Dr. Mahaney is a Pediatric Neurosurgeon with clinical interest in Hydrocephalus, Craniovertebral Junction abnormalities, Spasticity, Spinal dysraphism and Myelomeningocele, Central Nervous System tumors, and Pediatric Epilepsy surgery. She completed residency training at the University of Iowa Hospitals and Clinics and subspecialty Pediatric Neurosurgery training at The Hospital for Sick Children in Toronto and the Barrow Neurologic Institute at Phoenix Children's Hospital. She is interested in advancing Neuro-endoscopic techniques in Pediatric Neurosurgical practice. Dr. Mahaney's research focuses on delineating the role of iron in the development of post-hemorrhagic hydrocephalus.
- Spinal Dysraphism
- Craniovertebral Junction abnormalities
- Neurological Surgery Designation
Assistant Professor - University Medical Line, Neurosurgery
Interim Chief, Pediatric Neurosurgery Division, Stanford University Department of Neurosurgery (2022 - Present)
Boards, Advisory Committees, Professional Organizations
Member, AANS/CNS Joint Section on Pediatric Neurosurgery (2015 - Present)
Member, AANS/CNS Joint Section on Cerebrovascular Neurosurgery (2010 - Present)
Member, Congress of Neurologic Surgeons (2007 - Present)
Member, American Association of Neurologic Surgeons (2007 - Present)
Board Certification: American Board of Neurological Surgery, Neurological Surgery Designation (2019)
Residency: University of Iowa Hospitals and Clinics (2014) IA
Medical Education: St Louis University School of Medicine (2007) MO
Board Certification: American Board of Neurological Surgery, Neurological Surgery (2019)
Fellowship: Barrow Neurologic Institute at Phoenix Childrens Ped Neurosurgery Fellowship (2015) AZ
Independent Studies (2)
- Directed Reading in Neurosurgery
NSUR 299 (Aut)
- Medical Scholars Research
NSUR 370 (Aut, Win, Spr, Sum)
- Directed Reading in Neurosurgery
Elevated cerebrospinal fluid iron and ferritin associated with early severe ventriculomegaly in preterm posthemorrhagic hydrocephalus.
Journal of neurosurgery. Pediatrics
2022; 30 (2): 169-176
OBJECTIVE: Posthemorrhagic hydrocephalus (PHH) following preterm intraventricular hemorrhage (IVH) is among the most severe sequelae of extreme prematurity and a significant contributor to preterm morbidity and mortality. The authors have previously shown hemoglobin and ferritin to be elevated in the lumbar puncture cerebrospinal fluid (CSF) of neonates with PHH. Herein, they evaluated CSF from serial ventricular taps to determine whether neonates with PHH following severe initial ventriculomegaly had higher initial levels and prolonged clearance of CSF hemoglobin and hemoglobin degradation products compared to those in neonates with PHH following moderate initial ventriculomegaly.METHODS: In this observational cohort study, CSF samples were obtained from serial ventricular taps in premature neonates with severe IVH and subsequent PHH. CSF hemoglobin, ferritin, total iron, total bilirubin, and total protein were quantified using ELISA. Ventriculomegaly on cranial imaging was assessed using the frontal occipital horn ratio (FOHR) and was categorized as severe (FOHR > 0.6) or moderate (FOHR ≤ 0.6).RESULTS: Ventricular tap CSF hemoglobin (mean) and ferritin (initial and mean) were higher in neonates with severe versus moderate initial ventriculomegaly. CSF hemoglobin, ferritin, total iron, total bilirubin, and total protein decreased in a nonlinear fashion over the weeks following severe IVH. Significantly higher levels of CSF ferritin and total iron were observed in the early weeks following IVH in neonates with severe initial ventriculomegaly than in those with initial moderate ventriculomegaly.CONCLUSIONS: Among preterm neonates with PHH following severe IVH, elevated CSF hemoglobin, ferritin, and iron were associated with more severe early ventricular enlargement (FOHR > 0.6 vs ≤ 0.6 at first ventricular tap).
View details for DOI 10.3171/2022.4.PEDS21463
View details for PubMedID 35916101
Development of an Integrated Risk Scale for Prediction of Shunt Placement After Neonatal Intraventricular Hemorrhage
OXFORD UNIV PRESS INC. 2022: 37-38
View details for Web of Science ID 000783218700040
Development of an integrated risk scale for prediction of shunt placement after neonatal intraventricular hemorrhage.
Journal of neurosurgery. Pediatrics
Neonatal intraventricular hemorrhage (IVH) is a major cause of mortality and morbidity, particularly following premature birth. Even after the acute phase, posthemorrhagic hydrocephalus is a long-term complication, frequently requiring permanent ventriculoperitoneal shunt (VPS) placement. Currently, there are no risk classification methods integrating the constellation of clinical data to predict short- and long-term prognosis in neonatal IVH. To address this need, the authors developed a two-part machine learning approach for predicting short- and long-term outcomes after diagnosis of neonatal IVH. Integrating both maternal and neonatal characteristics, they developed a binary classifier to predict short-term mortality risk and a clinical scale to predict the long-term risk of VPS placement.Neonates with IVH were identified from the Optum Clinformatics Data Mart administrative claims database. Matched maternal and childbirth characteristics were obtained for all patients. The primary endpoints of interest were short-term (30 day) mortality and long-term VPS placement. Classification of short-term mortality risk was evaluated using 5 different machine learning approaches and the best-performing method was validated using a withheld validation subset. Prediction of long-term shunt risk was performed using a multivariable Cox regression model with stepwise variable selection, which was subsequently converted to an easily applied integer risk scale.A total of 5926 neonates with IVH were identified. Most patients were born before 32 weeks' gestation (67.2%) and with low birth weight (81.2%). Empirical 30-day mortality risk was 10.9% across all IVH grades and highest among grade IV IVH (34.3%). Among the neonates who survived > 30 days, actuarial 12-month postdiagnosis risk of shunt placement was 5.4% across all IVH grades and 31.3% for grade IV IVH. The optimal short-term risk classifier was a random forest model achieving an area under the receiver operating characteristic curve of 0.882 with important predictors ranging from gestational age to diverse comorbid medical conditions. Selected features for long-term shunt risk stratification were IVH grade, respiratory distress syndrome, disseminated intravascular coagulation, and maternal preeclampsia or eclampsia. An integer risk scale, termed the Shunt Prediction After IVH in Neonates (SPAIN) scale, was developed from these 4 features, which, evaluated on withheld cases, demonstrated improved risk stratification compared with IVH grade alone (Harrell's concordance index 0.869 vs 0.852).In a large cohort of neonates with IVH, the authors developed a two-pronged, integrated, risk classification approach to anticipate short-term mortality and long-term shunt risk. The application of such approaches may improve the prognostication of outcomes and identification of higher-risk individuals who warrant careful surveillance and early intervention.
View details for DOI 10.3171/2021.11.PEDS21390
View details for PubMedID 35090135
Incorporating patient-centered quality-of-life measures for outcome assessment after Chiari malformation type I decompression in a pediatric population: a pilot study.
Journal of neurosurgery. Pediatrics
OBJECTIVE: Optimal management of pediatric Chiari malformation type I (CM-I) is much debated, chiefly due to the lack of validated tools for outcome assessment, with very few tools incorporating patient-centered measures of health-related quality of life (HRQOL). Although posterior fossa decompression (PFD) benefits a subset of patients, prediction of its impact across patients is challenging. The primary aim of this study was to investigate the role of patient-centered HRQOL measures in the assessment and prediction of outcomes after PFD.METHODS: The authors collected HRQOL data from a cohort of 20 pediatric CM-I patients before and after PFD. The surveys included assessments of selected Patient-Reported Outcomes Measurement Information System (PROMIS) health domains and were used to generate the PROMIS preference (PROPr) score, which is a measure of HRQOL. PROMIS is a reliable standardized measure of HRQOL domains such as pain, fatigue, depression, and physical function, which are all relevant to CM-I. The authors then compared the PROPr scores with Chicago Chiari Outcome Scale (CCOS) scores derived from time-matched clinical documentation. Finally, the authors used the PROPr scores as an outcome measure to predict postsurgical HRQOL improvement at 1 year on the basis of patient demographic characteristics, comorbidities, and radiological and physical findings. The Wilcoxon signed-rank test, Mann-Whitney U-test, and Kendall's correlation were used for statistical analysis.RESULTS: Aggregate analysis revealed improvement of pain severity after PFD (p = 0.007) in anatomical patterns characteristic of CM-I. Most PROMIS domain scores trended toward improvement after surgery, with anxiety and pain interference reaching statistical significance (p < 0.002 and p < 0.03, respectively). PROPr scores also significantly improved after PFD (p < 0.008). Of the baseline patient characteristics, preexisting scoliosis was the most accurate negative predictor of HRQOL improvement after PFD (median -0.095 vs 0.106, p < 0.001). A correlation with modest magnitude (Kendall's tau range 0.19-0.47) was detected between the patient-centered measures and CCOS score.CONCLUSIONS: The authors observed moderate improvement of HRQOL, when measured using a modified panel of PROMIS question banks, in this pilot cohort of pediatric CM-I patients after PFD. Further investigations are necessary to validate this tool for children with CM-I and to determine whether these scores correlate with clinical and radiographic findings.
View details for DOI 10.3171/2021.8.PEDS21228
View details for PubMedID 34715646
Longitudinal CSF Iron Pathway Proteins in Post-Hemorrhagic Hydrocephalus: Associations with Ventricle Size and Neurodevelopmental Outcomes.
Annals of neurology
OBJECTIVE: Iron has been implicated in the pathogenesis of brain injury and hydrocephalus after preterm germinal matrix hemorrhage-intraventricular hemorrhage, however it is unknown how external or endogenous intraventricular clearance of iron pathway proteins affect outcome in this group.METHODS: This prospective multi-center cohort included patients with post-hemorrhagic hydrocephalus (PHH) who underwent temporary and permanent cerebrospinal fluid (CSF) diversion and Bayley Scales of Infant Development-III testing around 2years of age. CSF proteins in the iron handling pathway were analyzed longitudinally and compared to ventricle size and neurodevelopmental outcomes.RESULTS: Thirty-seven patients met inclusion criteria with a median estimated gestational age at birth of 25weeks; 65% were male. CSF hemoglobin, iron, total bilirubin, and ferritin decreased between temporary and permanent CSF diversion with no change in CSF ceruloplasmin, transferrin, haptoglobin and hepcidin; and an increase in CSF hemopexin. Larger ventricle size at permanent CSF diversion was associated with elevated CSF ferritin (p=0.015) and decreased CSF hemopexin (p=0.007). CSF levels of proteins at temporary CSF diversion were not associated with outcome, however higher CSF transferrin at permanent CSF diversion was associated with improved cognitive outcome (p=0.015). Importantly, longitudinal change in CSF iron pathway proteins, ferritin (decrease) and transferrin (increase) were associated with improved cognitive (p=0.04) and motor (p=0.03) scores and improved cognitive (p=0.04), language (p=0.035) and motor (p=0.008) scores, respectively.INTERPRETATION: Longitudinal changes in CSF transferrin (increase) and ferritin (decrease) are associated with improved neurodevelopmental outcomes in neonatal PHH, with implications for understanding pathogenesis of poor outcomes in PHH. This article is protected by copyright. All rights reserved.
View details for DOI 10.1002/ana.26133
View details for PubMedID 34080727
Electrophysiological Characterization of Glioma using a Biomimetic Spheroid Model
IEEE. 2021: 86-89
View details for DOI 10.1109/NER49283.2021.9441074
View details for Web of Science ID 000681358200017
Intraventricular Hemorrhage Clearance in Human Neonatal Cerebrospinal Fluid: Associations With Hydrocephalus.
Background and Purpose- Preterm neonates with intraventricular hemorrhage (IVH) are at risk for posthemorrhagic hydrocephalus and poor neurological outcomes. Iron has been implicated in ventriculomegaly, hippocampal injury, and poor outcomes following IVH. We hypothesized that levels of cerebrospinal fluid blood breakdown products and endogenous iron clearance proteins in neonates with IVH differ from those of neonates with IVH who subsequently develop posthemorrhagic hydrocephalus. Methods- Premature neonates with an estimated gestational age at birth <30 weeks who underwent lumbar puncture for clinical evaluation an average of 2 weeks after birth were evaluated. Groups consisted of controls (n=16), low-grade IVH (grades I-II; n=4), high-grade IVH (grades III-IV; n=6), and posthemorrhagic hydrocephalus (n=9). Control subjects were preterm neonates born at <30 weeks' gestation without brain abnormality or hemorrhage on cranial ultrasound, who underwent lumbar puncture for clinical purposes. Cerebrospinal fluid hemoglobin, total bilirubin, total iron, ferritin, ceruloplasmin, transferrin, haptoglobin, and hemopexin were quantified. Results- Cerebrospinal fluid hemoglobin levels were increased in posthemorrhagic hydrocephalus compared with high-grade IVH (9.45 versus 6.06 g/mL, P<0.05) and cerebrospinal fluid ferritin levels were increased in posthemorrhagic hydrocephalus compared with controls (511.33 versus 67.08, P<0.01). No significant group differences existed for the other cerebrospinal fluid blood breakdown and iron-handling proteins tested. We observed positive correlations between ventricular enlargement (frontal occipital horn ratio) and ferritin (Pearson r=0.67), hemoglobin (Pearson r=0.68), and total bilirubin (Pearson r=0.69). Conclusions- Neonates with posthemorrhagic hydrocephalus had significantly higher levels of hemoglobin than those with high-grade IVH. Levels of blood breakdown products, hemoglobin, ferritin, and bilirubin correlated with ventricular size. There was no elevation of several iron-scavenging proteins in cerebrospinal fluid in neonates with posthemorrhagic hydrocpehalus, indicative of posthemorrhagic hydrocephalus as a disease state occurring when endogenous iron clearance mechanisms are overwhelmed.
View details for DOI 10.1161/STROKEAHA.119.028744
View details for PubMedID 32397930
Successful Use of Frameless Stereotactic Radiosurgery for Treatment of Recurrent Brain Metastases in an 18 Month Old Child.
The International journal of neuroscience
There are very few reported cases of stereotactic radiosurgery delivered in children under 3 years of age. We report an 18 month old boy with metastatic recurrence of undifferentiated round cell sarcoma to the brain which was treated with chemotherapy, resection, and robotic frameless stereotactic radiosurgery (SRS). Frameless SRS was delivered without technical difficulties, acute adverse events, or clinical sequelae 1.5 months post-radiation. Longer term follow-up will be needed to evaluate local tumor control and effects on neurocognitive development, endocrine function, and growth. This report adds to the literature of the few reported cases of successfully attempted SRS in very young children.
View details for DOI 10.1080/00207454.2019.1655015
View details for PubMedID 31401906
Concurrent Venous Stenting of the Transverse and Occipito-Marginal Sinuses: An Analogy with Parallel Hemodynamic Circuits.
Journal of neurosciences in rural practice
2019; 10 (2): 334-338
Nonthrombotic intracranial venous occlusive disease (NIVOD) has been implicated in the pathophysiology of idiopathic intracranial hypertension (IIH) and various non-IIH headache syndromes. Endovascular stenting of stenotic, dominant transverse sinuses (TSs) may reduce trans-stenosis pressure gradients, decrease intracranial pressure, and alleviate symptoms in a subset of NIVOD patients. We present a case in which concurrent stenting of the occipito-marginal sinus obliterated the residual trans-stenosis pressure gradient across an initially stented dominant TS. We hypothesize that this observation may be explained using an electric-hydraulic analogy, and that this patient's dominant TS and occipito-marginal sinus may be modeled as a parallel hemodynamic circuit. Neurointerventionalists should be aware of parallel hemodynamic drainage patterns and consider manometry and possibly additional stenting of stenotic, parallel venous outflow pathways if TS stenting alone fails to obliterate the trans-stenosis pressure gradient.
View details for DOI 10.4103/jnrp.jnrp_259_18
View details for PubMedID 31001030
View details for PubMedCentralID PMC6454934
Concurrent Venous Stenting of the Transverse and Occipito-Marginal Sinuses: An Analogy with Parallel Hemodynamic Circuits
JOURNAL OF NEUROSCIENCES IN RURAL PRACTICE
2019; 10 (2): 334–38
View details for DOI 10.4103/jnrp.jnrp_259_18
View details for Web of Science ID 000462821600032
2018; 83 (3): 487
View details for Web of Science ID 000454359100053
Congenital Fistulae of the Stapedial Footplate and Round Window Membrane: An Unusual Cause of Recurrent Meningitis.
JAMA otolaryngology-- head & neck surgery
View details for DOI 10.1001/jamaoto.2017.2033
View details for PubMedID 29145546
Pediatric meningiomas: 65-year experience at a single institution.
Journal of neurosurgery. Pediatrics
OBJECTIVE Meningiomas are relatively common, typically benign neoplasms in adults; however, they are relatively rare in the pediatric population. Pediatric meningiomas behave very differently from their adult counterparts, tending to have more malignant histological subtypes and recur more frequently. The authors of this paper investigate the risk factors, pathological subtypes, and recurrence rates of pediatric meningiomas. METHODS A retrospective chart review was conducted at the University of Iowa to identify patients 20 years old and younger with meningiomas in the period from 1948 to 2015. RESULTS Sixty-seven meningiomas in 39 patients were identified. Eight patients had neurofibromatosis, 2 had a family history of meningioma, and 3 had prior radiation exposure. Twelve (31%) of the 39 patients had WHO Grade II or III lesions, and 15 (38%) had recurrent lesions after resection. CONCLUSIONS Pediatric meningiomas should be considered for early treatment and diligent follow-up.
View details for DOI 10.3171/2017.2.PEDS16497
View details for PubMedID 28474981
Age-related differences in unruptured intracranial aneurysms: 1-year outcomes
JOURNAL OF NEUROSURGERY
2014; 121 (5): 1024-1038
The aim of this study was to determine age-related differences in short-term (1-year) outcomes in patients with unruptured intracranial aneurysms (UIAs).Four thousand fifty-nine patients prospectively enrolled in the International Study of Unruptured Intracranial Aneurysms were categorized into 3 groups by age at enrollment: < 50, 50-65, and > 65 years old. Outcomes assessed at 1 year included aneurysm rupture rates, combined morbidity and mortality from aneurysm procedure or hemorrhage, and all-cause mortality. Periprocedural morbidity, in-hospital morbidity, and poor neurological outcome on discharge (Rankin scale score of 3 or greater) were assessed in surgically and endovascularly treated groups. Univariate and multivariate associations of each outcome with age were tested.The risk of aneurysmal hemorrhage did not increase significantly with age. Procedural and in-hospital morbidity and mortality increased with age in patients treated with surgery, but remained relatively constant with increasing age with endovascular treatment. Poor neurological outcome from aneurysm- or procedure-related morbidity and mortality did not differ between management groups for patients 65 years old and younger, but was significantly higher in the surgical group for patients older than 65 years: 19.0% (95% confidence interval [CI] 13.9%-24.4%), compared with 8.0% (95% CI 2.3%-13.6%) in the endovascular group and 4.2% (95% CI 2.3%-6.2%) in the observation group. All-cause mortality increased steadily with increasing age, but differed between treatment groups only in patients < 50 years of age, with the surgical group showing a survival advantage at 1 year.Surgical treatment of UIAs appears to be safe, prevents 1-year hemorrhage, and may confer a survival benefit in patients < 50 years of age. However, surgery poses a significant risk of morbidity and death in patients > 65 years of age. Risk of endovascular treatment does not appear to increase with age. Risks and benefits of treatment in older patients should be carefully considered, and if treatment is deemed necessary for patients older than 65 years, endovascular treatment may be the best option.
View details for DOI 10.3171/2014.6JNS121179
View details for Web of Science ID 000343530400006
View details for PubMedID 25170670
Intradiploic occipital pseudomeningocele in a patient with remote history of surgical treatment of Chiari malformation
JOURNAL OF NEUROSURGERY-SPINE
2014; 21 (5): 769-772
An intradiploic CSF pseudocyst is a rare entity that has been described in association with trauma, as a sequela of untreated hydrocephalus, or occasionally as a congenital finding in older adults. The authors present the case of a woman with a remote history of a posterior fossa intradural procedure, in which she underwent Chiari malformation decompression, Silastic substitute-assisted duraplasty, and occipitocervical fusion; she presented 19 years later with recurrent symptoms of Chiari malformation. She was found to have an occipital intradiploic pseudomeningocele, arising within her dorsal occipitocervical fusion mass and resulting in dorsal hindbrain compression. She underwent a posterior fossa decompression and revision of her failed duraplasty, and she had a good recovery. This case demonstrates intradiploic CSF pseudomeningocele as a rare potential delayed complication of an intradural procedure for the treatment of Chiari malformation with occipitocervical fusion.
View details for DOI 10.3171/2014.6.SPINE13785
View details for Web of Science ID 000343530000012
View details for PubMedID 25147975
Long-term incidence and risk factors for development of spinal deformity following resection of pediatric intramedullary spinal cord tumors.
Journal of neurosurgery. Pediatrics
2014; 13 (6): 613-621
Spinal deformity in pediatric patients with intramedullary spinal cord tumors (IMSCTs) may be either due to neurogenic disability or due to secondary effects of spinal decompression. It is associated with functional decline and impairment in health-related quality-of-life measures. The authors sought to identify the long-term incidence of spinal deformity in individuals who had undergone surgery for IMSCTs as pediatric patients and the risk factors and overall outcomes in this population.Treatment records for pediatric patients (age < 21 years) who underwent surgical treatment for histology-proven primary IMSCTs between 1975 and 2010 were reviewed. All patients were evaluated in consultation with the pediatric orthopedics service. Clinical records were reviewed for baseline and follow-up imaging studies, surgical fusion treatment, and long-term skeletal and disease outcomes.The authors identified 55 patients (30 males and 25 females) who were treated for pediatric IMSCTs between January 1975 and January 2010. The mean duration of follow-up (± SEM) was 11.4 ± 1.3 years (median 9.3 years, range 0.2-37.2 years). Preoperative skeletal deformity was diagnosed in 11 (20%) of the 55 patients, and new-onset postoperative deformity was noted in 9 (16%). Conservative management with observation or external bracing was sufficient in 8 (40%) of these 20 cases. Surgical fusion was necessary in 11 (55%). Posterior surgical fusion was sufficient in 6 (55%) of these 11 cases, while combined anterior and posterior fusion was undertaken in 5 (45%). Univariate and multivariate analysis of clinical and surgical treatment variables indicated that preoperative kyphoscoliosis (p = 0.0032) and laminectomy/laminoplasty at more than 4 levels (p = 0.05) were independently associated with development of spinal deformity that necessitated surgical fusion. Functional scores and 10-year disease survival outcomes were similar between the 2 groups.Long-term follow-up is essential to monitor for delayed development of spinal deformity, and regular surveillance imaging is recommended for patients with underlying deformity. The authors' extended follow-up highlights the risk factors associated with development of spinal deformity in patients treated for pediatric IMSCTs. Surgical fusion allows patients who develop progressive deformity to achieve long-term functional and survival outcomes comparable to those of patients who do not develop progressive deformity.
View details for DOI 10.3171/2014.1.PEDS13317
View details for PubMedID 24702614
Alternative grafts in anterior cervical fusion
CLINICAL NEUROLOGY AND NEUROSURGERY
2013; 115 (10): 2049-2055
The present retrospective study was conducted to compare the clinical and radiographic outcomes in patients undergoing anterior cervical discectomy with fusion (ACDF) using carbon fiber reinforced polymer (CFRP) cages, or allograft.We retrospectively reviewed cases of ACDF using allograft in 20 patients, and CFRP in 19 who had sequential radiographs before and after surgery, and at 1 year.There were no apparent significant differences between the 2 groups in age (p=0.057), gender (p=0.635), or complications (p=0.648). At 12 months, there were no cases of construct failure, and fusion appeared to have been achieved in patients of both groups. Lordosis was increased significantly in both groups after surgery (p<0.001 in allograft and p=0.025 in CFRP), and was maintained up until 1 year (p<0.018 in allograft and p=0.05 in CFRP) without a difference between groups (p=0.721). Anterior interbody height was significantly increased (p<0.001 in both groups at each time points) after surgery, without a significant difference between groups (p>0.21). This increase in height was greatest in magnitude immediately after surgery, and declined with the passage of time. There was no detectable health-related quality of life difference between allograft and CFRP group after surgery (p>0.05).The present study demonstrates that CFRP cages appear to have comparable fusion rates, restoration of lordosis and disc space height, and complication rates to patients who undergo ACDF with allograft.
View details for DOI 10.1016/j.clineuro.2013.07.013
View details for Web of Science ID 000325833200022
View details for PubMedID 23911002
Risk of hemorrhagic complication associated with ventriculoperitoneal shunt placement in aneurysmal subarachnoid hemorrhage patients on dual antiplatelet therapy.
Journal of neurosurgery
2013; 119 (4): 937-942
The use of an intracranial stent requires dual antiplatelet therapy to avoid in-stent thrombosis. In this study, the authors sought to investigate whether the use of dual antiplatelet therapy is a risk factor for hemorrhagic complications in patients undergoing permanent ventriculoperitoneal (VP) shunt for hydrocephalus following aneurysmal subarachnoid hemorrhage (aSAH).Patients were given 325 mg acetylsalicylic acid and 600 mg clopidogrel during the coil/stent procedure, and they were maintained on dual antiplatelet therapy with acetylsalicylic acid 325 mg daily and clopidogrel 75 mg daily during hospitalization and for 6 weeks posttreatment. Patients underwent placement of VP shunt at a later time during initial hospitalization, usually between 7 and 21 days following aSAH. Postoperative CT scans obtained in each study patient were reviewed for hemorrhages related to placement of the VP shunt.A total of 206 patients were admitted to the University of Iowa Hospitals and Clinics with aSAH between July 2009 and October 2010. Thirty-seven of these patients were treated with a VP shunt for persistent hydrocephalus. Twelve patients (32%) had previously undergone stent-assisted coiling and were on dual antiplatelet therapy with acetylsalicylic acid and clopidogrel. The remaining 25 patients (68%) had undergone surgical clipping or aneurysm coiling and were not receiving antiplatelet therapy at the time of surgery. Four cases (10.8%) of new intracranial hemorrhages associated with VP shunt placement were observed. All 4 hemorrhages (33%) occurred in patients on dual antiplatelet therapy for stent-assisted coiling. No new intracranial hemorrhages were observed in patients not receiving dual antiplatelet therapy. The difference in hemorrhagic complications between the 2 groups was statistically significant (4 [33%] of 12 vs 0 of 25, p = 0.0075]). All 4 hemorrhages occurred along the tract of the ventricular catheter. Only 1 hemorrhage (1 [8.3%] of 12) was clinically significant as it resulted in occlusion of the proximal shunt catheter and required revision of the VP shunt. The patient did not suffer any permanent morbidity related to the hemorrhage. The remaining 3 hemorrhages were not clinically significant.This small clinical series suggests that placement of a VP shunt in patients on dual antiplatelet therapy may be associated with an increased, but low, rate of symptomatic intracranial hemorrhage. It appears that in patients who are poor candidates for open surgical clipping and have aneurysms amenable to stent-assisted coiling, the risk of symptomatic hemorrhage may be an acceptable trade-off for avoiding risks associated with discontinuation of antiplatelet therapy. The authors' results are preliminary, however, and require confirmation in larger studies.
View details for DOI 10.3171/2013.5.JNS122494
View details for PubMedID 23808537
Acute postoperative neurological deterioration associated with surgery for ruptured intracranial aneurysm: incidence, predictors, and outcomes
JOURNAL OF NEUROSURGERY
2012; 116 (6): 1267-1278
Subarachnoid hemorrhage (SAH) results in significant morbidity and mortality, even among patients who reach medical attention in good neurological condition. Many patients have neurological decline in the perioperative period, which contributes to long-term outcomes. The focus of this study is to characterize the incidence of, characteristics predictive of, and outcomes associated with acute postoperative neurological deterioration in patients undergoing surgery for ruptured intracranial aneurysm.The Intraoperative Hypothermia for Aneurysm Surgery Trial (IHAST) was a multicenter randomized clinical trial that enrolled 1001 patients and assesssed the efficacy of hypothermia as neuroprotection during surgery to secure a ruptured intracranial aneurysm. All patients had a radiographically confirmed SAH, were classified as World Federation of Neurosurgical Societies (WFNS) Grade I-III immediately prior to surgery, and underwent surgery to secure the ruptured aneurysm within 14 days of SAH. Neurological assessment with the National Institutes of Health Stroke Scale (NIHSS) was performed preoperatively, at 24 and 72 hours postoperatively, and at time of discharge. The primary outcome variable was a dichotomized scoring based on an IHAST version of the Glasgow Outcome Scale (GOS) in which a score of 1 represents a good outcome and a score > 1 a poor outcome, as assessed at 90-days' follow-up. Data from IHAST were analyzed for occurrence of a postoperative neurological deterioration. Preoperative and intraoperative variables were assessed for associations with occurrence of postoperative neurological deterioration. Differences in baseline, intraoperative, and postoperative variables and in outcomes between patients with and without postoperative neurological deterioration were compared with Fisher exact tests. The Wilcoxon rank-sum test was used to compare variables reported as means. Multiple logistic regression was used to adjust for covariates associated with occurrence of postoperative deficit.Acute postoperative neurological deterioration was observed in 42.6% of the patients. New focal motor deficit accounted for 65% of postoperative neurological deterioration, while 60% was accounted for using the NIHSS total score change and 51% by Glasgow Coma Scale score change. Factors significantly associated with occurrence of postoperative neurological deterioration included: age, Fisher grade on admission, occurrence of a procedure prior to aneurysm surgery (ventriculostomy), timing of surgery, systolic blood pressure during surgery, ST segment depression during surgery, history of abnormality in cardiac valve function, use of intentional hypotension during surgery, duration of anterior cerebral artery occlusion, intraoperative blood loss, and difficulty of aneurysm exposure. Of the 426 patients with postoperative neurological deterioration at 24 hours after surgery, only 46.2% had a good outcome (GOS score of 1) at 3 months, while 77.7% of those without postoperative neurological deterioration at 24 hours had a good outcome (p < 0.05).Neurological injury incurred perioperatively or in the acute postoperative period accounts for a large percentage of poor outcomes in patients with good admission WFNS grades undergoing surgery for aneurysmal SAH. Avoiding surgical factors associated with postoperative neurological deterioration and directing investigative efforts at developing improved neuroprotection for use in aneurysm surgery may significantly improve long-term neurological outcomes in patients with SAH.
View details for DOI 10.3171/2012.1.JNS111277
View details for Web of Science ID 000304294000021
View details for PubMedID 22404668
Macrophage Imaging Within Human Cerebral Aneurysms Wall Using Ferumoxytol-Enhanced MRI: A Pilot Study
ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY
2012; 32 (4): 1032-1038
Macrophages play a critical role in cerebral aneurysm formation and rupture. The purpose of this study is to demonstrate the feasibility and optimal parameters of imaging macrophages within human cerebral aneurysm wall using ferumoxytol-enhanced MRI.Nineteen unruptured aneurysms in 11 patients were imaged using T2*-GE-MRI sequence. Two protocols were used. Protocol A was an infusion of 2.5 mg/kg of ferumoxytol and imaging at day 0 and 1. Protocol B was an infusion of 5 mg/kg of ferumoxytol and imaging at day 0 and 3. All images were reviewed independently by 2 neuroradiologists to assess for ferumoxytol-associated loss of MRI signal intensity within aneurysm wall. Aneurysm tissue was harvested for histological analysis. Fifty percent (5/10) of aneurysms in protocol A showed ferumoxytol-associated signal changes in aneurysm walls compared to 78% (7/9) of aneurysms in protocol B. Aneurysm tissue harvested from patients infused with ferumoxytol stained positive for both CD68+, demonstrating macrophage infiltration, and Prussian blue, demonstrating uptake of iron particles. Tissue harvested from controls stained positive for CD68 but not Prussian blue.Imaging with T2*-GE-MRI at 72 hours postinfusion of 5 mg/kg of ferumoxytol establishes a valid and useful approximation of optimal dose and timing parameters for macrophages imaging within aneurysm wall. Further studies are needed to correlate these imaging findings with risk of intracranial aneurysm rupture.
View details for DOI 10.1161/ATVBAHA.111.239871
View details for Web of Science ID 000301672300028
View details for PubMedID 22328774
View details for PubMedCentralID PMC3557844
Cerebral Aneurysm Sac Growth as the Etiology of Recurrence After Successful Coil Embolization
2012; 43 (3): 866-868
Coil compaction is thought to be the main mechanism for recurrence in cerebral aneurysms with previously successful coil embolization. We hypothesize that sac growth may be equally or more important. The objective was to study the relative roles of coil compaction and sac growth as explanations for aneurysm recurrence requiring retreatment in a study population using quantitative 3D image processing methods.From July 2009 to December 2010, 175 aneurysms were coiled at the University of Iowa hospitals and clinics. Eight aneurysms had major recurrence requiring retreatment (4.4-12.1 months between procedures; mean: 7.2 months). The 3D structures of the vessel and coil mass were reconstructed using rotational angiography data scanned before and after both initial coil embolization and retreatment. Changes in the sac and coil mass over time were visualized using model registration techniques and quantified using volume calculations.All 8 of the coiled aneurysms with major recurrence had significant aneurysm sac growth (15% to 102% increase in volume), independent of change in coil volume. Five aneurysms with major recurrence had sufficient data for assessment of coil compaction. The coil mass volume decreased in 1 aneurysm (12% compaction by volume), did not change significantly in 1 aneurysm (increased by 1%), and significantly increased in 3 aneurysms (8%, 21%, and 25%) between the first treatment and before the second treatment.In this study population, aneurysm sac growth, not coil compaction, was the primary mechanism associated with recurrence after initial coil embolization.
View details for DOI 10.1161/STROKEAHA.111.637827
View details for Web of Science ID 000300639400051
View details for PubMedID 22180247
View details for PubMedCentralID PMC3472954
Anterior-to-Posterior Circulation Approach for Mechanical Thrombectomy of an Acutely Occluded Basilar Artery Using the Penumbra Aspiration System
2012; 77 (2)
Prompt access to arterial occlusion is the key to successful endovascular revascularization in acute stroke. We present the first reported case utilizing anterior-to-posterior circulation approach for a successful mechanical thrombectomy and chemical thrombolysis of an acute basilar artery (BA) occlusion using the Penumbra Aspiration System.A 39-year-old man with known left vertebral artery (VA) occlusion presented with a rapid progression of top of the basilar syndrome, resulting in a comatose status with flaccid motor exam and no corneal reflex. Navigation of a guide catheter into the right VA was unsuccessful because of an acute angle created by the previously placed right VA ostial stent that herniated into the subclavian artery. Left internal carotid artery-selective angiography revealed a prominent left posterior communicating artery. A Penumbra 026 reperfusion catheter was advanced into the thrombosed BA via the left internal carotid artery, the posterior communicating artery, and the P1 segment. Mechanical thrombectomy and chemical thrombolysis were successfully performed.TIMI-3 in the BA and TIMI-2 flows in posterior cerebral arteries were restored 8 hours 16 minutes after symptom onset. The patient had recovered full strength in all four extremities at 10 hours after the onset and had a National Institutes of Health Stroke Scale score of 2 at discharge.In patients with unfavorable VA anatomy, anterior-to-posterior thrombectomy of the BA can be successfully achieved using the Penumbra catheter via an anatomically suitable posterior communicating artery.
View details for DOI 10.1016/j.wneu.2011.04.025
View details for Web of Science ID 000303233800055
View details for PubMedID 22120391
Aspirin as a Promising Agent for Decreasing Incidence of Cerebral Aneurysm Rupture
2011; 42 (11): 3156-3162
Chronic inflammation is postulated as an important phenomenon in intracranial aneurysm wall pathophysiology. This study was conducted to determine if aspirin use impacts the occurrence of intracranial aneurysm rupture.Subjects enrolled in the International Study of Unruptured Intracranial Aneurysms (ISUIA) were selected from the prospective untreated cohort (n=1691) in a nested case-control study. Cases were subjects who subsequently had a proven aneurysmal subarachnoid hemorrhage during a 5-year follow-up period. Four control subjects were matched to each case by site and size of aneurysm (58 cases, 213 control subjects). Frequency of aspirin use was determined at baseline interview. Aspirin frequency groups were analyzed for risk of aneurysmal hemorrhage. Bivariable and multivariable analyses were performed using conditional logistic regression.A trend of a protective effect for risk of unruptured intracranial aneurysm rupture was observed. Patients who used aspirin 3× weekly to daily had an OR for hemorrhage of 0.40 (95% CI, 0.18-0.87); reference group, no use of aspirin), patients in the "< once a month" group had an OR of 0.80 (95% CI, 0.31-2.05), and patients in the "> once a month to 2×/week" group had an OR of 0.87 (95% CI, 0.27-2.81; P=0.025). In multivariable risk factor analyses, patients who used aspirin 3 times weekly to daily had a significantly lower odds of hemorrhage (adjusted OR, 0.27; 95% CI, 0.11-0.67; P=0.03) compared with those who never take aspirin.Frequent aspirin use may confer a protective effect for risk of intracranial aneurysm rupture. Future investigation in animal models and clinical studies is needed.
View details for DOI 10.1161/STROKEAHA.111.619411
View details for Web of Science ID 000296574500264
View details for PubMedID 21980208
View details for PubMedCentralID PMC3432499
Variation of patient characteristics, management, and outcome with timing of surgery for aneurysmal subarachnoid hemorrhage
JOURNAL OF NEUROSURGERY
2011; 114 (4): 1045-1053
The past 30 years have seen a shift in the timing of surgery for aneurysmal subarachnoid hemorrhage (SAH). Earlier practices of delayed surgery that were intended to avoid less favorable surgical conditions have been replaced by a trend toward early surgery to minimize the risks associated with rebleeding and vasospasm. Yet, a consensus as to the optimal timing of surgery has not been reached. The authors hypothesized that earlier surgery, performed using contemporary neurosurgical and neuroanesthesia techniques, would be associated with better outcomes when using contemporary management practices, and sought to define the optimal time interval between SAH and surgery.Data collected as part of the Intraoperative Hypothermia for Aneurysm Surgery Trial (IHAST) were analyzed to investigate the relationship between timing of surgery and outcome at 3 months post-SAH. The IHAST enrolled 1001 patients in 30 neurosurgical centers between February 2000 and April 2003. All patients had a radiographically confirmed SAH, were World Federation of Neurosurgical Societies Grades I-III at the time of surgery, and underwent surgical clipping of the presumed culprit aneurysm within 14 days of the date of hemorrhage. Patients were seen at 90-day follow-up visits. The primary outcome variable was a Glasgow Outcome Scale score of 1 (good outcome). Intergroup differences in baseline, intraoperative, and postoperative variables were compared using the Fisher exact tests. Variables reported as means were compared with ANOVA. Multiple logistic regression was used for multivariate analysis, adjusting for covariates. A p value of less than 0.05 was considered to be significant.Patients who underwent surgery on Days 1 or 2 (early) or Days 7-14 (late) (Day 0 = date of SAH) fared better than patients who underwent surgery on Days 3-6 (intermediate). Specifically, the worst outcomes were observed in patients who underwent surgery on Days 3 and 4. Patients who had hydrocephalus or Fisher Grade 3 or 4 on admission head CT scans had better outcomes with early surgery than with intermediate or late surgery.Early surgery, in good-grade patients within 48 hours of SAH, is associated with better outcomes than surgery performed in the 3- to 6-day posthemorrhage interval. Surgical treatment for aneurysmal SAH may be more hazardous during the 3- to 6-day interval, but this should be weighed against the risk of rebleeding.
View details for DOI 10.3171/2010.11.JNS10795
View details for Web of Science ID 000288725900026
View details for PubMedID 21250801
ANATOMIC RELATIONSHIP OF THE OPTIC RADIATIONS TO THE ATRIUM OF THE LATERAL VENTRICLE: DESCRIPTION OF A NOVEL ENTRY POINT TO THE TRIGONE
2008; 63 (4): 195-202
The aim of this study was to delineate the anatomic relationship of the optic radiations to the atrium of the lateral ventricle using the Klingler method of white matter fiber dissection. These findings were applied to define a surgical approach to the trigone that avoids injury to the optic radiations.Sixteen cadaveric hemispheres were prepared by several cycles of freezing and thawing. With the use of wooden spatulas, the specimens were dissected in a stepwise fashion. Each hemisphere was dissected first from a lateromedial direction and then from a mediolateral approach, and careful attention was given to the course and direction of the optic radiation fibers at all points from Meyer's loop to their termination at the cuneus and the lingual gyrus.In all 16 dissected hemispheres, the following observations were made: 1) the entire lateral wall of the lateral ventricle-from the temporal horn to the trigone to the occipital horn-is covered by the optic radiations; and 2) the medial wall of the lateral ventricle in the area of the trigone is entirely free of the optic radiations.The results of this study confirm that the medial parieto-occipital interhemispheric approach to the ventricular trigone will avoid injury to the optic radiations and the calcarine cortex. The authors describe the most direct trajectory to the ventricular trigone using this approach and propose a point of entry that transects the cingulate gyrus at a point 5 mm superior and 5 mm posterior to the falcotentorial junction.
View details for DOI 10.1227/01.NEU.0000313121.58694.4A
View details for Web of Science ID 000260578700001
View details for PubMedID 18981826
Dural arteriovenous fistula of the anterior condylar confluence and hypoglossal canal mimicking a jugular foramen tumor - Case report
JOURNAL OF NEUROSURGERY
2008; 109 (2): 335-340
The anterior condylar confluence (ACC) is located on the external orifice of the canal of the hypoglossal nerve and provides multiple connections with the dural venous sinuses of the posterior fossa, internal jugular vein, and the vertebral venous plexus. Dural arteriovenous fistulas (DAVFs) of the ACC and hypoglossal canal (anterior condylar vein) are extremely rare. The authors present a case involving an ACC DAVF and hypoglossal canal that mimicked a hypervascular jugular bulb tumor. This 53-year-old man presented with right hypoglossal nerve palsy. A right pulsatile tinnitus had resolved several months previously. Magnetic resonance imaging demonstrated an enhancing right-sided jugular foramen lesion involving the hypoglossal canal. Cerebral angiography revealed a hypervascular lesion at the jugular bulb, with early venous drainage into the extracranial vertebral venous plexus. This was thought to represent either a glomus jugulare tumor or a DAVF. The patient underwent preoperative transarterial embolization followed by surgical exploration via a far-lateral transcondylar approach. At surgery, a DAVF was identified draining into the ACC and hypoglossal canal. The fistula was surgically obliterated, and this was confirmed on postoperative angiography. The patient's hypoglossal nerve palsy resolved. Dural arteriovenous fistulas of the ACC and hypoglossal canal are rare lesions that can present with isolated hypoglossal nerve palsies. They should be included in the differential diagnosis of hypervascular jugular bulb lesions. The authors review the anatomy of the ACC and discuss the literature on DAVFs involving the hypoglossal canal.
View details for DOI 10.3171/JNS/2008/109/8/0335
View details for PubMedID 18671650
An anteromedial approach to the temporal horn to avoid injury to the optic radiation fibers and uncinate fasciculus: anatomical and technical note.
2005; 18 (6B): E3-?
The aim of this study was to define an anteromedial approach to the temporal horn via a transsylvian approach to avoid injury to the optic radiation fibers as well as the uncinate fasciculus. This route was compared with standard surgical approaches to the temporal horn, and their relationship to the optic radiation and uncinate fasciculus was reviewed.Three cadaveric brain specimens were prepared with freezing and thawing cycles according to the Klingler technique. Dissection was performed in a lateral-to-medial fashion with the help of wooden spatulas. Photographs were taken through the operating microscope at every level of the dissection. The dissection was continued until the optic radiation was encountered. Particular attention was paid to the relationship of the uncinate fasciculus with the optic radiation. An anteromedial transsylvian approach was defined to enter the temporal horn without injuring the optic radiation or the uncinate fasciculus.A transsylvian anteromedial approach through the pyriform cortex at the level of the anterior and superior surface of the uncus enables a safe entry into the temporal horn without injury to the optic radiation fibers or the main part of the uncinate fasciculus.
View details for PubMedID 16048298