Migratory schwannoma of the cauda equina with a change in radicular pattern: illustrative case.

BACKGROUND: Intradural spinal tumors are an uncommon entity with a variety of pathologies and symptom patterns. Few cases reports in the literature have described tumor migration within the spinal canal. OBSERVATIONS: A 38-year-old male presented with bilateral upper lumbar radicular symptoms of anterior thigh pain, with an enhancing tumor of the cauda equina initially located at L1-2. He declined surgery initially, and at a follow-up 3 years later, his symptoms were unchanged but the tumor was now located at T12-L1. He again declined surgery, but 3 months later, he had a significant change in his pain distribution, which was now along his posterolateral right leg to his foot with associated dorsiflexion and extensor hallicus longus weakness. At this time, the tumor had migrated to L2-3. He underwent laminectomy and tumor resection with resolution of his radicular symptoms and improvement in his strength back to baseline by the 1-month follow-up. Pathology was consistent with a World Health Organization grade I schwannoma. LESSONS: Migratory schwannoma is a rare entity but should be considered when radicular symptoms acutely change in the setting of a known intradural tumor. Repeat imaging should be performed to avoid wrong-level surgery. Intraoperative imaging can also be used for tumor localization.

Minimally Invasive Far Lateral Lumbar Discectomy With Modified Technique: Symptomatic Relief and Intersegmental Stability Study.

OBJECTIVE: To evaluate the use of a modified minimally invasive surgery (MIS) technique for far lateral lumbar discectomy (FLDH) that minimizes the degree of bony drilling required for nerve root decompression, increasing postoperative pain reduction rate with reduced risk of iatrogenic spinal instability. SUMMARY OF BACKGROUND DATA: FLDH accounts for approximately 10% of all lumbar disc herniations and is increasingly recognized in the era of advanced imaging techniques. These disc herniations typically result in extra-foraminal nerve root compression. Minimally invasive spine techniques are increasingly performed with various degrees of foraminal and facet removal to decompress the affected nerve root. METHODS: The study design involves a single institutional, retrospective cohort technical review. The review was completed of all patients undergoing MIS far lateral lumbar discectomy between 2010 and 2020. Cross-sectional, summary statistics were calculated for all variables. Counts and percentages were recorded for categorical variables and mean and standard deviations were calculated for continuous variables. RESULTS: A total of 48 patients underwent MIS far lateral lumbar discectomies (FLLD) from 2010 to 2020. The mean age was 63 ± 11.5 years (60.4% males), the mean BMI was 28.5 ± 5.5, and 20.8% smokers. The most common presenting complaint was both low back and radicular pain (79.2%) with 8.3% of patients suffering from motor weakness preoperatively. The mean follow-up time was 4.3 ± 2.7. The mean length of stay was 1.3 ± 1.4 days with 77.1% of patients discharged postoperative day one. Forty-three patients (93.5%) had improvement in their symptoms. Twenty-seven (58.7%) had complete resolution in 2.6 months on average. Six patients (13%) had immediate symptom resolution postoperatively. CONCLUSIONS: Our modified technique for FLLD allows MIS access to the extra-foraminal site of nerve root compression without the need for bony drilling. This minimizes postoperative pain and reduces the risk of iatrogenic spinal instability without sacrificing symptom resolution.

Validity of the flap risk score in predicting nasoseptal flap use after endoscopic transsphenoidal pituitary mass resection.

Introduction: There remains a paucity of literature examining the decision algorithm for use of nasoseptal flap (NSF) after endoscopic endonasal approaches (EEA) to pituitary adenoma resection. In 2018, we published the first ever flap risk score (FRS) to predict the use of NSF. We present here a validity study examining the FRS as applied to our center. Methods: A retrospective review was completed of consecutive patients undergoing EEA from January 2015 to March 2021. The sensitivity, specificity, and predictive value of the FRS were calculated. A multivariate logistic model was used to determine the relative weight imaging characteristics in predicting need for NSF. The relative weighting of the FRS was then re-optimized. Results: A total of 376 patients underwent EEA for pituitary adenoma resection, with 113 (30.1%) requiring NSF. The FRS had a sensitivity and specificity of 43.4% and 94.7%, respectively. Sphenoid sinus extension increased the odds of needing a NSF equivalent to 19 mm of tumor height, as opposed to 6 mm in the original 2018 cohort. The re-optimized model had sensitivity and specificity of 79.6% and 76.4%, respectively. Conclusion: We present a validity study examining the utility of FRS in predicting the use of NSF after EEA for pituitary adenoma resection. Our results show that while FRS is still predictive of the need for NSF after EEA, it is not as predictive now as it was for its original cohort. Therefore, a more comprehensive model is necessary to more accurately stratify patients' preoperative risk for NSF.

Optimizing Surgical Efficiency in Complex Spine Surgery Using Virtual Reality as a Communication Technology to Promote a Shared Mental Model: A Case Series and Review.

BACKGROUND AND OBJECTIVES: Virtual reality (VR) is an emerging technology that can be used to promote a shared mental model among a surgical team. We present a case series demonstrating the use of 3-dimensional (3D) VR models to visually communicate procedural steps to a surgical team to promote a common operating objective. We also review the literature on existing uses of VR for preoperative communication and planning in spine surgery. METHODS: Narrations of 3 to 4-minute walkthroughs were created in a VR visualization platform, converted, and distributed to team members through text and email the night before surgical intervention. A VR huddle was held immediately before the intervention to refine surgical goals. After the intervention, the participating team members' perceptions on the value of the tool were assessed using a survey that used a 5-point Likert scale. MEDLINE, Google Scholar, and Dimensions AI databases were queried from July 2010 to October 2022 to examine existing literature on preoperative VR use to plan spine surgery. RESULTS: Three illustrative cases are presented with accompanying video. Postoperative survey results demonstrate a positive experience among surgical team members after reviewing preoperative plans created with patient-specific 3D VR models. Respondents felt that preoperative VR video review was "moderately useful" or more useful in improving their understanding of the operational sequence (71%, 5/7), in enhancing their ability to understand their role (86%, 6/7), and in improving the safety or efficiency of the case (86%, 6/7). CONCLUSION: We present a proof of concept of a novel preoperative communication tool used to create a shared mental model of a common operating objective for surgical team members using narrated 3D VR models. Initial survey results demonstrate positive feedback among respondents. There is a paucity of literature investigating VR technology as a means for preoperative surgical communication in spine surgery. ETHICS: Institutional review board approval (IRB-300009785) was obtained before this study.

A Rare Cause of Headache and an Unorthodox Transfer: A Case Report.

INTRODUCTION: Emergency department (ED) crowding and hospital diversion times are increasing nationwide, with negative effects on patient safety and an association with increased mortality. Crowding in referral centers makes transfer of complex or critical patients by rural emergency physicians (EP) more complicated and difficult. We present a case requiring an unorthodox transfer method to navigate extensive hospital diversion and obtain life-saving neurosurgical care. CASE REPORT: We present the case of a previously healthy 21-year-old male with two hours of headache and rapid neurologic decompensation en route to and at the ED. Computed tomography revealed obstructive hydrocephalus recognized by the EP, who medically managed the increased intracranial pressure (ICP) and began the transfer process for neurosurgical evaluation and management. After refusal by six referral centers in multiple states, all of which were on diversion, the EP initiated an unorthodox transfer procedure to the institution at which he trained, ultimately transferring the patient by air. Bilateral external ventricular drains were placed in the receiving ED, and the patient ultimately underwent neurosurgical resection of an obstructive colloid cyst. CONCLUSION: First, our case illustrates the difficulties faced by rural EPs when attempting to transfer critical patients when large referral centers are refusing transfers and the need for improvements in facilitating timely transfers of critically ill, time-sensitive patients. Second, EPs should be aware of colloid cysts as a rare but potentially catastrophic cause of rapid neurologic decline due to increased ICP, and the ED management thereof, which we review.

The effect of procedural end-tidal CO2 on infarct expansion during anterior circulation thrombectomy.

BACKGROUND: Carbon dioxide is a potent cerebral vasodilator that may influence outcomes after ischemic stroke. The objective of this study was to investigate the effect of intraprocedural mean end-tidal CO2 (ETCO2) levels on core infarct expansion and neurologic outcome following thrombectomy for anterior circulation ischemic stroke. METHODS: A retrospective review was conducted of consecutive patients from March 2020 to June 2021 who underwent mechanical thrombectomy for acute anterior circulation ischemic stroke under general anesthesia and achieved successful recanalization (Thrombolysis in Cerebral Infarction [TICI] ≥ 2b). Only patients with CT perfusion, procedural ETCO2, and postoperative MRI data were included. Segmentation software was used for multi-parametric image analysis. Normocarbia defined as mean ETCO2 of 35 mmHg was used to dichotomize subjects. Univariate and multivariate statistics were applied. RESULTS: Fifty-eight patients met criteria for analysis. Of these, 44 had TICI 3 recanalization, 9 had TICI 2c, and 5 had TICI 2b. Within this combined recanalization group, patients with mean ETCO2 > 35 had significantly higher rates of functional independence at 90 days. Although patients tended to salvage more penumbra and experience smaller final infarcts when ETCO2 exceeded 35 mmHg, this did not reach statistical significance. CONCLUSIONS: Stroke patients who underwent successful thrombectomy with general anesthesia achieved higher rates of functional independence when procedural ETCO2 exceeded 35 mmHg. Further studies to confirm this effect and investigate optimal ETCO2 parameters should be considered.

Outcomes of endovascular embolization for Vein of Galen malformations: An individual participant data meta-analysis.

Introduction: Understanding outcomes after Vein of Galen malformation (VOGM) embolization has been limited by small sample size in reported series and predominantly single center studies. To address these limitations, we perform an individual-participant meta-analysis (IPMA) to identify risk factors associated with all-cause mortality and clinical outcome after VOGM endovascular embolization. Methods: We performed a systematic review and IPMA of VOGM endovascular outcomes according to PRISMA guidelines. Individual patient characteristics including demographic, intra/post-operative adverse events, treatment efficacy (partial or complete occlusion), and clinical outcome were collected. Mixed-effects logistic regression with random effects modeling and Bonferroni correction was used (p ≤ 0.003 threshold for statistical significance). The primary and secondary outcomes were all-cause mortality and poor clinical outcome (moderate/severe developmental delay or permanent disabling injury), respectively. Data are expressed as (mean ± standard deviation (SD)) or (odds ratio (OR), 95% confidence interval (CI), I 2, p-value). Results: Thirty-five studies totaling 307 participants quantifying outcomes after endovascular embolization for VOGM were included. Follow up time was 42 (±57) months. Our analysis contained 42% neonates (<1 month) at first embolization, 45% infants (1 month ≤2 years), and 13% children (>2 years). Complete occlusion was reported in 48% of participants. Overall all-cause mortality was 16%. Overall, good clinical outcome was achieved in 68% of participants. First embolization as a neonate [OR = 6.93; 95% CI (1.99-24.08); I 2 < 0.01; p < 0.001] and incomplete embolization [OR = 10.87; 95% CI (1.86-63.55); I 2 < 0.01; p < 0.001] were associated with mortality. First embolization as a neonate [OR = 3.24; 95% CI (1.47-7.15); I 2 < 0.01; p < 0.001], incomplete embolization [OR = 5.26; 95% CI (2.06-13.43); I 2 < 0.01; p < 0.001], and heart failure at presentation [OR = 3.10; 95% CI (1.03-9.33); I 2 < 0.01; p = 0.002] were associated with poor clinical outcomes. Sex, angioarchitecture of lesion, embolization approach (transvenous vs. transarterial), and single or multistage embolization were not associated with mortality or clinical outcome. Conclusions: We identify incomplete VOGM embolization independently associated with mortality and poor clinical outcome. While this study provides the highest level of evidence for VOGM embolization to date, prospective multicenter studies are needed to understand the optimal treatment strategies, outcomes, and natural history after VOGM embolization.

Morphological characteristics of symptomatic and asymptomatic carotid webs.

OBJECTIVE: Carotid webs (CWs) are an increasingly recognized source of recurrent stroke among young patients without conventional vascular risk factors. There have been no previous studies demonstrating that specific web morphological characteristics correlate with a higher stroke risk. The authors aim to report distinct morphological features of symptomatic and asymptomatic CWs. METHODS: The authors performed a cross-sectional study of patients with CWs detected on CT angiography (CTA) of the neck. Patients were categorized based on whether or not they presented with stroke ipsilaterally and if it was likely to be attributable to their web. The following CW morphological variables were recorded and compared based on CTA: length, thickness, angle, and the proportion of carotid bulb lumen occupied by the web (web-to-bulb ratio [WBR]). RESULTS: A total of 86 CWs were identified, 14 of which presented with stroke (16.3%). Patients presenting with stroke had webs that were significantly longer (4.18 mm vs 2.20 mm, p = 0.001) and were situated at more acute angles relative to the carotid wall (73.2° vs 94.9°, p = 0.004). Additionally, patients presenting with stroke had higher WBRs compared to the asymptomatic cohort (0.50 vs 0.36, p = 0.008). The optimal threshold associated with stroke was web length ≥ 3.1 mm (OR 15.2, 95% CI 3.73-61.8; p < 0.001), web angle ≤ 90.1° (OR 5.00, 95% CI 1.42-17.6; p = 0.012), and WBR ≥ 0.50 (OR 30.0, 95% CI 5.94-151; p < 0.001). CONCLUSIONS: Patients with CWs that occupy more than half of the diameter of the carotid bulb lumen and are situated at acute angles relative to the carotid wall are more likely to present with acute ischemic stroke. Additional studies are needed to determine the long-term outcomes of these lesions.

Immunovirotherapy for the Treatment of Glioblastoma and Other Malignant Gliomas.

Glioblastoma multiforme (GBM) represents one of the most challenging malignancies due to many factors including invasiveness, heterogeneity, and an immunosuppressive microenvironment. Current treatment modalities have resulted in only modest effect on outcomes. The development of viral vectors for oncolytic immunovirotherapy and targeted drug delivery represents a promising therapeutic prospect for GBM and other brain tumors. A host of genetically engineered viruses, herpes simplex virus, poliovirus, measles, and others, have been described and are at various stages of clinical development. Herein we provide a review of the advances and current state of oncolytic virotherapy for the targeted treatment of GBM and malignant gliomas.

Arteriovenous malformation presenting as traumatic subdural hematoma: A case report.

BACKGROUND: Brain arteriovenous malformations (AVMs) are congenital aberrant connections between afferent arteries and draining veins with no intervening capillary bed or neural parenchyma. Other than seizures, the most common initial presentation of AVM is hemorrhage, which is typically intraparenchymal, subarachnoid, or intraventricular, and very rarely subdural. CASE DESCRIPTION: This patient is a 66-year-old male with a history of atrial fibrillation, chronically anticoagulated with apixaban, who presented through emergency services after a fall. On presentation, computed tomography (CT) of the head showed a small, 6 mm right subdural hematoma, and the patient was neurologically intact. The hematoma was evacuated by burr hole craniotomy and placement of a subdural drain 12 days after the initial presentation due to worsening headaches and further hematoma expansion. Two weeks postevacuation, the patient was readmitted for seizures, and at this time, CT angiography showed no intracranial vascular lesion. Approximately 1 month later, the patient was readmitted for decreased responsiveness, and CT head at this time found right frontal intraparenchymal hemorrhage. On subsequent catheter angiography, the right frontal AVM was discovered. It was treated with preoperative embolization followed by surgical resection. Postoperatively, the patient followed commands and tracked with his eyes. There was spontaneous antigravity movement of the right upper extremity, but still no movement of the left upper or bilateral lower extremities. CONCLUSION: This case emphasizes the importance of maintaining a high index of suspicion for underlying vascular lesions when evaluating intracranial bleeding, even in the setting of traumatic history, particularly in cases of hematoma expansion.

Delayed-Onset Cyst Formation After Laser Interstitial Thermal Therapy: Unreported Long-Term Complication.

BACKGROUND: The majority of complications following (LITT) therapy occur in the early postoperative period, with few long-term complications being reported. CASE DESCRIPTION: Here we present 2 cases of delayed-onset cyst formation occurring more than 1 year following ablation, a previously unreported complication. In the first case, a 59-year-old female who previously underwent LITT for a radiation-induced cavernoma developed a 2-cm cystic lesion 18 months after ablation, resulting in recurrent seizures. In the second case, a 53-year-old female with a recurrent left frontal cerebral metastasis developed a large cystic lesion 30 months post ablation. Both patients required craniotomies and resection of their cystic lesions. In both cases pathology demonstrated reactive gliosis and blood vessel sclerosis. CONCLUSIONS: We hypothesize chronic gliosis following LITT therapy results in blood vessel sclerosis leading to blood-brain barrier-breakdown and delayed cyst formation. These findings support the need for long-term surveillance of patients treated with LITT.

Isolated Abducens Nerve Palsy Associated with Ruptured Posterior Inferior Cerebellar Artery Aneurysm: Rare Neurologic Finding.

BACKGROUND: Isolated abducens nerve palsy can be the presenting sign of a ruptured PICA aneurysm. Few cases have been reported in the literature. In the majority of cases, cranial nerve VI resolved following microsurgical clipping. CASE DESCRIPTION: Here, we report a 56-year-old female who presented with a ruptured 4 mm × 3 mm left PICA aneurysm associated with a left abducens nerve palsy. The patient underwent endovascular coil embolization of the aneurysm and had complete resolution of her abducens nerve palsy. CONCLUSIONS: Here, we present the first case of an abducens nerve palsy associated with a ruptured PICA aneurysm to completely resolve following endovascular coil embolization. The direction and amount of subarachnoid hemorrhage extravasation from the ruptured aneurysm are most likely responsible for cranial nerve palsy.

Diabetes control decreases morbidity and mortality after carotid endarterectomy.

BACKGROUND: Single-institution studies have demonstrated a negative effect of diabetes mellitus on outcomes after carotid endarterectomy (CEA). The aim of this study was to compare patients with explicitly controlled and uncontrolled diabetes at the population level. METHODS: Using the National Inpatient Sample 2006-2013, we selected patients undergoing CEA. Rates of stroke, myocardial infarction (MI), and hospital mortality, as well as duration of stay and cost were compared among patients with uncontrolled diabetes (UCDM), well-controlled diabetes (WCDM), and those without diabetes (NDM). RESULTS: We reviewed data from 614,190 patients undergoing CEA. Patients with UCDM, compared with those with WCDM and NDM, had higher rates of stroke (3.27%, 0.93%, and 0.94%, respectively; P < .0001), MI (3.35%, 1.10%, and 0.87%, respectively; P < .0001), and higher hospital mortality (1.43%, 0.25%, and 0.27%, respectively; P < .0001). On multivariate analysis, patients with UCDM compared with WCDM were more likely to develop stroke (odds ratio[OR], 1.45; 95% confidence interval [CI], 1.23-1.71), and MI (OR, 2.26; 95% CI, 1.96-2.60) and were more likely to die (OR, 2.74; 95% CI, 2.19-3.42). Patients with WCDM compared with patients without diabetes had similar likelihoods of stroke (OR, 0.96; 95% CI, 0.90-1.02) and MI (OR, 1.04; 95% CI, 0.98-1.10) but were actually less likely to die (OR, 0.85; 95% CI, 0.76-0.95). CONCLUSION: Patients with uncontrolled diabetes had poorer outcomes after CEA than those with controlled diabetes, whose outcomes were comparable to if not better than individuals without diabetes.

Division I College Football Concussion Rates Are Higher at Higher Altitudes.

STUDY DESIGN: Retrospective cohort. BACKGROUND: Participating in sports at high altitude may have a protective effect on the brain, according to research studies. Research using validated data-collection methods in a previously unexplored cohort may better estimate the association between concussion injury risk and altitude. OBJECTIVES: To determine the association between concussion rates and altitude during college football games. METHODS: Athletic trainers from 21 Division I football programs provided exposure and injury data to the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP) from the 2009-2010 to 2013-2014 academic years. The elevation of each stadium was determined. Concussion rates per 1000 athlete-exposures (AEs) were compared in 2 ways, based on the sample of stadium elevations: (1) median split (elevation higher than 178 m or lower than 178 m), and (2) quartile split. Rate ratios (RRs), rate differences, and 95% confidence intervals (CIs) were computed. RESULTS: One hundred sixty-nine concussions were reported over 49 040 AEs (3.45/1000 AEs). Using the median split, the concussion rate above 178 m (RR = 4.18/1000 AEs) was 1.47 times the concussion rate below 178 m (RR = 2.84/1000 AEs; 95% CI: 1.09, 2.00; P = .01). The concussion rate at the highest altitude quartile (higher than 284 m; RR = 5.01/1000 AEs) was 1.67 times greater than the concussion rate at the lowest altitude quartile (lower than 43 m; RR = 3.00/1000 AEs; 95% CI: 1.13, 2.48; P = .01). CONCLUSION: College football game concussion rates appear to increase at higher altitudes. The clinical significance of this relatively small increase is unknown. Future research should explore potential physiologic underpinnings associated with concussion risk at relatively higher and lower altitudes. LEVEL OF EVIDENCE: Prognosis, level 2b.