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Introduction: Falcine meningiomas present significant surgical challenges because they often involve the falx bilaterally, are concealed by a significant amount of normal brain parenchyma and are frequently deep in location and in close proximity to the anterior cerebral arteries. Many prefer the interhemispheric approach for these lesions, but this operative corridor is not without risk as venous infarctions and cortical injury can occur., Clinical Presentation: We present an alternative technique utilizing a transcortical approach to resect a giant, bilobed falcine meningioma in a 68-year-old female who presented with progressive abulia, urinary incontinence, and bilateral lower extremity weakness over 2 years. A unilateral right frontal craniotomy and a corticectomy through the right superior frontal gyrus was used to safely resect the entire tumor. The patient tolerated the procedure well and was discharged home without issue. Pathology demonstrated that the lesion was an atypical meningioma and she subsequently received adjuvant fractionated radiotherapy. At 2-year follow-up, she has no neurologic deficits, never developed any postoperative seizures and has not had any evidence of tumor recurrence., Conclusion: The transcortical approach can be used as a safe alternative for resecting falcine meningiomas without adding significant undue risk to the patient.

Diagnostic accuracy of arteriovenous malformations (AVMs) is imperative for delineating management. The current standard is digital subtraction angiography (DSA). Arterial spin labeling (ASL) is an understudied noninvasive, non-contrast technique that allows angioarchitecture visualization and additionally quantifies cortical and AVM cerebral blood flow and hemodynamics. This meta-analysis aims to compare ASL and DSA imaging in detecting and characterizing cerebral AVMs. EMBASE, Medline, Scopus, and Cochrane databases were queried from inception to July 2022 for reports of AVMs evaluated by DSA and ASL imaging. Fourteen studies with 278 patients evaluated using DSA and ASL imaging prior to intervention were included; pCASL in 11 studies (n = 239, 85.37%) and PASL in three studies (n = 41, 14.64%). The overall AVM detection rate on ASL was 99% (CI 97-100%); subgroup analysis revealed no difference between pCASL vs. PASL (99%; CI 96-100% vs. 100%; CI 95-100% respectively, p = 0.42). The correlation value comparing ASL and DSA nidus size was 0.99. DSA and ASL intermodality agreement Cohen's k factor for Spetzler Martin Grading (SMG) was reported at a median of 0.98 (IQR 0.73-0.1), with a 1.0 agreement on SMG classification. A median of 25 arteries were detected by DSA (IQR 14.5-27), vs. 25 by ASL (IQR 14.5-27.5) at a median 0.92 k factor. ASL provides angioarchitectural visualization noninferior to DSA and additionally quantifies CBF. Our study suggests that ASL should be considered in the detection of AVMs, especially in patients with contrast contraindications or apprehension towards an invasive assessment., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Anterior inferior cerebellar artery-posterior inferior cerebellar artery (AICA-PICA) variant is a well-established variant of the vertebrobasilar system. AICA-PICA aneurysms are extremely rare.1-3 There are only 12 cases reported in the literature.1-3 Here, we are presenting a case of a previously ruptured AICA-PICA dissecting aneurysm which had undergone coil embolization twice at an outside institution. The aneurysm continued to grow, and therefore, the patient was transferred to our institution for definitive treatment. Placement of a flow diverter was felt not to be feasible because of the acute bend of the vessel at the neck of the aneurysm. After a retrosigmoid craniotomy, the aneurysm sac was opened to untether the coil mass from the neck of the aneurysm. Clip reconstruction was attempted but intraoperative blood flow measurements demonstrated no flow in the distal outflow artery, indicating that the clip was occluding the parent vessel at the neck because of the challenging geometry and atherosclerosis. We then proceeded with an excision and end-to-end anastomosis of the AICA-PICA. The details of vascular reconstruction while the inflow and outflow arteries are at acute angle are described. Intraoperative indocyanine video angiography demonstrated complete exclusion of the aneurysm from the circulation and patency of the bypass. Postoperative computed tomography angiography demonstrated bypass patency. Postoperatively, the patient required a temporary external ventricular drain for hydrocephalus; however, she was eventually discharged home without any neurological deficits. The patient gave informed consent for the surgery and video recording. Institutional Review Board approval was deemed unnecessary., (Copyright © Congress of Neurological Surgeons 2024. All rights reserved.)

Background: Neurological complications of bacterial endocarditis (BE) are common, including acute ischemic stroke (AIS). Although mechanical thrombectomy (MT) is effective for large vessel occlusion (LVO) stroke, data are limited on MT for LVOs in patients with endocarditis. We assess outcomes in patients treated with thrombectomy for LVOs with concurrent BE., Methods: The National Inpatient Sample (NIS) was used. The NIS was queried from October 2015-2019 for patients receiving MT for LVO of the middle cerebral artery. Odds ratios (OR) were calculated using a multivariate logistic regression model., Results: A total of 635 AIS with BE patients and 57 420 AIS only patients were identified undergoing MT. AIS with BE patients had a death rate of 26.8% versus 10.2% in the stroke alone cohort, and were also less likely to have a routine discharge (10.2% vs 20.9%, both P<0.0001). AIS with BE patients had higher odds of death (OR 3.94) and lower odds of routine discharge (OR 0.23). AIS with BE patients also had higher rates of post-treatment cerebral hemorrhage, 39.4% vs 23.7%, with an OR of 2.20 (P<0.0001 for both analyses). These patients also had higher odds of other complications, including hydrocephalus, respiratory failure, acute kidney injury, and sepsis., Conclusion: While MT can be used to treat endocarditis patients with LVOs, these patients have worse outcomes. Additional investigations should be undertaken to better understand their clinical course, and further develop treatments for endocarditis patients with stroke., Competing Interests: Competing interests: The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article. Robert M Starke has consulting and teaching agreements with Penumbra, Abbott, Medtronic, InNeuroCo, and Cerenovus., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Giant falcine meningiomas are surgically complex as they are deep in location, concealed by normal brain parenchyma, in close proximity to various neurovascular structures, and frequently involve the falx bilaterally. Although classically accessed using a bifrontal craniotomy and interhemispheric approach, little data exist on alternative operative corridors for these challenging tumors. We evaluated perioperative and long-term outcomes in patients undergoing transcortical resection of giant bilateral falcine meningiomas., Methods: From 2013 to 2022, fourteen patients with giant bilateral falcine meningiomas treated via a transcortical approach at our institution were identified. Perioperative and long-term outcomes were evaluated to determine predictors of adverse events. Corticectomy depth was also analyzed to determine if it correlated with increased postoperative seizure rates., Results: 57.1% of cases were WHO grade 2 meningiomas. Average tumor volume was 77.8 ± 46.5 cm 3 and near/gross total resection was achieved in 78.6% of patients. No patient developed a venous infarct or had seizures in the 6 months after surgery. Average corticectomy depth was 0.83 ± 0.71 cm and increasing corticectomy depth did not correlate with higher risk of postoperative seizures (P = 0.44). Increasing extent of tumor resection correlated with lower tumor grade (P = 0.011) and only 1 patient required repeat resection during a median follow-period of 24.9 months., Conclusions: The transcortical approach is a safe alternative corridor for accessing giant, falcine meningiomas, and postoperative seizures were not found to correlate with increasing corticectomy depth. Further prospective studies are necessary to determine the best approach to these surgically complex lesions., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Preliminary studies show that patients with large vessel occlusion (LVO) acute ischemic strokes have worse outcomes with concurrent COVID-19 infection. We investigated the outcomes for patients with LVO strokes undergoing mechanical thrombectomy (MT) with concurrent COVID-19 infection., Methods: The National Inpatient Database (NIS) was used for our analysis. Patients in the year 2020 with an ICD-10 diagnosis code for acute ischemic stroke and procedural code for MT were included with and without COVID-19. Odds ratios (OR) were calculated using a logistic regression model with age, sex, stroke location, Elixhauser comorbidity score, and other patient variables deemed clinically relevant as covariates., Results: Patients in the COVID-19 group were younger (64.3±14.4 vs 69.4±14.5 years, P<0.001), had a higher rate of inpatient mortality (22.4% vs 10.1%, P<0.001), and a longer length of stay (10 vs 6 days, P<0.001). Patients with COVID-19 had higher odds of death (OR 2.78, 95% CI 2.11 to 3.65) and lower odds of a routine discharge (OR 0.65, 95% CI 0.48 to 0.89). There was no difference in the odds of subsequent stroke and cerebral hemorrhage, but patients with COVID-19 had statistically significantly higher odds of respiratory failure, pulmonary embolism, deep vein thrombosis, myocardial infarction, acute kidney injury, and sepsis., Conclusions: Patients with LVOs undergoing MT within the 2020 NIS database had worse outcomes when co-diagnosed with COVID-19, likely due to non-neurological manifestations of COVID-19., Competing Interests: Competing interests: The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article. RMS has consulting and teaching agreements with Penumbra, Abbott, Medtronic, InNeuroCo, and Cerenovus., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: There has been a recent decrease in interventional management of cerebral arteriovenous malformations (AVMs). The objective of our study was to evaluate the changing patterns in management of AVMs in the first year of the COVID-19 pandemic., Methods: The National Inpatient Sample (NIS) database was used. From 2016 to 2020, patients with an International Classification of Diseases, 10th revision (ICD-10) diagnosis code for a cerebral AVM were included. An intervention was defined as ICD-10 code for surgical, endovascular, or stereotactic radiosurgery treatment. Odds ratios (ORs) were calculated using a logistic regression model with covariates deemed to be clinically relevant., Results: 63 610 patients with AVMs were identified between 2016 and 2020, 14 340 of which were ruptured. In 2020, patients had an OR of 0.69 for intervention of an unruptured AVM (P<0.0001) compared with 2016-19. The rate of intervention for unruptured AVMs decreased to 13.5% in 2020 from 17.6% in 2016-19 (P<0.0001). The rate of AVM rupture in 2020 increased to 23.9% from 22.2% in 2016-19 (P<0.0001). In 2020, patients with ruptured AVMs had an OR for inpatient mortality of 1.72 compared with 2016-19. Linear regression analysis from 2016 to 2020 showed an inverse relationship between intervention rate and rupture rate (slope -0.499, R 2 =0.88, P=0.019)., Conclusion: In 2020, the rate of intervention for unruptured cerebral AVMs decreased compared with past years, with an associated increase in the rate of rupture. Patients with ruptured AVMs also had a higher odds of mortality., Competing Interests: Competing interests: The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article. RMS has consulting and teaching agreements with Penumbra, Abbott, Medtronic, InNeuroCo, and Cerenovus., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Purpose: The goal of this study was to systematically review the metabolic profile of meningiomas using magnetic resonance spectroscopy in comparison to gliomas, as measured by mean metabolite ratios., Methods: Following the PRISMA guidelines, a systematic literature review was performed using the PubMed, Ovid Embase, Web of Science, and the Cochrane databases from inception to May 2021. Studies were selected based on predetermined inclusion and exclusion criteria., Results: Eight studies were ultimately selected with 207 patients included. Fifty-nine patients were diagnosed with meningioma (age = 48.4, 66.7% female) and 148 patients diagnosed with glioma (age = 56.4, 49.2% female). Three studies reported elevated Cho/Cr in meningiomas compared to gliomas (5.71 vs. 1.46, p < 0.05, 7.02 vs. 2.62, p < 0.05, and 4.64 vs. 2.52, p = 0.001). One study reported Ala/Cr to be significantly elevated in meningiomas compared to gliomas (1.30 vs. undetectable, p < 0.001). One study reported myo-Inositol/Cr to be significantly elevated in meningiomas in comparison to gliomas (1.44 vs. 1.08, p < 0.05). One study reported Glu/Cr to be significantly elevated in meningiomas in comparison to gliomas (3.47 vs. 0.89, p = 0.002). Two studies reported Cho/NAA to be significantly elevated in meningiomas in comparison to gliomas (4.46 vs. 2.6, p = 0.004, and 5.8 vs. 2.55, p < 0.05). Two studies reported NAA/Cr was significantly elevated in gliomas compared to meningiomas (undetectable vs. 1.54, p < 0.001 and undetectable vs. 0.58, p < 0.05)., Conclusions: Significant differences in metabolite ratios between tumor types were reported in Cho/Cr, Ala/Cr, Glu/Cr, Cho/NAA, myoI/Cr and NAA/Cr between meningiomas and gliomas., (© 2023. The Author(s) under exclusive licence to Belgian Neurological Society.)

Background: Pediatric tumors of the brain and central nervous system (CNS) are a worldwide issue with variances in epidemiology. How exactly incidence and mortality rates have changed over time has not been summarized. Correspondingly, the aim of this study was to quantitively define the global, regional, and national epidemiological trends of these tumors., Methods: A retrospective review of data from the Global Burden of Disease Study 2019 Database was performed incorporating data from 1999 to 2019. Global, regional, and national outcomes for pediatric CNS tumors were collected for incidence and mortality at a worldwide level, as well as across 7 continental regions, and then 204 countries and territories., Results: Globally, the latest incidence of pediatric CNS tumors was 47,600 (uncertainty interval, 36,500-55,200) at a rate of 1.8 (1.4-2.2) per 100,000, with 23,500 (18,000-27,500) deaths due to these tumors at a rate of 0.9 (0.7-1.1) per 100,000 population. Both rates per 100,000 have decreased over the past 2 decades. With respect to regions, East Asia and Pacific had the highest incidence and mortality cases overall, but in terms of rate per 100,000, North America and Latin America and Caribbean had the highest values, respectively. There were 3/7 (43%) and 6/7 (86%) regions with decreasing incidence and mortality rates per 100,000 over the past 2 decades. China, India, and Pakistan were the 3 countries with both the highest incidence and mortality cases overall; however, San Marino, Denmark, and Norway had the highest incidence rates per 100,000, and Albania, Armenia, and Haiti had the highest mortality rates per 100,000. In the past 2 decades, 79/204 (39%) and 120/204 (59%) countries observed decreasing incidence and mortality rates per 100,000, respectively., Conclusions: Pediatric CNS tumors remains a worldwide issue, with there being multiple regions and countries worldwide that continue to experience uptrending incidence and mortality rates per 100,000. For both incidence and mortality, there is a clear discordance between regions and countries that report the highest number of cases versus the highest rate of cases per 100,000. Future research efforts are needed to identify positive intervention measures that respect the epidemiology of these tumors at global, regional, and national levels., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: We report a unique case of a suspected recurrent intracranial epidermoid cyst (EDC) that was found on pathology to have undergone malignant transformation to squamous cell carcinoma (SCC) approximately 25 years after initial resection. Additionally, we performed a systematic review including 94 studies reporting intracranial EDC to SCC transformation., Methods: Ninety-four studies were included in our systematic review. PubMed, Scopus, Cochrane Central, and EMBASE were searched in April 2020 for studies regarding histologically confirmed SCC arising within an EDC. Kaplan-Meier estimations were used to estimate time to event including survival, and log rank tests were used to test for significance. All analyses were conducted using STATA 14.1 (StataCorp, College Station, Texas, USA); tests were two-sided, and statistical significance was defined using the alpha threshold of 0.05., Results: The overall median time to transformation was 60 months (95% confidence interval {CI}, 12-96). Transformation time was significantly shorter in the no surgery group (10 months, 95% CI undefined) versus the other 2 groups (60 months, 95% CI, 12-72 in surgery only and 70 months, 95% CI, 9-180 in surgery + adjuvant therapy group, both P < 0.01). Overall survival was significantly longer in the surgery + adjuvant therapy group (13 months, 95% CI, 9-24) versus the other 2 groups (3 months, 95% CI, 1-7 in surgery only and 6 months, 95% CI, 1-12 in the no surgery group, both P < 0.01)., Conclusions: We report a rare case of delayed malignant transformation of an intracranial EDC to SCC, occurring nearly 25 years after initial resection. Transformation time in the no-surgery group was statistically significantly shorter as compared to the surgery only and surgery + adjuvant therapy groups. Overall survival was statistically significantly higher in the surgery + adjuvant therapy group as compared to the surgery only and no surgery groups., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Pediatric brainstem lesions are diagnoses that require tissue sampling to advance our understanding of them and their management. Frameless, robot-assisted biopsy of these lesions has emerged as a novel, viable biopsy approach. Correspondingly, the aim of this study was to quantitively and qualitatively summarize the contemporary literature regarding the likelihood of achieving tumor diagnosis and experiencing any postoperative complications., Methods: Searches of 7 electronic databases from inception to September 2022 were conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Articles were screened against prespecified criteria. Outcomes were pooled by random-effects meta-analyses of proportions where possible., Results: A total of 8 cohort studies satisfied all criteria. They described 99 pediatric patients with brainstem lesions in whom frameless, robot-assisted biopsy was involved in their work-up. There were 62 (63%) male and 37 (37%) female patients with a median age of 9 years at time of biopsy. Overall, all patients had sufficient tissue obtained by initial biopsy for evaluation. Pooled estimate of achieving tumor diagnosis was 100% (95% confidence interval [CI] 97%-100%) across all studies with a high degree of certainty. Across all studies, there were no cases of procedure-related mortality. The pooled estimates of transient and permanent complications after biopsy were 10% (95% CI 4%-19%) and 0% (95% CI 0%-2%), respectively, of very low and low degrees of certainty each., Conclusions: The contemporary metadata demonstrates the frameless, robot-assisted biopsy of pediatric brainstem lesions is both effective and safe when performed in an experienced setting. Further research is needed to augment robot and automated technologies into workup algorithms., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Moyamoya disease is a chronic, progressive cerebrovascular disease involving occlusion or stenosis of the terminal portion of the internal carotid artery. We conducted an updated systematic review and meta-analysis to investigate clinical and angiographic outcomes comparing direct, combined, and indirect bypass for the treatment of moyamoya disease in adults., Methods: Two independent authors performed Preferred Reporting Items for Systematic reviews and Meta-Analyses guided literature searches in December 2021 to identify articles reporting clinical/angiographic outcomes in adult moyamoya disease patients undergoing bypass. Primary end points used were ischemic and hemorrhagic strokes, clinical outcomes, and angiographic revascularization. Study quality was evaluated with Newcastle-Ottawa and the Oxford Center for Evidence-Based Medicine scales., Results: Four thousand four hundred fifty seven articles were identified in the initial search; 143 articles were analyzed. There were 3827 direct, 3826 indirect, and 3801 combined bypasses. Average length of follow-up was 3.59±2.93 years. Pooled analysis significantly favored direct (odds ratio [OR], 0.62 [0.48-0.79]; P <0.0001; OR, 0.44 [0.32-0.59]; P <0.0001; OR, 0.56 [0.42-0.74]; P <0.0001; OR, 3.1 [2.5-3.8]; P =0.0001) and combined (OR, 0.53 [0.41-0.69]; P <0.0001; OR, 0.28 [0.2-0.41]; P <0.0001; OR, 0.41 [0.3-0.56]; P <0.0001; OR, 3.1 [2.8-4.3]; P =0.0001) over indirect bypass for early stroke, late stroke, late intracerebral hemorrhage, and favorable outcomes, respectively. Indirect bypass was favored over combined (OR, 3.1 [1.7-5.6]; P <0.0001) and direct (OR, 4.12 [2.34-7.25]; P <0.0001) for early intracerebral hemorrhage. The meta-analysis significantly favored direct (OR, 0.37 [0.23-0.60]; P <0.001; OR, 0.49 [0.31-0.77]; P =0.002) and combined (OR, 0.23 [0.12-0.43]; P <0.00001; OR, 0.30 [0.18-0.49]; P <0.00001) bypass over indirect bypass for late stroke and late hemorrhage, respectively. Combined bypass was favored over indirect bypass for favorable outcomes (OR, 2.06 [1.18-3.58]; P =0.01)., Conclusions: Based on combined meta-analysis (43 articles) and pooled analysis (143 articles), the existing literature indicates that combined and direct bypasses have significant benefits for patients suffering from late stroke and hemorrhage versus indirect bypass. Combined bypass was favored over indirect bypass for favorable outcomes. This is a strong recommendation based on low-quality evidence when utilizing the Grades of Recommendation, Assessment, Development, and Evaluation system. These findings have important implications for bypass strategy selection.

The management of base of skull (BS) chordomas is a neurosurgical conundrum owing to their close proximity to the critical neurovascular structures. Surgical resection is the gold standard treatment followed by adjuvant radiotherapy which includes photon therapy, proton beam therapy (PBT), gamma knife radiosurgery, etc. PBT has become an unparalleled therapeutic modality in the management of BS chordomas. The aim of this systematic review was to assess the outcomes in BS chordoma patients who received PBT as a primary or adjuvant therapy. PubMed and Cochrane databases were screened till May 2022. Following the PRISMA guidelines, studies were reviewed thoroughly, and the data of the included study was extracted. Statistical analysis was performed using the SAS 9.4 with P value < .05 considered as significant. Sixteen studies with 752 patients were included. The majority of the patients were adults (> 18 years) with a male:female ratio of 1.2. The most common clinical features were cranial nerve (3rd, 6th, or 12th) palsy and hearing impairment. Ninety-five percent of the patients underwent surgical resection before PBT. The mean PBT dose received was 74.02 cGe (cobalt gray equivalent). Eighty percent of the patients showed a positive response to the therapy defined in terms of tumor regression. Five-year local control (LC), overall survival (OS), and progression-free survival (PFS) were calculated as 76.6%, 79.6%, and 89%, respectively. Statistical analysis revealed none of the factors had any significant association with 5-year LC. PBT is a growing therapeutic technique that has revolutionized the treatment of BS chordomas., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: U.S. neurosurgery programs are increasingly using social media accounts. We performed a search and analysis of social media accounts across all U.S. neurosurgical training programs with an attempt at understanding the relative utilization by various subspecialties., Methods: We compiled a list of all Accreditation Council for Graduate Medical Education-accredited U.S. neurosurgery programs and the faculty. Each faculty member was classified on the basis of their subspecialty. Next, the Twitter, Facebook, and Instagram profiles were extensively searched for the number of followers and posts., Results: We analyzed 110 programs with 1829 clinical faculty. Programs with a larger number of faculty (P = 0.035; χ 2  = 13.528) and residents (P = 0.003; χ 2  = 11.865) were more likely to have a social media account. Likewise, faculty and resident numbers had a positive correlation to Twitter (P = 0.037 for faculty size; P = 0.008 for residents' size) and Instagram followers (P = 0.003 for faculty size; P < 0.001 for residents' size). We additionally found a significant association between subspecialty type and the presence of a Twitter and Instagram account (P = 0.001; P = 0.028) and the number of followers (P = 0.004; P = 0.013), especially the vascular and oncology subspecialties., Conclusions: Many U.S. neurosurgical programs have social media accounts with larger programs likely to have social media accounts. While there is a larger percentage of spine faculty within individual departments, vascular and oncology subspecialties are more likely to have a Twitter account. We suggest the need for increased engagement among spine faculty across social media platforms., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objective: The purpose of this study is to retrospectively evaluate the clinical and surgical outcomes of a large surgical series of vestibular schwannoma from North America over 20 years., Methods: After institutional review board approval a retrospective review of the senior author's personal case logs to identify patients who had operations for vestibular schwannoma was performed. The clinical notes, operative record, preoperative and postoperative imagings, and long-term clinical follow-up notes were evaluated., Results: A total of 415 patients who underwent 420 surgeries were identified from the years 1998-2021. The average length of follow-up was 3 years and 9 months. Overall, at last follow-up the rate of "good" facial nerve outcomes (House-Brackmann [HB] score I and II) was 86% and "poor" facial nerve outcomes (HB III-VI) was 14%. The amount of cerebellopontine angle extension (P = 0.023), tumor volume (P = 0.015), facial nerve consistency (P < 0.001), preoperative HB score (P < 0.001), and FN stimulation threshold at the end of the procedure (P < 0.001) were correlated to facial nerve function at the last follow-up., Conclusions: This study represents one of the largest recently reported surgical series of vestibular schwannoma in North American literature with available long term follow-up. Facial nerve outcomes correlated with cerebellopontine angle extension, tumor volume, facial nerve stimulation threshold, facial nerve consistency, preoperative facial nerve function, and history of a prior resection. Tumor recurrence remains significantly higher after subtotal resection. We believe the data supports a continuation of a strategy of general intent of gross total resection, greatly modifiable by intraoperative findings and judgment., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Cerebral extracranial-intracranial (EC-IC) direct bypass is a commonly used procedure for the treatment of cerebral hypoperfusion secondary to chronic steno-occlusive vasculopathy. We sought to determine clinical outcomes, intraoperative blood flow analysis, long term follow up, and long term patency rates from a single surgeon's series of direct cerebral bypass for moyamoya disease, moyamoya syndrome, and steno-occlusive disease., Methods: We reviewed clinical, demographic, operative and neuroimaging records for all patients who underwent a direct EC-IC bypass by the senior author between August 1999 and November 2020. Primary outcomes analyzed were functional long-term outcomes (by modified Rankin score [mRS]), surgical complications, and short-term and long-term bypass patency., Results: A total of 162 revascularization procedures in 124 patients were performed. Mean clinical follow up time was 2 years 11 months. The combined immediate and long term postoperative stroke and/or intracerebral hemorrhage rate was 6.2%. There were 17 bypasses (10%) that were found to be occluded at long-term follow-up, all but one were asymptomatic. Long-term graft occlusion was correlated with presence of complete collateralization on preoperative angiography but not cut flow index (CFI). Overall, patients had a significant clinical improvement with a mean mRS score 1.8 preoperatively and 1.2 postoperatively., Conclusions: In our consecutive series of patients treated with direct EC-IC cerebral bypass, there was significant improvement in functional outcome as measured by the mRS. The long term patency rate was 90%. There was a statistically significant correlation between complete or incomplete angiographic collateralization patterns and long-term bypass occlusion. There was no correlation between bypass type, clinical syndrome, or CFI and long-term occlusions. The role of bypass surgery and the need for surgical expertise remain strong in the treatment of moyamoya variants and a select group of atherosclerotic steno-occlusive patients., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Over 15 million epilepsy patients worldwide have drug-resistant epilepsy. Successful surgery is a standard of care treatment but can only be achieved through complete resection or disconnection of the epileptogenic zone, the brain region(s) where seizures originate. Surgical success rates vary between 20% and 80%, because no clinically validated biological markers of the epileptogenic zone exist. Localizing the epileptogenic zone is a costly and time-consuming process, which often requires days to weeks of intracranial EEG (iEEG) monitoring. Clinicians visually inspect iEEG data to identify abnormal activity on individual channels occurring immediately before seizures or spikes that occur interictally (i.e. between seizures). In the end, the clinical standard mainly relies on a small proportion of the iEEG data captured to assist in epileptogenic zone localization (minutes of seizure data versus days of recordings), missing opportunities to leverage these largely ignored interictal data to better diagnose and treat patients. IEEG offers a unique opportunity to observe epileptic cortical network dynamics but waiting for seizures increases patient risks associated with invasive monitoring. In this study, we aimed to leverage interictal iEEG data by developing a new network-based interictal iEEG marker of the epileptogenic zone. We hypothesized that when a patient is not clinically seizing, it is because the epileptogenic zone is inhibited by other regions. We developed an algorithm that identifies two groups of nodes from the interictal iEEG network: those that are continuously inhibiting a set of neighbouring nodes ('sources') and the inhibited nodes themselves ('sinks'). Specifically, patient-specific dynamical network models were estimated from minutes of iEEG and their connectivity properties revealed top sources and sinks in the network, with each node being quantified by source-sink metrics. We validated the algorithm in a retrospective analysis of 65 patients. The source-sink metrics identified epileptogenic regions with 73% accuracy and clinicians agreed with the algorithm in 93% of seizure-free patients. The algorithm was further validated by using the metrics of the annotated epileptogenic zone to predict surgical outcomes. The source-sink metrics predicted outcomes with an accuracy of 79% compared to an accuracy of 43% for clinicians' predictions (surgical success rate of this dataset). In failed outcomes, we identified brain regions with high metrics that were untreated. When compared with high frequency oscillations, the most commonly proposed interictal iEEG feature for epileptogenic zone localization, source-sink metrics outperformed in predictive power (by a factor of 1.2), suggesting they may be an interictal iEEG fingerprint of the epileptogenic zone., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objective: The objective of this retrospective study was to compare the survival of patients with biopsy-proven skull base chordoma who had undergone stereotactic radiosurgery (SRS) with versus without prior fractionated radiation therapy (RT)., Methods: Relevant articles from database inception to September 2021 were retrieved from the PubMed, Scopus, Web of Science, and Cochrane databases for a systematic review of treatment protocols. Studies were included if they 1) involved adult patients (age ≥ 18 years) with histologically and radiologically confirmed chordomas located within the clival skull base region and treated with SRS; 2) reported data on clinical features, SRS protocols, and outcomes; and 3) were written in the English language. Studies were excluded if they 1) were literature reviews, case reports, technical notes, abstracts, or autopsy reports; 2) did not clearly differentiate the data of patients with chordomas from the data of patients with different tumors or the data of patients with chordomas in locations other than the skull base; or 3) lacked histological confirmation or treatment and outcome data. Extracted data included the following: study author and publication year, patient age and sex, symptoms, cranial nerve involvement, invaded structures, lesion size, treatment modality, surgical details, histopathological type, RT modality, SRS parameters, complications, postradiosurgery outcomes, complications, and survival outcomes., Results: After the selection process, 15 articles describing 130 patients met the study eligibility criteria, including 94 patients who had undergone postresection SRS (NoRT group) and 36 who had undergone postresection fractionated RT and subsequent SRS (RT group). The NoRT and RT groups were comparable in age (51.3 vs 47.4 years, respectively), sex (57.1% vs 58.3% male), tumor volume (9.5 vs 11.2 cm3), SRS treatment parameters (maximum dose: 35.4 vs 42.2 Gy, marginal dose: 19.6 vs 20.6 Gy, treatment isodose line: 60.2% vs 65.2%), and SRS adverse effects (10.9% vs 17.6%). For the entire cohort, the 3-, 5-, and 10-year progression-free survival (PFS) rates were 23%, 9%, and 3%, respectively, and the overall survival (OS) rates were 94%, 82%, and 76%, respectively. In the NoRT group, SRS was adjuvant treatment after resection in 38 patients (40.4%), salvage treatment for recurrent tumor treated with resection alone in 10 (10.6%), and not specified in 46 (48.9%). In the RT group, SRS was boost treatment in 9 patients (25.0%), salvage treatment after recurrence in 22 (61.1%), and not specified in 5 (13.9%). There was no difference between the two groups in terms of median PFS (24.0 months [Q1 34.0, Q3 15.0] vs 23.8 months [34.0, 18.0], respectively; p = 0.8) or median OS (293.0 months [not reached, 137.4] vs not reached [not reached, 48.0], respectively; p = 0.36). The adverse radiation effect rates were comparable between the groups (10.9% vs 17.6%, respectively; p = 0.4)., Conclusions: The role of SRS in the management of skull base chordomas is still evolving. This systematic literature review of biopsy-proven chordoma revealed that tumor control and survival rates for SRS alone after chordoma surgery were not inferior to those encountered after SRS plus fractionated RT.

The role of prior head trauma in stimulating brain tumor development has been previously described in the literature but continues to be debated. The goal of this study was to conduct a systematic review interrogating the contemporary literature to delineate any possible relationship between traumatic brain injury and brain tumor development. A systematic review exploring development of post-TBI brain tumor was conducted by searching electronic databases. Abstracts from articles were read and selected for full-text review according to criteria previously established in the scientific literature. Relevant full-text articles were divided into case reports and single-arm studies and epidemiological studies. Of 1070 resultant articles, 18 case reports and single-arm studies (level of evidence of IV and V) with 45 patients were included. The most common cause of TBI was traffic accidents. The average period between TBI and subsequent tumor diagnosis was 12.8 years. Meningiomas represented the largest share of tumors, followed by gliomas. Most post-TBI brain tumors developed in the frontal and temporal lobes. Fifteen epidemiological studies were also interrogated from a variety of countries (level of evidence of III). Case-control studies were more common than cohort studies. There were 9 of 15 studies proposed a possible relationship between history of head trauma and development of brain tumor. The relationship between head trauma and neoplastic growth continues to be heavily debated. There are certainly case reports and epidemiological studies in the literature that suggest a correlational relationship between the two. However, there is no concrete evidence of a causal relationship between TBI and brain tumors. More research is needed to definitively delineate the extent of any such relationship., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: Although younger adults have been shown to have better functional outcomes after mechanical thrombectomy (MT) for acute ischemic stroke (AIS), the significance of this relationship in the adolescent and young adult (AYA) population is not well defined given its undefined rarity. Correspondingly, the goal of this study was to determine the prognostic significance of age in this specific demographic following MT for large-vessel occlusions., Methods: A prospectively maintained international multi-institutional database, STAR (Stroke Thrombectomy and Aneurysm Registry), was reviewed for all patients aged 12-18 (adolescent) and 19-25 (young adult) years. Parameters were compared using chi-square and t-test analyses, and associations were interrogated using regression analyses., Results: Of 7192 patients in the registry, 41 (0.6%) satisfied all criteria, with a mean age of 19.7 ± 3.3 years. The majority were male (59%) and young adults (61%) versus adolescents (39%). The median prestroke modified Rankin Scale (mRS) score was 0 (range 0-2). Strokes were most common in the anterior circulation (88%), with the middle cerebral artery being the most common vessel (59%). The mean onset-to-groin puncture and groin puncture-to-reperfusion times were 327 ± 229 and 52 ± 42 minutes, respectively. The mean number of passes was 2.2 ± 1.2, with 61% of the cohort achieving successful reperfusion. There were only 3 (7%) cases of reocclusion. The median mRS score at 90 days was 2 (range 0-6). Between the adolescent and young adult subgroups, the median mRS score at last follow-up was statistically lower in the adolescent subgroup (1 vs 2, p = 0.03), and older age was significantly associated with a higher mRS at 90 days (coefficient 0.33, p < 0.01)., Conclusions: Although rare, MT for AIS in the AYA demographic is both safe and effective. Even within this relatively young demographic, age remains significantly associated with improved functional outcomes. The implication of age-dependent stroke outcomes after MT within the AYA demographic needs greater validation to develop effective age-specific protocols for long-term care across both pediatric and adult centers.

Background: Bone density has been associated with a successful fusion rate in spine surgery. Hounsfield units (HUs) have more recently been evaluated as an indirect representation of bone density. Low preoperative HUs may be an early indicator of global disease and chronic process and, therefore, indicative of the need for future reoperation., Objective: To assess preoperative HUs and their association with future adjacent segment disease requiring surgical intervention through retrospective study., Methods: Patients who underwent lumbar interbody fusion at a single institution between 2007 and 2016 were retrospectively reviewed. Hounsfield unit values were measured from preoperative computed tomography (CT) using sagittal images, encircling cancellous portion of the vertebral body. Patient charts were reviewed for follow-up data and adjacent-level disease development., Results: A total of 793 patients (age: 56.1 ± 13.7 years, 54.4% female) were included in this study. Twenty-two patients required surgical intervention for adjacent segment disease. Patients who underwent lumbar interbody fusion and did not subsequently require surgical intervention for adjacent-level disease were found to have a higher mean preoperative HU than patients who did require reoperation (180.7 ± 70.0 vs 148.4 ± 8.1, P = .032). Preoperative CT HU was a significant independent predictor for the requirement of adjacent-level surgery after spinal arthrodesis (odds ratio = 0.891 [0.883-0.899], P = .029)., Conclusion: Patients who underwent lumbar interbody fusion that did not require reoperation for adjacent-level degeneration were found to have a higher mean preoperative HU than patients who did require surgical intervention. Lower preoperative CT HU was a significant independent predictor for the requirement of adjacent-level surgery after spinal arthrodesis., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Background and Objective: The goal of this study was to systematically review the usefulness of serum biomarkers in the setting of ischemic stroke (IS) to predict long-term outcome., Methods: A systematic literature review was performed using the PubMed and MEDLINE databases for studies published between 1986 and 2018. All studies assessing long-term functional outcome (defined as ≥30 days) after IS with respect to serum biomarkers were included. Data were extracted and pooled using a meta-analysis of odds ratios., Results: Of the 2928 articles in the original literature search, 183 studies were selected. A total of 127 serum biomarkers were included. Biomarkers were grouped into several categories: inflammatory (n = 32), peptide/enzymatic (n = 30), oxidative/metabolic (n = 28), hormone/steroid based (n = 23), and hematologic/vascular (n = 14). The most commonly studied biomarkers in each category were found to be CRP, S100β, albumin, copeptin, and D-dimer. With the exception of S100β, all were found to be statistically associated with >30-day outcome after ischemic stroke., Conclusions: Serum-based biomarkers have the potential to predict functional outcome in patients with IS. This meta-analysis has identified C-reactive protein, albumin, copeptin, and D-dimer to be significantly associated with long-term outcome after IS. These biomarkers have the potential to serve as a platform for prognosticating stroke outcomes after 30 days. These serum biomarkers, some of which are routinely ordered, can be combined with imaging biomarkers and used in artificial intelligence algorithms to provide refined predictive outcomes after injury. These tools will assist physicians in providing guidance to families regarding long-term independence of patients., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: Patients with fusiform dilatation of the carotid artery (FDCA) following pediatric craniopharyngioma resection typically have a benign clinical course. We reviewed the neurosurgical literature for FDCA outcomes after resection of these tumors., Methods: Using PubMed, Web of Science, and Cochrane databases, we identified surgical series or case reports reporting incidences of FDCA following craniopharyngioma resection. Inclusion criteria included FDCA outcomes reported specifically after craniopharyngioma resection, with at least 6 months of follow-up data., Results: Our literature search yielded 15 full-text articles comprising 799 patients (376 [52.3%] males). The weighted mean follow-up was 74.8 months (range, 9-140 months). Most tumors were suprasellar (62.1%), with traditional microsurgery being more commonly employed than endoscopic endonasal surgery (80.9% vs. 19.1%). Gross total resection was achieved in 42.6% of cases. There were 55 aneurysms reported, most commonly occurring at the terminal internal carotid artery (66.7%). Aneurysmal progression on follow-up occurred in 10 (18.5%) cases, with no reports of rupture. Ten (18.2%) aneurysms were treated with clipping, endovascular, or bypass techniques., Conclusions: FDCA is a rare complication following pediatric craniopharyngioma resection. The exact cause is unclear, and factors related to tumor invasiveness, size, location, and differences in surgical approach may contribute to FDCA development. Most patients who go on to develop FDCA have an innocuous course on follow-up, with no reports of rupture in the present literature. For this reason, patients rarely require surgical or endovascular intervention for these lesions, and conservative management is favored., (Copyright © 2021. Published by Elsevier Inc.)

The goal of the following article is to help the practicing physician learn to recognize conditions that mimic conditions requiring neurosurgical intervention. Each case vignette is presented with relevant clinical history and examination, imaging studies and findings, as well as other testing results. The management for the corresponding diagnosis is presented. Finally, the relevant mimics and differentiating features are discussed., (Copyright © 2021 Elsevier Inc. All rights reserved.)

As the aging population continues to grow, so will the incidence of age-related conditions, including idiopathic normal pressure hydrocephalus (iNPH). The pathogenesis of iNPH remains elusive, and this is due in part to the poor characterization of cerebral spinal fluid (CSF) dynamics within the brain. Advancements in technology and imaging techniques have enabled new breakthroughs in understanding CSF physiology, and therefore iNPH pathogenesis. This includes understanding the hemodynamic and microvascular components involved in CSF influx and flow. Namely, the glymphatic system appears to be the great mediator, facilitating perivascular CSF flow via astrocytic aquaporin channels located along the endothelium of the pial vasculature. The interplay between glymphatics and both arterial pulsatilty and venous compliance has also been recently demonstrated. It appears then that CSF flow, and therefore glymphatic function, are highly dependent on cardiocirculatory and vascular factors. Impairment in any one component, whether it be related to arterial pulsatility, microvascular changes, reduced venous drainage, or astrogliosis, contributes greatly to iNPH, although it is likely a combination thereof. The strong interplay between vascular hemodynamics and CSF flow suggests perfusion imaging and cerebral blood flow quantification may be a useful diagnostic tool in characterizing iNPH. In addition, studies detecting glymphatic flow with magnetic resonance imaging have also emerged. These imaging tools may serve to both diagnose iNPH and help delineate it from other similarly presenting disease processes. With a better understanding of the vascular and glymphatic factors related to iNPH pathogenesis, physicians are better able to select the best candidates for treatment., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Aim: To analyze the most-cited articles on cranial and spinal epidural hematomas (EDHs)., Material and Methods: A title-specific search was performed on the Scopus database using the term ?epidural hematoma? in June 2020, with no publication date restrictions. The top 100 most-cited articles were collected, reviewed, and analyzed., Results: A total of 2165 articles were published on EDH from 1949 to 2020, and the top 100 most-cited ones were published between 1966 and 2014, receiving an average citation of 84.7 per paper. Most papers were published in Neurosurgery and Journal of Neurosurgery (JNS). 48% of the most-cited articles on EDH originated from the United States of America (USA). Notably, studies on spinal EDH represented 75% of the most-cited articles in our review. The most-cited article on EDH was published by Lawton et al. in 1995, receiving a total of 412 citations at an annual citation rate of 16.4%., Conclusion: This report identifies the most influential publications on EDH as well as the publications trends over the last 70 years. Recognition of the most impactful work is an important tool for clinicians and researchers as it can reflect the enormous changes in the clinical practice. This report can serve as a guide for developing evidence-based practices and identifying areas of research inadequacy.

Objective: Bone morphogenetic protein (BMP) is a growth factor that aids in osteoinduction and promotes bone fusion. There is a lack of literature regarding recombinant human BMP-2 (rhBMP-2) dosage in different spine surgeries. This study aims to investigate the trends in rhBMP-2 dosage and the associated complications in spinal arthrodesis., Methods: A retrospective study was conducted investigating spinal arthrodesis using rhBMP-2. Variables including age, procedure type, rhBMP-2 size, complications, and postoperative imaging were collected. Cases were grouped into the following surgical procedures: anterior lumbar interbody fusion/extreme lateral interbody fusion (ALIF/XLIF), posterior lumbar interbody fusion/transforaminal lumbar interbody fusion (PLIF/TLIF), posterolateral fusion (PLF), anterior cervical discectomy and fusion (ACDF), and posterior cervical fusion (PCF)., Results: A total of 1209 patients who received rhBMP-2 from 2006 to 2020 were studied. Of these, 230 were categorized as ALIF/XLIF, 336 as PLIF/TLIF, 243 as PLF, 203 as ACDF, and 197 as PCF. PCF (P < 0.001), PLIF/TLIF (P < 0.001), and PLF (P < 0.001) demonstrated a significant decrease in the rhBMP-2 dose used per level, with major transitions seen in 2018, 2011, and 2013, respectively. In our sample, 129 complications following spinal arthrodesis were noted. A significant relation between rhBMP-2 size and complication rates (χ 2 = 73.73, P = 0.0029) was noted. rhBMP-2 dosage per level was a predictor of complication following spinal arthrodesis (odds ratio = 1.302 [1.05-1.55], P < 0.001)., Conclusions: BMP is an effective compound in fusing adjacent spine segments. However, it carries some regional complications. We demonstrate a decreasing trend in the dose/vertebral level. A decrease rhBMP-2 dose per level correlated with a decrease in complication rates., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Laser interstitial thermal therapy (LITT) for posterior fossa lesions remains rare as the small size of the infratentorial compartment, proximity to the brainstem, and thickness/angulation of the occipital bone creates barriers to procedural success. Furthermore, evaluation of the effect of ablation volume on outcomes is limited., Objective: To analyze our institutional experience with LITT in the posterior fossa stratifying perioperative and long-term outcomes by ablation volumes., Methods: Seventeen patients with posterior fossa lesions treated with LITT from 2013 to 2020 were identified. Local progression-free survival (PFS), overall survival, steroid dependence, and edema reduction were evaluated with Kaplan-Meier analysis grouped by ablation volume. Preoperative, postoperative, and last known Karnofsky Performance Status (KPS) were compared using a matched paired t test., Results: No differences in pathology, preoperative KPS, or preoperative lesion volume were found between patients with total (100%-200% increase in pre-LITT lesion volume) versus radical (>200% increase in pre-LITT lesion volume) ablations. Patients who underwent radical ablation had a higher postoperative KPS (93 vs 82, P = .02) and higher KPS (94 vs 87, P = .04) and greater reduction in perilesional edema at last follow-up (P = .01). Median follow-up was 80.8 wk., Conclusion: Despite obvious anatomical challenges, our results demonstrate that radical ablations are both feasible and safe in the posterior fossa. Furthermore, radical ablations may lead to greater decreases in perilesional edema and improved functional status both immediately after surgery and at last follow-up. Thus, LITT should be considered for patients with otherwise unresectable or radioresistant posterior fossa lesions., (© Congress of Neurological Surgeons 2021.)

Background: Malignant craniopharyngioma is a rare tumor with few published case reports. It can form de novo or transform from a benign variant and is associated with a dismal survival rate. We reviewed the literature for all published cases and studied the effect of radiation on the rate of malignant transformation. We analyzed the effect of chemotherapy on survival., Methods: We used various search engines to locate literature from 1980 onward and identified 31 case reports, one of which was excluded. Statistical analysis using the SAS software was conducted, and a significant value was identified if P < 0.05., Results: There was equal distribution among male and female patients. The average age at malignant diagnosis is 31.11 years (±15.16) and 12.19 years (±8.41) for the average interval of benign tumor progression to malignancy. The most common clinical presentation was visual loss and/or field deficits in 26/30 patients (86%). Almost 11/30 patients (37%) had endocrinological deficits, with panhypopituitarism as the most common in 8/11 patients (73%). Fifteen patients received radiation before malignant transformation (47%) and demonstrated no effect on malignant transformation ( P = 0.379). Gross total resection was achieved in 2/30 patients. The average time to mortality postoperatively is 5.3 months ± 4.3. Ten patients received chemotherapy, and five were alive at last follow-up ( P = 0.115)., Conclusion: Malignant craniopharyngioma carries a dismal prognosis with no apparent benefits of radiation therapy and chemotherapy on survival., Competing Interests: There are no conflicts of interest., (Copyright: © 2021 Surgical Neurology International.)

Dural arteriovenous fistulas (dAVFs) consist of abnormal anastomoses between 1 or multiple meningeal arteries to meningeal veins, venous sinuses, or subarachnoid veins.1 dAVFs account for 10% to 15% of all intracranial arteriovenous lesions.2 dAVFs can be challenging to treat with various approaches that include microsurgical ligation, endovascular embolization (transarterial or transvenous), and stereotactic radiosurgery. All these treatments share the common goal of disconnecting the draining vein from the fistulous point. We present a case of a 43-yr-old male who presented with progressive headaches and was found to have an incidental Zipfel type 3A3 right petrotentorial dAVF on catheter angiography. The patient underwent a right retrosigmoid craniotomy and clipping of 2 separate venous outflows. The case illustrates the principle that multiple venous outflows can exist in dAVF and a thorough analysis of the venous phase of the angiogram as well as corresponding inspection of the fistula at the time of surgical exploration is a necessity to avoid partial obliteration. The patient remained neurologically intact postoperatively and had complete resolution of his fistula on postoperative angiography. We review the neuroimaging, operative video, and technical nuances and provide a short literature review on the topic.4 The patient gave informed consent for the procedure and verbal consent for this publication. The patient consented to the publication of their image., (© Congress of Neurological Surgeons 2021.)

Background: Rathke cleft cyst (RCC) apoplexy is an uncommon type of lesion that is challenging to diagnose without histopathological samples. Very few articles have been published describing the details of RCC apoplexy. We studied a good number of published articles to analyze its demographics, clinical and hormonal presentations, and outcomes., Methods: A literature review of English language publications about RCC apoplexy or pituitary apoplexy was conducted using Medline and EMBASE search engines. Thirty articles with histological diagnosis of RCC apoplexy were identified, the earliest of which was published in 1990 and the latest in 2019. We combined the findings of these articles with our own case report and then compared the demographics, clinical and hormonal presentations, and outcomes between RCC apoplexy and pituitary adenoma apoplexy., Results: Our data included 29 patients with RCC, with a mean age of 36.87 years (8-72) and a predominance of female patients (68%). The hemorrhagic type was most common, reported in 86%. Headache was the most common presenting symptom, being reported in 93% followed by hypogonadism (73%) and hormonal deficits (52%). All but three patients improved neurologically (90%); however, 45% of patients required long-term hormonal replacement, mostly thyroid hormone. No cases of worsening neurological or hormonal status were reported., Conclusion: RCC apoplexy presents with less severe neurological and hormonal abnormalities than pituitary adenoma apoplexy; it also has a better prognosis in endocrine functional recovery. We recommend applying current management guidelines of pituitary adenoma apoplexy to RCC apoplexy., Competing Interests: There are no conflicts of interest., (Copyright: © 2021 Surgical Neurology International.)

Introduction: After the official announcement of the coronavirus disease-19 pandemic on March 11, 2020, the disease impacted most aspects of health care delivery, especially postgraduate education and training., Method: A cross-sectional, online questionnaire-based assessment was performed. The study participants involved neurosurgery residents and program directors (PDs) across the country between May 16 and May 27, 2020., Results: Approximately 74 of 95 (77.9%) of the residents experienced an impact on their training calendar. Before the pandemic, 51 residents (53.3%) were involved in 2-3 surgeries per week, but during the pandemic, 66 (69.5%) were attending 0-1 case per week. Fifty-three residents (55.8%) agreed that academic sessions were affected despite the helpful effort of online teaching sessions. Thirty-four (35.8%) residents graded their anxiety during coronavirus disease-19 times as high. Ten PDs (58.8%) confirmed spending 3-5 hours per week on educational activities normally, whereas during the pandemic, 15 PDs (88.2%) reduced their educational hours to 0-2 hours per week., Conclusion: Our study showed that educational activities significantly decreased and shifted toward virtual teaching methods. Operative volume showed a substantial reduction for both junior and senior residents. Academic and clinical teaching was the main concern for PDs, and they faced challenges interviewing newly matched residents., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Introduction: Melanoma brain metastases remain a devastating disease process with poor prognosis. Recently, there has been a surge in studies demonstrating the efficacy of oncolytic virotherapy for brain tumor treatment. Given their specificity and amenability to genetic modification, the authors explore the possible role of oncolytic virotherapy as a potential treatment option for patients with melanoma brain metastases., Methods: A comprehensive literature review including both preclinical and clinical evidence of oncolytic virotherapy for the treatment of melanoma brain metastasis was performed., Results: Oncolytic virotherapy, specifically T-VEC (Imlygic™), was approved for the treatment of melanoma in 2015. Recent clinical trials demonstrate promising anti-tumor changes in patients who have received T-VEC; however, there is little evidence for its use in metastatic brain disease based on the existing literature. To date, only two single cases utilizing virotherapy in patients with metastatic brain melanoma have been reported, specifically in patients with treatment refractory disease. Currently, there is not sufficient data to support the use of T-VEC or other viruses for intracranial metastatic melanoma. In developing a virotherapy treatment paradigm for melanoma brain metastases, several factors must be considered, including route of administration, need to bypass the blood-brain barrier, viral tumor infectivity, and risk of adverse events., Conclusions: Evidence for oncolytic virotherapy treatment of melanoma is limited primarily to T-VEC, with a noticeable paucity of data in the literature with respect to brain tumor metastasis. Given the promising findings of virotherapy for other brain tumor types, oncolytic virotherapy has great potential to offer benefits to patients afflicted with melanoma brain metastases and warrants further investigation.

Rotational vertebral artery (VA) occlusion syndrome, also known as bow hunter's syndrome, is an uncommon variant of vertebrobasilar insufficiency typically occurring with head rotation.1-3 The most common presenting symptom is dizziness (76.8%), followed by visual abnormalities and syncope (50.4% and 40.4%, respectively).2 Osteophytic compression due to spinal spondylosis has been shown to be the most common etiology (46.2%), with other factors, such as a fibrous band, muscular compression, or spinal instability, being documented.1,2 Treatment is dependent on the level and site of VA compression with anterior, anterolateral, or posterior approaches being described.1,4 We present the case of a 72-yr-old male with osteophytic compression of the V3 segment of the vertebral artery at the occipital-cervical junction. The patient underwent a C1 hemilaminectomy and removal of osteophytic compression from the occipital-cervical joint. The patient had complete resolution of compression of his vertebral artery on postoperative imaging and remained neurologically intact following the procedure. We review the literature on this topic, the technical nuances of the procedure performed, and review the different treatment modalities available for this rare condition.1-11  The patient consented to the procedure and to publication of their image., (© Congress of Neurological Surgeons 2021.)

Objective: Cerebral extracranial-intracranial (EC-IC) direct bypass is a commonly used procedure for ischemic vasculopathy. A previously described variation of this technique is to utilize one donor artery to supply two recipient arteries, which the authors designate as 1D2R. The purpose of this study is to present a single surgeon's series of 1D2R direct bypasses for moyamoya and ischemia using detailed clinical, angiographic, and intraoperative blood flow measurement data. To the authors' knowledge, this is the largest series reported to date., Methods: Hospital, office, and radiographic imaging records for all patients who underwent cerebral revascularization using a 1D2R bypass by the senior author were reviewed. The patients' demographic information, clinical presentation, associated medical conditions, intraoperative information, and postoperative course were obtained from reviewing the medical records., Results: A total of 21 1D2R bypasses were performed in 19 patients during the study period. Immediate bypass patency was 100% and was 90% on delayed follow-up. The mean initial cut flow index (CFI(i)) was 0.64 ± 0.33 prior to the second anastomosis and the mean final value (CFI(f)) was 0.94 ± 0.38 after the second anastomosis (p < 0.001). The overall bypass flow increased on average by 50% (mean 17.9 ml/min, range -10 to 40 ml/min) with the addition of the second anastomosis. There was no significant difference in the overall flow measurements when the end-to-side anastomosis or side-to-side anastomosis was performed first. There was a statistically significant difference in the proportion of patients with a modified Rankin Scale (mRS) score of 0 or 1 postoperatively compared to preoperatively (p < 0.01). Through the application of Poiseuille's law, the authors analyzed flow dynamics, deduced the component vascular resistances based on an analogy to electrical circuits and Ohm's law, and introduced the new concepts of "second anastomosis relative augmentation" and "second anastomosis sink index" in the evaluation of 1D2R bypasses., Conclusions: The application of the 1D2R technique in a series of 19 consecutive patients undergoing direct EC-IC bypass for flow augmentation demonstrated high patency rates, statistically significantly higher CFIs compared to 1D1R, and improved mRS scores at last clinical follow-up. Additionally, the technique allows a shorter dissection time and preserves blood flow to the scalp. The routine utilization of intraoperative volumetric flow measurements in such surgeries allows a deeper understanding of the hemodynamic impact on individual patients.

Dorsal internal carotid artery (ICA) blister aneurysms are an uncommon aneurysm variant constituting 0.3% to 1% of intracranial aneurysms and can be due to ulceration, atherosclerosis, or dissection.1-3 Despite its rarity, it carries a high risk of rupture with an estimation of 0.9% to 6.5% among intracranial aneurysms.1,2 Blister aneurysms are small in size, have no distinguishable neck, and have a friable wall that can easily rupture if manipulated, hence the difficulty in its treatment utilizing both microsurgical and endovascular techniques.1,2,4-6 Endovascular coiling of these lesions may not be adequate due to the broad-based size; stenting requires the use of antiplatelet medications, which could lead to rebleeding; flow diversion takes longer to exert its treatment effect.1,4 Conversely, microsurgical management carries a higher intraoperative rupture rate.2 Microsurgical options include clipping, clip reconstruction, trapping with bypass, and wrapping.4,7 We present a case of a 38-yr-old man who presented with a ruptured right dorsal ICA blister aneurysm treated with microsurgical trapping with intraoperative flow measurements. We demonstrate how the use of quantitative intraoperative flow measurements allows confident sacrifice of the supraclinoid ICA. We also demonstrate in contrast another case example of utilizing a clip-graft repair. The patient remained unchanged with an intact neurological exam, and postoperative imaging showed no aneurysm remnant and patent anterior choroidal artery. We review the literature and management of dorsal ICA aneurysms.8-15 We also review the technical nuances and different endovascular and microsurgical treatments that can be used for this condition.  The patient gave informed consent for the procedure and verbal consent to the publication., (© Congress of Neurological Surgeons 2021.)

Background: Computed tomography Hounsfield unit (HU) is an alternative tool to the dual energy x-ray absorptiometry scan T-score to quantify the bone quality. DEXA scan can overestimate the bone mineral density. We studied the correlation of the vertebral mid-axial and mid-sagittal HU to the T-score., Methods: We retrospectively reviewed the electronic medical records of patients who underwent dual energy x-ray absorptiometry and computed tomography scans within 1 year. Age, sex, mid-axial and mid-sagittal HU, and T-score were collected and statistically analyzed., Results: We identified 100 patients with computed tomography of the L1-L4. There were 80 female and 20 male patients. The average age was 60.25 years (±12.54 years). Nineteen patients were diagnosed with degenerative spine disease. There were 56 patients with a normal T-score, 33 with osteopenia, and 11 with osteoporosis. The average HU for the mid-sagittal view was 163 (±59) for L1, 159 (±62) for L2, 151 (±59) for L3, and 150 (±62) for L4. The mid-axial and mid-sagittal HU were positively correlated to the DEXA T-score (P < 0.001). The HU was 177 (95% CI: 160-194) for normal T-scores, 132 (120-143) for T-scores indicating osteopenia, and 106 (88-124) for T-scores indicating osteoporosis (P < 0.001). Post hoc analysis showed no difference between osteopenia and osteoporosis (P = 0.46)., Conclusions: Mid-sagittal HU is positively correlated to the T-score, similar to the mid-axial HU. Therefore, it can be used to acquire a general overview of the bone quality before spinal instrumentation., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Approaches to the pineal region are various, and each has its advantages and disadvantages. The authors present a case of a 50-year-old woman who presented with progressive hemiparesis and vertical gaze palsy; she was diagnosed with a midbrain cavernous malformation. The patient underwent an occipital posterior interhemispheric supratentorial transpineal approach with gross-total resection. On long-term follow-up, her symptoms significantly improved. The authors review the regional anatomy and present the operative video. They also discuss the various approaches with their indications, advantages, and disadvantages. The video can be found here: https://stream.cadmore.media/r10.3171/2021.4.FOCVID2133., Competing Interests: Disclosures Dr. Morcos reports other from Kogent and other from Leica outside the submitted work., (© 2021, The Authors.)

Cavernous malformations that have not previously bled have been reported to have an annual bleeding rate of 0.6% per year.1 Those with prior hemorrhage have been reported to have rebleeding rates of up to 4.5%.1 Additionally, infratentorial location, young age, and female gender have been associated with increased risk.1 We present the case of a 26-yr-old female who initially presented to an outside institution with left-sided weakness. She improved following her initial bleeding event and presented to us for further management. A large, cavernous malformation in the right pons was identified on imaging. The patient underwent a right expanded retrosigmoid craniotomy with splitting of the horizontal cerebellar fissure to completely remove the lesion. The expanded retrosigmoid craniotomy allows for an enhanced view of the medial pontine region and can be utilized for appropriately selected brainstem cavernous malformations. The case presentation, surgical anatomy, operative nuances, and postoperative course and outcome are reviewed. The patient gave verbal consent for participating in the procedure and surgical video. The patient also consented to the publication of her image., (© Congress of Neurological Surgeons 2021.)

Background: The optimal timing for performing cranioplasty and its effect on functional outcome remains debatable. Multiple confounding factors may come into role; including the material used, surgical technique, cognitive assessment tools, and the overall complications. The aim of this study is to assess the neurological outcome and postoperative complications in patients who underwent early versus late cranioplasty., Methods: A retrospective cohort study was conducted to investigate the neurological outcome and postoperative complications in patients who underwent cranioplasty between 2005 and 2018 at a Level l trauma center. Early and late cranioplasties were defined as surgeries performed within and more than 90 days of decompressive craniectomy, respectively. The Glasgow Outcome Score (GOS) and modified Rankin scale (mRS), recorded within 1 week of cranioplasty, were used to assess the neurological outcome., Results: A total of 101 cases of cranioplasty were included in the study. The mean age of the patients was 31.4 ± 13.9 years. Most patients ( n = 86; 85.1%) were male. The mean GOS for all patients was 4.0 ± 1.0. The mean mRS was 2.2 ± 1.78. Hydrocephalus was noted in 18 patients (early, n = 6; late, n = 12; P = 0.48). Seizures developed in 28 patients (early, n = 12; late, n = 16; P = 0.77)., Conclusion: The neurological outcome in patients who underwent early versus late cranioplasty is almost identical. The differences in the rates of overall postoperative complications between early versus late cranioplasty were statistically insignificant. The optimal timing for performing cranioplasty is mainly dependent on the resolution of cerebral swelling., Competing Interests: There are no conflicts of interest., (Copyright: © 2021 Surgical Neurology International.)

Objective: Moyamoya disease (MMD) is a progressive steno-occlusive cerebrovascular phenomenon with unknown pathogenesis. Considering the abundance of articles addressing Moyamoya disease, a detailed analysis concerning the publication trends is of paramount importance. The aim of the study is to report the current knowledge of the top-100 most cited articles on Moyamoya disease in the literature., Methods: A non-time restricted keyword-based search was performed in June 2020 using the Scopus database. The search keywords included the following: "Moyamoya", "Moyamoya disease", and "Moyamoya syndrome". The search result was used to rank the articles based on their citation count. The top-100 most-cited articles were obtained and classified into seven categories., Results: A total of 3,543 articles on Moyamoya disease were published between 1955 and 2020. The Top-100 articles were published between 1977 and 2016 with a total of 16,119 citations, per year, and 7.23% rate of self-citation. The 1990s was the most productive decade (N=42). The most contributing country to the list was Japan (N=60). Stroke was the most active journal (N=23). Houkin, K., a Japanese neurosurgeon, was the most prolific author (N=15)., Conclusions: Moyamoya disease has been extensively investigated in the literature throughout the years. The majority of articles published in the literature were addressing the surgical management and clinical outcome. Authors from neurosurgical backgrounds were the most active contributors to the field of Moyamoya disease.

Background: Proximal junctional kyphosis is a kyphotic deformity following spine instrumentation, predominantly seen in scoliosis patients. There have been previous attempts to develop classification schema of PJK. We analyzed the factors contributing to PJK based upon our own clinical experience with the goal of developing a clinical guidance tool which took into account both etiology and mechanism of failure., Methods: We performed a retrospective analysis of all re-operation thoracolumbar surgeries at a single institution over a 14-year period. Patients with PJK were identified and categorized based upon the etiology, mechanism of failure, and an indication of revision. Next, we conducted a systematic review on articles emphasizing a classification system for PJK., Results: Fourteen PJK patients were identified out of 121 patients who required revision spine surgery. The average age was 64.9 ± 10.2 years, with 10 males (71%) and 4 females (29%). Three primary etiologies were identified: 6/14 (47%) overcorrection, 6/14 (47%) osteopenia, and 2/14 (14%) ligamentous disruption. The mechanism of failure was likewise divided into three categories: 9/14 (64%) compression fracture, 1/14 (7%) hardware failure, and 4/14 (29%) disc degeneration. The relationship between osteopenia and the development of a compression fracture leading to PJK was statistically significant (p = 0.031)., Conclusion: There are multiple current classification systems for PJK. Our study findings were in line with previously published literature and suggest the need for a future classification system combining both etiology, mechanism of failure, and severity of disease., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

We present the case of an 18-yr-old female with 4 mo of progressive vision loss in the left eye. She underwent a computed tomography (CT) and magnetic resonance imaging (MRI), which revealed a large mass in the sphenoid sinus, sella, and anterior cranial fossa. This mass was T1 isointense, with heterogenous enhancement noted on T1 with gadolinium sequences. The mass was found to have calcifications and cystic portions on T2-weighted MRI scans and CT-based imaging. She underwent an endonasal endoscopic approach for resection of the mass. The tumor was found to be bloody, with islands of bone nests within the dura mater of the anterior cranial fossa. The patient improved postoperatively. The pathological diagnosis was found to be the psammomatoid variant of juvenile active ossifying fibroma (JAOF). We present the neuroimaging, anatomic nuances,1 and operative techniques used in this case. We also review the disease background of this rare lesion of the anterior skull base.2-4 The patient gave informed consent for the procedure and verbal consent for the publication of this article., (© Congress of Neurological Surgeons 2021.)

Objective: Vertebral compression fractures are common in multiple myeloma (MM). Modern treatment paradigms place emphasis on treatment with radiation, with surgery reserved for cases involving frank instability or severe neural compression. However, experience at the authors' institution has led them to suspect a more prominent role for surgical intervention in some settings. The authors undertook the present study to better understand the incidence of MM in undiagnosed patients who require urgent surgery for pathological vertebral fracture., Methods: The authors reviewed a prospectively collected database of all patients who underwent surgery with the senior author at their main hospital between June 1, 1998, and June 30, 2020. Patients admitted from the emergency room or after transfer from another hospital who then underwent surgery for pathological fracture during the same admission were included in the final analysis. Patients scheduled for elective surgery and those with previous cancer diagnoses were excluded., Results: Forty-three patients were identified as having undergone urgent surgical decompression and/or stabilization for pathological fracture. Histopathology confirmed diagnosis of MM in 22 (51%) patients, lung metastasis in 5 (12%) patients, and breast metastasis in 4 (9%) patients. Twelve (28%) patients were diagnosed with other types of metastatic carcinoma or undifferentiated disease. Sixteen of 29 (55%) men and 6 of 14 (42%) women were diagnosed with MM (p = 0.02). Seventeen of 34 (50%) patients who underwent surgery for neurological deficit, 5 of 6 (83%) patients who underwent surgery for spinal instability, and 0 (0%) patients who underwent surgery for pain with impending spinal cord injury were diagnosed with MM (p = 0.12)., Conclusions: A majority of patients presenting to the authors' hospital with no history of malignancy who required urgent surgery for pathological compression fracture were found to have MM or plasmacytoma. This disease process may affect a significant portion of patients requiring decompressive or stabilizing surgery for compression fracture in academic medical centers.

Background: Neuroendocrine tumors (NET) are rare tumors with a low incidence of brain metastasis, especially in grade 1 NET. The most common source of brain metastasis is the lung. We present an unusual case of NET grade 1 with multiple hemorrhagic brain metastases., Case Description: A 46-year-old woman, who initially presented with a seizure, was diagnosed with multiple brain and lung lesions. She was offered a biopsy for diagnosis, but she refused and lost to follow up. Eighteen years later, she developed progressive quadriparesis and confusion. A biopsy of the left frontal lobe lesions showed NET grade 1. A lung biopsy of the left upper lobe was consistent with the same diagnosis. The patient's functional status was poor with Eastern Cooperative Oncology Group (ECOG) grade 4. She only received palliative whole-brain radiation therapy (WBRT) and died 3 months after discharge., Clinical Discussion: NET is a spectrum that encompasses benign to malignant cells. There is a female predominance in lower grades and male predominance in higher grades. No effective management for brain metastases was described, and the prognosis remains poor., Conclusion: Multiple brain metastases can be the first presentation of patients with NET. Early diagnosis and treatment may have a more favorable impact on the outcome of this disease. The longstanding numerous hemorrhagic NET brain metastases is exceedingly rare. The neuroimaging appearance is similar to other neoplastic and non-neoplastic lesions. An important differential diagnosis to consider is metastatic melanoma and choriocarcinoma, familial cavernous malformation, diffuse axonal injury, cerebral vasculitis, and amyloid angiopathy., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: Dural arteriovenous fistula (DAVF) is a rare pathological vascular lesion with variable clinical manifestations. Since 1968, several articles have been published to address spinal and cranial DAVFs. The aim of this study is to identify, analyse, and review the pertinent literature of the top-100 most cited articles on DAVFs published to date., Methods: A title-specific, keyword-based search with no time restriction was performed in June 2020. The Scopus database was used to identify the top-100 most cited articles on DAVFs. The term "dural arteriovenous fistula" was used as a search keyword. The search results were arranged in descending order based on the total citation count. The top-100 articles were categorized into ten categories., Results: Between 1968 and 2020, a total of 2298 articles were published on DAVFs. The top-100 most cited articles were published between 1983 and 2012. The total number of citations for the top-100 articles was 12393 (123 citations/article). Most articles (34%) were investigating the clinical aspect of DAVFs. The country contributing to the most impactful and highest volume of publications (46%) was the United States. The Mayo Clinic was the most active institute in contribution. Most articles (29%) were published by the Journal of Neurosurgery., Conclusions: In the top-100 most cited articles on DAVF, most studies were published in neurosurgery/neuroradiology-dedicated journals. This bibliometric analysis identifies the publication trends and provides a comprehensive overview of the most influential articles addressing DAVFs.

Background: Citation analysis reflects the scientific recognition and influential performance of a published article within its field. We aim to identify the top 100 most-cited articles on astrocytoma using this bibliometric analysis method., Methods: In May 2020, we performed a thorough search in the Scopus database using the word "Astrocytoma." The top 100 most-cited articles were arranged based on citation count in descending order. The resultant articles were then analyzed with an assessment of pertinent factors., Results: The most-cited articles on astrocytoma had been cited 23,720 times. The top-cited article received a total of 682 citations, with an average of 34.1 citations annually. The list comprised eight clinical trials, in which the highest cited article received 625 citations. Articles were published from 1975 to 2015 with the 1995-2005 era as the most prolific period. Neuropathology studies were the most studied category, followed by clinical studies. The United States of America was the most significant contributor, with 49 published articles. The University of California San Francisco was the most contributing institution by producing 11 articles. Articles were published in 32 different journals led by the Cancer Research Journal, with a total of 12 publications. Approximately 160 authors contributed to the list in which Scheithauer, B.W. contributed the most with a total of eight articles., Conclusion: This report clustered the most impactful articles on astrocytoma. It serves as an adequate tool to identify publication trends and helps in achieving evidence-based clinical practice., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Surgical Neurology International.)

Background: Craniosynostosis is the premature closure of cranial sutures and it continues to be a therapeutic challenge due to the diversity and complexity of the syndrome. Bibliometric analysis is a study of ranking citations and exploring the most impactful articles in a respective discipline. It also demonstrates the chronological trends of publications., Methods: In May 2020, we performed a title-specific search of the Scopus database using "craniosynostosis" as our query term without publication date restrictions. The top 100 articles in craniosynostosis were retrieved and analyzed., Results: The top 100 most-cited articles in craniosynostosis received a total 13,826 citations, and an average of 138 citations per paper. The publication dates ranged from 1920 to 2015, with a peak period of top publications between 1996 and 2005. The most common category is clinical, followed by neurogenetics. The top cited article received 540 citation counts and 19.29 citations per year. The USA was the most contributing country to the list. The Journal of Plastic and Reconstructive Surgery published the largest number of top cited articles. Neurosurgery as a specialty contributed to most articles in the list (27 articles). The institute who contributed the most was the Assistance Publique Hopitaux Paris., Conclusion: Bibliometric analysis in craniosynostosis revealed major trend changes of research over the years, with a focus on neurogenetics and the different types of surgical corrections. The current collection of highly cited publications may assist physicians in gaining a better understanding of the evidence-based approach in craniosynostosis.