Michael Jensen, MD, PhD

All Publications

• 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

• Opioid Usage in Lumbar Disc Herniation Patients with Nonsurgical, Early Surgical, and Late Surgical Treatments WORLD NEUROSURGERY Zhou, Z., Jin, M. C., Jensen, M. R., Guinle, M., Ren, A., Agarwal, A. A., Leaston, J., Ratliff, J. K. 2023; 173

  Abstract

  Assess opioid usage in surgical and non-surgical patients with lumbar disc herniation receiving different treatment approaches and timing.Individuals with newly diagnosed lumbar intervertebral disc without myelopathy were queried from Optum Clinformatics DataMart. Patients were categorized into 3 cohorts: nonsurgical, early surgery, and late surgery. Early surgery cohort patients had surgery within 30-days post-diagnosis; late surgery cohort patients had surgery after 30 days but before 1-year post-diagnosis. The index date was defined as the diagnosis date for nonsurgical patients, and the initial surgery date for surgical patients. The primary outcome was the average daily opioid morphine milligram equivalent (MME) prescribed. Additional outcomes included the percentage of opioid-using patients and cumulative opioid burden.A total of 573,082 patients met inclusion criteria: 533,226 patients received nonsurgical treatments, 22,312 patients received early surgery, and 17,544 patients received late surgery. Both surgical cohorts experienced a "post-surgical hump" of opioid usage, which then sharply declined and gradually plateaued, with daily opioid MME consistently lower in the early as opposed to late surgery cohort. The early surgery cohort also consistently had a lower prevalence of opioid-using patients than the late surgery cohort. Patients receiving nonsurgical demonstrated the highest one-year post-index cumulative opioid burden, and the early surgery cohort consistently had lower cumulative opioid MME than the late surgery cohort.Early surgery in lumbar disc herniation patients is associated with lower long-term average daily MME, incidence of opioid use, and one-year cumulative MME burden compared to nonsurgical and late surgery treatment approaches.

  View details for DOI 10.1016/J.WNEU.2023.02.029

  View details for Web of Science ID 001001417400001

  View details for PubMedID 36775237

• Opioid usage in lumbar disc herniation patients with nonsurgical, early, and late surgical treatments. World neurosurgery Zhou, Z., Jin, M. C., Jensen, M. R., Barros Guinle, M. I., Ren, A., Agarwal, A. A., Leaston, J., Ratliff, J. K. 2023

  Abstract

  Assess opioid usage in surgical and non-surgical patients with lumbar disc herniation receiving different treatment approaches and timing.Individuals with newly diagnosed lumbar intervertebral disc without myelopathy were queried from Optum Clinformatics DataMart. Patients were categorized into 3 cohorts: nonsurgical, early surgery, and late surgery. Early surgery cohort patients had surgery within 30-days post-diagnosis; late surgery cohort patients had surgery after 30 days but before 1-year post-diagnosis. The index date was defined as the diagnosis date for nonsurgical patients, and the initial surgery date for surgical patients. The primary outcome was the average daily opioid morphine milligram equivalent (MME) prescribed. Additional outcomes included the percentage of opioid-using patients and cumulative opioid burden.A total of 573,082 patients met inclusion criteria: 533,226 patients received nonsurgical treatments, 22,312 patients received early surgery, and 17,544 patients received late surgery. Both surgical cohorts experienced a "post-surgical hump" of opioid usage, which then sharply declined and gradually plateaued, with daily opioid MME consistently lower in the early as opposed to late surgery cohort. The early surgery cohort also consistently had a lower prevalence of opioid-using patients than the late surgery cohort. Patients receiving nonsurgical demonstrated the highest one-year post-index cumulative opioid burden, and the early surgery cohort consistently had lower cumulative opioid MME than the late surgery cohort.Early surgery in lumbar disc herniation patients is associated with lower long-term average daily MME, incidence of opioid use, and one-year cumulative MME burden compared to nonsurgical and late surgery treatment approaches.

  View details for DOI 10.1016/j.wneu.2023.02.029

  View details for PubMedID 36775237

• 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

• Research reporting in cubital tunnel syndrome studies: an analysis of the literature. Acta neurochirurgica Hug, N. F., Smith, B. W., Sakamuri, S., Jensen, M., Purger, D. A., Spinner, R. J., Wilson, T. J. 1800

  Abstract

  PURPOSE: There is a strong need for a set of consensus outcomes to be utilized for future studies on cubital tunnel syndrome. The goal was to assess the outcome measures utilized in the cubital tunnel syndrome literature as a way of measuring popularity/acceptability and then to perform a literature review for the most commonly used outcomes.METHODS: A literature search was performed using the pubmed.gov database and Medical Subject Headings (MeSH). For each article, the following data were abstracted: study type, motor outcome(s), sensory outcome(s), composite outcome(s), patient-reported outcome (PRO) metric(s), pain outcome(s), psychological outcome(s), electrodiagnostic outcome(s), and any other outcomes that were used.RESULTS: A composite outcome was reported in 52/85 (61%) studies, with the modified Bishop score (27/85; 32%) most common. A motor outcome was reported in 44/85 (52%) studies, with dynamometry (38/85; 45%) most common. The majority of studies (55%) did not report a sensory outcome. The majority of studies (52%) did not report a PRO. A specific pain outcome was reported in the minority (23/85; 27%), with the visual analogue scale (VAS) (22/85; 26%) most common. Pre- and postoperative electrodiagnostic results were presented in 22/85 studies (26%).DISCUSSION: Understanding current clinical practice and historical outcomes reporting provides a foundation for discussion regarding the development of a core outcome set for cubital tunnel syndrome. We hope that the data provided in the current study will stoke a discussion that will culminate in a consensus statement for research reporting in cubital tunnel syndrome studies.

  View details for DOI 10.1007/s00701-021-05102-9

  View details for PubMedID 34993620

• Diagnosis of Sports-Related Peripheral Nerve Injury Neurosurgical Care of Athletes Hug, N. F., Jensen, M., Purger, D. A., Wilson, T. J. 2022
• 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

• Assessment of variability in motor grading and patient-reported outcome reporting: a multi-specialty, multi-national survey. Acta neurochirurgica Smith, B. W., Sakamuri, S., Flavin, K. E., Jensen, M., Purger, D. A., Yang, L. J., Spinner, R. J., Wilson, T. J. 2021

  Abstract

  BACKGROUND: The goal of this survey-based study was to evaluate the current practice patterns of clinicians who assess patients with peripheral nerve pathologies and to assess variance in motor grading on the Medical Research Council (MRC) scale using example case vignettes.METHODS: An electronic survey was distributed to clinicians who regularly assess patients with peripheral nerve pathology. Survey sections included (1) demographic data, (2) vignettes where respondents were asked to assess on the MRC scale, and (3) assessment of practice patterns regarding the use of patient-reported outcome measures. Inter-rater reliability statistics were calculated for the application of the MRC scale on example vignettes.RESULTS: There were 109 respondents. There was significant dispersion in motor grading seen on the example vignettes. For the raw responses grading the example vignettes on the MRC scale, Krippendorff's alpha was 0.788 (95% CI 0.604, 0.991); Gwet's AC2 was 0.808 (95% CI 0.683, 0.932); Fleiss' kappa was 0.416 (95% CI 0.413, 0.419). Most respondents reported not utilizing any patient-reported outcome measures across peripheral nerve pathologies.DISCUSSION: Our data show that there is significant disagreement among providers when applying the MRC scale. It is important for us to reassess our current tools for patient evaluation in order to improve upon both clinical evaluation and outcomes reporting. Consensus guidelines for outcomes reporting are needed, and domains outside of manual muscle testing should be included.

  View details for DOI 10.1007/s00701-021-04861-9

  View details for PubMedID 33990886

• Commentary: Transdural Spinal Cord Herniation: An Exceptional Complication of Thoracoscopic Discectomy. Operative neurosurgery (Hagerstown, Md.) Jensen, M., Zygourakis, C. 2021

  View details for DOI 10.1093/ons/opab083

  View details for PubMedID 33825873

• Case Report on Deep Brain Stimulation Rescue After Suboptimal MR-Guided Focused Ultrasound Thalamotomy for Essential Tremor: A Tractography-Based Investigation. Frontiers in human neuroscience Saluja, S. n., Barbosa, D. A., Parker, J. J., Huang, Y. n., Jensen, M. R., Ngo, V. n., Santini, V. E., Pauly, K. B., Ghanouni, P. n., McNab, J. A., Halpern, C. H. 2020; 14: 191

  Abstract

  Essential tremor (ET) is the most prevalent movement disorder in adults, and can often be medically refractory, requiring surgical intervention. MRI-guided focused ultrasound (MRgFUS) is a less invasive procedure that uses ultrasonic waves to induce lesions in the ventralis intermedius nucleus (VIM) to treat refractory ET. As with all procedures for treating ET, optimal targeting during MRgFUS is essential for efficacy and durability. Various studies have reported cases of tremor recurrence following MRgFUS and long-term outcome data is limited to 3-4 years. We present a tractography-based investigation on a case of DBS rescue for medically refractory ET that was treated with MRgFUS that was interrupted due to the development of dysarthria during the procedure. After initial improvement, her hand tremor started to recur within 6 months after treatment, and bilateral DBS was performed targeting the VIM 24 months after MRgFUS. DBS induced long-term tremor control with monopolar stimulation. Diffusion MRI tractography was used to reconstruct the dentatorubrothalamic (DRTT) and corticothalmic (CTT) tracts being modulated by the procedures to understand the variability in efficacy between MRgFUS and DBS in treating ET in our patient. By comparing the MRgFUS lesion and DBS volume of activated tissue (VAT), we found that the MRgFUS lesion was located ventromedially to the VAT, and was less than 10% of the size of the VAT. While the lesion encompassed the same proportion of DRTT streamlines, it encompassed fewer CTT streamlines than the VAT. Our findings indicate the need for further investigation of targeting the CTT when using neuromodulatory procedures to treat refractory ET for more permanent tremor relief.

  View details for DOI 10.3389/fnhum.2020.00191

  View details for PubMedID 32676015

  View details for PubMedCentralID PMC7333679

• 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

• EQ-5D Quality-of-Life Analysis and Cost-Effectiveness After Skull Base Meningioma Resection NEUROSURGERY Karsy, M., Jensen, M. R., Guan, J., Ravindra, V. M., Bisson, E. F., Couldwell, W. T. 2019; 85 (3): E543–E552

  View details for DOI 10.1093/neuros/nyz040

  View details for Web of Science ID 000489702900042

• Trends and Cost-Analysis of Lower Extremity Nerve Injury Using the National Inpatient Sample NEUROSURGERY Foster, C. H., Karsy, M., Jensen, M. R., Guan, J., Eli, I., Mahan, M. A. 2019; 85 (2): 250–56

  View details for DOI 10.1093/neuros/nyy265

  View details for Web of Science ID 000493103500088

• EQ-5D Quality-of-Life Analysis and Cost-Effectiveness After Skull Base Meningioma Resection. Neurosurgery Karsy, M., Jensen, M. R., Guan, J., Ravindra, V. M., Bisson, E. F., Couldwell, W. T. 2019

  Abstract

  BACKGROUND: Skull base meningioma management is complicated by their proximity to intracranial neurovascular structures because complete resection may pose a risk of worsening morbidity.OBJECTIVE: To assess the influence of clinical outcomes and surgical management on patient-perceived quality-of-life outcomes, value, and cost-effectiveness.METHODS: Patients who underwent resection of a skull base meningioma, had adequate clinical follow-up, and completed EQ-5D-3L questionnaires preoperatively and at 1 mo and 1 yr postoperatively were identified in a retrospective review. Cost data from the Value Driven Outcomes database were analyzed.RESULTS: A total of 52 patients (83.0% women, mean age 51.9 yr) were categorized by worsened (n=7), unchanged (n=24), or improved (n=21) EQ-5D-3L index scores at 1-mo follow-up. No difference in subcategory cost contribution or total cost was seen in the 3 groups. Patients with improved scores showed a steady improvement through each follow-up period, whereas those with unchanged or worsened scores did not. Mean quality-adjusted life years (QALYs) and cost per QALY improved for all groups but at a higher rate for patients with better outcomes at 30-d follow-up. Female sex, absence of proptosis, nonfrontotemporal approaches, no optic nerve decompression, and absence of surgical complications demonstrated improved EQ-5D-3L scores at 1-yr follow-up. A mean cost per QALY of $27 731.06±22 050.58 was observed for the whole group and did not significantly differ among patient groups (P=.1).CONCLUSION: Patients undergoing resection of skull base meningiomas and who experience an immediate improvement in EQ-5D are likely to show continued improvement at 1 yr, with improved QALY and reduced cost per QALY.

  View details for PubMedID 30869135

• Intravenous acetaminophen for postoperative supratentorial craniotomy pain: a prospective, randomized, double-blinded, placebo-controlled trial. Journal of neurosurgery Sivakumar, W., Jensen, M., Martinez, J., Tanana, M., Duncan, N., Hoesch, R., Riva-Cambrin, J. K., Kilburg, C., Ansari, S., House, P. A. 2019; 130 (3): 766-722

  Abstract

  Acute pain control after cranial surgery is challenging. Prior research has shown that patients experience inadequate pain control post-craniotomy. The use of oral medications is sometimes delayed because of postoperative nausea, and the use of narcotics can impair the evaluation of brain function and thus are used judiciously. Few nonnarcotic intravenous (IV) analgesics exist. The authors present the results of the first prospective study evaluating the use of IV acetaminophen in patients after elective craniotomy.The authors conducted a randomized, double-blinded, placebo-controlled investigation. Adults undergoing elective, supratentorial craniotomies between September 2013 and June 2015 were randomized into two groups. The experimental group received 1000 mg/100 ml IV acetaminophen every 8 hours for 48 hours. The placebo group received 100 ml of 0.9% normal saline on the same schedule. Both groups were also treated with a standardized pain control algorithm. The study was powered to detect a 30% difference in the primary outcome measures: narcotic consumption (morphine equivalents, ME) at 24 and 48 hours after surgery. Patient-reported pain scores immediately postoperatively and 48 hours after surgery were also recorded.A total of 204 patients completed the trial. No significant differences were found in narcotic consumption between groups at either time point (in the treatment and placebo groups, respectively, at 24 hours: 84.3 ME [95% CI 70.2–98.4] and 85.5 ME [95% CI 73–97.9]; and at 48 hours: 123.5 ME [95% CI 102.9–144.2] and 134.2 ME [95% CI 112.1–156.3]). The difference in improvement in patient-reported pain scores between the treatment and placebo groups was significant (p < 0.001).Patients who received postoperative IV acetaminophen after craniotomy did not have significantly decreased narcotic consumption but did experience significantly lower pain scores after surgery. The drug was well tolerated and safe in this patient population.

  View details for DOI 10.3171/2017.10.JNS171464

  View details for PubMedID 29676689

• Trends and Cost Analysis of Upper-Extremity Nerve Injury Using the National Inpatient Sample. World neurosurgery Karsy, M., Watkins, R., Jensen, M. R., Guan, J., Brock, A. A., Mahan, M. A. 2018

  Abstract

  BACKGROUND: Epidemiology in upper-extremity peripheral nerve injury (PNI) has not been comprehensively evaluated. The treatments and healthcare costs of PNI have not been examined.OBJECTIVE: To calculate an updated incidence of upper-extremity PNIs in the U.S. and examine clinical trends and costs using one national database.METHODS: The National Inpatient Sample was utilized to evaluate patients with upper-extremity PNI (ICD 9534, 9550-9559) in 2001-2013.RESULTS: A weighted total of 170,579 patients experienced upper-extremity PNI, representing a mean incidence of 43.8/1,000,000 people annually. The mean (±SEM) age of patients was 38.1±0.05 years; 74.3% of patients were males and 49.0% were Caucasian. PNIs occurred to the ulnar (17.8%), radial (15.1%), digital (18.0%), median (13.0%), multiple (11.5%), and other (10.1%) nerves and brachial plexus (14.5%). The number of upper-extremity PNIs decreased overall. The average care charge was $47,004±185, with an average increase of $4,623/year and compound annual growth rate of 9.59%. Although surgical nerve repair and home disposition were common with isolated PNIs, patients with brachial plexus PNIs did not have nerve surgery and were more likely to discharge to skilled nursing facilities. Multivariate analysis showed that length of stay (beta=0.677, p=0.0001) and number of procedures (beta=0.188, p=0.0001) most affected total patient charges.CONCLUSION: These results suggest an overall decrease in the number of PNIs, suggesting lower incidence or frequency of detection; however, the cost of care has increased. Despite recent advances in nerve repair techniques, nerve surgery rates have not increased, especially for brachial plexus injuries, which may be undertreated.

  View details for DOI 10.1016/j.wneu.2018.11.192

  View details for PubMedID 30502477

• Trends and Cost-Analysis of Lower Extremity Nerve Injury Using the National Inpatient Sample. Neurosurgery Foster, C. H., Karsy, M., Jensen, M. R., Guan, J., Eli, I., Mahan, M. A. 2018

  Abstract

  BACKGROUND: Peripheral nerve injuries (PNIs) of the lower extremities have been assessed in small cohort studies; however, the actual incidence, national trends, comorbidities, and cost of care in lower extremity PNI are not defined. Lack of sufficient data limits discussion on national policies, payors, and other aspects fundamental to the delivery of care in the US.OBJECTIVE: To establish estimates of lower extremity PNIs incidence, associated diagnoses, and cost in the US using a comprehensive database with a minimum of a decade of data.METHODS: The National Inpatient Sample was utilized to evaluate International Classification of Disease codes for specific lower extremity PNIs (9560-9568) between 2001 and 2013.RESULTS: Lower extremity PNIs occurred with a mean incidence of 13.3 cases per million population annually, which declined minimally from 2001 to 2013. The mean±SEM age was 41.6±0.1 yr; 61.1% of patients were males. Most were admitted via the emergency department (56.0%). PNIs occurred to the sciatic (16.6%), femoral (10.7%), tibial (6.0%), peroneal (33.4%), multiple nerves (1.3%), and other (32.0%). Associated diagnoses included lower extremity fracture (13.4%), complications of care (11.2%), open wounds (10.3%), crush injury (9.7%), and other (7.2%). Associated procedures included tibial fixation (23.3%), closure of skin (20.1%), debridement of open fractures (15.4%), fixation of other bones (13.5%), and wound debridement (14.5%). The mean annual unadjusted compounded growth rate of charges was 8.8%. The mean±SEM annual charge over the time period was $64 031.20±$421.10, which was associated with the number of procedure codes (beta=0.2), length of stay (beta=0.6), and year (beta=0.1) in a multivariable analysis (P=.0001).CONCLUSION: These data describe associations in the treatment of lower extremity PNIs, which are important for considering national policies, costs, research and the delivery of care.

  View details for PubMedID 29889258

• Thoracolumbar Cortical Screw Placement with Interbody Fusion: Technique and Considerations CUREUS Karsy, M., Jensen, M. R., Cole, K., Guan, J., Brock, A., Cole, C. 2017; 9 (7): e1419

  Abstract

  A surge in interest in cortical bone trajectory (CBT), first described by Santoni in 2009, may be a result of its numerous advantages, including reduced surgical incision length and lateral dissection, limited disruption of the facet joints, and decreased blood loss. In addition, CBT offers improved screw pullout strength and the ability to perform hybrid constructs with pedicle screws using minimally invasive approaches. However, one of the main limitations of the technique involves the small screw size, which limits the potential for long-segment constructs. We describe a technique involving a more in-line anatomical trajectory, allowing for larger screw diameters. A feasibility study using a cadaveric model was performed and evaluated. Moreover, a focused review of the literature on the use of CBT was performed. Screw entry points are located along the inferomedial aspect of the facet and angled superolaterally. The use of this technique allows for the placement of larger screws (4.5 to 6.5 mm diameter) without pedicle breaches along with the alignment of screw heads from L1 to S1. In addition, the technique can be performed using stereotactic navigation or fluoroscopy. A direct, more in-line technique allows for larger screws to be placed using CBT. This technique can be combined with minimally invasive approaches. The potential advantages of the CBT technique support its use as a probable alternative to traditional pedicle screw fixation techniques.

  View details for PubMedID 28875092

• Cornichons control ER export of AMPA receptors to regulate synaptic excitability. Neuron Brockie, P. J., Jensen, M., Mellem, J. E., Jensen, E., Yamasaki, T., Wang, R., Maxfield, D., Thacker, C., Hoerndli, F., Dunn, P. J., Tomita, S., Madsen, D. M., Maricq, A. V. 2013; 80 (1): 129-42

  Abstract

  The strength of synaptic communication at central synapses depends on the number of ionotropic glutamate receptors, particularly the class gated by the agonist AMPA (AMPARs). Cornichon proteins, evolutionarily conserved endoplasmic reticulum cargo adaptors, modify the properties of vertebrate AMPARs when coexpressed in heterologous cells. However, the contribution of cornichons to behavior and in vivo nervous system function has yet to be determined. Here, we take a genetic approach to these questions by studying CNI-1--the sole cornichon homolog in C. elegans. cni-1 mutants hyperreverse, a phenotype associated with increased glutamatergic synaptic transmission. Consistent with this behavior, we find larger glutamate-gated currents in cni-1 mutants with a corresponding increase in AMPAR number. Furthermore, we observe opposite phenotypes in transgenic worms that overexpress CNI-1 or vertebrate homologs. In reconstitution studies, we provide support for an evolutionarily conserved role for cornichons in regulating the export of vertebrate and invertebrate AMPARs.

  View details for DOI 10.1016/j.neuron.2013.07.028

  View details for PubMedID 24094107

  View details for PubMedCentralID PMC3795439

• The SOL-2/Neto auxiliary protein modulates the function of AMPA-subtype ionotropic glutamate receptors. Neuron Wang, R., Mellem, J. E., Jensen, M., Brockie, P. J., Walker, C. S., Hoerndli, F. J., Hauth, L., Madsen, D. M., Maricq, A. V. 2012; 75 (5): 838-50

  Abstract

  The neurotransmitter glutamate mediates excitatory synaptic transmission by gating ionotropic glutamate receptors (iGluRs). AMPA receptors (AMPARs), a subtype of iGluR, are strongly implicated in synaptic plasticity, learning, and memory. We previously discovered two classes of AMPAR auxiliary proteins in C. elegans that modify receptor kinetics and thus change synaptic transmission. Here, we have identified another auxiliary protein, SOL-2, a CUB-domain protein that associates with both the related auxiliary subunit SOL-1 and with the GLR-1 AMPAR. In sol-2 mutants, behaviors dependent on glutamatergic transmission are disrupted, GLR-1-mediated currents are diminished, and GLR-1 desensitization and pharmacology are modified. Remarkably, a secreted variant of SOL-1 delivered in trans can rescue sol-1 mutants, and this rescue depends on in cis expression of SOL-2. Finally, we demonstrate that SOL-1 and SOL-2 have an ongoing role in the adult nervous system to control AMPAR-mediated currents.

  View details for DOI 10.1016/j.neuron.2012.06.038

  View details for PubMedID 22958824

  View details for PubMedCentralID PMC3458792

• Wnt signaling regulates experience-dependent synaptic plasticity in the adult nervous system. Cell cycle (Georgetown, Tex.) Jensen, M., Brockie, P. J., Maricq, A. V. 2012; 11 (14): 2585-6

  Abstract

  Comment on: Jensen M, et al. Cell 2012; 149:173-87.

  View details for DOI 10.4161/cc.21138

  View details for PubMedID 22781061

  View details for PubMedCentralID PMC3409000

• Wnt signaling regulates acetylcholine receptor translocation and synaptic plasticity in the adult nervous system. Cell Jensen, M., Hoerndli, F. J., Brockie, P. J., Wang, R., Johnson, E., Maxfield, D., Francis, M. M., Madsen, D. M., Maricq, A. V. 2012; 149 (1): 173-87

  Abstract

  The adult nervous system is plastic, allowing us to learn, remember, and forget. Experience-dependent plasticity occurs at synapses--the specialized points of contact between neurons where signaling occurs. However, the mechanisms that regulate the strength of synaptic signaling are not well understood. Here, we define a Wnt-signaling pathway that modifies synaptic strength in the adult nervous system by regulating the translocation of one class of acetylcholine receptors (AChRs) to synapses. In Caenorhabditis elegans, we show that mutations in CWN-2 (Wnt ligand), LIN-17 (Frizzled), CAM-1 (Ror receptor tyrosine kinase), or the downstream effector DSH-1 (disheveled) result in similar subsynaptic accumulations of ACR-16/α7 AChRs, a consequent reduction in synaptic current, and predictable behavioral defects. Photoconversion experiments revealed defective translocation of ACR-16/α7 to synapses in Wnt-signaling mutants. Using optogenetic nerve stimulation, we demonstrate activity-dependent synaptic plasticity and its dependence on ACR-16/α7 translocation mediated by Wnt signaling via LIN-17/CAM-1 heteromeric receptors.

  View details for DOI 10.1016/j.cell.2011.12.038

  View details for PubMedID 22464329

  View details for PubMedCentralID PMC3375111