Image-based models of T-cell distribution identify a clinically meaningful response to a dendritic cell vaccine in patients with glioblastoma.

BACKGROUND: Glioblastoma is an extraordinarily heterogeneous tumor, yet the current treatment paradigm is a "one size fits all" approach. Hundreds of glioblastoma clinical trials have been deemed failures because they did not extend median survival, but these cohorts are comprised of patients with diverse tumors. Current methods of assessing treatment efficacy fail to fully account for this heterogeneity. METHODS: Using an image-based modeling approach, we predicted T-cell abundance from serial MRIs of patients enrolled in the dendritic cell (DC) vaccine clinical trial. T-cell predictions were quantified in both the contrast-enhancing and non-enhancing regions of the imageable tumor, and changes over time were assessed. RESULTS: A subset of patients in a DC vaccine clinical trial, who had previously gone undetected, were identified as treatment responsive and benefited from prolonged survival. A mere two months after initial vaccine administration, responsive patients had a decrease in model-predicted T-cells within the contrast-enhancing region, with a simultaneous increase in the T2/FLAIR region. CONCLUSIONS: In a field that has yet to see breakthrough therapies, these results highlight the value of machine learning in enhancing clinical trial assessment, improving our ability to prospectively prognosticate patient outcomes, and advancing the pursuit towards individualized medicine.

Craniofacial Chondromyxoid Fibromas: A Systematic Review and Analysis Based on Anatomic Locations.

BACKGROUND: Craniofacial chondromyxoid fibromas (CMFs) are a rare benign tumor of cartilaginous origin. They are commonly misdiagnosed due to the paucity of information on tumor characteristics. We performed a systematic review to characterize CMFs located in different regions of the craniofacial skeleton. METHODS: A search of the literature was executed using the search phrase "chondromyxoid fibroma" and included articles from 1990-2020. Sixty-eight articles met the inclusion criteria, with a total of 91 patients with analyzable data (22 with calvarial and 69 with sinonasal tumor locations). Descriptive analyses were performed to compare pre-selected characteristics between the 2 groups. RESULTS: Sinonasal CMF frequently presented with cranial nerve palsy and expectedly had a high rate of nasal symptoms. Calvarial tumors frequently presented with an external mass and headache. Gross total resection (GTR) was achieved in a higher proportion of cases in the calvarial group versus the sinonasal group (83.3% vs. 53.1%). Overall recurrence rate at 17.7% was higher in sinonasal CMF compared with the calvarial tumors at 8.3%. Recurrences after GTR were similar in the sinonasal and calvarial groups (9.7% vs. 9.1%). In patients who did not achieve GTR, recurrence was higher in the sinonasal compared with the calvarial group (27.6% vs. 0%). CONCLUSIONS: Craniofacial CMF in calvarial and sinonasal locations have distinct clinical characteristics and response to treatment. Sinonasal lesions tend to have higher recurrence compared to calvarial CMF. Performance of GTR is associated with decreased recurrence in all CMFs.

The Relationship Between Obstructive Sleep Apnea and Ruptured Intracranial Aneurysms.

STUDY OBJECTIVES: The role of obstructive sleep apnea (OSA) in the overall outcome of ruptured intracranial aneurysms (RIAs) is unknown. We have investigated the role of OSA in overall outcome of RIAs. METHODS: Data from 159 consecutive patients were retrospectively reviewed. A chi-square test and regression analysis were performed to determine the significant difference. A value of P < .05 was considered significant. RESULTS: The prevalence of OSA in RIAs was fivefold higher in the nonaneurysm patient group, P = .002. The number of patients with hypertension (P < .0001), body mass index ≥ 30 (P < .0001), hyperlipidemia (P = .018), chronic heart disease (P = .002) or prior ischemic stroke (P = .001) was significantly higher in the OSA group. Similarly, the number of wide-neck aneurysms (P < .0001) and aneurysm > 7 mm (P = .004), poor Hunt and Hess grade IV-V (P = .005), vasospasms, (P = .03), and patients with poor Modified Rankin Scale scores (3-6) was significantly higher in the OSA group (P < .0001). Interestingly, for the first time in univariate (P = .01) and multivariate (P = .003) regression analysis, OSA was identified as an individual predictor of unfavorable outcome of RIAs. In addition, hypertension (P = .04), smoking (P = .049), chronic heart disease (P = .01), and Hunt and Hess grade IV-V (P = .04) were revealed as predictors of poor outcome of RIAs. CONCLUSIONS: This is a novel study to determine the association between OSA and ruptured cerebral aneurysm in terms of comorbidities, size of aneurysm, severity of symptoms, and outcomes after treatment. In addition, for the first time, OSA is identified as a positive predictor of unfavorable outcome of RIAs.

Mechanical Thrombectomy and Thrombolysis for Dural Venous Sinus Thrombosis.

Dural venous sinus thrombosis is a rare yet major cause of stroke and mortality, especially affecting young women and children. Anticoagulation is the mainstay of therapy; however, nearly 13% of the patients experience poor outcome with anticoagulation alone.1 In addition, nearly one third of the patients with severe presentation have a risk of incomplete recovery with systemic anticoagulation.2 The subgroup of patients who have incomplete recovery or who develop rapid deterioration in spite of anticoagulation can benefit from mechanical thrombectomy with or without intrasinus thrombolysis. Our patient is a 33-year-old lady on oral contraceptive pills who developed extensive dural venous sinus thrombosis after undergoing lumboperitoneal shunt for pseudotumor cerebri (Video 1). In view of clinical deterioration despite systemic heparin therapy, we performed mechanical thrombectomy and intrasinus thrombolysis using an Angiojet device (Boston Scientific Corporation or its affiliates Inc., Marlborough, Massachusetts, USA). The Angiojet system has the unique capability of a Power Plus technique in which thrombolytic agents can simultaneously be used to facilitate clot removal. However, its utility for intracranial use is limited by the stiffness, large (6-French) catheter diameter, and short length (120 cm). After the procedure, the patient achieved rapid clinical improvement and was maintained on systemic oral anticoagulation. In addition to the case presentation, the video article also demonstrates the technical aspects of mechanical venous thrombectomy.

Retromastoid Approach for Posterior Fossa Skull Base Rosai-Dorfman Disease-A Rare Pathology: 3-Dimensional Operative Video.

Rosai-Dorfman disease, originally described by Juan Rosai and Ronald F. Dorfman, is a rare benign histiocytic proliferative disorder, classically presenting with massive lymphadenopathy and a self-limiting clinical course.1 Isolated intracranial skull base involvement is extremely rare and often resembles meningiomas, schwannomas, or other benign skull base lesions.2 The disease is difficult to diagnose radiographically, and tissue diagnosis with open skull base approaches has significant perioperative risks.2,3 We present the case of a 48-yr-old Caucasian male presenting with progressively worsening headaches, giddiness, hearing difficulty, and diplopia. Magnetic resonance imaging of the brain revealed T1-weighted isointense, T2-weighted hypointense, and contrast-enhancing dural-based lesion in the left cerebellopontine angle. The patient underwent maximally safe resection of the lesion through the retromastoid approach with careful preservation of the lower cranial nerve complex. The intraoperative findings of a variegated and lobulated mass adherent to the skull base, the surgical strategy of safe resection, and eventual good outcome in this patient are depicted in this 3-dimensional video presentation. The majority of patients with skull base Rosai-Dorfman disease reported in literature have had stable or regression of disease (78%) after initial conservative surgical treatment and hence aggressive surgical resection is of unproven efficacy.3 The patient has consented to depiction of his surgical video and intraoperative images in this video manuscript.

Repeat Gamma Knife radiosurgery versus microvascular decompression following failure of GKRS in trigeminal neuralgia: a systematic review and meta-analysis.

OBJECTIVE: Gamma Knife radiosurgery (GKRS) has emerged as a promising treatment modality for patients with classical trigeminal neuralgia (TN); however, considering that almost half of the patients experience post-GKRS failure or lesion recurrence, a repeat treatment is typically necessary. The existing literature does not offer clear evidence to establish which treatment modality, repeat GKRS or microvascular decompression (MVD), is superior. The present study aimed to compare the overall outcome of patients who have undergone either repeat GKRS or MVD after failure of their primary GKRS; the authors do so by conducting a systematic review and meta-analysis of the literature and analysis of data from their own institution. METHODS: The authors conducted a systematic review and meta-analysis of the PubMed, Cochrane Library, Web of Science, and CINAHL databases to identify studies describing patients who underwent either repeat GKRS or MVD after initial failed GKRS for TN. The primary outcomes were complete pain relief (CPR) and adequate pain relief (APR) at 1 year. The secondary outcomes were rate of postoperative facial numbness and the retreatment rate. The pooled data were analyzed with R software. Bias and heterogeneity were assessed using funnel plots and I2 tests, respectively. A retrospective analysis of a series of patients treated by the authors who underwent repeat GKRS or MVD after post-GKRS failure or relapse is presented. RESULTS: A total of 22 studies met the selection criteria and were included for final data retrieval and meta-analysis. The search did not identify any study that had directly compared outcomes between patients who had undergone repeat GKRS versus those who had undergone MVD. Therefore, the authors' final analysis included two groups: studies describing outcome after repeat GKRS (n = 17) and studies describing outcome after MVD (n = 5). The authors' institutional study was the only study with direct comparison of the two cohorts. The pooled estimates of primary outcomes were APR in 83% of patients who underwent repeat GKRS and 88% of those who underwent MVD (p = 0.49), and CPR in 46% of patients who underwent repeat GKRS and 72% of those who underwent MVD (p = 0.02). The pooled estimates of secondary outcomes were facial numbness in 32% of patients who underwent repeat GKRS and 22% of those who underwent MVD (p = 0.11); the retreatment rate was 19% in patients who underwent repeat GKRS and 13% in those who underwent MVD (p = 0.74). The authors' institutional study included 42 patients (repeat GKRS in 15 and MVD in 27), and the outcomes 1 year after retreatment were APR in 80% of those who underwent repeat GKRS and 81% in those who underwent MVD (p = 1.0); CPR was achieved in 47% of those who underwent repeat GKRS and 44% in those who underwent MVD (p = 1.0). There was no difference in the rate of postoperative facial numbness or retreatment. CONCLUSIONS: The current meta-analysis failed to identify any superiority of one treatment over the other with comparable outcomes in terms of APR, postoperative facial numbness, and retreatment rates. However, MVD was shown to provide a better chance of CPR compared with repeat GKRS.

Microsurgical Anatomy of Medial Temporal Lobe in North-West Indian Population: Cadaveric Brain Dissection.

AIM: The medial temporal lobe (MTL) is a highly complex neuroanatomical structure of tremendous neurosurgical importance. It is a common site for epilepsy, vascular lesions, and tumors. Owing to the critical location behind the sphenoid wing, it is more prone for traumatic contusion often with surgical implications. Hence, its microneurosurgical anatomy needs to be evaluated in detail. MATERIALS AND METHODS: Twelve formalin-fixed human cadaveric brains from North-west Indian population were dissected under neurosurgical microscope and various dimensions of the MTL and their distance from important neurovascular structures were measured. RESULTS: The MTL consists of important neural structures such as parahippocampal gyrus, uncus, hippocampus, temporal horn, and choroidal fissure. The average distance of tentorium from the uncus was 1.96 mm. The temporal horn and the inferior choroidal point were located from the anterior temporal pole at 22.9 mm and 30.9 mm, respectively. Important vessels that are intimately related to the MTL were anterior choroidal artery (AchA), posterior communicating artery, the P1 segment of posterior cerebral artery, and the M1 segment of middle cerebral artery. CONCLUSION: Complex anatomic and cytostructural organization makes the MTL unique. In this study, along with the descriptive anatomy, morphometric measurements of various structures were performed. The uncus and its relation to other neurovascular structures is well described in literature, but its exact distance from them as determined in this study is particularly helpful in guiding the surgeons while approaching in this area. Knowledge of the distance of the temporal horn from various surfaces is important while opening the temporal horn to avoid unnecessary damage to nearby structures.

Safety profile of superior petrosal vein (the vein of Dandy) sacrifice in neurosurgical procedures: a systematic review.

OBJECTIVE Walter E. Dandy described for the first time the anatomical course of the superior petrosal vein (SPV) and its significance during surgery for trigeminal neuralgia. The patient's safety after sacrifice of this vein is a challenging question, with conflicting views in current literature. The aim of this systematic review was to analyze the current surgical considerations regarding Dandy's vein, as well as provide a concise review of the complications after its obliteration. METHODS A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A thorough literature search was conducted on PubMed, Web of Science, and the Cochrane database; articles were selected systematically based on the PRISMA protocol and reviewed completely, and then relevant data were summarized and discussed. RESULTS A total of 35 publications pertaining to the SPV were included and reviewed. Although certain studies report almost negligible complications of SPV sectioning, there are reports demonstrating the deleterious effects of SPV obliteration when achieving adequate exposure in surgical pathologies like trigeminal neuralgia, vestibular schwannoma, and petroclival meningioma. The incidence of complications after SPV sacrifice (32/50 cases in the authors' series) is 2/32 (6.2%), and that reported in various case series varies from 0.01% to 31%. It includes hemorrhagic and nonhemorrhagic venous infarction of the cerebellum, sigmoid thrombosis, cerebellar hemorrhage, midbrain and pontine infarct, intracerebral hematoma, cerebellar and brainstem edema, acute hydrocephalus, peduncular hallucinosis, hearing loss, facial nerve palsy, coma, and even death. In many studies, the difference in incidence of complications between the SPV-sacrificed group and the SPV-preserved group was significant. CONCLUSIONS The preservation of Dandy's vein is a neurosurgical dilemma. Literature review and experiences from large series suggest that obliterating the vein of Dandy while approaching the superior cerebellopontine angle corridor may be associated with negligible complications. However, the counterview cannot be neglected in light of some series showing an up to 30% complication rate from SPV sacrifice. This review provides the insight that although the incidence of complications due to SPV obliteration is low, they can happen, and the sequelae might be worse than the natural history of the existing pathology. Therefore, SPV preservation should be attempted to optimize patient outcome.

Meningioma: The Tumor That Taught Us Neurosurgery.

The history of neurosurgery is ever fascinating. The journey has been tedious; nevertheless, in the landscape of success and failures we have become more efficient and polished. Skills were learned, innovations were made, and in the process we evolved. The immense contribution of meningioma surgery in this maturation process is attested by history itself. Countless stories that testify the momentous role of meningioma in the process of evolution and reformation of neurosurgical techniques exist in the literature. With every step and every attempt at conquering this tumor, we reformed to be better surgeons, more skilled and more precise. In this paper we have walked down the lane of neurosurgery and paid a due tribute to this "necessary evil."

Primary Focal Intracranial Leptomeningeal Glioma: Case Report and Review of the Literature.

BACKGROUND: Primary focal intracranial leptomeningeal glioma (PFILG) is considered a rare solitary glial tumor arising from the leptomeninges without brain attachment or evidence of primary neoplasm elsewhere within the neuraxis. We report a case of PFILG in a left parietal location and provide a concise review on its clinicoradiologic, histopathologic, and management characteristics. CASE PRESENTATION: A 75-year-old woman presented with focal motor seizures involving the right upper limb with associated occasional headache. Magnetic resonance imaging (MRI) of the brain revealed a small focal lesion attached to the left parietal dura with underlying brain parenchymal signal changes, and contrast-enhanced images showed heterogeneous enhancement of the tumor and meninges. The repeated MRI brain images within a month of primary imaging revealed significant progression of the size of lesion along with invasion of underlying parietal lobe parenchyma. The patient underwent gross total resection of the lesion, and the histopathologic diagnosis was glioblastoma multiforme (GBM), World Health Organization grade 4, isocitrate dehydrogenase wild type. The patient recovered well from surgery without deficits; however, she refused adjuvant treatment. MRI of the brain repeated 3 months after surgery revealed significant progression of the GBM with mass effect. Although adjuvant treatment was then started, she could not tolerate it and died 4 months after surgery. CONCLUSION: The possibility of high-grade PFILG should be considered in any aggressive extra-axial focal lesion. The definitive diagnosis can be made after histologic examination. Although surgery followed by adjuvant treatment is considered the mainstay of treatment, the overall prognostic outcome of high-grade PFILG is dismal.

Tuberculous Spondylolisthesis: A Reappraisal of the Clinicoradiologic Spectrum and Surgical Treatment Paradigm.

INTRODUCTION: Spinal tuberculosis (TB) is a common infectious disease prevalent in developing countries and an increasing issue in developed countries. The association of tuberculosis with spondylolisthesis is rarely reported in literature. The aim of our review is to analyze the clinical features and radiologic characteristics of TB spondylolisthesis and to provide a concise update on its surgical management, based on the literature. METHODS: A systematic review was performed after conducting a thorough search of the PubMed database. Articles were selected systematically and reviewed completely and relevant data were summarized and discussed. RESULTS: Nineteen articles were selected for the review. The most common clinical manifestation was focal back pain, followed by motor deficit. Most patients had grade 2 listhesis and associated tubercular abscess. The anterior as well as the posterior surgical approach have their own advantages and the choice of approach depends on the location of disease, ease of access, achievement of spinal stability, and avoidance of spread of contiguous infection. Although a posterior approach and fixation using pedicular screws and rods along with debridement of pus or granulation tissue is the favored approach in dorsolumbar TB, an anterior approach, corpectomy, and fusion are preferred in cervical TB. CONCLUSIONS: Treatment of TB spondylolisthesis encompasses a wide spectrum of surgical options. However, the mainstay of treatment is chemotherapy. The indications for which surgical management may have an upper hand over medical management are spinal cord compression, significant instability, large tubercular abscess, painful vertebral lesions, kyphosis, and infection by multidrug-resistant TB or extreme drug-resistant TB, when medical management alone does not help. Surgery is effective in these situations by achieving radical debridement, permanent stability, prevention of further neurologic deterioration, and early recovery. Even although conservative management may help in certain cases, a posterior approach, decompression, and fusion are preferred for unstable dorsolumbar disease, whereas an anterior approach is preferred for cervical disease. Combined approaches can be considered in pediatric spinal TB for the correction of kyphotic deformity and its consequent maintenance.

Long-Term Outcome of Nonfunctioning and Hormonal Active Pituitary Adenoma After Gamma Knife Radiosurgery.

INTRODUCTION: Stereotactic radiosurgery (SRS), particularly Gamma Knife radiosurgery (GKRS) is an established treatment option for residual and recurrent pituitary adenoma tumors. It helps in the preservation of surrounding normal neuronal, vascular, and hormone-producing structures and causes fewer neurologic deficits. The aim of this research was to evaluate the efficacy and define the role of GKRS in the treatment of nonfunctioning (NFA) and hormonal active (HAA) pituitary adenoma. METHODS: A retrospective analysis of 111 patients with histologically proven pituitary adenoma who underwent GKRS treatment at Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA, over a 17-year period was conducted presented. The clinical and radiologic data were collected from the database. The tumors were categorized into NFA and HAA based on the endocrinology profile. The relevant statistical analysis was conducted with SPSS software, version 22.0. RESULTS: The median age of the patients was 58 years. The study comprised 87 patients with NFA and 24 patients with HAA tumors. Thirty-eight patients (34.2%) had hypopituitarism symptoms, and 8 patients (7%) had panhypopituitarism symptoms. The mean tumor volume before to GKRS was 3.8 cm3. Suprasellar and cavernous extension of the tumor was noted in 28 patients (25.2%) and 34 (30.6%) patients, respectively. We observed >70% reduction in the size of tumors in the shrinkage cohort after GKRS; the median time for shrinkage was 48.4 months. However, increase in tumor size was noted in the progression cohort (pre-GKRS 3.8 cm3 vs. post-GKRS 6.5 cm3). Seventy patients (63.1%) had neurologic improvement, and 26 patients (23.4%) had endocrinologic worsening after GKRS. CONCLUSIONS: GKRS plays a significant role in the treatment of NFA and HAA. It affords a high rate of tumor control and offers a low risk of collateral neurologic or endocrine axis injury. Our study shows that control of tumor growth was achieved in 90% of patients, shrinkage of tumor in 54%, and arrest of progression in 36% after GKRS treatment. The biochemical remission rate in growth hormone secreting adenoma was 57%, in adrenocorticotropic hormone adenoma 67%, and prolactinoma 40%. Age below 50 years and tumor volume less than 5 cm3 were associated with a favorable radiosurgical outcome.

Microsurgical Resection of Suprasellar Craniopharyngioma-Technical Purview.

Objectives Complete surgical resection is an important prognostic factor for recurrence and is the best management for craniopharyngioma. This operative video demonstrates the technical nuances in achieving complete resection of a suprasellar craniopharyngioma. Design and Setting The surgery was performed in a middle-aged lady who presented with the history of progressive bitemporal hemianopia and excessive sleepiness over 8 months. On imaging, suprasellar craniopharyngioma was identified. The tumor was approached through opticocarotid cistern and lamina terminalis. Exposure of bilateral optic nerves, right internal carotid artery, anterior cerebral artery, and its perforator branches was then afforded and the tumor was gross totally resected. Results The author demonstrates step-by-step technique of microsurgical resection of suprasellar craniopharyngioma. The narrow corridor to deeper structures, intricacies of multiple perforator vessels, and the technique of arachnoid and capsule dissection are the main challenging factors for the gross total resection of craniopharyngioma. The tumor portion which lies under the ipsilateral optic nerve is a blind spot region with a high chance of leaving residual tumor. Mobilization of optic nerve may endanger visual function too. The use of handheld mirror ['mirror-technique'] helps in better visualization of this blind spot and achieve complete excision. Conclusions The technical pearls of craniopharyngioma surgery include the optimum utilization of translamina terminalis route, wide opening of the cisterns, meticulous separation of deep perforator vessels, capsular mobilization/traction avoidance, and the use of "mirror-technique" for blind-spot visualization. These surgical strategies help to achieve complete resection without causing neurological deficit. The link to the video can be found at: https://youtu.be/9wHJ4AUpG50 .

Surgery of Tuberculum Sellae Meningioma: A Technical Purview on Pterional Approach.

Objective Amidst the raging debate between transnasal and transcranial approaches, the critical factor that dictates success lies in the meticulous dissection of the tumor from the optic apparatus, anterior communicating artery complex, and the pituitary stalk. In this surgical video, we describe the resection of a tuberculum sellae meningioma through the pterional approach highlighting dissection through the appropriate arachnoidal plane. Case Description The patient is a 75-year-old female who presented with optic nerve compression with bitemporal hemianopia and endocrine function abnormalities. A transcranial approach was done to effectively decompress the optic nerve. The video includes a detailed discussion on the surgical techniques including working between the different surgical corridors, working in the arachnoid plane to dissect the neurovascular structures away from the tumor, identification, and preservation of pituitary stalk. Postoperatively, the patient's visual field deficit improved with a remaining isolated right temporal field defect at 2 months follow-up. Her endocrine function improved after the surgery. Conclusion In the era of endoscopic surgery, transcranial approaches for suprasellar tumors like tuberculum sellae meningiomas still have a distinct surgical role. Our discussion extends to reiterate the strengths and weaknesses of the transcranial approach to this region as compared with the endoscopic approach. We believe decompression of optic nerves, separation of Acom complex from the tumor, and preservation of pituitary stalk are better achieved through a transcranial approach. The link to the video can be found at : https://youtu.be/kw5eP3oUd6Q .

Differential Tumor Progression Patterns in Skull Base Versus Non-Skull Base Meningiomas: A Critical Analysis from a Long-Term Follow-Up Study and Review of Literature.

BACKGROUND: To analyze the differences in tumor progression patterns and histopathologic characteristics between skull base meningiomas (SBMs) and non-skull base meningiomas (NSBMs). METHODS: Retrospective data of 382 patients with SBMs and 200 patients with NSBMs who underwent primary microsurgical resection between January 1995 and December 2016 were analyzed. Data related to clinical history, neuroimaging, surgical technique, and follow-up were reviewed. A separate prospective cohort of 78 meningiomas operated on from June 2016 to July 2017 was analyzed (World Health Organization [WHO] grade and Ki-67 proliferation index) for biologic comparison. RESULTS: Skull base location, WHO grade II tumor, and subtotal resection were independent predictors of unfavorable outcome. The overall tumor progression rate in the SBM group (33%) was higher than in the NSBM group (19.7%) (P = 0.006) (mean follow-up period, 51 months). The 3-year, 5-year, and 10-year progression-free survival (PFS) was 78%, 60%, and 45% in the SBM group, whereas it was 90%, 80%, and 53% in the NSBM group, respectively. Interestingly, there was no difference in the median PFS after 10 years of follow-up (SBMs 210 months vs. NSBM 212 months, P = 0.93). In the prospective cohort of 78 meningiomas, there was no statistically significant difference in the proportion of WHO grade I tumors and in the mean Ki-67 index of WHO grade I meningiomas between the 2 groups. CONCLUSION: There is a divergent tumor progression pattern for surgically treated SBMs vis-à-vis NSBMs. Differences in tumor biology and the proportion of Simpson grade I resections are likely attributable factors.

Tentorial Meningiomas: Reappraisal of Surgical Approaches and Their Outcomes.

BACKGROUND: Tentorial meningiomas are notorious for their critical location. Selection of a suitable approach that exposes the multicompartmental growth of tumor is important for a complete and safe resection. This paper discusses about various operative approaches and their overall surgical outcome. METHODS: We retrospectively reviewed our 41 patients with tentorial meningiomas. They were classified according to the modified Yasargil classification. The symptomatic improvement and progression-free survival (PFS) were analyzed at follow-up. RESULTS: Tumors were almost equally distributed in all location groups. Tumors along the lateral tentorial hiatus were operated on via a subtemporal or transsylvian approach. Tumors along the posterior tentorial hiatus, tentorial membrane, or torcula were operated on by an occipital interhemispheric transtentorial, infratentorial supracerebellar, or a combined approach. Tumors along the petrous attachment were operated on by a retromastoid suboccipital or a combined presigmoid-retrosigmoid approach. Seventy-six percent had total excision (Simpson grade 1 and 2). Group II tumors had the highest total resection rate (100%). Headache and diplopia were the symptoms that significantly improved postoperatively. Over a median follow-up of 65 months, 13 patients (31.7%) had recurrence. There was no significant difference in recurrence rates and PFS in tumors at different locations. Extent of excision and tumor grade were the significant factors affecting PFS in both univariate and multivariate analysis (P = 0.01 and 0.03, respectively). CONCLUSIONS: Similar to intracranial meningiomas at other locations, extent of resection and tumor grade significantly affect the PFS for tentorial meningiomas. Careful preoperative planning based on the location and extension of the tumor guides the optimal surgical approach that translates into maximal safe resection.