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ObjectiveMeningiomas are the most common primary intracranial tumor, and resection is a mainstay of treatment. It is unclear what duration of imaging follow-up is reasonable for WHO grade I meningiomas undergoing complete resection. This study examined recurrence rates, timing of recurrence, and risk factors for recurrence in patients undergoing a complete resection (as defined by both postoperative MRI and intraoperative impression) of WHO grade I meningiomas.MethodsThe authors conducted a retrospective, single-center study examining recurrence risk for adult patients with a single intracranial meningioma that underwent complete resection. Uni- and multivariate nominal logistic regression and Cox proportional hazards analyses were performed to identify variables associated with recurrence and time to recurrence. Two supervised machine learning algorithms were then implemented to confirm factors within the cohort that were associated with recurrence.ResultsThe cohort consisted of 823 patients who met inclusion criteria, and 56 patients (6.8%) had recurrence on imaging follow-up. The median age of the cohort was 56 years, and 77.4% of patients were female. The median duration of head imaging follow-up for the entire cohort was 2.7 years, but for the subgroup of patients who had a recurrence, the median follow-up was 10.1 years. Estimated 1-, 5-, 10-, and 15-year recurrence-free survival rates were 99.8% (95% confidence interval [CI] 98.8%-99.9%), 91.0% (95% CI 87.7%-93.6%), 83.6% (95% CI 78.6%-87.6%), and 77.3% (95% CI 69.7%-83.4%), respectively, for the entire cohort. On multivariate analysis, MIB-1 index (odds ratio [OR] per 1% increase: 1.34, 95% CI 1.13-1.58, p = 0.0003) and follow-up duration (OR per year: 1.12, 95% CI 1.03-1.21, p = 0.012) were both associated with recurrence. Gradient-boosted decision tree and random forest analyses both identified MIB-1 index as the main factor associated with recurrence, aside from length of imaging follow-up. For tumors with an MIB-1 index < 8, recurrences were documented up to 8 years after surgery. For tumors with an MIB-1 index ≥ 8, recurrences were documented up to 12 years following surgery.ConclusionsLong-term imaging follow-up is important even after a complete resection of a meningioma. Higher MIB-1 labeling index is associated with greater risk of recurrence. Imaging screening for at least 8 years in patients with an MIB-1 index < 8 and at least 12 years for those with an MIB-1 index ≥ 8 may be needed to detect long-term recurrences.

BackgroundWhile genetic alterations in brain metastases (BMs) have been previously explored, there are limited data examining their association with recurrence after surgical resection. This study aimed to identify genetic alterations within BMs associated with CNS recurrence after surgery across multiple cancer types.MethodsA retrospective, single-center study was conducted with patients who underwent resection of a BM with available clinical and gene sequencing data available. Local and remote CNS recurrence were the primary study outcomes. Next-generation sequencing of the coding regions in over 500 oncogenes was performed in brain metastasis specimens. Cox proportional hazards analyses were performed to identify clinical features and genomic alterations associated with CNS recurrence.ResultsA total of 90 patients undergoing resection of 91 BMs composed the cohort. Genes most frequently mutated in the cohort included TP53 (64%), CDKN2A (37%), TERT (29%), CDKN2B (23%), NF1 (14%), KRAS (14%), and PTEN (13%), all of which occurred across multiple cancer types. CDKN2A/B co-deletion was seen in 21 (23.1%) brain metastases across multiple cancer types. In multivariate Cox proportional hazard analyses including patient, tumor, and treatment factors, CDKN2A/B co-deletion in the brain metastasis was associated with increased risk of local (HR 4.07, 95% CI 1.32-12.54, P = 0.014) and remote (HR 2.28, 95% CI 1.11-4.69, P = 0.025) CNS progression. Median survival and length of follow-up were not different based on CDKN2A/B mutation status.ConclusionsCDKN2A/B co-deletion detected in BMs is associated with increased CNS recurrence after surgical resection. Additional work is needed to determine whether more aggressive treatment in patients with this mutation may improve outcomes.

Background/objectiveTo compare functional hearing and tinnitus outcomes in treated large (~ 3 cm) vestibular schwannoma (VS) and posterior fossa meningioma cohorts, and construct willingness-to-accept profiles for an experimental brain implant to treat unilateral hearing loss.MethodsA two-way MANOVA model with two independent variables (tumor type; time from treatment) and three dependent variables (hearing effort of tumor ear; abbreviated Speech, Spatial, and Qualities of Hearing scale (SSQ12); Tinnitus Functional Index (TFI)) was used to analyze data from VS (N = 32) and meningioma (N = 50) patients who were treated at a tertiary care center between 2010 and 2020. A query to probe acceptance of experimental treatment for hearing loss relative to expected benefit was used to construct willingness-to-accept profiles.ResultsTumor type was statistically significant on the combined dependent variables analysis (F[3, 76] = 19.172, p  2 years) (p ≤ .017). At the 60% speech understanding level, 77% of respondents would accept an experimental brain implant.ConclusionHearing outcome is better for posterior fossa meningioma compared to VS. Most patients with hearing loss in the tumor ear would consider a brain implant if the benefit level would be comparable to a cochlear implant.Level of evidence2.

ObjectiveInterfacility transfers represent a large proportion of neurosurgical admissions to tertiary care centers each year. In this study, the authors examined the impact of the COVID-19 pandemic on the number of transfers, timing of transfers, demographic profile of transfer patients, and clinical outcomes including rates of surgical intervention.MethodsA retrospective review of neurosurgical transfer patients at a single tertiary center was performed. Patients transferred from April to November 2020 (the "COVID Era") were compared with an institutional database of transfer patients collected before the COVID-19 pandemic (the "Pre-COVID Era"). During the COVID Era, both emergent and nonemergent neurosurgical services had resumed. A comparison of demographic and clinical factors between the 2 cohorts was performed.ResultsA total of 674 patients were included in the study (331 Pre-COVID and 343 COVID-Era patients). Overall, there was no change in the average monthly number of transfers (P = 0.66) or in the catchment area of referral hospitals. However, COVID-Era patients were more likely to be uninsured (1% vs. 4%), had longer transfer times (COVID vs. Pre-COVID Era: 18 vs. 9 hours; P < 0.001), required higher rates of surgical intervention (63% vs. 50%, P = 0.001), had higher rates of spine pathology (17% vs. 10%), and less frequently were admitted to the intensive care unit (34% vs. 52%, P < 0.001). Overall, COVID-Era patients did not experience delays to surgical intervention (3.1 days vs. 3.6 days, P = 0.2). When analyzing the subgroup of COVID-Era patients, COVID infection status did not impact the time of transfer or rates of operation, although COVID-infected patients experienced a longer time to surgery after admission (14 vs. 2.9 days, P < 0.001).ConclusionThe COVID-19 pandemic did not reduce the number of monthly transfers, operation rates, or catchment area for transfer patients. Transfer rates of uninsured patients increased during the COVID Era, potentially reflecting changes in access to community neurosurgery care. Shorter time to surgery seen in COVID-Era patients possibly reflects institutional policies that improved operating room efficiency to compensate for surgical backlogs. COVID status affeted time to surgery, reflecting the preoperative care that these patients require before intervention.

Introduction  The management of recurrent craniopharyngioma is complex with limited data to guide decision-making. Some reports suggest reoperation should be avoided due to an increased complication profile, while others have demonstrated that safe reoperation can be performed. For other types of skull base lesions, maximal safe resection followed by adjuvant therapy has replaced radical gross total resection due to the favorable morbidity profiles. Methods  Seventy-one patients underwent resection over a 9-year period for craniopharyngioma and were retrospectively reviewed. Patients were separated into primary resection and reoperation cohorts and stratified by surgical approach (endonasal vs. cranial) and survival analyses were performed based on cohort and surgical approach. Results  Fifty patients underwent primary resection, while 21 underwent reoperation for recurrence. Fifty endonasal transsphenoidal surgeries and 21 craniotomies were performed. Surgical approaches were similarly distributed across cohorts. Subtotal resection was achieved in 83% of all cases. There were no differences in extent of resection, visual outcomes, subsequent neuroendocrine function, and complications across cohorts and surgical approaches. The median time to recurrence was 87 months overall, and there were no differences by cohort and approach. The 5-year survival rate was 81.1% after reoperation versus 93.2% after primary resection. Conclusion  Compared with primary resection, reoperation for craniopharyngioma recurrence is associated with similar functional and survival outcomes in light of individualized surgical approaches. Maximal safe resection followed by adjuvant radiotherapy for residual tumor likely preserves vision and endocrine function without sacrificing overall patient survival.

Intravestibular schwannomas are rare tumors within the intralabyrinthine region and involve different management considerations compared to more common vestibular schwannomas. In this report, the authors review a case of a 52-year-old woman who presented with hearing loss and vestibular symptoms and was found to have a left intravestibular schwannoma. Given her debilitating vestibular symptoms, she underwent microsurgical resection. In this video, the authors review the relevant anatomy, surgical technique, and management considerations in these patients. The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID2187.

While the use of image-guided navigation is an excellent adjunct to the use of anatomical landmarks, dynamic changes that may occur in the position of critical structures are not accounted for during and after tumor resection. Unlike navigation, Doppler ultrasonography provides real-time imaging of the anterior skull base and can be used to accurately identify the location of vital structures during skull base surgery. A 56-year-old female initially presented with new onset left eye visual deficits. She previously underwent sublabial transsphenoidal subtotal resection of the tumor, confirmed as clival chordoma. She subsequently presented to our institution. She was treated with an expanded endonasal resection of the remaining chordoma followed by CyberKnife radiosurgery. Two years later, surveillance imaging identified tumor recurrence within the right clivus posterior to the carotid artery. Intraoperatively, in the previously operated irradiated skull base, the normal bony architecture of the sella was absent, resulting in the inability to distinguish the anterior genu of the internal carotid artery (ICA) from the adjacent tumor. Using Doppler ultrasonography, the course of the ICA was imaged in real time, allowing for safe, gross total tumor resection. In the setting of prior operation, radiation, or extensive disease, the normal bony architecture of the sella may be disrupted, placing the cavernous ICA at risk. We report what we believe is the first use of intraoperative ultrasound during the endoscopic endonasal approach in the setting of a previously operated, radiated sella.

ObjectiveSurgical site infection (SSI) is a complication linked to increased costs and length of hospital stay. Prevention of SSI is important to reduce its burden on individual patients and the healthcare system. The authors aimed to assess the efficacy of preoperative chlorhexidine gluconate (CHG) showers on SSI rates following cranial surgery.MethodsIn November 2013, a preoperative CHG shower protocol was implemented at the authors' institution. A total of 3126 surgical procedures were analyzed, encompassing a time frame from April 2012 to April 2016. Cohorts before and after implementation of the CHG shower protocol were evaluated for differences in SSI rates.ResultsThe overall SSI rate was 0.6%. No significant differences (p = 0.11) were observed between the rate of SSI of the 892 patients in the preimplementation cohort (0.2%) and that of the 2234 patients in the postimplementation cohort (0.8%). Following multivariable analysis, implementation of preoperative CHG showers was not associated with decreased SSI (adjusted OR 2.96, 95% CI 0.67-13.1; p = 0.15).ConclusionsThis is the largest study, according to sample size, to examine the association between CHG showers and SSI following craniotomy. CHG showers did not significantly alter the risk of SSI after a cranial procedure.

In this review, we describe Schwann cell development from embryonic neural crest cells to terminally differentiated myelinated and nonmyelinated mature Schwann cells. We focus on the genetic drivers and signaling mechanisms mediating decisions to proliferate versus differentiate during Schwann cell development, highlighting pathways that overlap with Schwann cell development and are dysregulated in tumorigenesis. We conclude by considering how our knowledge of the events underlying Schwann cell development and mouse models of schwannoma, neurofibroma, and malignant peripheral nerve sheath tumor can inform novel therapeutic strategies for patients with cancers derived from Schwann cell lineages.

BackgroundPrognostic markers for meningioma are needed to risk-stratify patients and guide postoperative surveillance and adjuvant therapy.ObjectiveTo identify a prognostic gene signature for meningioma recurrence and mortality after resection using targeted gene-expression analysis.MethodsTargeted gene-expression analysis was used to interrogate a discovery cohort of 96 meningiomas and an independent validation cohort of 56 meningiomas with comprehensive clinical follow-up data from separate institutions. Bioinformatic analysis was used to identify prognostic genes and generate a gene-signature risk score between 0 and 1 for local recurrence.ResultsWe identified a 36-gene signature of meningioma recurrence after resection that achieved an area under the curve of 0.86 in identifying tumors at risk for adverse clinical outcomes. The gene-signature risk score compared favorably to World Health Organization (WHO) grade in stratifying cases by local freedom from recurrence (LFFR, P

ObjectiveDuring the COVID-19 pandemic, quaternary-care facilities continue to provide care for patients in need of urgent and emergent invasive procedures. Perioperative protocols are needed to streamline care for these patients notwithstanding capacity and resource constraints.MethodsA multidisciplinary panel was assembled at the University of California, San Francisco, with 26 leaders across 10 academic departments, including 7 department chairpersons, the chief medical officer, the chief operating officer, infection control officers, nursing leaders, and resident house staff champions. An epidemiologist, an ethicist, and a statistician were also consulted. A modified two-round, blinded Delphi method based on 18 agree/disagree statements was used to build consensus. Significant disagreement for each statement was tested using a one-sided exact binomial test against an expected outcome of 95% consensus using a significance threshold of p < 0.05. Final triage protocols were developed with unblinded group-level discussion.ResultsOverall, 15 of 18 statements achieved consensus in the first round of the Delphi method; the 3 statements with significant disagreement (p < 0.01) were modified and iteratively resubmitted to the expert panel to achieve consensus. Consensus-based protocols were developed using unblinded multidisciplinary panel discussions. The final algorithms 1) quantified outbreak level, 2) triaged patients based on acuity, 3) provided a checklist for urgent/emergent invasive procedures, and 4) created a novel scoring system for the allocation of personal protective equipment. In particular, the authors modified the American College of Surgeons three-tiered triage system to incorporate more urgent cases, as are often encountered in neurosurgery and spine surgery.ConclusionsUrgent and emergent invasive procedures need to be performed during the COVID-19 pandemic. The consensus-based protocols in this study may assist healthcare providers to optimize perioperative care during the pandemic.

Meningiomas are the most common primary intracranial tumors, but the molecular drivers of meningioma tumorigenesis are poorly understood. We hypothesized that investigating intratumor heterogeneity in meningiomas would elucidate biologic drivers and reveal new targets for molecular therapy. To test this hypothesis, here we perform multiplatform molecular profiling of 86 spatially-distinct samples from 13 human meningiomas. Our data reveal that regional alterations in chromosome structure underlie clonal transcriptomic, epigenomic, and histopathologic signatures in meningioma. Stereotactic co-registration of sample coordinates to preoperative magnetic resonance images further suggest that high apparent diffusion coefficient (ADC) distinguishes meningioma regions with proliferating cells enriched for developmental gene expression programs. To understand the function of these genes in meningioma, we develop a human cerebral organoid model of meningioma and validate the high ADC marker genes CDH2 and PTPRZ1 as potential targets for meningioma therapy using live imaging, single cell RNA sequencing, CRISPR interference, and pharmacology.

Background Posterior fossa craniotomies can be complicated by cerebrospinal fluid (CSF) leaks, infection, meningitis, neurologic deficits, and intracranial hypotension caused by defective closure of the dura. Secondary dural closures such as pericranial graft, muscle graft, glue, sealants, or fat graft are used. However, there have been few studies examining the use of sealants with a polyethylene glycol and polyethylenimine component. Objective We studied the effect of one such sealant, Adherus® (HyperBranch Medical Technology, Durham, NC, USA), as an adjunct to secondary closure methods in the reduction of the use of abdominal fat grafting and lumbar puncture/drains. Methods We retrospectively reviewed the surgical records of all patients undergoing posterior fossa cranial surgery during a two-year period at a tertiary university affiliated medical center. Results Overall, data a total of 122 patients (62 in the no Adherus and 60 in the Adherus group) were collected. There was no statistically significant difference in the 30-day incisional CSF leak rate (4.1% vs. 6.5%; p=0.183), 30-day non-incisional CSF leak rate (11.3% vs. 5.0%; p=0.205), and 30-day pseudomeningocele rate (16.1% vs. 13.3%; p=0.663) in the no Adherus and Adherus groups, respectively. However, there was a significant reduction in the use of abdominal fat grafting (0% vs. 30.7%; p

The Neurological Pupil index (NPi) is a standardized method for evaluating pupil reactivity that removes inter-examiner variability. Changes in the NPi can predict clinical deterioration in patients with traumatic brain injury (TBI); however, its use to predict visual impairment after the resection of parasellar meningiomas has not been described. A 71-year-old female underwent a modified expanded bifrontal craniotomy for resection of a 3.1 cm tuberculum sella meningioma that caused compression of the optic chiasm and resulted in left temporal and right superior temporal visual field deficits. Postoperatively, she lost vision in the right eye. Pupillometer measurements demonstrated an asymmetrically low NPi at that time, which improved to normal prior to partial vision recovery. The average NPi in the right pupil was 1.67 during the time of vision loss compared to 3.47 in the left pupil (p=1.7x10-10). Statistical analysis was performed with the Student's t-test and the significance level was set at p-value < 0.01. Resection of parasellar meningiomas is challenging because of the proximity of the optic apparatus. We report a case of unilateral vision loss after resection of a tuberculum sella meningioma in which the impaired eye's NPi value correlated closely with visual function. NPi values that decrease below 3 predict spikes in intracranial pressure in TBI patients; similarly, increases in the NPi value above 2.5-3 predict improvement in vision in the case reported here. By monitoring the proximal portion of the oculomotor reflex, the NPi can be a marker of visual impairment after surgery.

Arterial injuries are the most feared complication of endoscopic skull base surgery. During resection of the middle fossa component of a large ventral skull base chondrosarcoma, arterial bleeding was encountered near the right internal carotid artery (ICA). Durable hemostasis could not be achieved with packing and the patient was taken for an emergent angiogram that revealed a pseudoaneurysm of the proximal intradural ICA. Given the presence of good collateral flow through the anterior and posterior communicating arteries, the right ICA was sacrificed by coil embolization. The patient was taken back to the operating room for closure then transferred to the intensive care unit and maintained on vasopressors for five days to ensure adequate perfusion. The right ICA was coil embolized and the patient was taken back to the operating room for closure. The patient recovered without complication. Arterial injuries, although serious, are not always catastrophic. Critical steps are immediate recognition of bleeding, vascular imaging, and vessel sacrifice if necessary.

Objectives  Foramen magnum meningiomas (FMM) are complex lesions because of their proximity to the brain stem and posterior cerebrovasculature. The objective of this study is to report surgical outcomes and complications after resection of FMM. Methods  A retrospective chart review was conducted on patients with FMM from 1998 to 2015. Univariate logistic regression and recursive partitioning analysis were used to identify risk factors associated with complications and extent of resection (EOR). Results  We identified 28 patients with FMM. Median follow-up was 5.9 years. Tumors were World Health Organization grade I (92.9%) or grade II (7.1%). The vertebral artery was completely encased (25%), partially encased (11%), or not encased (64%). Median size was 11.9 cm 3 . EOR was gross total (39%) and subtotal (61%). The observed recurrence rate was 4% ( n  = 1). There were 38 complications in 12 patients (43%), and 6 patients (21%) had complications requiring additional surgery. Complications included cerebrospinal fluid leak/hydrocephalus ( n  = 7, 25%), weakness ( n  = 4, 14%), numbness ( n  = 4, 14%), and cranial nerve deficits: IX, X ( n  = 4, 14%), XI ( n  = 2, 7%), XII ( n  = 5, 18%). Medical complications included pneumonia ( n  = 1, 4%) and meningitis ( n  = 1, 4%). Tumor volume greater than 14 cm 3 (odds ratio [OR] = 21.7, p  = 0.0010), any vertebral artery encasement (OR 6.1, p  = 0.0386), and subtotal resection (OR 6.4, p  = 0.0398) were significantly associated with complications. Tumor volume greater than 14 cm 3 was also significantly associated with subtotal resection (OR 8.3, p  = 0.0201). Conclusions  Resection of FMM carries perioperative morbidity that increases with larger tumor size. Despite the morbidity, long-term recurrence-free survival is achievable with maximal safe resection and adjuvant radiation.

BackgroundPetrous face meningiomas (PFMs) are challenging tumors because of their proximity to the cranial nerves, brainstem, and critical vasculature. The objective of this study is to present surgical outcomes and support an anatomic classification for PFM based on clinical presentation.MethodsA retrospective chart review was performed, and 51 PFMs were identified. Tumors were classified by location along the petrous face into anterior, middle, and posterior. Presentation and outcomes were analyzed with logistic regression.ResultsThe median follow-up was 31.6 months. Tumors were World Health Organization grade I (n = 50), with 1 World Health Organization grade II tumor. Location was anterior (22%), middle (14%), posterior (53%), and overlapping (12%). Median tumor diameter was 3.0 cm (range, 0.8-6.2 cm). Anterior location was associated with facial pain/numbness on presentation (P < 0.0001), middle location with hearing loss/vestibular dysfunction (P = 0.0035), and posterior with hydrocephalus (P = 0.0190), headache (P = 0.0039), and vertigo (P = 0.0265). Extent of resection was gross total (63%), near total (14%), and subtotal (25%). The observed radiographic recurrence rate was 15%. Mean progression-free survival after diagnosis was 9.1 years with 2-year, 5-year, and 10-year progression-free survival of 91.8%, 78.6%, and 62.9%, respectively. The complication rate was 27%. Age, location, and approach were not associated with complications.ConclusionsPFMs present with distinct clinical syndromes based on their location along the petrous face: anterior with trigeminal symptoms, middle with auditory/vestibular symptoms, and posterior with symptoms of mass effect/hydrocephalous. Surgical resection is associated with excellent long-term survival and a low rate of recurrence, which can be managed with radiotherapy.

OBJECTIVE Glioblastoma (GBM) is an aggressive brain malignancy with a short overall patient survival, yet there remains significant heterogeneity in outcomes. Although access to health care has previously been linked to impact on prognosis in several malignancies, this question remains incompletely answered in GBM. METHODS This study was a retrospective analysis of 354 newly diagnosed patients with GBM who underwent first resection at the authors' institution (2007-2015). RESULTS Of the 354 patients (median age 61 years, and 37.6% were females), 32 (9.0%) had no insurance, whereas 322 (91.0%) had insurance, of whom 131 (40.7%) had Medicare, 45 (14%) had Medicaid, and 146 (45.3%) had private insurance. On average, insured patients survived almost 2-fold longer (p < 0.0001) than those who were uninsured, whereas differences between specific insurance types did not influence survival. The adjusted hazard ratio (HR) for death was higher in uninsured patients (HR 2.27 [95% CI 1.49-3.33], p = 0.0003). Age, mean household income, tumor size at diagnosis, and extent of resection did not differ between insured and uninsured patients, but there was a disparity in primary care physician (PCP) status-none of the uninsured patients had PCPs, whereas 72% of insured patients had PCPs. Postoperative adjuvant treatment rates with temozolomide (TMZ) and radiation therapy (XRT) were significantly less in uninsured (TMZ in 56.3%, XRT in 56.3%) than in insured (TMZ in 75.2%, XRT in 79.2%; p = 0.02 and p = 0.003) patients. Insured patients receiving both agents had better prognosis than uninsured patients receiving the same treatment (9.1 vs 16.34 months; p = 0.025), suggesting that the survival effect in insured patients could only partly be explained by higher treatment rates. Moreover, having a PCP increased survival among the insured cohort (10.7 vs 16.1 months, HR 1.65 [95% CI 1.27-2.15]; p = 0.0001), which could be explained by significant differences in tumor diameter at initial diagnosis between patients with and without PCPs (4.3 vs 4.8 cm, p = 0.003), and a higher rate of clinical trial enrollment, suggesting a critical role of PCPs for a timelier diagnosis of GBM and proactive cancer care management. CONCLUSIONS Access to health care is a strong determinant of prognosis in newly diagnosed patients with GBM. Any type of insurance coverage and having a PCP improved prognosis in this patient cohort. Higher rates of treatment with TMZ plus XRT, clinical trial enrollment, fewer comorbidities, and early diagnosis may explain survival disparities. Lack of health insurance or a PCP are major challenges within the health care system, which, if improved upon, could favorably impact the prognosis of patients with GBM.

BACKGROUND:Open transcranial approaches to the anterior skull base remain an integral component of current skull base practice. Evolution of these and other techniques has resulted in revisions of standard, tried-and-true methods in attempts to improve patient outcomes and cosmesis, while still providing the best combination of surgical exposure and ergonomics. OBJECTIVE:To describe a modified approach for midline tumors of the anterior skull base. METHODS:We describe the anatomy and techniques of a modified extended bifrontal craniotomy for anterior skull base tumors. Case examples and a postoperative 3-dimensional computed tomographic reconstruction of the craniotomy are provided. RESULTS:The technique has been employed with success in 3 tuberculum sellae meningiomas where the anterior limit of the tumor is several centimeters back from the inner table of the frontal bone. The mean distance from the tumor to inner table was 2.8 cm (range 1.3-3.8 cm). Mean tumor dimensions were 3.0 cm (transverse), 3.5 cm (anterior-posterior), and 2.2 cm (craniocaudal). Average operative time was 557 min. No cases had new T2/fluid-attenuated inversion recovery magnetic resonance imaging signal of the inferior frontal lobe to indicate retraction injury. CONCLUSION:The tailored extended bifrontal craniotomy for anterior skull base tumors provides adequate access to the anterior cranial fossa and has replaced our standard extended bifrontal approach. Keeping the osteotomy cut lines outside of the orbit reduces orbital swelling and mechanical disruption of conjugate eye movements in the early postoperative period, while allowing for minimal frontal lobe retraction and providing sufficient surgical exposure along the anterior skull base.

Salmonella is an uncommon cause of meningitis, especially after neurosurgery. Here, we present a case of Salmonella meningitis after craniotomy, likely due to physical contact with a snake after surgery, with contiguous spread from the patient's hand to her wound. The purpose of this report is to serve as a reminder that patients undergoing neurosurgery should avoid contact with pets, including snakes and other reptiles, in the postoperative period and practice good hand hygiene.

A 42-year-old woman at 29 weeks gestation via in vitro fertilization who presented with eight metastatic brain lesions received Gamma Knife stereotactic radiosurgery (GKSRS) at our institution. In this study, we report our clinical experience and a general procedure of determining the fetal dose from patient-specific treatment plans and we describe quality assurance measurements to guide the safe practice of multi-target GKSRS of pregnant patients. To estimate fetal dose pre-treatment, peripheral dose-to-focal dose ratios (PFRs) were measured in a phantom at the distance approximating the fundus of uterus. Post-treatment, fetal dose was calculated from the actual patient treatment plan. Quality assurance measurements were carried out via the extrapolation dosimetry method in a head phantom at increasing distances along the longitudinal axis. The measurements were then empirically fitted and the fetal dose was extracted from the curve. The computed and measured fetal dose values were compared with each other and associated radiation risk was estimated. Based on low estimated fetal dose from preliminary phantom measurements, the patient was accepted for GKSRS. Eight brain metastases were treated with prescription doses of 15-19 Gy over 143 min involving all collimator sizes as well as composite sector mixed shots. Direct fetal dose computation based on the actual patient's treatment plan estimated a maximum fetal dose of 0.253 cGy, which was in agreement with surface dose measurements at the level of the patient's uterine fundus during the actual treatment. Later phantom measurements also estimated fetal dose to be in the range of 0.21-0.28 cGy (dose extrapolation curve R2 = 0.998). Using the National Council on Radiation Protection and Measurements (NCRP) population-based model, we estimate the fetal risk of secondary malignancy, which is the primary toxicity after 25 weeks gestation, to be less than 0.01%. Of note, the patient delivered the baby via scheduled cesarean section at 36 weeks without complications attributable to the GKSRS procedure. GKSRS of multiple brain metastases was demonstrated to be safe and feasible during pregnancy. The applicability of a general patient-specific fetal dose determination method was also demonstrated for the first time for such a treatment.

While immunotherapy may offer promising new approaches for high grade meningiomas, little is currently known of the immune landscape in meningiomas. We sought to characterize the immune microenvironment and a potentially targetable antigen mesothelin across WHO grade I-III cases of meningiomas, and how infiltrating immune populations relate to patient outcomes. Immunohistochemistry was performed on tissue microarrays constructed from 96 meningioma cases. The cohort included 16 WHO grade I, 62 WHO grade II, and 18 WHO grade III tumors. Immunohistochemistry was performed using antibodies against CD3, CD8, CD20, CD68, PD-L1, and mesothelin. Dual staining using anti-PD-L1 and anti-CD68 antibodies was performed, and automated cell detection and positive staining detection algorithms were utilized. Greater degree of PD-L1 expression was found in higher grade tumors. More specifically, higher grade tumors contained increased numbers of intratumoral CD68-, PD-L1+ cells (p = 0.022), but did not contain higher numbers of infiltrating CD68+, PD-L1+ cells (p = 0.30). Higher PD-L1+/CD68- expression was independently predictive of worse overall survival in our cohort when accounting for grade, performance status, extent of resection, and recurrence history (p = 0.014). Higher expression of PD-L1+/CD68- was also present in tumors that had undergone prior radiotherapy (p = 0.024). Approximately quarter of meningiomas overexpressed mesothelin to levels equivalent to those found in pancreatic carcinomas and malignant mesotheliomas. The association with poor survival outcomes in our study suggests that PD-L1 may play a significant biologic role in the aggressive phenotype of higher grade meningiomas. Thus, immunotherapeutic strategies such as checkpoint inhibition may have clinical utility in PD-L1 overexpressing meningiomas.

Background Surgery for small vestibular schwannomas (Koos grade I and II) has been increasingly rejected as the optimal primary treatment, instead favoring radiosurgery and observation that offer lower morbidity and potentially equal efficacy. Our study assesses the outcomes of contemporary surgical strategies including tumor control, functional preservation, and implications of pathologic findings. Design Retrospective review. Setting/Participants Eighty consecutive patients (45 women, 35 men; mean: 47 years of age). Main Outcomes Measures Approaches included retrosigmoid approach (52%), translabyrinthine (40%), and middle fossa (8%). Operated on by the same surgical team, we analyzed presentation, radiographic imaging, surgical data, and outcomes. Results At last follow-up (mean: 34 months), 95% had good facial nerve function (House-Brackmann grade I or II); 36% who presented with serviceable hearing retained it; and 93% who presented with vestibular dysfunction reported resolution. Pathology identified two grade I meningiomas. Conclusions As one of the largest contemporary surgical series of small vestibular schwannomas, we discuss some nuances to help refine treatment algorithms. Although observation and radiosurgery have established roles, our results reinforce microsurgery as a viable, safe option for a subgroup of patients.

Objective Modern surgical experience with intracranial neuroenteric cysts is limited in the literature. We review our 15-year institutional experience with these rare lesions. Design Single-institution retrospective study. Setting Large North American tertiary care center. Participants Histologically confirmed cases of intracranial neuroenteric cyst from January 2000 to September 2014. Main Outcome Measures Pre- and postoperative modified Rankin Scale (mRS) scores, extent of resection, and postoperative complications are reported. Clinical presentation, imaging features, pathology, and operative approach are discussed. Results Five spinal and six intracranial neuroenteric cysts were surgically treated over a 15-year period. Median age at presentation for the intracranial cysts was 38.5 years. Mean cyst diameter was 3.8 cm. Five cysts were located in the pre-pontomedullary cistern, and one was located in the third ventricle. Gross total resection was achieved in four of the five posterior fossa cysts through a far lateral transcondylar approach. Postoperative complications included aseptic meningitis (one), transient abducens palsy (one), and pseudomeningocele requiring reoperation (three). Postoperative mRS scores improved to ≤1 by 6.5 months median follow-up. Conclusions Intracranial neuroenteric cysts are rare lesions with a variable imaging appearance. Complete surgical resection through a far lateral transcondylar approach is possible and usually results in symptom improvement or resolution.

Glioblastoma (WHO grade IV astrocytoma) is the most common and most aggressive primary brain tumor in adults. Optimal treatment of a patient with glioblastoma requires collaborative care across numerous specialties. The diagnosis of glioblastoma may be suggested by the symptomatic presentation and imaging, but it must be pathologically confirmed via surgery, which can have dual diagnostic and therapeutic roles. Standard of care postsurgical treatment for newly diagnosed patients involves radiation therapy and oral temozolomide chemotherapy. Despite numerous recent trials of novel therapeutic approaches, this standard of care has not changed in over a decade. Treatment options under active investigation include molecularly targeted therapies, immunotherapeutic approaches, and the use of alternating electrical field to disrupt tumor cell division. These trials may be aided by new insights into glioblastoma heterogeneity, allowing for focused evaluation of new treatments in the patient subpopulations most likely to benefit from them. Because glioblastoma is incurable by current therapies, frequent clinical and radiographic assessment is needed after initial treatment to allow for early intervention upon progressive tumor when it occurs.

Objectives We compare surgical exposures to the clivus by Le Fort I osteotomy (LFO) and the expanded endoscopic endonasal approach (EEEA). Methods Ten cadaveric specimens were imaged with 1.25-mm computed tomography. After stereotactic navigation, EEEA was performed followed by LFO. Clival measurements included lateral and vertical limits to the midline lower extent of exposure (t test). Results For EEFA and LFO, respectively, maximal lateral exposure in millimeters (mean ± standard deviation) was 24.5 ± 3.7 and 24.5 ±  - 3.8 (p = 0.99) at the opticocarotid recess (OCR) and 25.1 ±  - 4.1 and 24.1 ±  - 3.0 (p = 0.53) at the foramen lacerum level; lateral reach at the hypoglossal canals was 39.0 ±  - 5.88 and 56.1 ±   - 5.3 (p = 0.0004); and vertical extension was 56.0 ±  - 4.1 and 56.3 ±  - 3.4 (p = 0.78). Conclusions For clival exposures, LFO and EEEA were similar craniocaudally and laterally at the levels of the OCR and foramen lacerum. LFO achieved greater exposure at the level of the hypoglossal canal.