Delaying Postoperative Radiotherapy in Low-Grade Esthesioneuroblastoma: Is It Worth the Wait?

Background Consensus in timing of radiotherapy is yet to be established in esthesioneuroblastoma (ENB). Objective This study was aimed to investigate if planned adjuvant radiotherapy improves tumor control after complete margin negative resection of low Hyams' grade (1 or 2) ENB. Methods A retrospective review of patients with pathologically confirmed negative margin resection of Kadish's stage B or C and Hyams' grade 1 and 2 ENBs was conducted. Seventeen patients meeting the criteria were divided into the following two groups for cohort study: (1) those who underwent planned immediate postoperative adjuvant radiotherapy (IR group) and (2) those who did not (delayed radiotherapy [DR] group). Results The IR group included nine patients (Kadish's stage B in one and stage C in eight; Hyams' grade 1 in two and grade 2 in seven). Mean follow-up was 140.8 months. Seven patients (78%) had disease progression (DP) at a median of 88 months (four with cervical lymph node metastasis [CLNM], one with distant metastasis, and two with both local recurrence and CLNM). One patient experienced frontal lobe abscess. The DR group included eight patients (Kadish's stage B in six and stage C in two; all Hyams' grade 2). Mean follow-up was 123.3 months. Four (50%) patients who developed DP (all local recurrence) were salvaged with surgery and adjuvant radiotherapy at a median of 37.5 months. There was no statistically significant difference in DP rate ( p = 0.23), time to DP ( p = 0.26), or the local tumor control rate ( p = 0.23). Conclusion In our limited cohort, immediate postoperative radiotherapy did not demonstrate superiority in tumor control, although risk of radiotherapy toxicity appears low.

Radiosurgical Management of Patients With Persistent or Recurrent Cushing Disease After Prior Transsphenoidal Surgery: A Management Algorithm Based on a 25-Year Experience.

BACKGROUND: Patients with persistent or recurrent Cushing disease (CD) after prior transsphenoidal surgery require further treatment to reduce the disease's metabolic consequences. OBJECTIVE: To assess patient outcomes after stereotactic radiosurgery (SRS) for persistent or recurrent CD from adrenocorticotropin hormone (ACTH)-secreting pituitary adenomas and propose a management algorithm. METHODS: Retrospective review of 38 patients without prior radiation treatment having SRS for ACTH-secreting pituitary adenomas from 1990 to 2015. Favorable outcome was defined as biochemical remission and tumor growth control. Patients were evaluated separately if they underwent bilateral adrenalectomy (Adx). RESULTS: Twenty patients (53%) were treated with Adx and SRS (median margin dose, 25 Gy) and 18 patients (47%) received SRS alone (median margin dose, 22.5 Gy). Median follow-up after SRS was 76 mo. Of patients undergoing Adx, 18/20 (90%) had a favorable outcome. Two patients (10%) had tumor growth requiring additional treatment. A favorable outcome was achieved in 13/18 patients (72%) having SRS alone (median, 14 mo; interquartile range, 8-23). Five patients (28%) required additional treatment due to persistent hypercortisolemia (n = 4) or hypercortisolemia and tumor growth (n = 1). Favorable outcomes were more frequent in the Adx and SRS group at 1 yr (100% vs 33%; P < .001) and 3 yr (100% vs 62%; P < .01), but no different at 5 yr (88% vs 77%; P = .63). CONCLUSION: SRS was effective for patients with persistent or recurrent CD. Patients with mild to moderate CD can be safely managed with SRS alone; patients with severe CD should be considered for Adx with either concurrent SRS or SRS performed at a later date if tumor growth occurs.

Is There a Need for a 6-Month Postradiosurgery Magnetic Resonance Imaging in the Treatment of Vestibular Schwannoma?

BACKGROUND: Stereotactic radiosurgery (SRS) is a common treatment modality for vestibular schwannoma (VS), with a role in primary and recurrent/progressive algorithms. At our institution, routine magnetic resonance imaging (MRI) is obtained at 6 and 12 mo following SRS for VS. OBJECTIVE: To analyze the safety and financial impact of eliminating the 6-mo post-SRS MRI in asymptomatic VS patients. METHODS: A prospectively maintained SRS database was retrospectively reviewed for VS patients with 1 yr of post-treatment follow-up, 2005 to 2015. Decisions at 6-mo MRI were binarily categorized as routine follow-up vs clinical action-defined as a clinical visit, additional imaging, or an operation as a direct result of the 6-mo study. RESULTS: A total of 296 patients met screening criteria, of whom 53 were excluded for incomplete follow-up and 8 for NF-2. Nine were reimaged prior to 6 mo due to clinical symptoms. Routine 6-mo post-SRS MRI was completed by 226 patients (76% of screened cohort), following from which zero instances of clinical action occurred. When scaled using national insurance database-derived financials-which estimated the mean per-study charge for MRI of the brain with and without contrast at $1767-the potential annualized national charge reduction was approximated as $1 611 504. CONCLUSION: For clinically stable VS, 6-mo post-SRS MRI does not contribute significantly to management. We recommend omitting routine MRI before 12 mo, in patients without new or progressive neurological symptoms. If extrapolated nationally to the more than 100 active SRS centers, thousands of patients would be spared an inconvenient, nonindicated study, and national savings in health care dollars would be on the order of millions annually.

Transsylvian, Carotid-Oculomotor Triangle Approach for Resection of a Rapidly Enlarging Midbrain-Pontine Cavernous Malformation: 3-Dimensional Operative Video.

Cavernous malformations (CM) of the anterior midbrain are best reached through an orbitozygomatic (OZ) approach with removal of the orbital rim and wide Sylvian fissure dissection. Our surgical video demonstrates this approach to resect a ruptured CM in a 36-yr-old woman who presented with headaches, left face and left arm paresthesias/weakness, and right-sided partial oculomotor nerve (CN III) palsy. Initial magnetic resonance imaging (MRI) showed a midbrain CM, and the patient was managed conservatively. However, 1 wk later, she presented again with worsened left arm and leg weakness and complete CN III palsy. Seven Tesla MRI demonstrated a larger hematoma, and the CM with new mass effect and upper pons extension. The patient underwent a right modified OZ craniotomy and Sylvian fissure split under guidance of intraoperative neuronavigation and with neuromonitoring. The carotid-oculomotor triangle and the Liliequist membrane were dissected to access the midbrain, and CN III was identified and followed posteriorly to the midbrain. Confirmed with neuronavigation, a longitudinal incision of the midbrain was performed, and the CM was encountered. The hematoma and CM were debulked and removed in a piece-meal fashion, leaving hemosiderin-stained brain intact to prevent unnecessary additional damage to the midbrain. Postoperative MRI confirmed gross-total resection, and the patient's weakness recovered substantially. In this video, we demonstrate that the brainstem is no longer forbidden surgical territory, and show how the use of neuronavigation for surgical planning, positioning, and approach, in addition to the understanding of safe entry zones and meticulous microsurgical technique have made safe and effective surgery on the brainstem possible.

Esthesioneuroblastoma and Olfactory Preservation: Is it Reasonable to Attempt Smell Preservation?

Objective Olfactory preservation after resection of esthesioneuroblastoma (ENB) has been reported, however, the ability to predict tumor involvement of the olfactory system is critical to this surgical strategy. This study aims to answer the question: Can a surgeon predict, based on preoperative imaging, whether there is unilateral involvement of the olfactory system allowing for safe attempt of olfactory preservation? Methods This is a retrospective review of post-resection ENB meeting inclusion criteria of having bilateral olfactory tracts and bulbs submitted at the time of primary resection for pathologic margins. Five board-certified skull base surgeons blinded to the pathology individually reviewed the preoperative MRI scans to predict degree of tumor involvement. Results Olfactory bulb involvement occurred in both bulbs in 35% of cases and unilateral in 39% of cases, and there was no involvement in 26% of cases sampled. When comparing physician prediction of involved tracts or bulbs, involvement was appropriate or over-called (i.e., called positive when pathology was in fact negative) in 96% of cases. Conclusion This study demonstrates unilateral or no pathologic olfactory involvement of the olfactory system in 65% of cases. Our ability to predict this involvement, which may allow for a management strategy that attempts to preserve olfactory function, was accurate at 96%. Therefore, interpretation of imaging and proceeding with smell preservation in ENB appears reasonable in this cohort. LEVEL OF EVIDENCE: Level 2b.

Beyond Gross Total and Subtotal: Does Volumetric Resection Matter in Nonfunctioning Pituitary Macroadenomas?

INTRODUCTION: No study has volumetrically examined resection degree and recurrence in pituitary macroadenoma (PMA). We analyzed the impact of volumetric tumor resection on prediction of tumor recurrence and retreatment in a cohort of patients with nonfunctioning PMA ≥2 cm. METHODS: Records were reviewed from 1998-2008 for patients with null cell or nonsecreting PMA ≥2 cm. Inclusion criteria were surgically resected PMA and ≥4 years' follow-up or recurrence before 4 years. Seventy-eight patients were found. PMA tissue volume preoperatively and postoperatively was quantified by a board-certified neuroradiologist. Extent of resection (EOR) was calculated. The primary end point was tumor recurrence with a secondary end point of treated tumor recurrence. RESULT: Median age was 58 (20-85). Forty-one (53%) had no tumor recurrence at a median of 113 (48-203) months. Thirty-seven (47%) patients had tumor recurrence with a median time of 55 (9-176) months. On univariate analysis, increasing age, decreasing preoperative and postoperative volumes, and increasing EOR were statistically significant for decreasing the risk of recurrence or treated recurrence. On multivariate analysis, only age and EOR remained significant. Receiver operating characteristic showed EOR <86% was associated with PMA regrowth. Kaplan-Meier analysis demonstrated a statistically significant difference for recurrence comparing groups by EOR ≥86% or <85%. CONCLUSIONS: We found younger age and increasing EOR are significant predictors of tumor regrowth and retreatment. These results indicate EOR assessment may have a role in large PMA. Further study with volumetric analysis is needed in a larger cohort of patients.

Estimating the Global Incidence of Aneurysmal Subarachnoid Hemorrhage: A Systematic Review for Central Nervous System Vascular Lesions and Meta-Analysis of Ruptured Aneurysms.

INTRODUCTION: There is increasing acknowledgement that surgical care is important in global health initiatives. In particular, neurosurgical care is as limited as 1 per 10 million people in parts of the world. We performed a systematic literature review to examine the worldwide incidence of central nervous system vascular lesions and a meta-analysis of aneurysmal subarachnoid hemorrhage (aSAH) to define the disease burden and inform neurosurgical global health efforts. METHODS: A systematic review and meta-analysis were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to estimate the global epidemiology of central nervous system vascular lesions, including unruptured and ruptured aneurysms, arteriovenous malformations, cavernous malformations, dural arteriovenous fistulas, developmental venous anomalies, and vein of Galen malformations. Results were organized by World Health Organization regions. After literature review, because of a lack of data from particular World Health Organization regions, we determined we could only provide an estimate of aSAH. Using data from studies with aSAH and 12 high-quality stroke studies from regions lacking data, we meta-analyzed the yearly crude incidence of aSAH per 100,000 persons. Estimates were generated via random-effects models. RESULTS: From an initial yield of 1492 studies, 46 manuscripts on aSAH incidence were included. The final meta-analysis included 58 studies from 31 different countries. We estimated the global crude incidence for aSAH to be 6.67 per 100,000 persons with a wide variation across WHO regions from 0.71 to 12.38 per 100,000 persons. CONCLUSIONS: Worldwide, almost 500,000 individuals will suffer from aSAH each year, with almost two-thirds in low- and middle-income countries.

Diagnosis and Outcome of Biopsies of Indeterminate Lesions of the Cavernous Sinus and Meckel's Cave: A Retrospective Case Series in 85 Patients.

BACKGROUND: When clinical presentation, laboratory studies, or imaging cannot diagnose cavernous sinus (CS) and/or Meckel's cave (MC) lesions, biopsy may be necessary. OBJECTIVE: To review our institutional series of biopsies of indeterminate CS and MC lesions. METHODS: Records from January 1994 to June 2016 were searched for biopsied indeterminate CS and MC lesions. We defined indeterminate as having an atypical imaging appearance or a broad differential and the need for tissue for definitive diagnosis. We defined primary tumors as originating from cells inherent or near the CS and MC. RESULTS: Eighty-five patients were included (median age 59 [2-85] yr); 22 (28%) had a cancer history. Approaches included frontotemporal craniotomy (n = 48, 56%), endoscopic endonasal (n = 20, 24%), percutaneous transforamen ovale (n = 12, 14%), or retrosigmoid craniotomy (n = 5, 6%). Final diagnosis was metastatic in 27 (32%), primary in 21 (25%), inflammatory in 13 (15%), hematologic in 11 (13%), fungal in 5 (5%), and nondefinitive or nondiagnostic in 8 (10%) patients. Thirteen (59%) patients with a cancer history (n = 22) had a diagnosis consistent with their prior cancer; the remaining had a second pathology (n = 6, 27%) or nondiagnostic biopsy (n = 3, 14%). Two patients had surgical complications resulting in death. CONCLUSION: In this patient cohort, metastatic tumors were the most likely pathology. The biopsy threshold should be lower in patients with a cancer history if clinical or radiographic diagnosis is uncertain as 27% had a second disease. However, we consider biopsy as a last resort because the risk of major morbidity/mortality, while low, is not zero.

Adult Pilocytic Astrocytoma: An Institutional Series and Systematic Literature Review for Extent of Resection and Recurrence.

INTRODUCTION: Pilocytic astrocytoma is a classically benign tumor that most often affects pediatric patients. Rarely, it occurs during adulthood. We present a case series and systematic literature review of adult pilocytic astrocytoma (APA) to examine the clinical presentation, extent of resection, and recurrence rate associated with this tumor in this population. MATERIALS AND METHODS: Our institutional records were retrospectively reviewed for cases of pilocytic astrocytoma in adults. A PubMed search identified English-language studies of pathology-proven APA. A meta-analysis was performed to determine the relationship between extent of tumor resection and recurrence. RESULTS: Forty-six patients with APA were diagnosed at our institution (mean age 33.6 ± 13.3; 24 [52%] female). Twenty-four patients (52%) underwent gross total resection, 11 (24%) subtotal resection, 4 (9%) near total resection, 4 (9%) observation after biopsy, and 3 (6%) radiotherapy alone. Tumors recurred or progressed in 6 (13%) patients, of whom 4 were treated by STR and 2 were treated by radiotherapy alone. Thirty-nine (95%) patients were still alive at last follow-up. A systematic literature review identified 415 patients with APA in 38 studies. Including our case series, 7 studies reported extent of resection, follow-up, and recurrence. Of 254 patients with a weighted mean follow-up of 77.7 ± 49.6 (31-250) months, 129 (51%) were treated with gross total resection, and 125 (49%) underwent subtotal resection. Tumor recurred in 79 (31%) patients, 22 (27%) after gross total resection and 57 (73%) after subtotal resection (P < 0.001). CONCLUSIONS: Pilocytic astrocytoma rarely presents during adulthood. Overall, prognosis is favorable and survival rates are high. APA recurrence is more likely after STR, and the goal of surgery should always be GTR when feasible.

Effect of body mass index on outcome after aneurysmal subarachnoid hemorrhage treated with clipping versus coiling.

OBJECTIVE It has been suggested that increased body mass index (BMI) may confer a protective effect on patients who suffer from aneurysmal subarachnoid hemorrhage (aSAH). Whether the modality of aneurysm occlusion influences the effect of BMI on patient outcomes is not well understood. The authors aimed to compare the effect of BMI on outcomes for patients with aSAH treated with surgical clipping versus endovascular coiling. METHODS The authors retrospectively reviewed the outcomes for patients admitted to their institution for the management of aSAH treated with either clipping or coiling. BMI at the time of admission was recorded and used to assign patients to a group according to low or high BMI. Cutoff values for BMI were determined by classification and regression tree analysis. Predictors of poor functional outcome (defined as modified Rankin Scale score > 2 measured ≥ 90 days after the ictus) and posttreatment cerebral hypodensities detected during admission were then determined separately for patients treated with clipping or coiling using stepwise multivariate logistic regression analysis. RESULTS Of the 469 patients admitted to the authors' institution with aSAH who met the study's inclusion criteria, 144 were treated with clipping and 325 were treated with coiling. In the clipping group, the frequency of poor functional outcome was higher in patients with BMI ≥ 32.3 kg/m2 (47.6% vs 19.0%; p = 0.007). In contrast, in the coiling group, patients with BMI ≥ 32.3 kg/m2 had a lower frequency of poor functional outcome at ≥ 90 days (5.8% vs 30.9%; p < 0.001). On multivariate analysis, high BMI was independently associated with an increased (OR 3.92, 95% CI 1.20-13.41; p = 0.024) and decreased (OR 0.13, 95% CI 0.03-0.40; p < 0.001) likelihood of poor functional outcome for patients treated with clipping and coiling, respectively. For patients in the surgical group, BMI ≥ 28.4 kg/m2 was independently associated with incidence of cerebral hypodensities during admission (OR 2.44, 95% CI 1.16-5.25; p = 0.018) on multivariate analysis. For patients treated with coiling, BMI ≥ 33.2 kg/m2 was independently associated with reduced odds of hypodensities (OR 0.45, 95% CI 0.21-0.89; p = 0.021). CONCLUSIONS The results of this study suggest that BMI may differentially affect functional outcomes after aSAH, depending on treatment modality. These findings may aid in treatment selection for patients with aSAH.

Trends in Management of Intracranial Meningiomas: Analysis of 49,921 Cases from Modern Cohort.

OBJECTIVE: We sought to characterize patterns and treatment for intracranial meningiomas in the Surveillance, Epidemiology, and End Results set of cancer registries. METHODS: SEER data was queried from 2004-2012 for cases of intracranial meningioma using appropriate topography and histology codes. RESULTS: A total of 49,921 patients with intracranial meningioma were identified. The vast majority of cases were associated with a benign histology (n = 47,047, 94.2%). There were 21,145 patients (42.4%) who underwent surgical management, 2783 who received radiation alone (5.6%), and 25,993 who underwent surveillance only (52.1%). Surgical management decreased in frequency from 48.8% of all cases in 2004 to 38.3% of cases in 2012 (P < 0.001). Radiation alone remained stable over time with a range of 4.8%-6.3% of cases. Observation increased from 45.0% of cases in 2004 to 56.7% of cases in 2012 (P < 0.001). On unadjusted analysis, surgical management was associated with younger age and larger tumor size. The incidence of tumors <2 cm in size increased significantly over the study period from 29.7% in 2004 to 41.7% in 2012 (P < 0.001). After adjusting for tumor size, multivariable analysis demonstrated that the odds of observation as a primary management strategy were greater in 2012 relative to 2004 (odds ratio 1.33, 95% confidence interval 1.21-1.45). CONCLUSION: The incidence of intracranial meningiomas increased, while tumor size at the time of diagnosis decreased. Moreover, the number undergoing no treatment increased as a treatment strategy and was more likely employed for older patients, those of African-American race, and those with smaller tumors.

Slip interface imaging based on MR-elastography preoperatively predicts meningioma-brain adhesion.

PURPOSE: To investigate the ability of slip interface imaging (SII), a recently developed magnetic resonance elastography (MRE)-based technique, to predict the degree of meningioma-brain adhesion, using findings at surgery as the reference standard. MATERIALS AND METHODS: With Institutional Review Board approval and written informed consent, 25 patients with meningiomas >2.5 cm in maximal diameter underwent preoperative SII assessment. Intracranial shear motions were introduced using a soft, pillow-like head driver and the resulting displacement field was acquired with an MRE pulse sequence on 3T MR scanners. The displacement data were analyzed to determine tumor-brain adhesion by assessing intensities on shear line images and raw as well as normalized octahedral shear strain (OSS) values along the interface. The SII findings of shear line images, OSS, and normalized OSS were independently and blindly correlated with surgical findings of tumor adhesion by using the Cohen's κ coefficient and chi-squared test. RESULTS: Neurosurgeons categorized the surgical plane as extrapial (no adhesion) in 15 patients, mixed in four, and subpial (adhesion) in six. Both shear line images and OSS agreed with the surgical findings in 18 (72%) cases (fair agreement, κ = 0.37, 95% confidence interval [CI]: 0.05-0.69), while normalized OSS was concordant with the surgical findings in 23 (92%) cases (good agreement, κ = 0.86, 95% CI: 0.67-1). The correlation between SII predictions (shear line images, OSS, and normalized OSS) and the surgical findings were statistically significant (chi-squared test, P = 0.02, P = 0.02, and P < 0.0001, respectively). CONCLUSION: SII preoperatively evaluates the degree of meningioma-brain adhesion noninvasively, allowing for improved prediction of surgical risk and tumor resectability. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1007-1016.

Orbitofrontal Cholesterol Granuloma: Four Case Reports and a Systematic Review of the English Literature.

INTRODUCTION: Primary orbitofrontal cholesterol granuloma (OFCG) is rare. We present 4 cases of OFCG and a systematic literature review to examine patient characteristics, presentation, treatment, and outcome. METHODOLOGY: Our institutional records were reviewed for OFCG cases. A systematic literature review was performed using PubMed. Inclusion criteria were English-language studies with pathology-proven OFCG. Exclusion criteria were OFCG in a craniofacial sinus. The search-string yielded 172 results. Fifty studies met inclusion criteria (39 primary and 11 secondary), and relevant data were reviewed. RESULTS: Four patients underwent surgery for OFCG at our institution (ages 53, 43, 34, and 43; 3 females, 1 male). All patients were treated with surgery using a tailored frontal-orbital craniotomy with complete resection. There was no recurrence at 12-month, 4-year, 10-year, and 22-year follow-up for each patient, respectively. Systematic review of the literature identified 172 patients. Follow-up was available in 93 patients (54.1%) with a mean follow-up of 43.3 months. Seven patients demonstrated recurrence at a median of 36 months following surgery. Combining our 4 cases with the 93 patients with reported follow-up gives a recurrence rate of 7% (7/97). Recurrence was associated with incomplete resection and an orbital approach. CONCLUSION: Thorough removal of the lesion with curettage of the boney cavity is recommended for OFCG. Recurrence following complete removal of OFCG is rare.

Magnetic resonance elastography detects tumoral consistency in pituitary macroadenomas.

INTRODUCTION: Most pituitary macroadenomas (PMA) are soft and suckable allowing transsphenoidal resection. A small percentage of PMA are firm, which significantly alters the time, technical difficulty, and effectiveness of transsphenoidal surgery. No current imaging technology can reliably assess PMA viscoelastic consistency in preparation for surgery. Magnetic resonance elastography (MRE) is an MRI-based technique that measures the propagation of mechanically induced shear waves through tissue to calculate stiffness. We prospectively evaluated MRE in 10 patients undergoing transsphenoidal resection of PMA to determine feasibility and potential usefulness. METHODS: 10 patients with PMA > 2.0 cm in maximum diameter were prospectively imaged with MRE prior to transsphenoidal surgery. Mean patient age was 59.5 ± 16.2 (22-78) years. Five were female and five male. MRE was performed with a modified single-shot spin-echo echo-planar-imaging pulse sequence on a 3T MRI. MRE values were independently calculated. The surgeon, blinded to the MRE results, graded tumor consistency at surgery as soft, intermediate, or firm. Chi-squared test compared surgical grading and MRE stiffness values. RESULTS: MRE was accomplished in all patients with excellent resolution. By surgical categorization, six tumors were soft and four intermediate. The mean MRE value for soft tumors was 1.38 ± 0.36 (1.08-1.87) kPa, while for intermediate tumors it was 1.94 ± 0.26 (1.72-2.32) kPa (p = 0.020). CONCLUSION: Determination of PMA stiffness is feasible with MRE. There was a statistically significant difference in MRE values between soft and intermediate PMAs. Further study in a larger series is ongoing to determine whether MRE will prove useful in preoperative planning for PMA.

Slip Interface Imaging Predicts Tumor-Brain Adhesion in Vestibular Schwannomas.

PURPOSE: To test the clinical feasibility and usefulness of slip interface imaging (SII) to identify and quantify the degree of tumor-brain adhesion in patients with vestibular schwannomas. MATERIALS AND METHOD: S With institutional review board approval and after obtaining written informed consent, SII examinations were performed in nine patients with vestibular schwannomas. During the SII acquisition, a low-amplitude mechanical vibration is applied to the head with a pillow-like device placed in the head coil and the resulting shear waves are imaged by using a phase-contrast pulse sequence with motion-encoding gradients synchronized with the applied vibration. Imaging was performed with a 3-T magnetic resonance (MR) system in less than 7 minutes. The acquired shear motion data were processed with two different algorithms (shear line analysis and calculation of octahedral shear strain [OSS]) to identify the degree of tumor-brain adhesion. Blinded to the SII results, neurosurgeons qualitatively assessed tumor adhesion at the time of tumor resection. Standard T2-weighted, fast imaging employing steady-state acquisition (FIESTA), and T2-weighted fluid-attenuated inversion recovery (FLAIR) imaging were reviewed to identify the presence of cerebral spinal fluid (CSF) clefts around the tumors. The performance of the use of the CSF cleft and SII to predict the degree of tumor adhesion was evaluated by using the κ coefficient and McNemar test. RESULTS: Among the nine patients, SII agreed with the intraoperative assessment of the degree of tumor adhesion in eight patients (88.9%; 95% confidence interval [CI]: 57%, 98%), with four of four, three of three, and one of two cases correctly predicted as no adhesion, partial adhesion, and complete adhesion, respectively. However, the T2-weighted, FIESTA, and T2-weighted FLAIR images that used the CSF cleft sign to predict adhesion agreed with surgical findings in only four cases (44.4% [four of nine]; 95% CI: 19%, 73%). The κ coefficients indicate good agreement (0.82 [95% CI: 0.5, 1]) for the SII prediction versus surgical findings, but only fair agreement (0.21 [95% CI: -0.21, 0.63]) between the CSF cleft prediction and surgical findings. However, the difference between the SII prediction and the CSF cleft prediction was not significant (P = .103; McNemar test), likely because of the small sample size in this study. CONCLUSION: SII can be used to predict the degree of tumor-brain adhesion of vestibular schwannomas and may provide a method to improve preoperative planning and determination of surgical risk in these patients.

Risk factors for hydrocephalus requiring external ventricular drainage in patients with intraventricular hemorrhage.

OBJECT: External ventricular drainage (EVD) after intraventricular hemorrhage (IVH) without symptomatic hydrocephalus is controversial. The object of this study was to examine indicators or the timeframe for hydrocephalus in patients not immediately treated with EVD after IVH. METHODS: Records from 2007 to 2014 were searched for "intraventricular hemorrhage" or "IVH." Inclusion criteria were IVH after intracerebral hemorrhage (ICH), trauma, tumor, or vascular anomalies. Exclusion criteria were IVH with more than minimal subarachnoid hemorrhage, catastrophic ICH, layering IVH only, or hydrocephalus treated immediately with EVD. IVH was measured with the modified Graeb Score (mGS). An mGS of 5 indicates a full ventricle with dilation. Statistics included chi-square, Student's t-test, and Mann-Whitney tests; receiver operating characteristics; and uni- and multivariate logistic regression. RESULTS: One hundred five patients met the criteria; of these, 30 (28.6%) required EVD. Panventricular IVH was the most common pattern (n = 49, 46.7%), with 25 of these patients (51%) requiring EVD. The median mGS was 18 ± 5.4 (range 12-29) and 9 ± 4.5 (range 2-21) in the EVD and No-EVD groups, respectively (p < 0.001). Factors associated with EVD were radiological hydrocephalus at presentation, midline shift > 5 mm, Glasgow Coma Scale (GCS) score < 8, mGS > 13, third ventricle mGS = 5, and fourth ventricle mGS = 5. On multivariate analysis, GCS score < 8 [4.02 (range 1.13-14.84), p = 0.032], mGS > 13 [3.83 (range 1.02-14.89), p = 0.046], and fourth ventricle mGS = 5 [5.01 (range 1.26-22.78), p = 0.022] remained significant. Most patients treated with EVD (n = 25, 83.3%) required it soon after presentation [6.4 ± 3.3 (range 1.5-14) hrs]. The remaining 5 patients (16.7%) had a delayed EVD requirement [70.7 ± 22.7 (range 50-104.5) hrs]. CONCLUSIONS: In this study population, the risk for EVD was variable, but greater with mGS > 13, coma, and a dilated fourth ventricle. While the need for EVD occurs within the 1st day after IVH in most patients, a minority require EVD after 48 hours.

Incidentally Discovered Unruptured AICA Aneurysm After Radiosurgery for Vestibular Schwannoma: A Case Report and Review of the Literature.

OBJECTIVE: This is a case report and review of the literature of aneurysm formation after stereotactic radiosurgery (SRS) in the posterior fossa. Cerebral aneurysm formation is not a commonly recognized complication of SRS. We present the first case of an unruptured anteroinferior cerebellar artery aneurysm incidentally found at surgery in a patient with trigeminal neuralgia secondary to a vestibular schwannoma (VS) first treated with Gamma Knife radiosurgery. Other cases of posterior fossa aneurysms associated with SRS and the pathogenesis of vascular injury by radiation are discussed. PATIENT: A 57-year-old woman with medically intractable severe trigeminal neuralgia secondary to a 1.4-cm VS treated with SRS 10 years previously at an outside institution. INTERVENTION: The patient underwent a left retrosigmoid craniotomy for tumor debulking. MAIN OUTCOME AND RESULTS: During resection, two small aneurysms on the tumor's ventral side arising from the main trunk of the anteroinferior cerebellar artery were encountered and treated with direct clip ligation, sparing the parent vessel. The patient did well after surgery and was discharged home on Hospital Day 4 at her neurologic baseline, with normal facial nerve function and without trigeminal pain. CONCLUSION: Although aneurysms associated with posterior fossa SRS are rare, there are at least seven reports, including the current case, in the past decade. Because the relationship between radiation and aneurysm formation is unproven and controversial, further study, especially examining long-term effects, is needed. Given the overall rarity and uncertain association between SRS and aneurysm formation, we do not recommend routine aneurysm surveillance screening in patients undergoing Gamma Knife radiosurgery for VS. Surgeons should be aware of the rare possibility of encountering an aneurysm during surgical exploration in patients with VS who fail SRS.

Higher-Resolution Magnetic Resonance Elastography in Meningiomas to Determine Intratumoral Consistency.

BACKGROUND: Magnetic resonance elastography (MRE) analyzes shear wave movement through tissue to determine stiffness. In a prior study, measurements with first-generation brain MRE techniques correlated with intraoperative observations of overall meningioma stiffness. OBJECTIVE: To evaluate the diagnostic accuracy of a higher-resolution MRE technique to preoperatively detect intratumoral variations compared with surgeon assessment. METHODS: Fifteen meningiomas in 14 patients underwent MRE. Tumors with regions of distinctly different stiffness were considered heterogeneous. Intratumoral portions were considered hard if there was a significant area ≥6 kPa. A 5-point scale graded intraoperative consistency. A durometer semiquantitatively measured surgical specimen hardness. Statistics included χ, sensitivity, specificity, positive and negative predicative values, and Spearman rank correlation coefficient. RESULTS: For MRE and surgery, 9 (60%) and 7 (47%) tumors were homogeneous, 6 (40%) and 8 (53%) tumors were heterogeneous, 6 (40%) and 10 (67%) tumors had hard portions, and 14 (93%) and 12 (80%) tumors had soft portions, respectively. MRE sensitivity, specificity, and positive and negative predictive values were as follows: for heterogeneity, 75%, 100%, 100%, and 87%; for hardness, 60%, 100%, 100%, and 56%; and for softness, 100%, 33%, 86%, and 100%. Overall, 10 tumors (67%) matched well with MRE and intraoperative consistency and correlated between intraoperative observations (P = .02) and durometer readings (P = .03). Tumor size ≤3.5 cm or vascular tumors were more likely to be inconsistent (P < .05). CONCLUSION: MRE was excellent at ruling in heterogeneity with hard portions but less effective in ruling out heterogeneity and hard portions, particularly in tumors more vascular or <3.5 cm. MRE is the first technology capable of prospectively evaluating intratumoral stiffness and, with further refinement, will likely prove useful in preoperative planning.

Body Mass Index and Aneurysmal Subarachnoid Hemorrhage: Decreasing Mortality with Increasing Body Mass Index.

BACKGROUND: Labeled the "obesity paradox," obesity has been shown to provide a survival advantage in coronary artery disease, stroke, and intracerebral hemorrhage. Studies on body mass index (BMI) in aneurysmal subarachnoid hemorrhage (SAH) show conflicting results and none examined a North American population with long-term follow-up. METHODS: A total of 305 consecutive SAH patients (2002 to 2011) were retrospectively reviewed to collect demographics, BMI (kg/m(2)), comorbidities, Glascow Coma Scale, World Federation of Neurologic Surgeons Scale, aneurysm treatment, delayed cerebral ischemia, radiographic infarction, and short-term and long-term (> 24 months) morbidity, and mortality. Patients were stratified by BMI into category 1, < 25 kg/m(2); category 2, 25 -< 30 kg/m(2); and category 3, ≥ 30 kg/m(2). RESULTS: Categories 1, 2, and 3 had 93, 100, and 87 patients with mean BMIs of 22.4 ± 1.8, 27.6 ± 1.4, and 35.7 ± 4.6 (P < 0.05), respectively. By category, 24-month follow-up was available in 92%, 85%, and 85%. Category 3 had more hypertension, diabetes mellitus, and clipping than category 1. Short-term mortality rates were 17%, 12%, and 8%; long-term mortality rates were 34%, 26%, and 19% (P > 0.05 at all points between categories 1 vs. 3, but not 1 vs. 2 or 2 vs. 3). On univariate analysis, BMI was inversely associated with short-term (odds ratio, 0.91; 95% confidence interval 0.84-0.98; P = 0.009) and long-term (odds ratio, 0.92; 95% confidence interval 0.87-0.97; P = 0.001) mortality. On multivariate analysis including age, World Federation of Neurologic Surgeons Scale, delayed cerebral ischemia, and radiographic infarction, BMI remained significant for short-term (odds ratio, 0.91; 95% confidence interval 0.81-0.99; P = 0.047) and long-term (odds ratio, 0.92; 95% confidence interval 0.85-0.98; P = 0.021) mortality. On Kaplan-Meier survival analysis, P > 0.05 for categories 1 versus 2 and 2 versus 3, but P = 0.005 for categories 1 versus 3. CONCLUSIONS: In our SAH population, higher BMI resulted in less short-term and long-term mortality, but no difference in functional outcome.