operating characteristic curve (AUC) as predictions were applied to independent validation data and compared with the Charlson comorbidity score.The model was developed from 279,135 records of patients with a minimum duration of follow-up of 30 days. Preliminary assessment showed an adverse-event rate of 13.95%, well within norms reported in the literature. We used the first 80% of the records for training (to predict adverse events) and the remaining 20% of the records for validation. There was remarkable similarity among methods, with an AUC of 0.70 for predicting the occurrence of adverse events. The AUC using the Charlson comorbidity score was 0.61. The described model was more accurate than Charlson scoring (p < 0.01).We present a modeling effort based on administrative claims data that predicts the occurrence of complications after spine surgery.We believe that the development of a predictive modeling tool illustrating the risk of complication occurrence after spine surgery will aid in patient counseling and improve the accuracy of risk modeling strategies.

  View details for DOI 10.2106/JBJS.15.00301

  View details for Web of Science ID 000378644500009

  View details for PubMedID 27194492

• Neurorestoration after stroke NEUROSURGICAL FOCUS Azad, T. D., Veeravagu, A., Steinberg, G. K. 2016; 40 (5)

  Abstract

  Recent advancements in stem cell biology and neuromodulation have ushered in a battery of new neurorestorative therapies for ischemic stroke. While the understanding of stroke pathophysiology has matured, the ability to restore patients' quality of life remains inadequate. New therapeutic approaches, including cell transplantation and neurostimulation, focus on reestablishing the circuits disrupted by ischemia through multidimensional mechanisms to improve neuroplasticity and remodeling. The authors provide a broad overview of stroke pathophysiology and existing therapies to highlight the scientific and clinical implications of neurorestorative therapies for stroke.

  View details for DOI 10.3171/2016.2.FOCUS15637

  View details for Web of Science ID 000375119300001

  View details for PubMedID 27132523

  View details for PubMedCentralID PMC4916840

• Abducens Nerve Avulsion and Facial Nerve Palsy After Temporal Bone Fracture: A Rare Concomitance of Injuries. World neurosurgery Azad, T. D., Veeravagu, A., Corrales, C. E., Chow, K. K., Fischbein, N. J., Harris, O. A. 2016; 88: 689 e5-8

  Abstract

  Avulsion of the abducens nerve in the setting of geniculate ganglion injury after temporal bone fracture is unreported previously. We discuss clinical assessment and management of a patient with traumatic avulsion of cranial nerve (CN) VI in the setting of an ipsilateral CN VII injury after temporal bone fracture and call attention to this unusual injury.A 26-year-old man suffered a temporal bone fracture after a motor vehicle accident and developed diplopia and right-sided facial droop. Six weeks after the accident, the patient was readmitted with worsening diplopia and ipsilateral facial weakness. He demonstrated absent lateral gaze on the right suggestive of either restrictive movement or right.In addition, he had right-sided facial palsy graded as 6/6 House-Brackmann. High-resolution computed tomography demonstrated a right-sided longitudinal otic capsule-sparing temporal bone fracture that propagated into the facial nerve canal and geniculate fossa. Magnetic resonance imaging revealed discontinuity of the right CN VI between the pons and the Dorello canal, as well as injury to the ipsilateral geniculate ganglion. CN VII was intact proximally, from the pons through the internal auditory canal. Consensus was reached to proceed with conservative management. At 13 months after injury, the patient reported 1/6 House-Brackmann with no improvement in CN VI function.This case illustrates 2 subtle findings on imaging with potential therapeutic implications, notably the role of surgical intervention for facial nerve palsy.

  View details for DOI 10.1016/j.wneu.2015.11.076

  View details for PubMedID 26723286

• Junior Seau: An Illustrative Case of Chronic Traumatic Encephalopathy and Update on Chronic Sports-Related Head Injury WORLD NEUROSURGERY Azad, T. D., Li, A., Pendharkar, A. V., Veeravagu, A., Grant, G. A. 2016; 86

  Abstract

  Few neurologic diseases have captured the nation's attention more completely than chronic traumatic encephalopathy (CTE), which has been discovered in the autopsies of professional athletes, most notably professional football players. The tragic case of Junior Seau, a Hall of Fame, National Football League linebacker, has been the most high-profile confirmed case of CTE. Here we describe Seau's case, which concludes an autopsy conducted at the National Institutes of Health that confirmed the diagnosis.Since 1990, Junior Seau had a highly distinguished 20-year career playing for the National Football League as a linebacker, from which he sustained multiple concussions. He committed suicide on May 2, 2012, at age 43, after which an autopsy confirmed a diagnosis of CTE. His clinical history was significant for a series of behavioral disturbances. Seau's history and neuropathologic findings were used to better understand the pathophysiology, diagnosis, and possible risk factors for CTE.This high-profile case reflects an increasing awareness of CTE as a long-term consequence of multiple traumatic brain injuries. The previously unforeseen neurologic risks of American football have begun to cast doubt on the safety of the sport.

  View details for DOI 10.1016/j.wneu.2015.10.032

  View details for Web of Science ID 000369625300104

  View details for PubMedID 26493714

• A brief history of endoscopic spine surgery. Neurosurgical focus Telfeian, A. E., Veeravagu, A., Oyelese, A. A., Gokaslan, Z. L. 2016; 40 (2): E2-?

  Abstract

  Few neurosurgeons practicing today have had training in the field of endoscopic spine surgery during residency or fellowship. Nevertheless, over the past 40 years individual spine surgeons from around the world have worked to create a subfield of minimally invasive spine surgery that takes the point of visualization away from the surgeon's eye or the lens of a microscope and puts it directly at the point of spine pathology. What follows is an attempt to describe the story of how endoscopic spine surgery developed and to credit some of those who have been the biggest contributors to its development.

  View details for DOI 10.3171/2015.11.FOCUS15429

  View details for PubMedID 26828883

• Postoperative Visual Loss Following Lumbar Spine Surgery: A Review of Risk Factors by Diagnosis WORLD NEUROSURGERY Li, A., Swinney, C., Veeravagu, A., Bhatti, I., Ratliff, J. 2015; 84 (6): 2010-2021

  Abstract

  Postoperative visual loss (POVL) is a potentially devastating complication of lumbar spine surgery that may lead to significant functional impairment. Although POVL is rare, a review of the literature shows that it is being reported with increasing frequency. A systematic analysis detailing the etiology and prognosis of the 3 main types of POVL has yet to be published. We reviewed potential preoperative and intraoperative risk factors for ischemic optic neuropathy (ION), central retinal artery occlusion (CRAO), and cortical blindness (CB) after lumbar spine surgery.A PubMed and Google literature search was completed in the absence of time constraints. Relevant articles on POVL after spine surgery were identified and reviewed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.We identified 4 large-scale studies that statistically analyzed risk factors for POVL. ION, CRAO, and CB were the most frequently reported POVL types in the literature. Data were abstracted from 19 ION case reports, 3 CRAO case reports, and 5 CB case reports.We reviewed the preoperative and intraoperative risk factors for each of the 3 main POVL types, using several published case reports to supplement the limited large-scale studies available. ION risks may be influenced by a longer operative time in the prone position with anemia, hypotension, and blood transfusion. The risk for CRAO is usually due to improper positioning during the surgery. Prone positioning and obesity were found to be most commonly associated with CB development. The prognosis, prevention techniques, and treatment of each POVL type can vary considerably.

  View details for DOI 10.1016/j.wneu.2015.08.030

  View details for Web of Science ID 000366286300087

  View details for PubMedID 26341434

• Craniotomy for Resection of Meningioma: An Age-Stratified Analysis of the MarketScan Longitudinal Database WORLD NEUROSURGERY Connolly, I. D., Cole, T., Veeravagu, A., Popat, R., Ratliff, J., Li, G. 2015; 84 (6): 1864-1870

  Abstract

  We sought to describe complications after resection for meningioma with the use of longitudinal administrative data, which our group has shown recently to be superior to nonlongitudinal administrative data.We identified patients who underwent resection for meningioma between 2010 and 2012 in the Thomson Reuters MarketScan database. Current Procedural Terminology coding at inpatient visit was used to select for meningioma resection procedure. Comorbidities and complications were obtained by use of the International Classification of Diseases, Ninth Revision or Current Procedural Terminology coding. Associations between complications and demographic and clinical factors were evaluated with logistic regression.We identified a total of 2216 patients. Approximately 41% developed 1 or more perioperative complications. Approximately 15% were readmitted within 30 days of their procedure. The most frequent complications that occurred in our cohort were new postoperative seizures (11.8%), postoperative dysrhythmia (7.9%), intracranial hemorrhage (5.9%), and cerebral artery occlusion (5.4%). General neurosurgical complications and general neurologic complications occurred in 4.4% and 16.1% of patients, respectively. Nearly 55% of elderly patients (≥ 70 years) developed 1 or more perioperative complication (vs. 39% of nonelderly patients). After we adjusted for comorbidities, elderly status and male sex were found to be significantly associated with increased odds for a variety of complications.In this study, we report complication rates in patients undergoing resection for meningioma. Because of the longitudinal nature of the MarketScan database, we were able to capture a wide array of specific postoperative complications associated with meningioma resection procedures. Care should be taken in the selection of candidates for meningioma resection.

  View details for DOI 10.1016/j.wneu.2015.08.018

  View details for PubMedID 26318633

• Improved capture of adverse events after spinal surgery procedures with a longitudinal administrative database JOURNAL OF NEUROSURGERY-SPINE Veeravagu, A., Cole, T. S., Azad, T. D., Ratliff, J. K. 2015; 23 (3): 374-382

  Abstract

  The significant medical and economic tolls of spinal disorders, increasing volume of spine surgeries, and focus on quality metrics have made it imperative to understand postoperative complications. This study demonstrates the utility of a longitudinal administrative database for capturing overall and procedure-specific complication rates after various spine surgery procedures.The Thomson Reuters MarketScan Commercial Claims and Encounters and the Medicare Supplemental and Coordination of Benefits database was used to conduct a retrospective analysis of longitudinal administrative data from a sample of approximately 189,000 patients. Overall and procedure-specific complication rates at 5 time points ranging from immediately postoperatively (index) to 30 days postoperatively were computed.The results indicated that the frequency of individual complication types increased at different rates. The overall complication rate including all spine surgeries was 13.6% at the index time point and increased to 22.8% at 30 days postoperatively. The frequencies of wound dehiscence, infection, and other wound complications exhibited large increases between 10 and 20 days postoperatively, while complication rates for new chronic pain, delirium, and dysrhythmia increased more gradually over the 30-day period studied. When specific surgical procedures were considered, 30-day complication rates ranged from 8.6% in single-level anterior cervical fusions to 27.3% in multilevel combined anterior and posterior lumbar spine fusions.This study demonstrates the usefulness of a longitudinal administrative database in assessing postoperative complication rates after spine surgery. Use of this database gave results that were comparable to those in prospective studies and superior to those obtained with nonlongitudinal administrative databases. Longitudinal administrative data may improve the understanding of overall and procedure-specific complication rates after spine surgery.

  View details for DOI 10.3171/2014.12.SPINE14659

  View details for Web of Science ID 000360027300017

• Improved capture of adverse events after spinal surgery procedures with a longitudinal administrative database. Journal of neurosurgery. Spine Veeravagu, A., Cole, T. S., Azad, T. D., Ratliff, J. K. 2015; 23 (3): 374-382

  Abstract

  The significant medical and economic tolls of spinal disorders, increasing volume of spine surgeries, and focus on quality metrics have made it imperative to understand postoperative complications. This study demonstrates the utility of a longitudinal administrative database for capturing overall and procedure-specific complication rates after various spine surgery procedures.The Thomson Reuters MarketScan Commercial Claims and Encounters and the Medicare Supplemental and Coordination of Benefits database was used to conduct a retrospective analysis of longitudinal administrative data from a sample of approximately 189,000 patients. Overall and procedure-specific complication rates at 5 time points ranging from immediately postoperatively (index) to 30 days postoperatively were computed.The results indicated that the frequency of individual complication types increased at different rates. The overall complication rate including all spine surgeries was 13.6% at the index time point and increased to 22.8% at 30 days postoperatively. The frequencies of wound dehiscence, infection, and other wound complications exhibited large increases between 10 and 20 days postoperatively, while complication rates for new chronic pain, delirium, and dysrhythmia increased more gradually over the 30-day period studied. When specific surgical procedures were considered, 30-day complication rates ranged from 8.6% in single-level anterior cervical fusions to 27.3% in multilevel combined anterior and posterior lumbar spine fusions.This study demonstrates the usefulness of a longitudinal administrative database in assessing postoperative complication rates after spine surgery. Use of this database gave results that were comparable to those in prospective studies and superior to those obtained with nonlongitudinal administrative databases. Longitudinal administrative data may improve the understanding of overall and procedure-specific complication rates after spine surgery.

  View details for DOI 10.3171/2014.12.SPINE14659

  View details for PubMedID 26068273

• Anterior Versus Posterior Approach for Multilevel Degenerative Cervical Disease A Retrospective Propensity Score-Matched Study of the MarketScan Database SPINE Cole, T., Veeravagu, A., Zhang, M., Azad, T. D., Desai, A., Ratliff, J. K. 2015; 40 (13): 1033-1038

  Abstract

  Retrospective 2:1 propensity score-matched analysis on a national longitudinal database between 2006 and 2010.To compare rates of adverse events, revisions procedure rates, and payment differences in anterior cervical fusion procedures compared with posterior laminectomy and fusion procedures with at least 3 levels of instrumentation.The comparative benefits of anterior versus posterior approach to multilevel degenerative cervical disease remain controversial. Recent systematic reviews have reached conflicting conclusions. We demonstrate the comparative economic and clinical outcomes of anterior and posterior approaches for multilevel cervical degenerative disk disease.We identified 13,662 patients in a national billing claims database who underwent anterior or posterior cervical fusion procedures with 3 or more levels of instrumentation. Cohorts were balanced using 2:1 propensity score matching and outcomes were compared using bivariate analysis.With the exception of dysphagia (6.4% in anterior and 1.4% in posterior), overall 30-day complication rates were lower in the anterior approach group. The rate of any complication excluding dysphagia with anterior approaches was 12.3%, significantly lower (P < 0.0001) than that of posterior approaches, 17.8%. Anterior approaches resulted in lower hospital ($18,346 vs. $23,638) and total payments ($28,963 vs. $33,526). Patients receiving an anterior surgical approach demonstrated significantly lower rate of 30-day readmission (5.1% vs. 9.9%, P < 0.0001), were less likely to require revision surgery (12.8% vs. 18.1%, P < 0.0001), and had a shorter length of stay by 1.5 nights (P < 0.0001).Anterior approaches in the surgical management of multilevel degenerative cervical disease provide clinical advantages over posterior approaches, including lower overall complication rates, revision procedure rates, and decreased length of stay. Anterior approach procedures are also associated with decreased overall payments. These findings must be interpreted in light of limitations inherent to retrospective longitudinal studies including absence of subjective and radiographical outcomes.3.

  View details for DOI 10.1097/BRS.0000000000000872

  View details for Web of Science ID 000357946000009

• Anterior Versus Posterior Approach for Multilevel Degenerative Cervical Disease: A Retrospective Propensity Score-Matched Study of the MarketScan Database. Spine Cole, T., Veeravagu, A., Zhang, M., Azad, T. D., Desai, A., Ratliff, J. K. 2015; 40 (13): 1033-1038

  Abstract

  Retrospective 2:1 propensity score-matched analysis on a national longitudinal database between 2006 and 2010.To compare rates of adverse events, revisions procedure rates, and payment differences in anterior cervical fusion procedures compared with posterior laminectomy and fusion procedures with at least 3 levels of instrumentation.The comparative benefits of anterior versus posterior approach to multilevel degenerative cervical disease remain controversial. Recent systematic reviews have reached conflicting conclusions. We demonstrate the comparative economic and clinical outcomes of anterior and posterior approaches for multilevel cervical degenerative disk disease.We identified 13,662 patients in a national billing claims database who underwent anterior or posterior cervical fusion procedures with 3 or more levels of instrumentation. Cohorts were balanced using 2:1 propensity score matching and outcomes were compared using bivariate analysis.With the exception of dysphagia (6.4% in anterior and 1.4% in posterior), overall 30-day complication rates were lower in the anterior approach group. The rate of any complication excluding dysphagia with anterior approaches was 12.3%, significantly lower (P < 0.0001) than that of posterior approaches, 17.8%. Anterior approaches resulted in lower hospital ($18,346 vs. $23,638) and total payments ($28,963 vs. $33,526). Patients receiving an anterior surgical approach demonstrated significantly lower rate of 30-day readmission (5.1% vs. 9.9%, P < 0.0001), were less likely to require revision surgery (12.8% vs. 18.1%, P < 0.0001), and had a shorter length of stay by 1.5 nights (P < 0.0001).Anterior approaches in the surgical management of multilevel degenerative cervical disease provide clinical advantages over posterior approaches, including lower overall complication rates, revision procedure rates, and decreased length of stay. Anterior approach procedures are also associated with decreased overall payments. These findings must be interpreted in light of limitations inherent to retrospective longitudinal studies including absence of subjective and radiographical outcomes.3.

  View details for DOI 10.1097/BRS.0000000000000872

  View details for PubMedID 25768690

• Nelson Syndrome: Update on Therapeutic Approaches WORLD NEUROSURGERY Azad, T. D., Veeravagu, A., Kumar, S., Katznelson, L. 2015; 83 (6): 1135-1140

  Abstract

  To review the pathophysiology and therapeutic modalities availble for Nelson syndrome.We reviewed the current literature including managment for Nelson syndrome.For patients with NS, surgical intervention is often the first-line therapy. With refractory NS or tumors with extrasellar involvement, radiosurgery offers an important alternative or adjuvant option. Pharmacologic interventions have demonstrated limited usefulness, although recent evidence supports the feasibility of a novel somatostatin analog for patients with NS. Modern neuroimaging, improved surgical techniques, and the advent of stereotactic radiotherapy have transformed the management of NS.An up-to-date understanding of the pathophysiology underlying Nelson Syndrome and evidence-based management is imperative. Early detection may allow for more successful therapy in patients with Nelson Syndrome. Improved radiotherapeutic interventions and rapidly evolving pharmacologic therapies offer an opportunity to create targeted, multifocal treatment regiments for patients with Nelson Syndrome.

  View details for DOI 10.1016/j.wneu.2015.01.038

  View details for Web of Science ID 000356138800052

• Nelson Syndrome: Update on Therapeutic Approaches. World neurosurgery Azad, T. D., Veeravagu, A., Kumar, S., Katznelson, L. 2015; 83 (6): 1135-1140

  Abstract

  To review the pathophysiology and therapeutic modalities availble for Nelson syndrome.We reviewed the current literature including managment for Nelson syndrome.For patients with NS, surgical intervention is often the first-line therapy. With refractory NS or tumors with extrasellar involvement, radiosurgery offers an important alternative or adjuvant option. Pharmacologic interventions have demonstrated limited usefulness, although recent evidence supports the feasibility of a novel somatostatin analog for patients with NS. Modern neuroimaging, improved surgical techniques, and the advent of stereotactic radiotherapy have transformed the management of NS.An up-to-date understanding of the pathophysiology underlying Nelson Syndrome and evidence-based management is imperative. Early detection may allow for more successful therapy in patients with Nelson Syndrome. Improved radiotherapeutic interventions and rapidly evolving pharmacologic therapies offer an opportunity to create targeted, multifocal treatment regiments for patients with Nelson Syndrome.

  View details for DOI 10.1016/j.wneu.2015.01.038

  View details for PubMedID 25683128

• Perspective on "the role of adjuvant radiotherapy after gross total resection of atypical meningiomas". World neurosurgery Veeravagu, A., Azad, T. D., Chang, S. D. 2015; 83 (5): 737-738

  View details for DOI 10.1016/j.wneu.2015.01.047

  View details for PubMedID 25681598

• National trends in burn and inhalation injury in burn patients: results of analysis of the nationwide inpatient sample database. Journal of burn care & research Veeravagu, A., Yoon, B. C., Jiang, B., Carvalho, C. M., Rincon, F., Maltenfort, M., Jallo, J., Ratliff, J. K. 2015; 36 (2): 258-265

  Abstract

  The aim of this study was describe national trends in prevalence, demographics, hospital length of stay (LOS), hospital charges, and mortality for burn patients with and without inhalational injury and to compare to the National Burn Repository. Burns and inhalation injury cause considerable mortality and morbidity in the United States. There remains insufficient reporting of the demographics and outcomes surrounding such injuries. The National Inpatient Sample database, the nation's largest all-payer inpatient care data repository, was utilized to select 506,628 admissions for burns from 1988 to 2008 based on ICD-9-CM recording. The data were stratified based on the extent of injury (%TBSA) and presence or absence of inhalational injury. Inhalation injury was observed in only 2.2% of burns with <20% TBSA but 14% of burns with 80 to 99% TBSA. Burn patients with inhalation injury were more likely to expire in-hospital compared to those without (odds ratio, 3.6; 95% confidence interval, 2.7-5.0; P < .001). Other factors associated with higher mortality were African-American race, female sex, and urban practice setting. Patients treated at rural facilities and patients with hyperglycemia had lower mortality rates. Each increase in percent of TBSA of burns increased LOS by 2.5%. Patients with burns covering 50 to 59% of TBSA had the longest hospital stay at a median of 24 days (range, 17-55). The median in-hospital charge for a burn patient with inhalation injury was US$32,070, compared to US$17,600 for those without. Overall, patients who expired from burn injury accrued higher in-hospital charges (median, US$50,690 vs US$17,510). Geographically, California and New Jersey were the states with the highest charges, whereas Vermont and Maryland were states with the lowest charges. The study analysis provides a broad sampling of nationwide demographics, LOS, and in-hospital charges for patients with burns and inhalation injury.

  View details for DOI 10.1097/BCR.0000000000000064

  View details for PubMedID 24918946

• Intracranial fat migration: A newly described complication of autologous fat repair of a cerebrospinal fluid leak following supracerebellar infratentorial approach. International journal of surgery case reports Ludwig, C. A., Aujla, P., Moreno, M., Veeravagu, A., Li, G. 2015; 7C: 1-5

  Abstract

  Intracranial fat migration following autologous fat graft and placement of a lumbar drain for cerebrospinal fluid leak after pineal cyst resection surgery has not been previously reported.The authors present a case of a 39-year-old male with a history of headaches who presented for removal of a pineal cyst from the pineal region. He subsequently experienced cerebrospinal fluid leak and postoperative Escherichia coli (E. Coli) wound infection, and meningitis, which were treated initially with wound washout and antibiotics in addition to bone removal and primary repair with primary suture-closure of the durotomy. A lumbar drain was left in place. The cerebrospinal fluid leak returned two weeks following removal of the lumbar drain; therefore, autologous fat graft repair and lumbar drain placement were performed. Three days later, the patient began experiencing right homonymous hemianopia and was found via computed tomography and magnetic resonance imaging to have autologous fat in the infra‑ and supratentorial space, including intraparenchymal and subarachnoid spread. Symptoms began to resolve with supportive care over 48 hours and had almost fully resolved within one week.This is the first known report of a patient with an autologous fat graft entering the subarachnoid space, intraparenchymal space, and ventricles following fat graft and lumbar drainage.This case highlights the importance of monitoring for complications of lumbar drain placement.

  View details for DOI 10.1016/j.ijscr.2014.12.008

  View details for PubMedID 25557086

• Retrosigmoid Versus Translabyrinthine Approach for Acoustic Neuroma Resection: An Assessment of Complications and Payments in a Longitudinal Administrative Database. Cure¯us Cole, T., Veeravagu, A., Zhang, M., Azad, T., Swinney, C., Li, G. H., Ratliff, J. K., Giannotta, S. L. 2015; 7 (10)

  Abstract

  Object Retrosigmoid (RS) and translabyrinthine (TL) surgery remain essential treatment approaches for symptomatic or enlarging acoustic neuromas (ANs). We compared nationwide complication rates and payments, independent of tumor characteristics, for these two strategies. Methods We identified 346 and 130 patients who underwent RS and TL approaches, respectively, for AN resection in the 2010-2012 MarketScan database, which characterizes primarily privately-insured patients from multiple institutions nationwide. Results Although we found no difference in 30-day general neurological or neurosurgical complication rates, in TL procedures there was a decreased risk for postoperative cranial nerve (CN) VII injury (20.2% vs 10.0%, CI 0.23-0.82), dysphagia (10.4% vs 3.1%, CI 0.10-0.78), and dysrhythmia (8.4% vs 2.3%, CI 0.08-0.86). Overall, there was no difference in surgical repair rates of CSF leak; however, intraoperative fat grafting was significantly higher in TL approaches (19.8% vs 60.2%, CI 3.95-9.43). In patients receiving grafts, there was a trend towards a higher repair rate after RS approach, while in those without grafts, there was a trend towards a higher repair rate after TL approach. Median total payments were $16,856 higher after RS approaches ($67,774 vs $50,918, p < 0.0001), without differences in physician or 90-day postoperative payments. Conclusions  Using a nationwide longitudinal database, we observed that the TL, compared to RS, approach for AN resection experienced lower risks of CN VII injury, dysphagia, and dysrhythmia. There was no significant difference in CSF leak repair rates. The payments for RS procedures exceed payments for TL procedures by approximately $17,000. Data from additional years and non-private sources will further clarify these trends.

  View details for DOI 10.7759/cureus.369

  View details for PubMedID 26623224

  View details for PubMedCentralID PMC4659577

• The use of bone morphogenetic protein in thoracolumbar spine procedures: analysis of the MarketScan longitudinal database SPINE JOURNAL Veeravagu, A., Cole, T. S., Jiang, B., Ratliff, J. K., Gidwani, R. A. 2014; 14 (12): 2929-2937

  Abstract

  The use of recombinant human bone morphogenetic protein (BMP) in the thoracolumbar spine remains controversial, with many questioning the risks and benefits of this new biologic.To describe national trends, incidence of complications, and revision rates associated with BMP use in thoracolumbar spine procedures.Administrative database study.A matched cohort of 52,259 patients undergoing thoracolumbar fusion surgery from 2006 to 2010 were identified in the MarketScan database. Patients without BMP treatment were matched 2:1 to patients receiving intraoperative BMP.Revision rates and postoperative complications.The MarketScan database was used to select patients undergoing thoracolumbar fusion procedures, with and without intraoperative BMP. We ascertained outcome measures using either International Classification of Disease, ninth revision, or Current Procedural Terminology coding, and matched groups were evaluated using a bivariate and multivariate analyses. Kaplan-Meier estimates of fusions failure rates were also calculated.Patients receiving intraoperative BMP underwent fewer refusions, decompressions, posterior and anterior revisions, or any revision procedure (single level 4.53% vs. 5.85%, p<.0001; multilevel 5.02% vs. 6.83%, p<.0001; overall cohort 4.73% vs. 6.09%, p<.0001). After adjusting for comorbidities, demographics, and levels of procedure, BMP was not associated with the postoperative development of cancer (odds ratio 0.92). Bone morphogenetic protein use was associated with an increase in any complication at 30 days (15.8% vs. 14.9%, p=.0065), which is only statistically significant among multilevel procedures (19.74% vs. 18.02%, p=.0013). Thirty-day complications in multilevel procedures associated with BMP use included new dysrhythmia (4.68% vs. 4.01%, p=.0161) and delirium (1.08% vs. 0.69%, p=.0024). A new diagnosis of chronic pain was associated with BMP use in both single-level (2.74% vs. 2.15%, p=.0019) and multilevel (3.7% vs. 2.52%, p<.0001) procedures. Bone morphogenetic protein was negatively associated with infection in single-level procedures (2.12% vs. 2.64%, p=.0067) and wound dehiscence in multilevel procedures (0.84% vs. 1.18%, p=.0167).In national data analysis of thoracolumbar procedures, we found that BMP was associated with decreased incidence of revision spinal surgery and with a slight increased risk of overall complications at 30 days. Although no BMP-associated increased risk of malignancy was found, lack of long-term follow-up precludes detection of between-group differences in malignancies and other rare events that may not appear until later.

  View details for DOI 10.1016/j.spinee.2014.05.010

  View details for Web of Science ID 000345429500023

• The use of bone morphogenetic protein in thoracolumbar spine procedures: analysis of the MarketScan longitudinal database. spine journal Veeravagu, A., Cole, T. S., Jiang, B., Ratliff, J. K., Gidwani, R. A. 2014; 14 (12): 2929-2937

  Abstract

  The use of recombinant human bone morphogenetic protein (BMP) in the thoracolumbar spine remains controversial, with many questioning the risks and benefits of this new biologic.To describe national trends, incidence of complications, and revision rates associated with BMP use in thoracolumbar spine procedures.Administrative database study.A matched cohort of 52,259 patients undergoing thoracolumbar fusion surgery from 2006 to 2010 were identified in the MarketScan database. Patients without BMP treatment were matched 2:1 to patients receiving intraoperative BMP.Revision rates and postoperative complications.The MarketScan database was used to select patients undergoing thoracolumbar fusion procedures, with and without intraoperative BMP. We ascertained outcome measures using either International Classification of Disease, ninth revision, or Current Procedural Terminology coding, and matched groups were evaluated using a bivariate and multivariate analyses. Kaplan-Meier estimates of fusions failure rates were also calculated.Patients receiving intraoperative BMP underwent fewer refusions, decompressions, posterior and anterior revisions, or any revision procedure (single level 4.53% vs. 5.85%, p<.0001; multilevel 5.02% vs. 6.83%, p<.0001; overall cohort 4.73% vs. 6.09%, p<.0001). After adjusting for comorbidities, demographics, and levels of procedure, BMP was not associated with the postoperative development of cancer (odds ratio 0.92). Bone morphogenetic protein use was associated with an increase in any complication at 30 days (15.8% vs. 14.9%, p=.0065), which is only statistically significant among multilevel procedures (19.74% vs. 18.02%, p=.0013). Thirty-day complications in multilevel procedures associated with BMP use included new dysrhythmia (4.68% vs. 4.01%, p=.0161) and delirium (1.08% vs. 0.69%, p=.0024). A new diagnosis of chronic pain was associated with BMP use in both single-level (2.74% vs. 2.15%, p=.0019) and multilevel (3.7% vs. 2.52%, p<.0001) procedures. Bone morphogenetic protein was negatively associated with infection in single-level procedures (2.12% vs. 2.64%, p=.0067) and wound dehiscence in multilevel procedures (0.84% vs. 1.18%, p=.0167).In national data analysis of thoracolumbar procedures, we found that BMP was associated with decreased incidence of revision spinal surgery and with a slight increased risk of overall complications at 30 days. Although no BMP-associated increased risk of malignancy was found, lack of long-term follow-up precludes detection of between-group differences in malignancies and other rare events that may not appear until later.

  View details for DOI 10.1016/j.spinee.2014.05.010

  View details for PubMedID 24842396

• Intraoperative Neuromonitoring in Single-Level Spinal Procedures A Retrospective Propensity Score-Matched Analysis in a National Longitudinal Database SPINE Cole, T., Veeravagu, A., Zhang, M., Li, A., Ratliff, J. K. 2014; 39 (23): 1950-1959

  Abstract

  Study Design. Retrospective propensity score-matched analysis on a national database (MarketScan) between 2006 and 2010.Objective. To compare rates of neurological deficits after elective single level spinal procedures with and without intraoperative neuromonitoring, as well as associated payment differences and geographic variance.Summary of Background Data. Intraoperative neurophysiologic monitoring is a technique that may contribute to avoiding permanent neurological injury during some spine surgery procedures. However, it is unclear if all patients undergoing spine surgery benefit from neuromonitoring.Methods. An identified 85,640 patients underwent single level spinal procedures including anterior cervical discectomy and fusion (ACDF), lumbar fusion, lumbar laminectomy, or lumbar discectomy. Neuromonitoring was identified with appropriate Current Procedural Terminology (CPT) codes. Cohorts were balanced on baseline comorbidities and procedure characteristics using propensity score matching. Trauma and spinal tumors cases were excluded.Results. 12.66% patients received neuromonitoring intraoperatively. Lumbar laminectomies had reduced 30-day neurological complication rate with neuromonitoring (0.0% vs 1.18%, p = 0.002). Neuromonitoring did not correlate with reduced intraoperative neurological complications in ACDFs (0.09% vs 0.13%), lumbar fusions (0.32% vs 0.58%), or lumbar discectomy (1.24% vs. 0.91%). With the addition of neuromonitoring, payments for ACDFs increased 16.24% ($3,842), lumbar fusions 7.84% ($3,540), lumbar laminectomies 24.33% ($3,704), and lumbar discectomies 22.54% ($2.859). Significant geographic variation was evident. Some states had no recorded single-level spinal cases with concurrent neuromonitoring. Rates for ACDFs and lumbar fusions, laminectomies, and discectomies ranged as high as 61%, 58%, 22%, and 21%, respectively.Conclusions. With intraoperative neurological monitoring in single level procedures, neurological complications were only decreased among lumbar laminectomies. No difference was observed in ACDFs, lumbar fusions, or lumbar discectomies. There was a significant increase in total payments associated with the index procedure and hospitalization. We demonstrate significant geographic variation in neuromonitoring.

  View details for DOI 10.1097/BRS.0000000000000593

  View details for Web of Science ID 000344606100014

• Intraoperative neuromonitoring in single-level spinal procedures: a retrospective propensity score-matched analysis in a national longitudinal database. Spine Cole, T., Veeravagu, A., Zhang, M., Li, A., Ratliff, J. K. 2014; 39 (23): 1950-1959

  Abstract

  Study Design. Retrospective propensity score-matched analysis on a national database (MarketScan) between 2006 and 2010.Objective. To compare rates of neurological deficits after elective single level spinal procedures with and without intraoperative neuromonitoring, as well as associated payment differences and geographic variance.Summary of Background Data. Intraoperative neurophysiologic monitoring is a technique that may contribute to avoiding permanent neurological injury during some spine surgery procedures. However, it is unclear if all patients undergoing spine surgery benefit from neuromonitoring.Methods. An identified 85,640 patients underwent single level spinal procedures including anterior cervical discectomy and fusion (ACDF), lumbar fusion, lumbar laminectomy, or lumbar discectomy. Neuromonitoring was identified with appropriate Current Procedural Terminology (CPT) codes. Cohorts were balanced on baseline comorbidities and procedure characteristics using propensity score matching. Trauma and spinal tumors cases were excluded.Results. 12.66% patients received neuromonitoring intraoperatively. Lumbar laminectomies had reduced 30-day neurological complication rate with neuromonitoring (0.0% vs 1.18%, p = 0.002). Neuromonitoring did not correlate with reduced intraoperative neurological complications in ACDFs (0.09% vs 0.13%), lumbar fusions (0.32% vs 0.58%), or lumbar discectomy (1.24% vs. 0.91%). With the addition of neuromonitoring, payments for ACDFs increased 16.24% ($3,842), lumbar fusions 7.84% ($3,540), lumbar laminectomies 24.33% ($3,704), and lumbar discectomies 22.54% ($2.859). Significant geographic variation was evident. Some states had no recorded single-level spinal cases with concurrent neuromonitoring. Rates for ACDFs and lumbar fusions, laminectomies, and discectomies ranged as high as 61%, 58%, 22%, and 21%, respectively.Conclusions. With intraoperative neurological monitoring in single level procedures, neurological complications were only decreased among lumbar laminectomies. No difference was observed in ACDFs, lumbar fusions, or lumbar discectomies. There was a significant increase in total payments associated with the index procedure and hospitalization. We demonstrate significant geographic variation in neuromonitoring.

  View details for DOI 10.1097/BRS.0000000000000593

  View details for PubMedID 25202940

• Usage of Recombinant Human Bone Morphogenetic Protein in Cervical Spine Procedures: Analysis of the MarketScan Longitudinal Database. journal of bone and joint surgery. American volume Cole, T., Veeravagu, A., Jiang, B., Ratliff, J. K. 2014; 96 (17): 1409-1416

  Abstract

  Usage of recombinant human bone morphogenetic protein (rhBMP) in anterior cervical discectomy and fusion (ACDF) procedures is controversial. Studies suggest increased rates of dysphagia, hematoma or seroma, and severe airway compromise in anterior cervical spine procedures using rhBMP. The purpose of the present study was to determine and describe national utilization trends and complication rates associated with rhBMP usage in anterior cervical spine procedures.The MarketScan database from 2006 to 2010 was retrospectively queried to identify 91,543 patients who underwent ACDF with or without cervical corpectomy. Patient selection and outcomes were ascertained with use of ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification) and CPT (Current Procedural Terminology) coding. A total of 3197 patients were treated with rhBMP intraoperatively. Mean follow-up was 588 days (interquartile range [IQR], 205 to 886 days) in the non-treated cohort and 591 days (IQR, 203 to 925 days) in the rhBMP-treated cohort. Multivariate logistic regression as well as propensity score analysis were used to evaluate the association of rhBMP usage with postoperative complications.In propensity score-adjusted models, rhBMP usage was associated with an increased risk of any complication (odds ratio [OR] = 1.34, 95% confidence interval [CI] = 1.2 to 1.5) and specific complications such as hematoma or seroma (OR = 1.8, 95% CI = 1.4 to 2.3), dysphagia (OR = 1.3, 95% CI = 1.1 to 1.5), and any pulmonary complication (OR = 1.5, 95% CI = 1.2 to 1.8) within thirty days postoperatively. There were no significant differences in the rates of readmission, in-hospital mortality, referral to pain management, new malignancy, or reoperation between the two cohorts. Usage of rhBMP was associated with a mean increase of $5545 (19%) in total payments to the hospital and primary physician (p < 0.001).We found an increased overall rate of postoperative complications in patients receiving rhBMP for cervical spinal fusion procedures compared with patients not receiving rhBMP. Hematoma or seroma, pulmonary complications, and dysphagia were also more common in the rhBMP cohort. Usage of rhBMP in a case was associated with $311 greater payments to the surgeon and $4213 greater payments to the hospital.Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

  View details for DOI 10.2106/JBJS.M.01016

  View details for PubMedID 25187578

• Usage of Recombinant Human Bone Morphogenetic Protein in Cervical Spine Procedures JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME Cole, T., Veeravagu, A., Jiang, B., Ratliff, J. K. 2014; 96A (17): 1409-1416

  Abstract

  Usage of recombinant human bone morphogenetic protein (rhBMP) in anterior cervical discectomy and fusion (ACDF) procedures is controversial. Studies suggest increased rates of dysphagia, hematoma or seroma, and severe airway compromise in anterior cervical spine procedures using rhBMP. The purpose of the present study was to determine and describe national utilization trends and complication rates associated with rhBMP usage in anterior cervical spine procedures.The MarketScan database from 2006 to 2010 was retrospectively queried to identify 91,543 patients who underwent ACDF with or without cervical corpectomy. Patient selection and outcomes were ascertained with use of ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification) and CPT (Current Procedural Terminology) coding. A total of 3197 patients were treated with rhBMP intraoperatively. Mean follow-up was 588 days (interquartile range [IQR], 205 to 886 days) in the non-treated cohort and 591 days (IQR, 203 to 925 days) in the rhBMP-treated cohort. Multivariate logistic regression as well as propensity score analysis were used to evaluate the association of rhBMP usage with postoperative complications.In propensity score-adjusted models, rhBMP usage was associated with an increased risk of any complication (odds ratio [OR] = 1.34, 95% confidence interval [CI] = 1.2 to 1.5) and specific complications such as hematoma or seroma (OR = 1.8, 95% CI = 1.4 to 2.3), dysphagia (OR = 1.3, 95% CI = 1.1 to 1.5), and any pulmonary complication (OR = 1.5, 95% CI = 1.2 to 1.8) within thirty days postoperatively. There were no significant differences in the rates of readmission, in-hospital mortality, referral to pain management, new malignancy, or reoperation between the two cohorts. Usage of rhBMP was associated with a mean increase of $5545 (19%) in total payments to the hospital and primary physician (p < 0.001).We found an increased overall rate of postoperative complications in patients receiving rhBMP for cervical spinal fusion procedures compared with patients not receiving rhBMP. Hematoma or seroma, pulmonary complications, and dysphagia were also more common in the rhBMP cohort. Usage of rhBMP in a case was associated with $311 greater payments to the surgeon and $4213 greater payments to the hospital.Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

  View details for DOI 10.2106/JBJS.M.01016

  View details for Web of Science ID 000343799600010

• Acute Lung Injury in Patients with Subarachnoid Hemorrhage: A Nationwide Inpatient Sample Study WORLD NEUROSURGERY Veeravagu, A., Chen, Y., Ludwig, C., Rincon, F., Maltenfort, M., Jallo, J., Choudhri, O., Steinberg, G. K., Ratliff, J. K. 2014; 82 (1-2): E235-E241

  Abstract

  Subarachnoid hemorrhage (SAH) causes significant morbidity and mortality. Pulmonary complications may be particularly frequent, but national data is lacking on the outcomes associated with acute respiratory distress syndrome (ARDS) in SAH patients. The aim of this study is to determine national trends for SAH patients with ARDS.The Nationwide Inpatient Sample Database (NIS) was utilized to sample 193,209 admissions for SAH with and without ARDS from 1993 to 2008 using ICD-9-CM coding. A multivariate stepwise regression analysis was performed.The incidence of ARDS in SAH has increased from 35.51% in 1993 to 37.60% in 2008. However, the overall mortality in SAH patients and in SAH patients with ARDS has decreased in the same period, from 42.30% to 31.99% and from 75.13% to 60.76% respectively. Multivariate analysis showed that the predictors of developing ARDS in SAH patients include older age, larger hospital size, and comorbidities such as epilepsy, cardiac arrest, sepsis, congestive heart failure, hypertension, chronic obstructive pulmonary disease, and hematologic, renal, or neurological dysfunction. Predictors of mortality in SAH patients include age and hospital complications such as coronary artery disease, ARDS, cancer, and hematologic, or renal dysfunction.SAH patients are at increased risk of developing ARDS and the identification of certain risk factors may alert and aid the practitioner in preventing worsening disease.

  View details for DOI 10.1016/j.wneu.2014.02.030

  View details for Web of Science ID 000342911400067

• Acute lung injury in patients with subarachnoid hemorrhage: a nationwide inpatient sample study. World neurosurgery Veeravagu, A., Chen, Y., Ludwig, C., Rincon, F., Maltenfort, M., Jallo, J., Choudhri, O., Steinberg, G. K., Ratliff, J. K. 2014; 82 (1-2): e235-41

  Abstract

  Subarachnoid hemorrhage (SAH) causes significant morbidity and mortality. Pulmonary complications may be particularly frequent, but national data is lacking on the outcomes associated with acute respiratory distress syndrome (ARDS) in SAH patients. The aim of this study is to determine national trends for SAH patients with ARDS.The Nationwide Inpatient Sample Database (NIS) was utilized to sample 193,209 admissions for SAH with and without ARDS from 1993 to 2008 using ICD-9-CM coding. A multivariate stepwise regression analysis was performed.The incidence of ARDS in SAH has increased from 35.51% in 1993 to 37.60% in 2008. However, the overall mortality in SAH patients and in SAH patients with ARDS has decreased in the same period, from 42.30% to 31.99% and from 75.13% to 60.76% respectively. Multivariate analysis showed that the predictors of developing ARDS in SAH patients include older age, larger hospital size, and comorbidities such as epilepsy, cardiac arrest, sepsis, congestive heart failure, hypertension, chronic obstructive pulmonary disease, and hematologic, renal, or neurological dysfunction. Predictors of mortality in SAH patients include age and hospital complications such as coronary artery disease, ARDS, cancer, and hematologic, or renal dysfunction.SAH patients are at increased risk of developing ARDS and the identification of certain risk factors may alert and aid the practitioner in preventing worsening disease.

  View details for DOI 10.1016/j.wneu.2014.02.030

  View details for PubMedID 24560705

• Revision rates and complication incidence in single- and multilevel anterior cervical discectomy and fusion procedures: an administrative database study. spine journal Veeravagu, A., Cole, T., Jiang, B., Ratliff, J. K. 2014; 14 (7): 1125-1131

  Abstract

  The natural history of cervical degenerative disease with operative management has not been well described. Even with symptomatic and radiographic evidence of multilevel cervical disease, it is unclear whether single- or multilevel anterior cervical discectomy and fusion (ACDF) procedures produce superior long-term outcomes.To describe national trends in revision rates, complications, and readmission for patients undergoing single and multilevel ACDF.Administrative database study.Between 2006 and 2010, 92,867 patients were recorded for ACDF procedures in the Thomson Reuters MarketScan database. Restricting to patients with >24 months follow-up, 28,777 patients fulfilled our inclusion criteria, of which 12,744 (44%) underwent single-level and 16,033 (56%) underwent multilevel ACDFs.Revision rates and postoperative complications.We used the MarketScan database from 2006 to 2010 to select ACDF procedures based on Current Procedural Terminology coding at inpatient visit. Outcome measures were ascertained using either International Classification of Disease version 9 or Current Procedural Terminology coding.Perioperative complications were more common in multilevel procedures (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.2-1.6; p<.0001). Single-level ACDF patients had higher rates of postoperative cervical epidural steroid injections (OR, 0.88; 95% CI, 0.8-1.0; p=.01). Within 30 days after index procedure, the multilevel ACDF cohort was 1.6 times more likely to have undergone revision (OR, 1.6; 95% CI, 1.1-2.4; p=.02). At 2 years follow-up, revision rates were 9.13% in the single-level ACDF cohort and 10.7% for multilevel ACDFs (OR, 1.2; 95% CI, 1.1-1.3; p<.0001). In a multivariate analysis at 2 years follow-up, patients from the multilevel cohort were more likely to have received a surgical revision (OR, 1.1; 95% CI, 1.0-1.2; p=.001), to be readmitted into the hospital for any cause (OR, 1.2; 95% CI, 1.1-1.4; p=.007), and to have suffered complications (OR, 1.3; 95% CI, 1.1-1.5; p=.0003).In this study, we report rates of adverse events and the need for revision surgery in patients undergoing single versus multilevel ACDFs. Increasing number of levels fused at the time of index surgery correlated with increased rate of reoperations. Multilevel ACDF patients requiring additional surgery more often underwent more extensive revision surgeries.

  View details for DOI 10.1016/j.spinee.2013.07.474

  View details for PubMedID 24126076

• Revision rates and complication incidence in single- and multilevel anterior cervical discectomy and fusion procedures: an administrative database study SPINE JOURNAL Veeravagu, A., Cole, T., Jiang, B., Ratliff, J. K. 2014; 14 (7): 1125-1131

  Abstract

  The natural history of cervical degenerative disease with operative management has not been well described. Even with symptomatic and radiographic evidence of multilevel cervical disease, it is unclear whether single- or multilevel anterior cervical discectomy and fusion (ACDF) procedures produce superior long-term outcomes.To describe national trends in revision rates, complications, and readmission for patients undergoing single and multilevel ACDF.Administrative database study.Between 2006 and 2010, 92,867 patients were recorded for ACDF procedures in the Thomson Reuters MarketScan database. Restricting to patients with >24 months follow-up, 28,777 patients fulfilled our inclusion criteria, of which 12,744 (44%) underwent single-level and 16,033 (56%) underwent multilevel ACDFs.Revision rates and postoperative complications.We used the MarketScan database from 2006 to 2010 to select ACDF procedures based on Current Procedural Terminology coding at inpatient visit. Outcome measures were ascertained using either International Classification of Disease version 9 or Current Procedural Terminology coding.Perioperative complications were more common in multilevel procedures (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.2-1.6; p<.0001). Single-level ACDF patients had higher rates of postoperative cervical epidural steroid injections (OR, 0.88; 95% CI, 0.8-1.0; p=.01). Within 30 days after index procedure, the multilevel ACDF cohort was 1.6 times more likely to have undergone revision (OR, 1.6; 95% CI, 1.1-2.4; p=.02). At 2 years follow-up, revision rates were 9.13% in the single-level ACDF cohort and 10.7% for multilevel ACDFs (OR, 1.2; 95% CI, 1.1-1.3; p<.0001). In a multivariate analysis at 2 years follow-up, patients from the multilevel cohort were more likely to have received a surgical revision (OR, 1.1; 95% CI, 1.0-1.2; p=.001), to be readmitted into the hospital for any cause (OR, 1.2; 95% CI, 1.1-1.4; p=.007), and to have suffered complications (OR, 1.3; 95% CI, 1.1-1.5; p=.0003).In this study, we report rates of adverse events and the need for revision surgery in patients undergoing single versus multilevel ACDFs. Increasing number of levels fused at the time of index surgery correlated with increased rate of reoperations. Multilevel ACDF patients requiring additional surgery more often underwent more extensive revision surgeries.

  View details for DOI 10.1016/j.spinee.2013.07.474

  View details for Web of Science ID 000338467000008

• Neurosurgical interventions for spondyloepiphyseal dysplasia congenita: clinical presentation and assessment of the literature. World neurosurgery Veeravagu, A., Lad, S. P., Camara-Quintana, J. Q., Jiang, B., Shuer, L. 2013; 80 (3-4): 437 e1-8

  Abstract

  BACKGROUND: Spondyloepiphyseal dysplasia (SED) is a rare disease that causes vertebral abnormalities and short-trunk dwarfism. The two forms of SED are congenita and tarda. Each form arises in a genetically distinct fashion and manifests with a different set of complications. SED congenita is more severe, and patients usually display atlantoaxial instability and odontoid hypoplasia. Patients often have various neurologic deficits caused by compression of the spinal cord. The region most affected is the craniovertebral junction (CVJ). METHODS: A review of the PubMed Database, 1970 to the present, was performed using the search term "spondyloepiphyseal dysplasia" and limited to English-language articles. The search identified 22 articles discussing COL2A1 gene mutations and 10 clinical articles describing patients with SED and associated spinal abnormalities. RESULTS: Findings from the literature concerning diagnosis, presenting symptoms, and intervention taken are discussed. Additionally, a patient with a diagnosis of SED congenita who presented with bilateral hand numbness is described. The patient underwent a suboccipital craniotomy; posterior decompression of the foramen magnum, the arch of C1, and the lamina of C2; and instrumented fusion of C1-3 to relieve his symptoms. CONCLUSIONS: In this article, the authors survey the current literature surrounding neurosurgical interventions and present an algorithm for treatment.

  View details for DOI 10.1016/j.wneu.2012.01.030

  View details for PubMedID 22381876

• CyberKnife radiosurgery for the management of skull base and spinal chondrosarcomas. Journal of neuro-oncology Jiang, B., Veeravagu, A., Feroze, A. H., Lee, M., Harsh, G. R., Soltys, S. G., Gibbs, I. C., Adler, J. R., Chang, S. D. 2013; 114 (2): 209-218

  Abstract

  The use of CyberKnife (CK) stereotactic radiosurgery (SRS) for the management of central nervous system chondrosarcomas has not been previously reported. To evaluate outcomes of primary, recurrent, and metastatic chondrosarcomas of the skull base and spine treated with CK SRS, a retrospective observational study of 16 patients treated between 1996 and 2011 with CK SRS was performed using an IRB-approved database at Stanford University Medical Center. Twenty lesions (12 cranial, 8 spinal) across six males and ten females were analyzed. The median age at SRS was 51 years and median follow-up was 33 months. Median tumor volume was 11.0 cm³ and median marginal dosages were 22, 24, 26, 27, and 30 Gy for one to five fractionations, respectively. Overall Kaplan-Meier survival rates were 88, 88, 80, and 66 % at 1, 3, 5, and 10 years after initial presentation. Survival rates at 1, 3, and 5 years after CK were 81, 67, and 55 %, respectively. Actuarial tumor control was 41 ± 13 % at 60 months. At 36 months follow-up, tumor control was 80 % in primary lesions, 50 % in recurrent lesions, and 0.0 % in metastatic disease (p = 0.07). Tumor control was 58 % in cranial lesions and 38 % in spinal lesions. Radiation injury was reported in one patient. CK SRS appears to be a safe adjuvant therapy and offers moderate control for primary cranial chondrosarcoma lesions. There appears to be a clinically, albeit not statistically, significant trend towards poorer outcomes in similarly treated metastatic, recurrent, and spinal chondrosarcomas (p = 0.07). Lesions not candidates for single fraction SRS may be treated with hypofractionated SRS without increased risk for radiation necrosis.

  View details for DOI 10.1007/s11060-013-1172-9

  View details for PubMedID 23748573

• Volumetric Analysis of Intracranial Arteriovenous Malformations Contoured for CyberKnife Radiosurgery With 3-Dimensional Rotational Angiography vs Computed Tomography/Magnetic Resonance Imaging. Neurosurgery Veeravagu, A., Hansasuta, A., Jiang, B., Karim, A. S., Gibbs, I. C., Chang, S. D. 2013; 73 (2): 262-270

  Abstract

  BACKGROUND:: Accurate target delineation has significant impact on brain arteriovenous malformations (AVMs) obliteration, treatment success, and potential complications of stereotactic radiosurgery. OBJECTIVE:: We compare the nidal contouring of AVMs using fused images of contrasted computerized tomography (CT) and magnetic resonance (MRI) with matched images of three-dimensional (3-D) cerebral angiography for Cyberknife radiosurgery (CKRS) treatment planning. METHODS:: Between May 2009 and April 2012, 3-D cerebral angiography was integrated into CKRS target planning for thirty consecutive patients. The AVM nidal target volumes were delineated using fused CT and MRI scans versus fused CT, MRI, and 3-D cerebral angiography for each patient. RESULTS:: The mean volume of the AVM nidus contoured with the addition of 3-D cerebral angiography to the CT/MRI fusion (9.09 cm, 95% CI 5.39-12.8 cm) was statistically smaller than the mean volume contoured with CT/ MRI fused scans alone (14.1 cm, 95% CI 9.16-19.1 cm), with a mean volume difference of δ=5.01 cm (p=0.001). Diffuse AVM nidus was associated with larger mean volume differences in comparison to a compact nidus (δ=6.51 vs. 2.11 cm, p=0.02). The mean volume difference was not statistically associated with the patient's gender (male δ=5.61, female δ=5.06, p=0.84), prior hemorrhage status (yes δ=5.69, no δ=5.23, p=0.86), or prior embolization status (yes δ=6.80, no δ=5.95, p=0.11). CONCLUSION:: For brain AVMs treated with CKRS, the addition of 3-D cerebral angiography to CT/MRI fusions for diagnostic accuracy results in a statistically significant reduction in contoured nidal volume as compared to standard CT/MRI fusion-based contouring.

  View details for DOI 10.1227/01.neu.0000430285.00928.30

  View details for PubMedID 23615081

• Fungal infection of a ventriculoperitoneal shunt: histoplasmosis diagnosis and treatment. World neurosurgery Veeravagu, A., Ludwig, C., Camara-Quintana, J. Q., Jiang, B., Lad, N., Shuer, L. 2013; 80 (1-2): 222 e5-222 e13

  View details for DOI 10.1016/j.wneu.2012.12.016

  View details for PubMedID 23247021

• Fungal infection of a ventriculoperitoneal shunt: histoplasmosis diagnosis and treatment. World neurosurgery Veeravagu, A., Ludwig, C., Camara-Quintana, J. Q., Jiang, B., Lad, N., Shuer, L. 2013; 80 (1-2): 222 e5-13

  Abstract

  BACKGROUND: Histoplasmosis is a fungal disease caused by Histoplasma capsulatum, commonly found in the Americas, and Histoplasma duboisii, located in Africa. In the United States, H. capsulatum is prevalent in the Ohio and Mississippi river valleys. In rare circumstances, central nervous system (CNS) histoplasmosis infection can be caused by shunt placement. We present a case report of a 45-year-old woman in whom CNS histoplasmosis developed after having a ventriculoperitoneal (VP) shunt placed for communicating hydrocephalus. A review of the literature on fungal infections after CNS shunt placement as well as treatment options for this subset of patients was undertaken. METHODS: The PubMed database current to 1958 was filtered and limited to English-language articles. Fifty-eight articles were selected for review based on evidence of information regarding the fungal organism responsible for shunt infection, symptoms, treatment, and/or outcomes. Also included in this review is our case study. RESULTS: A thorough analysis of the PubMed database revealed 58 reported cases of CNS shunt-related fungal infections in the English-language medical literature as well as 7 therapeutic agents used to treat patients in whom postshunt fungal infections developed. CONCLUSIONS: We describe the steps in diagnosis of histoplasmosis after shunt placement, provide an effective therapeutic regimen, and review the present understanding of CNS fungal infections. The medical literature was surveyed to compare and analyze various CNS fungal infections that can arise from shunt placement as well as treatments rendered.

  View details for DOI 10.1016/j.wneu.2012.12.016

  View details for PubMedID 23247021

• Acute respiratory distress syndrome and acute lung injury in patients with vertebral column fracture(s) and spinal cord injury: a nationwide inpatient sample study SPINAL CORD Veeravagu, A., Jiang, B., Rincon, F., Maltenfort, M., Jallo, J., Ratliff, J. K. 2013; 51 (6): 461-465

  Abstract

  Study design:Retrospective Nationwide Inpatient Sample (NIS) study.Objectives:To determine national trends in prevalence, risk factors and mortality for vertebral column fracture (VCF) and spinal cord injury (SCI) patients with and without acute respiratory distress syndrome/acute lung injury (ARDS/ALI).Setting:United States of America, 1988 to 2008.Methods:The NIS was utilized to select 284 612 admissions for VCF with and without acute SCI from 1988 to 2008 based on ICD-9-CM. The data were stratified for in-hospital complications of ARDS/ALI.Results:Patients with SCI were more likely to develop ARDS/ALI compared with those without (odds ratio (OR): 4.9, 95% confidence interval (CI) 4.7-5.2, P<0.001). Compared with patients with lumbar fractures, those with cervical, thoracic and sacral fractures were more likely to develop ARDS/ALI (P<0.001). ARDS/ALI was statistically more prevalent (P<0.01) in VCF/SCI patients with epilepsy, sepsis, cardiac arrest, congestive heart failure (CHF), hypertension, chronic obstructive pulmonary disease and metabolic disorders. Patients with female gender, surgery at rural practice setting, and coronary artery disease and diabetes were less likely to develop ARDS/ALI (P<0.001). VCF/SCI patients who developed ARDS/ALI were more likely to die in-hospital than those without ARDS/ALI (OR 6.5, 95% CI 6.0-7.1, P<0.001). Predictors of in-hospital mortality after VCF/SCI include: older age, male sex, epilepsy, sepsis, hypertension, CHF, chronic obstructive pulmonary disease and liver disease. Patients who developed ARDS/ALI stayed a mean of 25 hospital days (30-440 days) while patients without ARDS/ALI stayed a mean of 6 days (7-868 days, P<0.001).Conclusion:Our analysis demonstrates that SCI patients are more at risk for ARDS/ALI, which carries a significantly higher risk of mortality.Spinal Cord advance online publication, 12 March 2013; doi:10.1038/sc.2013.16.

  View details for DOI 10.1038/sc.2013.16

  View details for Web of Science ID 000320224100007

  View details for PubMedID 23478670

• Brain tuberculoma in a non-endemic area. Infectious disease reports Lober, R. M., Veeravagu, A., Singh, H. 2013; 5 (1)

  Abstract

  Brain tuberculoma has previously accounted for up to a third of new intracranial lesions in areas endemic with tuberculosis, but is unexpected in the United States and other Western countries with improved disease control. Here we show the importance of considering this diagnosis in at-risk patients, even with no definitive pulmonary involvement. We describe a young man who presented with partial seizures and underwent craniotomy for resection of a frontoparietal tuberculoma. He subsequently completed six months of antituberculosis therapy and was doing well without neurological sequelae or evidence of recurrence five months after completion of therapy. With resurgence of tuberculosis cases in the United States and other Western countries, intracerebral tuberculoma should remain a diagnostic consideration in at-risk patients with new space occupying lesions. Mass lesions causing neurological sequelae can be safely addressed surgically and followed with antituberculosis therapy.

  View details for DOI 10.4081/idr.2013.e1

  View details for PubMedID 24470952

• Biopsy versus resection for the management of low-grade gliomas. Cochrane database of systematic reviews Veeravagu, A., Jiang, B., Ludwig, C., Chang, S. D., Black, K. L., Patil, C. G. 2013; 4: CD009319-?

  Abstract

  Low-grade gliomas (LGG) constitute a class of slow-growing primary brain neoplasms. Patients with clinically and radiographically suspected LGG have two initial surgical options, biopsy or resection. Biopsy can provide a histological diagnosis with minimal risk but does not offer a direct treatment. Resection may have additional benefits such as increasing survival and delaying recurrence, but is associated with a higher risk for surgical morbidity. There remains controversy about the role of biopsy versus resection and the relative clinical outcomes for the management of LGG.To assess the clinical effectiveness of biopsy compared to surgical resection in patients with a new lesion suspected to be a LGG.The following electronic databases were searched: Cochrane Central Register of Controlled Trials (CENTRAL) (2012, Issue 11), MEDLINE (1950 to week 3 November 2012), EMBASE (1980 to Week 46 2012). Unpublished and grey literature including Metaregister, Physicians Data Query, www.controlled-trials.com/rct, www.clinicaltrials.gov, and www.cancer.gov/clinicaltrials were also queried for ongoing trials.Patients of any age with a suspected intracranial LGG receiving biopsy or resection within a randomized clinical trial (RCT) or controlled clinical trial (CCT) were included. Patients with prior resections, radiation therapy, or chemotherapy for LGG were excluded. Outcome measures included overall survival (OS), progression free survival (PFS), functionally independent survival (FIS), adverse events, symptom control, and quality of life (QoL).A total of 2764 citations were searched and critically analyzed for relevance. This effort was undertaken by three independent review authors.No RCTs of biopsy or resection for LGG were identified. Twenty other studies were retrieved for analysis based on pre-specified selection criteria. Ten studies were retrospective or literature reviews. Three studies were prospective but were limited to tumor recurrence or the extent of resection. One study was a population-based parallel cohort and not an RCT. Four studies were RCTs, however patients were randomized with respect to varying radiotherapy regimens to assess timing and dose of radiation. One RCT was focused on high-grade gliomas and not LGG. One last RCT evaluated diffusion tensor imaging (DTI)-based neuro-navigation for surgical resection.Currently there are no randomized clinical trials or controlled clinical trials available on which to base clinical decisions. Therefore, physicians must approach each case individually and weigh the risks and benefits of each intervention until further evidence is available. Future research could focus on randomized clinical trials to determine outcomes benefits for biopsy versus resection.

  View details for DOI 10.1002/14651858.CD009319.pub2

  View details for PubMedID 23633369

• Traumatic epistaxis: Skull base defects, intracranial complications and neurosurgical considerations. International journal of surgery case reports Veeravagu, A., Joseph, R., Jiang, B., Lober, R. M., Ludwig, C., Torres, R., Singh, H. 2013; 4 (8): 656-661

  Abstract

  Endonasal procedures may be necessary during management of craniofacial trauma. When a skull base fracture is present, these procedures carry a high risk of violating the cranial vault and causing brain injury or central nervous system infection.A 52-year-old bicyclist was hit by an automobile at high speed. He sustained extensive maxillofacial fractures, including frontal and sphenoid sinus fractures (Fig. 1). He presented to the emergency room with brisk nasopharyngeal hemorrhage, and was intubated for airway protection. He underwent emergent stabilization of his nasal epistaxis by placement of a Foley catheter in his left nare and tamponade with the Foley balloon. A six-vessel angiogram showed no evidence of arterial dissection or laceration. Imaging revealed inadvertent insertion of the Foley catheter and deployment of the balloon in the frontal lobe (Fig. 2). The balloon was subsequently deflated and the Foley catheter removed. The patient underwent bifrontal craniotomy for dural repair of CSF leak. He also had placement of a ventriculoperitoneal shunt for development of post-traumatic hydrocephalus. Although the hospital course was a prolonged one, he did make a good neurological recovery.The authors review the literature involving violation of the intracranial compartment with medical devices in the settings of craniofacial trauma.Caution should be exercised while performing any endonasal procedure in the settings of trauma where disruption of the anterior cranial base is possible.

  View details for DOI 10.1016/j.ijscr.2013.04.033

  View details for PubMedID 23792475

  View details for PubMedCentralID PMC3710897

• Spontaneous intracranial hypotension secondary to anterior thoracic osteophyte: Resolution after primary dural repair via posterior approach. International journal of surgery case reports Veeravagu, A., Gupta, G., Jiang, B., Berta, S. C., Mindea, S. A., Chang, S. D. 2013; 4 (1): 26-29

  Abstract

  Spontaneous intracranial hypotension (SIH) is an uncommon syndrome widely attributed to CSF hypovolemia, typically secondary to spontaneous CSF leak. Although commonly associated with postural headache and variable neurological symptoms, one of the most severe consequences of SIH is bilateral subdural hematomas with resultant neurological deterioration.We present the case of a patient diagnosed with SIH secondary to an anteriorly positioned thoracic osteophyte with resultant dural disruption, who after multiple attempts at nonsurgical management developed bilateral subdural hematomas necessitating emergent surgical intervention. The patient underwent a unilateral posterior repair of his osteophyte with successful anterior decompression. At 36months follow up, the patient reported completely resolved headaches with no focal neurological deficits.We outline our posterior approach to repair of the dural defect and review the management algorithm for the treatment of patients with SIH. We also examine the current hypotheses as to the origin, pathophysiology, diagnosis and treatment of this syndrome.A posterior approach was utilized to repair the dural defect caused by an anterior thoracic osteophyte in a patient with severe SIH complicated by bilateral subdural hematomas. This approach minimizes morbidity compared to an anterior approach and allowed for removal of the osteophyte and repair of the dural defect.

  View details for DOI 10.1016/j.ijscr.2012.06.009

  View details for PubMedID 23108168

  View details for PubMedCentralID PMC3537944

• CyberKnife stereotactic radiosurgery for the treatment of intramedullary spinal cord metastases JOURNAL OF CLINICAL NEUROSCIENCE Veeravagu, A., Lieberson, R. E., Mener, A., Chen, Y., Soltys, S. G., Gibbs, I. C., Adler, J. R., Tian, A. G., Chang, S. D. 2012; 19 (9): 1273-1277

  Abstract

  Spinal cord intramedullary metastases are uncommon and treatment options are limited. We reviewed our experience treating these lesions with radiosurgery to assess safety and efficacy, and to define preliminary treatment recommendations. With Institutional Review Board approval, we identified nine patients with 11 metastases treated with radiosurgery at Stanford University Hospital, between 2000 and 2010. We also reviewed all available published series discussing the treatment of spinal cord metastases. Our patients ranged in age from 33 years to 77 years (median 63 years) and included seven women and two men. Tumors ranged in size from 0.12 cm(3) to 6.4 cm(3) (median 0.48 cm(3)). Five were from breast cancer, two were non-small cell lung cancers, one was a cystic adenocarcinoma, and one was from an epithelioid hemangioepithelioma. All patients had neurologic deficits and multiple other metastases. We delivered 14 Gy to 27 Gy (median 21 Gy) in one to five (median 3) fractions. Complete follow-up was available for all nine patients. One patient remains alive 14 months after therapy. Of the eight deceased patients, survival ranged from one month and two days to nine months and six days (median four months and four days). There were no local recurrences or worsened neurological deficits. To our knowledge this is the largest reported series of spinal cord intramedullary metastases treated with radiosurgery. Survival was poor due to systemic disease, but radiosurgery appears to be safe and prevented local recurrences. With fewer sessions than conventional radiation and less morbidity than surgery, we feel radiosurgery is appropriate for the palliative treatment of these lesions.

  View details for DOI 10.1016/j.jocn.2012.02.002

  View details for Web of Science ID 000308730900014

  View details for PubMedID 22766103

• The effect of centralization of caseload for primary brain tumor surgeries: trends from 2001-2007 ACTA NEUROCHIRURGICA Nuno, M., Mukherjee, D., Carico, C., Elramsisy, A., Veeravagu, A., Black, K. L., Patil, C. G. 2012; 154 (8): 1343-1350

  Abstract

  Improved patient outcomes have been associated with high-caseload hospitals for a multitude of conditions. This study analyzed adult patients undergoing surgical resection or biopsy of primary brain tumors. The aim of this study is two-fold: (1) to evaluate whether the trend towards centralization of primary brain tumor care in the US has continued during the period of between 2001 and 2007, and (2) to analyze volume-outcome effects.Surgical volume trends of adults undergoing resection/biopsy of primary supratentorial brain tumors were analyzed using the Nationwide Inpatient Sample. High- and low-caseload hospitals were defined as those performing in the highest and lowest quintile of procedures, respectively. Length of stay (LOS), mortality and discharge disposition were the main outcomes of interest.NIS estimated 124,171 patients underwent resection/biopsy of primary supratentorial brain tumors between 2001 and 2007 in the US. The average number of annual resections in the highest 2 % and lowest 25 % caseload hospitals were 322 and 12 cases, respectively. Surgeries in high-caseload hospitals increased by 137 %, while those in low-caseload centers declined by 16.0 %. Overall, mortality decreased 35 %, with a reduction of 45 % in high- (from 2.2 % to 1.2 %) and 19 % in low- (from 3.2 % to 2.6 %) caseload hospitals. High-caseload centers had lower LOS than hospitals with lower caseload centers (6.4 vs. 8.0 days, p < 0.001). Multivariate analysis showed that patients treated in low-volume hospitals had an increased risk of death (OR 1.8, CI: 1.2-2.7, p = 0.006) and adverse discharge (OR 1.4, CI: 1.1-1.7, p = 0.01).Neurosurgical caseload at the nation's high volume craniotomy centers has continued to rise disproportionately, while low-caseload centers have seen a decrease in overall surgical volume. Over the time period between 2001 and 2007 there was a trend towards improved in-hospital mortality, LOS and discharge disposition for all hospitals; however, the trend is convincingly favorable for high-caseload hospitals.

  View details for DOI 10.1007/s00701-012-1358-5

  View details for Web of Science ID 000307242500003

  View details for PubMedID 22661296

• Management of intracranial and extracranial chordomas with CyberKnife stereotactic radiosurgery JOURNAL OF CLINICAL NEUROSCIENCE Jiang, B., Veeravagu, A., Lee, M., Harsh, G. R., Lieberson, R. E., Bhatti, I., Soltys, S. G., Gibbs, I. C., Adler, J. R., Chang, S. D. 2012; 19 (8): 1101-1106

  Abstract

  Chordomas are rare, malignant bone tumors of the axial skeleton, occurring particularly at the cranial base or in the sacro-coccygeal region. Although slow growing, chordomas are locally aggressive and challenging to treat. We evaluate the outcomes of skull base and spinal chordomas in 20 patients treated with CyberKnife (CK) stereotactic radiosurgery (SRS) (Accuray, Sunnyvale, CA, USA) between 1994 and 2010 at Stanford Hospital. There were 12 males and eight females (10-78 years; median age: 51.5 years). Eleven patients received CK as primary adjuvant therapy and nine patients received CK for multiple recurrences. The average tumor volume treated was 16.1cm(3) (2.4-45.9 cm(3)), with a mean marginal dose of 32.5 Gy (18-50 Gy). Median follow-up was 34 months (2-131 months). Overall, tumor control was achieved in 11 patients (55%), with eight patients showing tumor size reduction. However, nine patients showed progression and eventually succumbed to the disease (mean time from CK to death was 26.3 months). Of the patients treated with CK as the primary adjuvant therapy, 81.8% had stable or improved outcomes. Only 28.6% of those treated with CK for recurrences had stable or improved outcomes. The overall Kaplan-Meyer survival at five years from the first CK treatment was 52.5%. Moderate tumor control rates can be achieved with few complications with CK SRS. Poor control is associated with complex multiple surgical resections, long delay between initial resection and CK therapy, and recurrently aggressive disease uncontrolled by prior radiation.

  View details for DOI 10.1016/j.jocn.2012.01.005

  View details for Web of Science ID 000306500400009

  View details for PubMedID 22727205

• Renal Osteodystrophy: Neurosurgical Considerations and Challenges WORLD NEUROSURGERY Veeravagu, A., Ponnusamy, K., Jiang, B., Bydon, M., McGirt, M., Gottfried, O. N., Witham, T., Gokaslan, Z. L., Bydon, A. 2012; 78 (1-2)

  Abstract

  Dialysis-associated destructive spondyloarthropathy (DSA) is the major bony complication of end-stage renal disease, most commonly found in the lower cervical region. The risk factors for developing dialysis-associated DSA include duration of hemodialysis and patient age. Patients with DSA have a higher incidence of osteoporosis and poor bone mineral density, which may place them at greater risk of atraumatic fractures, instrumentation failure, and neurologic compromise.We describe a case of cervical radiculopathy due to dialysis-associated DSA atraumatic vertebral body fractures with a postoperative course that was complicated by instrumentation failure. We reviewed the literature regarding all 138 published cases, presenting the complications, surgical treatment options, and outcomes.A 44-year-old dialysis-dependent man presented with acute neck pain, radiculopathy, and weakness due to atraumatic fracture of C5 and C6 vertebral bodies. He underwent anterior C5 and C6 corpectomies, reconstruction with mesh cage and plate, and supplemental posterior instrumentation (C4-T1). Six weeks later, a computed tomography scan revealed anterior translation across the instrumented area with failure of the posterior instrumentation. He subsequently underwent traction, revision reinstrumentation from C2 to T5, and placement of external halo ring/jacket for 6 months. At 18 months later, he remains ambulatory without evidence of construct failure.Patients with renal osteodystrophy present a challenge for the spine surgeon due to compromised bone density. Hardware failure at the bone-construct interface is common in these patients, with revision surgery needed in 22% of published cases. Longer constructs with circumferential instrumentation and halo immobilization may minimize the risk of pseudoarthrosis and construct pull-out.

  View details for DOI 10.1016/j.wneu.2011.09.027

  View details for Web of Science ID 000307933400050

  View details for PubMedID 22120255

• Intramedullary spinal cord metastasis from prostate carcinoma: a case report. Journal of medical case reports Lieberson, R. E., Veeravagu, A., Eckermann, J. M., Doty, J. R., Jiang, B., Andrews, R., Chang, S. D. 2012; 6 (1): 139-?

  Abstract

  Although vertebral and epidural metastases are common, intradural metastases and intramedullary spinal cord metastases are rare. The indications for the treatment of intramedullary spinal cord metastases remain controversial. We present the first biopsy-proven case of an intramedullary spinal cord metastasis from adenocarcinoma of the prostate.Our patient was a 68-year-old right-handed Caucasian man with a Gleason grade 4 + 3 prostate adenocarcinoma who had previously undergone a prostatectomy, androgen blockade and transurethral debulking. He presented with new-onset saddle anesthesia and fecal incontinence. Magnetic resonance imaging demonstrated a spindle-shaped intramedullary lesion of the conus medullaris. Our patient underwent decompression and an excisional biopsy; the lesion's pathology was consistent with metastatic adenocarcinoma of the prostate. Postoperatively, our patient received CyberKnife® radiosurgery to the resection cavity at a marginal dose of 27Gy to the 85% isodose line. At three months follow-up, our patient remains neurologically stable with no new deficits or lesions.We review the literature and discuss the indications for surgery and radiosurgery for intramedullary spinal cord metastases. We also report the novel use of stereotactic radiosurgery to sterilize the resection cavity following an excisional biopsy of the metastasis.

  View details for DOI 10.1186/1752-1947-6-139

  View details for PubMedID 22657386

  View details for PubMedCentralID PMC3419088

• CyberKnife Stereotactic Radiosurgery for Recurrent, Metastatic, and Residual Hemangiopericytomas JOURNAL OF HEMATOLOGY & ONCOLOGY Veeravagu, A., Jiang, B., Patil, C. G., Lee, M., Soltys, S. G., Gibbs, I. C., Chang, S. D. 2011; 4

  Abstract

  Hemangiopericytoma is a rare and aggressive meningeal tumor. Although surgical resection is the standard treatment, hemangiopericytomas often recur with high incidences of metastasis. The purpose of this study was to evaluate the role of CyberKnife stereotactic radiosurgery (CK) in the management of recurrent, metastatic, and residual hemangiopericytomas.In a review of the Stanford radiosurgery database between 2002 and 2009, the authors found 14 patients who underwent CK therapy for recurrent, metastatic, and residual hemangiopericytomas. A total of 24 tumors were treated and the median patient age was 52 years (range 29-70 years) at the time of initial CK therapy. The median follow-up period was 37 months (10-73 months) and all patients had been previously treated with surgical resection. Mean tumor volume was 9.16 cm3 and the mean marginal and maximum radiosurgical doses to the tumors were 21.2 Gy and 26.8 Gy, respectively.Of the 24 tumors treated, 22 have clinical follow-up data at this time. Of those 22 tumors, 12 decreased in size (54.5%), 6 remained unchanged (27.3%), and 4 showed recurrence (18.2%) after CK therapy. Progression-free survival rate was 95%, 71.5%, and 71.5% at 1, 3, and 5 years after multiple CK treatments. The 5-year survival rate after CK was 81%.CK is an effective and safe management option for hemangiopericytomas. The current series demonstrates a tumor control of 81.8%. Other institutions have demonstrated similar outcomes with stereotactic radiosurgery, with tumor control ranging from 46.4% to 100%.

  View details for DOI 10.1186/1756-8722-4-26

  View details for Web of Science ID 000291817100001

  View details for PubMedID 21645367

  View details for PubMedCentralID PMC3118387

• Craniotomy for resection of meningioma in the elderly: a multicentre, prospective analysis from the National Surgical Quality Improvement Program JOURNAL OF NEUROLOGY NEUROSURGERY AND PSYCHIATRY Patil, C. G., Veeravagu, A., Lad, S. P., Boakye, M. 2010; 81 (5): 502-505

  Abstract

  Whether there is an increased surgical risk in elderly patients who undergo craniotomy for meningioma resection remains a point of controversy. Utilising multicentre, prospective data from the National Surgical Quality Improvement Program, the present study sought to address this controversy.All patients who underwent a craniotomy for resection of intracranial meningioma (current procedural terminology codes 61512 and 61519) between 1997 and 2006 at 123 VA hospitals around the country were included. After controlling for preoperative factors such as ASA class, race, diabetes mellitus, disseminated cancer, tobacco use, tumour location and functional health status in a multivariate logistic regression model, the effect of elderly age (age greater than 70 years) on 30 day mortality was determined.Our study included 1281 patients who underwent surgical resection of an intracranial meningioma. Although each VA completed a different number of operations, we are able to provide case volume data for approximately 60 of the 123 hospitals. The elderly cohort represented 21.2% (n=258) of our total study population. Elderly patients had a higher 30 day mortality (12.0%) than younger subjects (4.6%) (p<0.0001). Similarly, elderly patients were more likely to have one or more complications (29.8% vs 13.1%, p<0.0001). Multivariate logistic regression identified age, functional status, preoperative disseminated cancer and tumour location as important predictors of 30 day mortality. After controlling for preoperative comorbidities and risk factors, the odds of perioperative mortality in elderly patients were three times that of younger patients (OR 3.0, 95% CI 1.7 to 5.3, p=0.0102).After carefully controlling for various patient characteristics, ASA class and functional status, elderly patients have poorer outcome after surgical resection of intracranial meningioma than younger subjects.

  View details for DOI 10.1136/jnnp.2009.185074

  View details for Web of Science ID 000277541800011

  View details for PubMedID 19828483

• The role of radiosurgery in the treatment of craniopharyngiomas NEUROSURGICAL FOCUS Veeravagu, A., Lee, M., Jiang, B., Chang, S. D. 2010; 28 (4)

  Abstract

  The treatment of craniopharyngiomas is composed of an intricate balance of multiple modalities. Resection and radiotherapy have been combined to synergistically control tumor growth while preventing undue harm to crucial neurovascular structures. Although a craniopharyngioma is a benign lesion pathologically, it may induce severe neurological injury due to its location and rate of growth. More recently, the advent of targeted, fractionated radiotherapy has allowed for more aggressive tumor control while reducing the necessity for large resections. Initial studies have demonstrated significant tumor control in patients who are treated with resection combined with radiation therapy, versus surgery alone, with a lower rate of treatment-associated neurological deficits. In this review, a detailed account of the current studies evaluating the role of stereotactic radiosurgery in the management of craniopharyngiomas is presented. The authors also provide a short account of their experience to aid in defining the role of CyberKnife radiosurgery.

  View details for DOI 10.3171/2010.2.FOCUS09311

  View details for Web of Science ID 000276212900014

  View details for PubMedID 20367355

• Resolution of syringomyelia after release of tethered cord SURGICAL NEUROLOGY Hsu, A. R., Hou, L. C., Veeravagu, A., Barnes, P. D., Huhn, S. L. 2009; 72 (6): 657-661

  Abstract

  Syringomyelia is an abnormal cystic dilatation of the spinal cord caused by excessive accumulation of CSF. Patients can develop various neurologic deficits secondary to untreated syringomyelia, some of which can be permanent despite surgical intervention.The authors present a patient with syringomyelia, aortic coarctation, and tethered cord syndrome. Serial radiographic imaging demonstrated initial significant reduction of the thoracic syrinx after coarctation repair and release of tethered cord. However, subsequent follow-up imaging revealed partial recurrence.This case provides evidence of a possible cause-effect relationship between syringomyelia and tethered cord. It demonstrates the indication of surveillance imaging of the entire spine to ensure that all potential etiologies of syringomyelia are identified and treated. Furthermore, it illustrates the complex dynamic nature of syrinx physiology and reinforces the importance of serial follow-up studies after surgical intervention.

  View details for DOI 10.1016/j.surneu.2009.05.016

  View details for Web of Science ID 000279233900026

  View details for PubMedID 19604546

• HMG-CoA Reductase Inhibition Causes Increased Necrosis and Apoptosis in an In Vivo Mouse Glioblastoma Multiforme Model ANTICANCER RESEARCH Bababeygy, S. R., Polevaya, N. V., Youssef, S., Sun, A., Xiong, A., Prugpichailers, T., Veeravagu, A., Hou, L. C., Steinman, L., Tse, V. 2009; 29 (12): 4901-4908

  Abstract

  Statins are thought to have tumorolytic properties, reducing angiogenesis by inhibiting pro-angiogenic factors and inducing apoptosis of mural pericytes within the tumor vascular tree.An orthotopic mouse glioblastoma (GL-26) model was used to investigate the effect of simvastatin on glioblastoma vasculature in vivo. GL-26 cells were implanted into the striatum of C5LKa mice treated with either control, low- or high-dose simvastatin. Brains were analyzed for necrotic volume, apoptosis, morphology and pericytic cells within the vascular tree.Low-dose simvastatin increased necrosis and apoptosis compared to both control and high-dose simvastatin groups. High-dose simvastatin increased vessel caliber by reducing pericytic cells along the tumor vessel wall compared to both control and low-dose simvastatin groups.Simvastatin has a dual effect on tumorigenesis. At high doses, it may worsen instead of 'normalizing' tumor angio-architecture, albeit low doses affect tumor cell survival by promoting necrosis and apoptosis.

  View details for Web of Science ID 000273365700001

  View details for PubMedID 20044596

• Risk Factors for Postoperative Spinal Wound Infections After Spinal Decompression and Fusion Surgeries SPINE Veeravagu, A., Patil, C. G., Lad, S. P., Boakye, M. 2009; 34 (17): 1869-1872

  Abstract

  This is a multivariate analysis of a prospectively collected database.To determine preoperative, intraoperative, and patient characteristics that contribute to an increased risk of postoperative wound infection in patients undergoing spinal surgery.Current literature sites a postoperative infection rate of approximately 4%; however, few have completed multivariate analysis to determine factors which contribute to risk of infection.Our study identified patients who underwent a spinal decompression and fusion between 1997 and 2006 from the Veterans Affairs' National Surgical Quality Improvement Program database. Multivariate logistic regression analysis was used to determine the effect of various preoperative variables on postoperative infection.Data on 24,774 patients were analyzed. Wound infection was present in 752 (3.04%) patients, 287 (1.16%) deep, and 468 (1.89%) superficial. Postoperative infection was associated with longer hospital stay (7.12 vs. 4.20 days), higher 30-day mortality (1.06% vs. 0.5%), higher complication rates (1.24% vs. 0.05%), and higher return to the operating room rates (37% vs. 2.45%). Multivariate logistic regression identified insulin dependent diabetes (odds ratios [OR] = 1.50), current smoking (OR = 1.19) ASA class of 3 (OR = 1.45) or 4 to 5 (OR = 1.66), weight loss (OR = 2.14), dependent functional status (1.36) preoperative HCT <36 (1.37), disseminated cancer (1.83), fusion (OR = 1.24) and an operative duration of 3 to 6 hours (OR = 1.33) or >6 hours (OR = 1.40) as statistically significant predictors of postoperative infection.Using multivariate analysis of a large prospectively collected data from the National Surgical Quality Improvement Program database, we identified the most important risk factors for increased postoperative spinal wound infection. We have demonstrated the high mortality, morbidity, and hospitalization costs associated with postoperative spinal wound infections. The information provided should help alert clinicians to presence of these risks factors and the likelihood of higher postoperative infections and morbidity in spinal surgery patients.

  View details for DOI 10.1097/BRS.0b013e3181adc989

  View details for Web of Science ID 000268720000018

  View details for PubMedID 19644339

• Integrin alpha(v)beta(3)-Targeted Radioimmunotherapy of Glioblastoma Multiforme CLINICAL CANCER RESEARCH Veeravagu, A., Liu, Z., Niu, G., Chen, K., Jia, B., Cai, W., Jin, C., Hsu, A. R., Connolly, A. J., Tse, V., Wang, F., Chen, X. 2008; 14 (22): 7330-7339

  Abstract

  Abegrin is a monoclonal antibody to human integrin alphavbeta3, a cell adhesion molecule highly expressed on actively angiogenic endothelium and glioblastoma multiforme tumor cells. The purpose of this study was to evaluate the efficacy of a novel 90Y-Abegrin radioimmunotherapeutic agent in murine xenograft glioblastoma models with noninvasive in vivo molecular imaging modalities.A s.c. U87MG human glioblastoma xenograft model was used to determine maximum tolerated dose (MTD), biodistribution, dose response, and efficacy of 90Y-Abegrin. Antitumor efficacy was also characterized in an orthotopic U87MG and in a HT-29 colorectal cancer model, a low integrin-expressing carcinoma. Small-animal positron emission tomography imaging was used to correlate histologic findings of treatment efficacy.MTD and dose response analysis revealed 200 microCi per mouse as appropriate treatment dose with hepatic clearance and no organ toxicity. 90Y-Abegrin-treated U87MG tumor mice showed partial regression of tumor volume, with increased tumor volumes in 90Y-IgG, Abegrin, and saline groups. 18F-FDG imaging revealed a reduction of cell proliferation and metabolic activity whereas 18F-FLT reflected decreased DNA synthesis in the 90Y-Abegrin group. Ki67 analysis showed reduced proliferative index and quantitative terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive analysis revealed increased DNA fragmentation and apoptosis in 90Y-Abegrin animals. CD31 and 4',6-diamidino-2-phenylindole staining showed increased vascular fragmentation and dysmorphic vessel structure in 90Y-Abegrin animals only. Orthotopic U87MG tumors treated with 90Y-Abegrin displayed reduced tumor volume. HT-29 tumors showed no significant difference among the various groups.Radioimmunotherapy with 90Y-labeled Abegrin may prove promising in the treatment of highly vascular, invasive, and heterogeneous malignant brain tumors.

  View details for DOI 10.1158/1078-0432.CCR-08-0797

  View details for Web of Science ID 000261014500021

  View details for PubMedID 19010848

• The temporal correlation of dynamic contrast-enhanced magnetic resonance imaging with tumor angiogenesis in a murine glioblastoma model 56th Annual Meeting of the Congress-of-Neurological-Surgeons Veeravagu, A., Hou, L. C., Hsu, A. R., Cai, W., Greve, J. M., Chen, X., Tse, V. MANEY PUBLISHING. 2008: 952–59

  Abstract

  Glioblastoma multiforme (GBM) is a WHO grade IV malignant brain tumor with poor prognosis, despite advances in surgical and adjuvant therapy. GBM is characterized by areas of central necrosis and high levels of angiogenesis, during which increased vascular permeability allows for the extravasation of endothelial progenitor cells to support blood vessel and tumor growth. The purpose of this study was to characterize changes in tumor vascular permeability, vascular density and vessel morphology in vivo during angiogenesis.An orthotropic murine (GL26) glioblastoma model was used in this study. in vivo serial dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in combination with histologic and molecular genetic analyses was performed to correlate in vivo imaging of vascular development.DCE-MRI revealed a significant change in tumor vessel permeability dependent upon tumor progression and size. Time to max signal intensity displayed a stepwise increase between days 21 and 24 (p<0.05), a critical period before exponential tumor growth during which a significant increase in tumor vascular density and vessel caliber is observed on histology. Furthermore, quantitative real-time PCR revealed a corollary increase in angiogenic signaling molecules before the observed changes on DCE-MRI.In vivo changes of orthotopic glioma blood vessel permeability as shown by DCE-MRI correlates with histologic quantification of vascular density and vessel caliber as well as with the molecular expression of angiogenic factors. DCE-MRI is a useful tool for non-invasive in vivo monitoring of angiogenesis in pre-clinical tumor models.

  View details for DOI 10.1179/174313208X322761

  View details for Web of Science ID 000261323000013

  View details for PubMedID 18662497

• The Cancer Stem Cell-Vascular Niche Complex in Brain Tumor Formation STEM CELLS AND DEVELOPMENT Veeravagu, A., Bababeygy, S. R., Kalani, M. Y., Hou, L. C., Tse, V. 2008; 17 (5): 859-867

  Abstract

  The cancer stem cell (CSC) theory hypothesizes that a small subpopulation of cells within a tumor mass is responsible for the initiation and maintenance of the tumor. The idea that brain tumors arise from this specific subset of self-renewing, multipotent cells that serve as the locus for tumor formation, has gained great support as evidenced by recent advancements in the biology of breast and colon cancer. It is well established that recruitment of bone marrow-derived proangiogenic progenitor cells and angiogenesis are key events in the process of brain tumor formation; however, the orchestration of these events by the CSC population has only recently been unveiled. In this review, we first introduce the CSC theory and examine the functional development of the vascular niche, its purpose, constituents, and contribution to the development of the CSC-vascular niche complex. Through this discussion, we aim to shed light on the events that may be targeted for therapeutic intervention.

  View details for DOI 10.1089/scd.2008.0047

  View details for Web of Science ID 000260190100004

  View details for PubMedID 18429673

• Outcomes after repeat transsphenoidal surgery for recurrent Cushing's disease NEUROSURGERY Patil, C. G., Veeravagu, A., Prevedello, D. A., Katznelson, L., Vance, M. L., Laws, E. R., Kelly, D. F., Oyesiku, N. M., Post, K. D., Esposito, F., Cappabianca, P. 2008; 63 (2): 266-271

  Abstract

  To systematically analyze patient outcomes after repeat transsphenoidal (TS) surgery for recurrent Cushing's disease.We retrospectively reviewed records of all patients with recurrent Cushing's disease who underwent repeat TS surgery for resection of a pituitary corticotroph adenoma at the University of Virginia Medical Center from 1992 to 2006. Remission at follow-up was defined as a normal postoperative 24-hour urine free cortisol, or continued need for glucocorticoid replacement after repeat TS surgery. Recurrence of the disease was defined as an elevated 24-hour urine free cortisol with clinical symptoms consistent with Cushing's disease while not receiving glucocorticoid replacement. Multivariate logistic regression was performed to evaluate the effect of potential predictors on remission. Recurrence rates, subsequent treatments, and the final endocrine status of the patients are presented.We identified 36 patients who underwent repeat TS surgery for recurrent Cushing's disease. The mean age of the patients was 40.3 years (range, 17.1-63.0 yr), and 26 were women. The median time to recurrence after initial successful TS surgery was 36 months (range, 4 mo-16 yr). Remission after repeat TS surgery was observed in 22 (61%) of the 36 patients. During the same time period, of the 338 patients who underwent first-time TS surgery for Cushing's disease, remission was achieved in 289 (85.5%). The odds of failure (to achieve remission) for patients with repeat TS surgery for recurrent Cushing's disease were 3.7 times that of patients undergoing first-time TS surgery (odds ratio, 3.7; 95% confidence interval, 1.8-7.8). Two of the 22 patients with successful repeat TS surgery had a second recurrence at 6 and 11 months, respectively. Complete biochemical and clinical remission after stereotactic radiosurgery, adrenalectomy, and ongoing ketoconazole therapy was achieved in 30 (83.3%) of the 36 patients, and active disease continued in 6 patients (16.7%).Although the success of repeat TS surgery for recurrence of Cushing's disease is less than that of initial surgery, a second procedure offers a reasonable possibility of immediate remission. If the operation is not successful, other treatments, including pituitary radiation, medical therapy, and even bilateral adrenalectomy, are required.

  View details for DOI 10.1227/01.NEU.0000313117.35824.9F

  View details for Web of Science ID 000258944100017

  View details for PubMedID 18797356

• Moyamoya disease in pediatric patients: outcomes of neurosurgical interventions NEUROSURGICAL FOCUS Veeravagu, A., Guzman, R., Patil, C. G., Hou, L. C., Lee, M., Steinberg, G. K. 2008; 24 (2)

  Abstract

  Neurosurgical interventions for moyamoya disease (MMD) in pediatric patients include direct, indirect, and combined revascularization procedures. Each technique has shown efficacy in the treatment of pediatric MMD; however, no single study has demonstrated the superiority of one technique over another. In this review, the authors explore the various studies focused on the use of these techniques for MMD in the pediatric population. They summarize the results of each study to clearly depict the clinical outcomes achieved at each institution that had utilized direct, indirect, or combined techniques. In certain studies, multiple techniques were used, and the clinical or radiological outcomes were compared accordingly. Direct techniques have been shown to aid a reduction in perioperative strokes and provide immediate revascularization to ischemic areas; however, these procedures are technically challenging, and not all pediatric patients are appropriate candidates. Indirect techniques have also shown efficacy in the pediatric population but may require a longer period for revascularization to occur and perfusion deficits to be reversed. The authors concluded that the clinical efficacy of one technique over another is still unclear, as most studies have had small populations and the same outcome measures have not been applied. Authors who compared direct and indirect techniques noted approximately equal clinical outcomes with differences in radiological findings. Additional, larger studies are needed to determine the advantages and disadvantages of the different techniques for the pediatric age group.

  View details for DOI 10.3171/FOC/2008/24/2/E16

  View details for Web of Science ID 000256268400018

  View details for PubMedID 18275292

• Glutaric acidemia type I: a neurosurgical perspective JOURNAL OF NEUROSURGERY Hou, L. C., Veeravagu, A., Hsu, A. R., Enns, G. M., Huhn, S. L. 2007; 107 (2): 167-172

  Abstract

  Glutaric acidemia type I (GA-I) is a rare, autosomal recessive metabolic disorder that leads to severe dystonia, basal ganglia degeneration, and bilaterally enlarged anterior middle cranial fossae. The current management of this disease includes early diagnosis with newborn screening, prevention of catabolism, carnitine supplementation, and a strict dietary protein restriction. Neurosurgical evaluation and intervention may be necessary in patients with structural lesions associated with this disease. In this report, the authors present two pediatric patients with GA-I and discuss the neurosurgical aspects of this rare medical disorder.

  View details for DOI 10.3171/PED-07/08/167

  View details for PubMedID 18459892

• Integrin alpha(v)beta(3) antagonists for anti-angiogenic cancer treatment RECENT PATENTS ON ANTI-CANCER DRUG DISCOVERY Hsu, A. R., Veeravagu, A., Cai, W., Hou, L. C., Tse, V., Chen, X. 2007; 2 (2): 143-158

  Abstract

  Direct contact between cellular and extracellular matrix (ECM) proteins is necessary for a diverse array of physiologic processes including cellular activation, migration, proliferation, and differentiation. These direct interactions are modulated by cell adhesion molecules (CAMs) such as integrins, selectins, cadherins, and immunoglobulins. Integrin signaling also plays a key role in tumor growth, angiogenesis, and metastasis. Recent advances in the discovery and characterization of CAMs and their receptors, most notably integrin alpha(v)beta(3), and the clarification of their roles in disease states have laid the groundwork for the development and clinical implementation of novel anti-cancer treatments. Integrin alpha (v)beta(3) is a glycoprotein membrane receptor which recognizes ECM proteins expressing an arginine-glycine-aspartic acid (RGD) peptide sequence. The receptor is highly expressed on activated tumor endothelial cells, but not resting endothelial cells and normal organ systems, thus making alpha(v)beta(3) an appropriate target for anti-angiogenic therapeutics. In addition, alpha(v)beta(3) is also expressed on tumor cells, allowing for both tumor cell and tumor vasculature targeting of anti-integrin therapy. Throughout the past decade, numerous patents have been published and issued using alpha(v)beta(3) antagonists for the prevention and/or treatment of cancer, with many antagonists demonstrating positive pre-clinical anti-angiogenic and anti-tumor results. This review will focus on the key points and distinguishing factors for patents which use antibodies, RGD peptides, non-RGD peptides, peptidomimetics, and amine salts as alpha(v)beta(3) antagonists.

  View details for Web of Science ID 000247259700004

  View details for PubMedID 18221059

• Multimodality molecular imaging of glioblastoma growth inhibition with vasculature-targeting fusion toxin VEGF(121)/rGel JOURNAL OF NUCLEAR MEDICINE Hsu, A. R., Cai, W., Veeravagu, A., Mohamedali, K. A., Chen, K., Kim, S., Vogel, H., Hou, L. C., Tse, V., Rosenblum, M. G., Chen, X. 2007; 48 (3): 445-454

  Abstract

  Vascular endothelial growth factor A (VEGF-A) and its receptors, Flt-1/FLT-1 (VEGFR-1) and Flk-1/KDR (VEGFR-2), are key regulators of tumor angiogenesis and tumor growth. The purpose of this study was to determine the antiangiogenic and antitumor efficacies of a vasculature-targeting fusion toxin (VEGF(121)/rGel) composed of the VEGF-A isoform VEGF(121) linked with a G(4)S tether to recombinant plant toxin gelonin (rGel) in an orthotopic glioblastoma mouse model by use of noninvasive in vivo bioluminescence imaging (BLI), MRI, and PET.Tumor-bearing mice were randomized into 2 groups and balanced according to BLI and MRI signals. PET with (64)Cu-1,4,7,10-tetraazacyclododedane-N,N',N'',N'''-tetraacetic acid (DOTA)-VEGF(121)/rGel was performed before VEGF(121)/rGel treatment. (18)F-Fluorothymidine ((18)F-FLT) scans were obtained before and after treatment to evaluate VEGF(121)/rGel therapeutic efficacy. In vivo results were confirmed with ex vivo histologic and immunohistochemical analyses.Logarithmic transformation of peak BLI tumor signal intensity revealed a strong correlation with MRI tumor volume (r = 0.89, n = 14). PET with (64)Cu-DOTA-VEGF(121)/rGel before treatment revealed a tumor accumulation (mean +/- SD) of 11.8 +/- 2.3 percentage injected dose per gram at 18 h after injection, and the receptor specificity of the tumor accumulation was confirmed by successful blocking of the uptake in the presence of an excess amount of VEGF(121). PET with (18)F-FLT revealed significant a decrease in tumor proliferation in VEGF(121)/rGel-treated mice compared with control mice. Histologic analysis revealed specific tumor neovasculature damage after treatment with 4 doses of VEGF(121)/rGel; this damage was accompanied by a significant decrease in peak BLI tumor signal intensity.The results of this study suggest that future clinical multimodality imaging and therapy with VEGF(121)/rGel may provide an effective means to prospectively identify patients who will benefit from VEGF(121)/rGel therapy and then stratify, personalize, and monitor treatment to obtain optimal survival outcomes.

  View details for PubMedID 17332623

• Molecular events of brain metastasis. Neurosurgical focus Santarelli, J. G., Sarkissian, V., Hou, L. C., Veeravagu, A., Tse, V. 2007; 22 (3): E1-?

  Abstract

  The brain is a privileged site of systemic cancer metastasis. The stages of the metastatic journey from the periphery to the brain are driven by molecular events that tie the original site of disease to the distant host tissue. This preference is not arbitrary but rather a directed phenomenon that includes such critical steps as angiogenesis and the preparation of the premetastatic niche. It appears that the connection between naive brain and cancer cells is made in advance of any metastatic breach of the blood-brain barrier. This contributes to the preferential homing of cancer cells to the brain. Delineation of the guidance mechanisms and elements that influence cancer cell motility and dormancy are important for the advancement of treatment modalities aimed at the remediation of this devastating disease.

  View details for PubMedID 17608351

• Spinal gout in a renal transplant patient: a case report and literature review SURGICAL NEUROLOGY Hou, L. C., Hsu, A. R., Veeravagu, A., Boakye, M. 2007; 67 (1): 65-73

  Abstract

  Gout in the axial spine is rare. We present a case report on a renal transplant patient who developed fever and acute back pain at the L5 through S1 level secondary to sodium urate deposits. We review the literature on this rare disease and propose a management algorithm based on a resulting analysis.A 37-year-old man with a history of gout and a renal transplant for IgA nephropathy presented with acute back pain and fever without evidence of neurological deficits. Magnetic resonance imaging revealed a uniformly contrast-enhancing infiltrative process involving the right pedicle, lamina, and inferior facet of the L5 vertebra. Computed tomography-guided needle biopsy revealed a friable white tissue consistent with sodium urate crystals. Conservative treatment with steroids and narcotics was used with good symptomatic relief.Although few cases of gout involving the spine have been reported, its prevalence is likely grossly underestimated. Most patients have a history of gout and have elevated levels of serum urate level on presentation. The disease most commonly involves the lumbar spine. Patients usually have neurological deficits on presentation, and surgical decompression produces favorable outcomes. However, conservative medical management is appropriate for those with back pain only. Aggressive control of hyperuricemia is essential regardless of the method of treatment.

  View details for DOI 10.1016/j.surneu.2006.03.038

  View details for Web of Science ID 000243798000014

  View details for PubMedID 17210304

• Vascular endothelial growth factor and vascular endothelial growth factor receptor inhibitors as anti-angiogenic agents in cancer therapy RECENT PATENTS ON ANTI-CANCER DRUG DISCOVERY Veeravagu, A., Hsu, A. R., Cai, W., Hou, L. C., Tse, V. C., Chen, X. 2007; 2 (1): 59-71

  Abstract

  New blood vessel formation (angiogenesis) is fundamental to the process of tumor growth, invasion, and metastatic dissemination. The vascular endothelial growth factor (VEGF) family of ligands and receptors are well established as key regulators of these processes. VEGF is a glycoprotein with mitogenic activity on vascular endothelial cells. Specifically, VEGF-receptor pathway activation results in signaling cascades that promote endothelial cell growth, migration, differentiation, and survival from pre-existing vasculature. Thus, the role of VEGF has been extensively studied in the pathogenesis and angiogenesis of human cancers. Recent identification of seven VEGF ligand variants (VEGF [A-F], PIGF) and three VEGF tyrosine kinase receptors (VEGFR- [1-3]) has led to the development of several novel inhibitory compounds. Clinical trials have shown inhibitors to this pathway (anti-VEGF therapies) are effective in reducing tumor size, metastasis and blood vessel formation. Clinically, this may result in increased progression free survival, overall patient survival rate and will expand the potential for combinatorial therapies. Having been first described in the 1980s, VEGF patenting activity since then has focused on anti-cancer therapeutics designed to inhibit tumoral vascular formation. This review will focus on patents which target VEGF-[A-F] and/or VEGFR-[1-3] for use in anti-cancer treatment.

  View details for Web of Science ID 000246564300004

  View details for PubMedID 18221053

• CyberKnife radiosurgical rhizotomy for the treatment of atypical trigeminal nerve pain. Neurosurgical focus Patil, C. G., Veeravagu, A., Bower, R. S., Li, G., Chang, S. D., Lim, M., Adler, J. R. 2007; 23 (6): E9-?

  Abstract

  Patients with atypical trigeminal neuralgia (TN) have unilateral pain in the trigeminal distribution that is dull, aching, or burning in nature and is constant or nearly constant. Studies of most radiosurgical and surgical series have shown lower response rates in patients with atypical TN. This study represents the first report of the treatment of atypical TN with frameless CyberKnife stereotactic radiosurgery (SRS).Between 2002 and 2007, 7 patients that satisfied the criteria for atypical TN and underwent SRS were included in our study. A 6-8-mm segment of the trigeminal nerve was targeted, excluding the proximal 3 mm at the brainstem. All patients were treated in a single session with a median maximum dose of 78 Gy and a median marginal dose of 64 Gy.Outcomes in 7 patients with a mean age of 61.6 years and a median follow-up of 20 months are reported. Following SRS, 4 patients had complete pain relief, 2 had minimal pain relief with some decrease in the intensity of their pain, and 1 patient experienced no pain relief. Pain relief was reported within 1 week of SRS in 4 patients and at 4 months in 2 patients. After a median follow-up of 28 months, pain did not recur in any of the 4 patients who had reported complete pain relief. Complications after SRS included bothersome numbness in 3 patients and significant dysesthesias in 1 patient.The authors have previously reported a 90% rate of excellent pain relief in patients with classic TN treated with CyberKnife SRS. Compared with patients with classic TN, patients with atypical TN have a lower rate of pain relief. Nevertheless, the nearly 60% rate of success after SRS achieved in this study is still comparable to or better than results achieved with any other treatment modality for atypical TN.

  View details for PubMedID 18081486

• In vivo near-infrared fluorescence imaging of integrin alpha(v)beta(3) in an orthotopic glioblastoma model MOLECULAR IMAGING AND BIOLOGY Hsu, A. R., Hou, L. C., Veeravagu, A., Greve, J. M., Vogel, H., Tse, V., Chen, X. 2006; 8 (6): 315-323

  Abstract

  Expression of cell adhesion molecule integrin alpha(v)beta(3) is significantly up-regulated during tumor growth, and sprouting of tumor vessels and correlates well with tumor aggressiveness. The purpose of this study was to visualize tumor integrin alpha(v)beta(3) expression in vivo by using near-infrared fluorescence (NIRF) imaging of Cy5.5-linked cyclic arginine-glycine-aspartic acid (RGD) peptide in an orthotopic brain tumor model.U87MG glioma cells transfected with the firefly luciferase gene were stereotactically injected into nude mice in the right frontal lobe. Bioluminescence imaging (BLI) using D: -luciferin substrate and small animal magnetic resonance imaging (MRI) using gadolinium contrast enhancement were conducted weekly after tumor cell inoculation to monitor intracranial tumor growth. Integrin alpha(v)beta(3) expression was assessed by using a three-dimensional optical imaging system (IVIS 200) 0-24 hours after administration of 1.5 nmol monomeric Cy5.5-RGD via the tail vein. Animals were injected intravenously with both Texas Red-tomato lectin and Cy5.5-RGD prior to sacrifice to visualize peptide localization to tumor vasculature using histology.Fluorescence microscopy demonstrated specific Cy5.5-RGD binding to both U87MG tumor vessels and tumor cells with no normal tissue binding. NIRF imaging showed highest tumor uptake and tumor to normal brain tissue ratio two hours postinjection (2.64 +/- 0.20). Tumor uptake of Cy5.5-RGD was effectively blocked by using unlabeled c(RGDyK), and injection of Cy5.5 dye alone showed nonspecific binding.Optical imaging via BLI and NIRF offer a simple, effective, and rapid technique for noninvasive in vivo monitoring and semiquantitative analysis of intracranial tumor growth and integrin alpha(v)beta(3) expression. This study suggests that NIRF via fluorescently labeled RGD peptides may provide enhanced surveillance of tumor angiogenesis and anti-integrin treatment efficacy in orthotopic brain tumor models.

  View details for DOI 10.1007/s11307-006-0059-y

  View details for PubMedID 17053862

• Recurrent glioblastoma multiforme: a review of natural history and management options. Neurosurgical focus Hou, L. C., Veeravagu, A., Hsu, A. R., Tse, V. C. 2006; 20 (4): E5-?

  Abstract

  Glioblastoma multiforme (GBM) is one of the most aggressive primary brain tumors, with a grim prognosis despite maximal treatment. Advancements in the past decades have not significantly increased the overall survival of patients with this disease. The recurrence of GBM is inevitable, its management often unclear and case dependent. In this report, the authors summarize the current literature regarding the natural history, surveillance algorithms, and treatment options of recurrent GBM. Furthermore, they provide brief discussions regarding current novel efforts in basic and clinical research. They conclude that although recurrent GBM remains a fatal disease, the literature suggests that a subset of patients may benefit from maximal treatment efforts. Nevertheless, further research effort in all aspects of GBM diagnosis and treatment remains essential to improve the overall prognosis of this disease.

  View details for PubMedID 16709036