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Background: To date, few data are available on the cognitive function of patients with vestibular schwannoma (VS) before treatment., Objective: To provide a cognitive profile of patients with VS., Methods: This cross-sectional observational study recruited 75 patients with an untreated VS and 60 age-, sex-, and education-matched healthy control subjects. A set of neuropsychological tests were administered to each participant., Results: Compared with the matched controls, patients with VS exhibited impaired general cognitive function, memory, psychomotor speed, visuospatial ability, attention and processing speed, and executive function. The subgroup analyses displayed that patients with severe-to-profound unilateral hearing loss were more cognitively impaired than patients with no-to-moderate unilateral hearing loss. In addition, patients with right-sided VS scored worse than those with left-sided VS on tests of memory, attention and processing speed, and executive function. No differences were observed in cognitive performance between patients with or without brainstem compression and those with or without tinnitus. We also found that worse hearing and longer hearing loss duration were associated with poorer cognitive performance in patients with VS., Conclusion: The findings of this study provide evidence for cognitive impairment in patients with untreated VS. It can thus be said that including cognitive assessment in the routine clinical management of patients with VS may facilitate more appropriate clinical decision-making and improve patients' quality of life., (Copyright © Congress of Neurological Surgeons 2023. All rights reserved.)

Background: Vestibular schwannomas (VSs) related to neurofibromatosis type 2 (NF2) are challenging tumors. The increasing use of stereotactic radiosurgery (SRS) necessitates further investigations of its role and safety., Objective: To evaluate tumor control, freedom from additional treatment (FFAT), serviceable hearing preservation, and radiation-related risks of patients with NF2 after SRS for VS., Methods: We performed a retrospective study of 267 patients with NF2 (328 VSs) who underwent single-session SRS at 12 centers participating in the International Radiosurgery Research Foundation. The median patient age was 31 years (IQR, 21-45 years), and 52% were male., Results: A total of 328 tumors underwent SRS during a median follow-up time of 59 months (IQR, 23-112 months). At 10 and 15 years, the tumor control rates were 77% (95% CI: 69%-84%) and 52% (95% CI: 40%-64%), respectively, and the FFAT rate were 85% (95% CI: 79%-90%) and 75% (95% CI: 65%-86%), respectively. At 5 and 10 years, the serviceable hearing preservation rates were 64% (95% CI: 55%-75%) and 35% (95% CI: 25%-54%), respectively. In the multivariate analysis, age (hazards ratio: 1.03 [95% CI: 1.01-1.05]; P = .02) and bilateral VSs (hazards ratio: 4.56 [95% CI: 1.05-19.78]; P = .04) were predictors for serviceable hearing loss. Neither radiation-induced tumors nor malignant transformation were encountered in this cohort., Conclusion: Although the absolute volumetric tumor progression rate was 48% at 15 years, the rate of FFAT related to VS was 75% at 15 years after SRS. None of the patients with NF2-related VS developed a new radiation-related neoplasm or malignant transformation after SRS., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Congress of Neurological Surgeons.)

Background: Previous studies comparing hearing outcomes in patients managed with stereotactic radiosurgery (SRS) and a watch-and-wait strategy were limited by small sample sizes that prevented controlling for potential confounders, including initial hearing status, tumor size, and age., Objective: To compare hearing outcomes for patients with vestibular schwannomas (VS) managed with observation and SRS while controlling for confounders with propensity score matching., Methods: Propensity score matching was used to compare 198 patients with unilateral VS with initial serviceable hearing (99 treated with SRS and 99 managed with observation alone) and 116 with initial class A hearing (58 managed with SRS and 58 with observation), matched by initial hearing status, tumor volume, age, and sex. Kaplan-Meier survival methods were used to compare risk of losing class A and serviceable hearing., Results: Between patients with VS managed with SRS or observation alone, there was no significant difference in loss of class A hearing (median time 27.2 months, 95% CI 16.8-43.4, and 29.2 months, 95% CI 20.4-62.5, P = .88) or serviceable hearing (median time 37.7 months, 95% CI 25.7-58.4, and 48.8 months, 95% CI 38.4-86.3, P = .18). For SRS patients, increasing mean cochlear dose was not related to loss of class A hearing (hazard ratio 1.3, P = .17) but was associated with increasing risk of serviceable hearing loss (hazard ratio of 1.5 per increase in Gy, P = .017)., Conclusion: When controlling for potential confounders, there was no significant difference in loss of class A or serviceable hearing between patients managed with SRS or with observation alone., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Background: For patients with vestibular schwannoma (VS), stereotactic radiosurgery (SRS) has proven effective in controlling tumor growth while hearing preservation remains a key goal., Objective: To evaluate hearing outcomes in the modern era of cochlear dose restriction., Methods: During the years 2013 to 2018, 353 patients underwent Gamma knife surgery for VS at our institution. We followed 175 patients with pre-SRS serviceable hearing (Gardner-Robertson Score, GR 1 and 2). Volumetric and dosimetry data were collected, including biological effective dose, integral doses of total and intracanalicular tumor components, and hearing outcomes., Results: The mean age was 56 years, 74 patients (42%) had a baseline GR of 2, and the mean cochlear dose was 3.5 Gy. The time to serviceable hearing loss (GR 3-4) was 38 months (95% CI 26-46), with 77% and 62% hearing preservation in the first and second years, respectively. Patients optimal for best hearing outcomes were younger than 58 years with a baseline GR of 1, free canal space ≥0.041 cc (diameter of 4.5 mm), and mean cochlear dose <3.1 Gy. For such patients, hearing preservation rates were 92% by 12 months and 81% by 2 years, staying stable for >5 years post-SRS, significantly higher than the rest of the population., Conclusion: Hearing preservation after SRS for patients with VS with serviceable hearing is correlated to the specific baseline GR score (1 or 2), age, cochlear dose, and biological effective dose. Increased tumor-free canal space correlates with better outcomes. The most durable hearing preservation correlates with factors commonly associated with smaller tumors away from the cochlea., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Background: Patient frailty is predictive of higher neurosurgical morbidity and mortality. However, existing frailty measures are hindered by lack of specificity to neurosurgery., Objective: To analyze the association between 3 risk stratification scores and outcomes for nationwide vestibular schwannoma (VS) resection admissions and develop a custom VS risk stratification score., Methods: We identified all VS resection admissions in the National Inpatient Sample (2002-2017). Three risk stratification scores were analyzed: modified Frailty Index-5, modified Frailty Index-11(mFI-11), and Charlson Comorbidity Index (CCI). Survey-weighted multivariate regression evaluated associations between frailty and inpatient outcomes, adjusting for patient demographics, hospital characteristics, and disease severity. Subsequently, we used k -fold cross validation and Akaike Information Criterion-based model selection to create a custom risk stratification score., Results: We analyzed 32 465 VS resection admissions. High frailty, as identified by the mFI-11 (odds ratio [OR] = 1.27, P = .021) and CCI (OR = 1.72, P < .001), predicted higher odds of perioperative complications. All 3 scores were also associated with lower routine discharge rates and elevated length of stay (LOS) and costs (all P < .05). Our custom VS-5 score ( https://skullbaseresearch.shinyapps.io/vs-5&#95;calculator/ ) featured 5 variables (age ≥60 years, hydrocephalus, preoperative cranial nerve palsies, diabetes mellitus, and hypertension) and was predictive of higher mortality (OR = 6.40, P = .001), decreased routine hospital discharge (OR = 0.28, P < .001), and elevated complications (OR = 1.59, P < .001), LOS (+48%, P < .001), and costs (+23%, P = .001). The VS-5 outperformed the modified Frailty Index-5, mFI-11, and CCI in predicting routine discharge (all P < .001), including in a pseudoprospective cohort (2018-2019) of 3885 admissions., Conclusion: Patient frailty predicted poorer inpatient outcomes after VS surgery. Our custom VS-5 score outperformed earlier risk stratification scores., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Background: The wait-and-scan modality has emerged as an important strategy in the management of vestibular schwannoma (VS) as it has been demonstrated that many tumors grow slowly or do not show any growth over long periods., Objective: To analyze long-term outcomes of wait-and-scan in the treatment of patients with VS, discuss the factors contributing to the decision making, determine the inherent risks of the policy, and compare our results with literature., Methods: In total, 576 patients with sporadic unilateral VS who were managed with wait-and-scan were reviewed retrospectively. Of these, a subset of 154 patients with 5-yr follow-up was separately analyzed. The tumor characteristics including patterns of growth, rate of growth, hearing outcomes, and likely factors affecting the above parameters were analyzed., Results: The mean period of follow-up was 36.9 ± 30.2 mo. The mean age was 59.2 ± 11.6 yr. Thirteen different patterns of tumor growth were observed. Eighty-four (54.5%) of 154 tumors with 5-yr follow-up showed no growth throughout 5 yr. Fifty-six (36.4%) tumors showed mixed growth rates. Only 57 (37%) patients had serviceable hearing at the start of follow-up, but 32 (56.1%) maintained it at the end of follow-up. One hundred fifty (26%) of the 576 patients who failed wait-and-scan had to be taken up for surgery., Conclusion: While there may be no price to pay in wait-and-scan as far as hearing is concerned, this may not be the case for facial nerve outcomes, wherein the results may be better if the patients are taken earlier for surgery.

Question 1: What is the expected diagnostic yield for vestibular schwannomas when using a magnetic resonance imaging (MRI) to evaluate patients with previously published definitions of asymmetric sensorineural hearing loss?, Target Population: These recommendations apply to adults with an asymmetric sensorineural hearing loss on audiometric testing., Recommendation: Level 3: On the basis of an audiogram, it is recommended that MRI screening on patients with ≥10 decibels (dB) of interaural difference at 2 or more contiguous frequencies or ≥15 dB at 1 frequency be pursued to minimize the incidence of undiagnosed vestibular schwannomas. However, selectively screening patients with ≥15 dB of interaural difference at 3000 Hz alone may minimize the incidence of MRIs performed that do not diagnose a vestibular schwannoma., Question 2: What is the expected diagnostic yield for vestibular schwannomas when using an MRI to evaluate patients with asymmetric tinnitus, as defined as either purely unilateral tinnitus or bilateral tinnitus with subjective asymmetry?, Target Population: These recommendations apply to adults with subjective complaints of asymmetric tinnitus., Recommendation: Level 3: It is recommended that MRI be used to evaluate patients with asymmetric tinnitus. However, this practice is low yielding in terms of vestibular schwannoma diagnosis (<1%)., Question 3: What is the expected diagnostic yield for vestibular schwannomas when using an MRI to evaluate patients with a sudden sensorineural hearing loss?, Target Population: These recommendations apply to adults with a verified sudden sensorineural hearing loss on an audiogram., Recommendation: Level 3: It is recommended that MRI be used to evaluate patients with a sudden sensorineural hearing loss. However, this practice is low yielding in terms of vestibular schwannoma diagnosis (<3%).  The full guideline can be found at: https://www.cns.org/guidelines/guidelines-management-patients-vestibular-schwannoma/chapter&#95;2., (Copyright © 2017 by the Congress of Neurological Surgeons)

Background: There are limited data on the long-term auditory symptoms in patients with sporadic small- and medium-sized vestibular schwannoma (VS). The initial treatment strategy for VS is controversial., Objective: To characterize auditory symptoms in a large cohort of patients with VS., Methods: Patients with ≤3 cm VS who underwent primary microsurgery, gamma knife surgery, or observation between 1998 and 2008 at 2 independent hospitals were identified. Clinical data were extracted from existing VS databases. At a mean time of 7.7 years after initial treatment, patients were surveyed via mail with the use of the Hearing Handicap Inventory for Adults (HHIA) and the Tinnitus Handicap Inventory., Results: The response rate was 79%; a total of 539 respondents were analyzed. Overall, the hearing prognosis was poor, because more than 75% of all patients had nonserviceable hearing at the last clinical follow-up. Good baseline hearing proved to be a strong predictor for maintained serviceable hearing. Treatment modality was independently associated with both audiometric outcome and HHIA results. Active treatment with microsurgery or gamma knife surgery did not appear to be protective, because patients who were observed had the greatest probability of durable hearing. Patients in the surgical series had the greatest hearing loss. Tinnitus Handicap Inventory results were less predictable. The only predictors of tinnitus handicap were age and HHIA score., Conclusion: The overall prognosis for hearing in sporadic VS is poor regardless of treatment strategy. Treatment modality was an independent predictor of hearing status; observation was associated with the highest rate of hearing preservation. .

Background: Vestibular schwannoma patients with Gardner-Robertson (GR) class I hearing seek to maintain high-level hearing whenever possible., Objective: To evaluate hearing outcomes at 2 to 3 years in GR class I patients who underwent Gamma Knife radiosurgery (GKRS)., Methods: Sixty-eight patients with GR class I hearing were identified between 2006 and 2009. Twenty-five patients had no subjective hearing loss (group A) and 43 patients reported subjective hearing loss (group B) before GKRS. The median tumor volume (1 cm) and tumor margin dose (12.5 Gy) were the same in both groups., Results: Serviceable hearing retention rates (GR grade I or II) were 100% for group A compared with 81% at 1 year, 60% at 2 years, and 57% at 3 years after GKRS for group B patients. Group A patients had significantly higher rates of hearing preservation in either GR class I (P < .001) or GR class II (P < .001). Patients with a pure tone average (PTA) <15 dB before GKRS had significantly higher rates of preservation of GR class I or II hearing., Conclusion: At 2 to 3 years after GKRS, patients without subjective hearing loss or a PTA <15 dB had higher rates of grade I or II hearing preservation. Modification of the GR hearing classification into 2 groups of grade I hearing (group A, those with no subjective hearing loss and a PTA <15 dB; and group B, those with subjective hearing loss and a PTA >15 dB) may be useful to help predict hearing preservation rates at 2 to 3 years after GKRS.

Background: Cochlear dose has been identified as a potentially modifiable contributor to hearing loss after stereotactic radiosurgery (SRS) for vestibular schwannoma (VS)., Objective: To evaluate the association between computed tomography-based volumetric cochlear dose and loss of serviceable hearing after SRS, to assess intraobserver and interobserver reliability when determining modiolar point dose with the use of magnetic resonance imaging and computed tomography, and to discuss the clinical significance of the cochlear dose with regard to radiosurgical planning strategy., Methods: Patients with serviceable pretreatment hearing who underwent SRS for sporadic VS between the use of Gamma Knife Perfexion were studied. Univariate and multivariate associations with the primary outcome of time to nonserviceable hearing were evaluated., Results: A total of 105 patients underwent SRS for VS during the study period, and 59 (56%) met study criteria and were analyzed. Twenty-one subjects (36%) developed nonserviceable hearing at a mean of 2.2 years after SRS (SD, 1.0 years; median, 2.1 years; range 0.6-3.8 years). On univariate analysis, pretreatment pure tone average, speech discrimination score, American Academy of Otolaryngology-Head and Neck Surgery hearing class, marginal dose, and mean dose to the cochlear volume were statistically significantly associated with time to nonserviceable hearing. However, after adjustment for baseline differences, only pretreatment pure tone average was statistically significantly associated with time to nonserviceable hearing in a multivariable model., Conclusion: Cochlear dose is one of many variables associated with hearing preservation after SRS for VS. Until further studies demonstrate durable tumor arrest with reduced dose protocols, routine tumor dose planning should not be modified to limit cochlear dose at the expense of tumor control.

Background: Management of neurofibromatosis type 2 (NF2)-associated vestibular schwannomas (VSs) remains controversial. Stereotactic radiosurgery (SRS) with conventional dosing is less effective for NF2-related VS compared with sporadic lesions., Objective: To evaluate optimal SRS dose parameters for NF2-related VS and to report long-term outcomes., Methods: A prospective database was reviewed and outcome measures, including radiographic progression, American Academy of Otolaryngology-Head and Neck Surgery hearing class, and facial nerve function, were analyzed. Progression-free survival was estimated with Kaplan-Meier methods. Associations between tumor progression and radiosurgical treatment parameters, tumor volume, and patient age were explored with the use of Cox proportional hazards regression., Results: Between 1990 and 2010, 26 patients with 32 NF2-related VSs underwent SRS. Median marginal dose and tumor volume were 14 Gy and 2.7 cm, respectively. Twenty-seven tumors (84%) showed no growth (median follow-up, 7.6 years). Kaplan-Meier estimates for 5- and 10-year progression-free survival were 85% and 80%, respectively. Cox proportional hazards demonstrated a significant inverse association between higher marginal doses and tumor progression (hazard ratio, 0.49; 95% confidence interval, 0.17-0.92; P = .02). Audiometric data were available in 30 ears, with 12 having class A/B hearing before SRS. Only 3 maintained serviceable hearing at the last follow-up. Four underwent cochlear implantation. Initially, 3 achieved open-set speech recognition, although only 1 experienced long-term benefit. Facial nerve function remained stable in 50% of cases., Conclusion: Higher marginal doses than commonly prescribed for sporadic VS were associated with improved tumor control in patients with NF2. Hearing outcomes were poor even when contemporary reduced marginal doses were used. However, SRS allows an anatomically preserved cochlear nerve and may permit hearing rehabilitation with cochlear implantation. Further consideration should be given to optimum dosing to achieve long-term control while maximizing functional outcomes., Abbreviations: HB, House-BrackmannNF2, neurofibromatosis type 2SRS, stereotactic radiosurgeryVS, vestibular schwannoma.

Background: Fractionated stereotactic radiotherapy (FSRT) is a noninvasive treatment for acoustic neuromas (ANs). Initial reports from our institution demonstrated that the reduction of treatment dose to 46.8 Gy resulted in improved preservation of functional hearing status., Objective: We now report the tumor control (TC), symptomatic outcome, and hearing preservation (HP) rate in patients treated with reduced-dose FSRT., Methods: We analyzed all patients with AN treated from 2002 to 2011. All patients received 46.8 Gy in 1.8-Gy fractions. Follow-up audiogram and magnetic resonance imaging were performed in ≤ 1-year intervals. TC and HP were calculated by the Kaplan-Meier method. Analysis of HP, defined as Gardner-Robertson value ≤ 2, was determined by audiometric data. Non-hearing-related symptoms were defined by Common Terminology Criteria for Adverse Events version 4., Results: In total, 154 patients were analyzed. At a median follow-up of 35 months (range, 4-108), TC was achieved in 96% of patients (n = 148/154) and at 3 and 5 years was 99% and 93%. Eighty-seven patients had serviceable hearing at the time of FSRT and evaluable audiometric follow-up. Overall HP was 67% and at 3 and 5 years was 66% and 54%. Pure tone average decreased by a median of 13 dB in all patients. Nineteen percent (n = 31) of patients experienced symptom improvement, and 8% (n = 13) had worsening of symptoms. Cranial nerve dysfunction occurred in 3.8% of patients (n = 6)., Conclusion: Reduced-dose FSRT to 46.8 Gy for AN achieves excellent functional HP rates and limited toxicity without compromising long-term TC. Based on these promising outcomes, further attempts at dose deescalation may be warranted.

Background: As new treatment modalities develop for the management of vestibular schwannomas (VS) in patients with neurofibromatosis type 2, it remains crucial to ascertain the natural history of the disease., Objective: To determine the relationship between hearing and tumor growth in patients undergoing conservative VS management., Methods: Patients harboring bilateral VS with at least 1 year of radiological follow-up were selected. Conservative management was proposed based on the small tumor size and/or serviceable hearing at presentation. Tumor size was calculated by using the 2-component box model and reported as mean tumor diameter. Hearing was evaluated by using pure-tone average and the American Academy of Otololaryngologists and Head and Neck Surgery classification., Results: Forty-six patients harboring 92 VS were included. The mean clinical and radiological follow-up times were 6.0 and 4.2 years, respectively. The mean tumor diameter was 13 mm at presentation and 20 mm at the end of follow-up. Mean tumor growth rate was 1.8 mm/year. During follow-up, 17 patients (37%) underwent surgery for VS. Surgery-free rate for VS was 88% at 5 years. The number of patients with at least 1 serviceable ear was 39 (85%) at presentation and 34 (74%) at the end of follow-up, including 22 (66%) with binaural serviceable hearing maintained. There was no statistical correlation between tumor growth rate and preservation of serviceable hearing. Tumor growth rates and age at presentation were inversely correlated., Conclusion: This study illustrates the high variability among neurofibromatosis type 2 patients regarding hearing status and VS growth rate and justifies the choice of initial conservative management in selected cases., Abbreviations: : AAO-HNS, American Academy of Otololaryngologists and Head and Neck Surgery classificationMTD, mean tumor diameterNF2, neurofibromatosis type 2PTA, pure-tone averageSDS, speech discrimination scoreVS, vestibular schwannomas.

Background: Because only a limited proportion of vestibular schwannomas display growth after diagnosis, an increasing number of patients are managed conservatively. Tumor growth during "wait and scan" may, however, necessitate surgery. In these cases, increased tumor size is likely to increase the risk of impaired facial nerve function after surgery., Objective: To compare facial nerve function in patients operated on soon after diagnosis with patients allocated to conservative management and the subgroup of these who later had surgery because of tumor growth., Methods: A total of 1378 consecutive patients diagnosed with a vestibular schwannoma 20 mm extrameatal or smaller were included; 419 patients were operated on soon after diagnosis, and 959 patients were initially managed conservatively. In the latter group, 161 patients were subsequently operated on owing to tumor growth., Results: All conservatively managed patients had normal facial nerve function at the end of observation. Good facial nerve outcome was found in 87% of patients operated on at diagnosis and in 84% of patients operated on after established tumor growth. For the subgroup of small extrameatal tumors, this difference was significant. When all patients allocated primarily to conservative management were pooled, good facial function was found in 97%, which was significantly better than the result for primary operation (87%)., Conclusion: Overall, conservative management of small to medium-sized vestibular schwannomas is the best option in terms of preservation of facial nerve function. Tumor growth during observation is found in only a minor proportion of the patients, and in these cases, surgery or irradiation should be performed immediately.

Background: Cystic vestibular schwannomas (VSs) are described as being more aggressive than solid tumors., Objective: We examined 468 VS patients to evaluate whether the presence of cystic components in VSs may be an important feature for predicting postoperative outcome., Methods: We selected all VS patients from a prospectively collected database (1984-2009) who underwent microsurgical resection for VS. Hearing data were analyzed using American Association of Otolaryngology-Head and Neck Surgery. Facial nerve dysfunction was analyzed using the House-Brackmann scale. We used univariate comparisons to determine the clinical impact of cystic changes on preoperative and postsurgical hearing and facial nerve preservation., Results: We identified 58 patients (11%) with cystic changes and 410 patients with solid VSs. In this analysis, cystic VS patients tended to have larger tumors (78% of patients with >2.0 cm extrameatal extension) compared with the solid VS group, which consisted of many smaller and medium-sized tumors (P < .0001). Univariate analyses found that tumors with cystic changes did not lead to worse rates of preoperative hearing loss (χ(2), P = not significant) compared with solid VSs. Cystic changes conferred worse postoperative hearing in patients with medium-sized tumors (P = .035). Cystic changes also did not significantly affect facial nerve outcomes (χ(2), P = not significant)., Conclusion: Cystic tumors tend to be larger than noncystic tumors and affect outcomes by reducing the rate at which hearing preservation is attempted and by worsening hearing outcome in medium-sized tumors. Further, peripheral cysts cause lower rates of hearing preservation compared with centrally located cysts.

Background and Importance: Stereotactic radiosurgery (SRS) has been employed with increasing frequency in the treatment of benign intracranial tumors. While the risk for radiation-induced malignancy has been well studied for fractionated external beam radiation, reports of SRS-associated malignancy have only begun to emerge over the past 10 years., Clinical Presentation: We present a case of a rapidly enlarging, presumed sporadic vestibular schwannoma in a 51-year-old man treated with SRS. Serial imaging over the next 7.5 years demonstrated good radiographic response with consistent involution of the tumor. The patient then developed rapid neurologic deterioration and sustained tumor growth on follow-up imaging. The tumor was resected via a translabyrinthine approach, and pathologic analysis demonstrated undifferentiated high-grade pleomorphic sarcoma (UHGPS)., Conclusion: This is the first report of undifferentiated high-grade pleomorphic sarcoma (formerly called malignant fibrous histiocytoma) following SRS. This case demonstrates the difficulty of establishing malignant degeneration of a neoplasm following SRS without pretreatment tissue diagnosis. Patients with presumed benign tumors should be counseled about the rare risk of malignant transformation prior to undertaking SRS., (Copyright (C) by the Congress of Neurological Surgeons)

Background: Intracanalicular vestibular schwannomas have a range of treatment options that can preserve hearing: microsurgery, stereotactic radiotherapy, and conservative observation., Objective: To evaluate the natural course of hearing deterioration during a period of conservative observation., Methods: A retrospective case review was performed on 47 patients with a unilateral intracanalicular vestibular schwannoma. Evaluation of growth was monitored by repeat MRI scanning. Repeated pure-tone and speech audiometry results were evaluated for subgroups of patients showing growth or no growth and by subsite location of tumor in the internal auditory canal., Results: Patients had a mean follow-up of 3.6 years. Over the entire population, the pure-tone average thresholds at 0.5, 1, 2, and 3 kHz and the word recognition scores both significantly deteriorated from 38 to 51 dB HL, and from 66% to 55%, respectively. Overall, 74% of subjects with good hearing, according to the 50/50 rule, maintained hearing above this rule. There were no significant differences in hearing loss by subsite in the internal auditory canal (porus, fundus, central) or by growth status (stable, growing, shrinking). Only 6 patients showed a large hearing change. This happened early during follow-up, with relatively stable hearing after this., Conclusion: Hearing will deteriorate in some intracanalicular vestibular schwannomas, regardless of tumor growth. Hearing deterioration, if on a large scale, most likely occurs early in follow-up. The present results using conservative management in these tumors appear similar to those reported for stereotactic radiotherapy or microsurgery.

Background: Quality of life (QOL) has come into focus after treatment for cerebellopontine angle (CPA) lesions., Objective: This study compared subjective (tinnitus, vertigo) and objective (hearing loss, facial palsy) results of CPA surgery with patient-perceived impairment of QOL., Methods: A retrospective analysis of a consecutive series of 48 patients operated on for either a vestibular schwannoma or a meningioma in the CPA was performed. Patient's subjective impairment of QOL by tinnitus, vertigo, hearing loss, and facial nerve palsy was assessed by a visual analog scale (VAS). Objective facial nerve and hearing function were determined using House-Brackmann and Gardner-Robertson classification systems, respectively., Results: The return rate of questionnaires was 64.4%, with mean follow-up time of 417.2 (+/- 46.4) days. Mean preoperative tinnitus score was 2.5 (+/- 0.5) and increased to 4.6 (+/- 0.7) postoperatively (P < .01). The vertigo score increased from 2.0 (+/- 0.3) to 5.8 (+/- 0.6) (P < .001). Pre- and postoperative values for hearing loss were 3.4 (+/- 0.6) and 5.9 (+/- 0.7), respectively (P < .01), and for facial nerve palsy 0.7 (+/- 0.4) compared with 3.1 (+/- 0.6) postoperatively (P < .01). House-Brackmann grade 1 or 2 was determined in 87.1% of patients before and in 80.6% after surgery. Serviceable hearing (Gardner-Robertson classes I-III) was found in 75% before and in 64.3% after surgery., Conclusion: Preservation of facial nerve and hearing function are not the only important criteria defining QOL after CPA surgery. Tinnitus and vertigo may have a significant underestimated impact on the patient's postoperative course and QOL.

Objective: The aim of this study was to evaluate long-term hearing preservation after gamma knife radiosurgery (GKS) for vestibular schwannomas in patients with initially normal or subnormal hearing (Gardner-Robertson Class 1) and to determine the predictive factors for functional hearing preservation., Methods: Since July 1992, more than 2053 vestibular schwannomas have been treated by GKS and followed at the Timone University Hospital, Marseille. A minimum of 3 years of follow-up (range, 3-11 years; median, 48 months) is available for 74 patients (without neurofibromatosis Type 2 or previous surgery) with Gardner-Robertson Class 1 hearing., Results: The average age of the patients was 47.5 years (range, 17-76 years). The number of tumors in Koos Stage I was 8, the average number in Stage II was 21, the average number in Stage III was 43, and the average number in Stage IV was 2. The median number of isocenters was 8 (range, 2-45), and the median marginal dose was 12 Gy (range, 9-13 Gy). At the time of the last follow-up evaluation, 78.4% of the patients had preserved functional hearing. Tumor control was achieved in 93% of the cases. The probability of preserving functional hearing was higher in patients who had an initial symptom other than hearing decrease (91.1%), in patients younger than 50 years (83.7%), and in those treated with a dose to the cochlea of less than 4 Gy (90.9%)., Conclusion: This study shows that the probability of preserving functional hearing in the long term after GKS for patients presenting with unilateral vestibular schwannomas is very high. The positive predictive factors appear to be young age, an initial symptom other than hearing decrease, and a low dose to the cochlea.

Objective: Tumor control, facial function preservation, and hearing preservation are important criteria for successful management of intracanalicular vestibular schwannomas, whether observation, microsurgery, or radiosurgery is chosen. We collected data prospectively to assess hearing preservation after intracanalicular vestibular schwannoma radiosurgery., Methods: Between 1987 and 2003, 96 patients (65 men and 31 women) underwent gamma knife stereotactic radiosurgery (SRS) for intracanalicular tumors. The median patient age was 54 years (range, 22-80 years). Hearing was graded using the Gardner-Robertson (GR) and the American Academy of Otolaryngology-Head and Neck Surgery classifications. Dose planning was performed on intraoperative stereotactic images using multiple 4-mm isocenters. The median tumor volume was 0.112 mm3 (range, 0.05-0.447 mm3), and the median margin dose was 13 Gy (range, 10-18 Gy)., Results: The mean and median audiologic follow-up periods were 42 months and 28 months (range, 12-144 months), respectively. Serviceable hearing was preserved in 31 of 40 (77.5%) patients with initial American Academy of Otolaryngology-Head and Neck Surgery Class A hearing. Serviceable hearing was preserved in 40 of 79 (64.5%) patients with GR Grade I or II pre-SRS hearing. Ninety-two patients had GR Grade I, II, or III hearing before SRS, and GR Grade I, II, or III hearing was maintained in 78 patients (85%). Hearing grades improved in 7 patients. Facial and trigeminal nerve function was preserved in all patients. The tumor control rate (freedom from additional intervention) was 99.0% (95 of 96) at a median follow-up of 28 months (range, 12-144 months). One patient underwent tumor resection 18 months after radiosurgery., Conclusion: SRS is a minimally invasive first-line management option for patients with intracanalicular tumors and provides high rates of hearing preservation with minimal morbidity.

Objective: Patients with neurofibromatosis Type 2 (NF2) patients typically have bilateral vestibular schwannomas (VS) and are at risk for developing bilateral deafness, bilateral trigeminal, and bilateral facial nerve function loss. Previous reports suggested that treatment outcomes in these patients are worse compared with those for patients with sporadic solitary VS. Very few reports, however, have been published on linear accelerator-based radiosurgery (RS) and stereotactic radiation therapy (SRT) in patients with NF2. In particular, in patients with NF2 who already have unilateral hearing loss, avoidance of hearing loss on the opposite side poses a challenge for RS and SRT. We studied our treatment results in patients with NF2 with bilateral VS, treated with linear accelerator-based RS and SRT., Methods: In 204 patients with VS treated with RS or SRT in Amsterdam starting from 1992, we identified 25 patients with NF2 who had bilateral tumors. Indications for treatment were either tumor progression on sequential magnetic resonance imaging scans and/or progressive hearing loss. Mean tumor diameter was 2.5 cm. Stereotactic irradiation was administered to all patients using five noncoplanar arcs with a single isocenter to a dose of 10 to 12.5 Gy in a single fraction or 20 to 25 Gy in five fractions in 1 week prescribed to the 80% isodose encompassing the tumor. On the untreated side, all patients showed hearing loss and eight (32%) had ipsilateral deafness. Five patients were followed for less than 1 year. Of the remaining 20 patients, five had ipsilateral deafness before treatment. Consequently, 15 patients were at risk for treatment-related hearing loss. They showed a mean pure tone average (PTA) of 51 dB (8-112 dB) before treatment. After treatment all patients were assessed at yearly intervals including magnetic resonance imaging and pure tone audiometry., Results: Median follow-up time was 51 months (12-109 mo). Local tumor control was obtained in all 20 patients, and no treatment-related trigeminal or facial nerve toxicity was observed. Hearing status was assessed yearly after treatment. This assessment revealed that the mean PTA in the 15 hearing patients dropped from 51 to 77 dB (40-120 dB). In six patients (40%) the additional PTA loss ranged from 0 to 15 dB, in another six (40%) it ranged from 15 to 45 dB, and in three of these patients (20%), it was more than 45 dB. No additional hearing loss was observed beyond 36 months after treatment., Conclusion: In this largest series in the literature of linear accelerator-based RS and SRT for VS NF2 patients, excellent local control rates were found with minimal facial and trigeminal nerve toxicity. Although more than 40% of the patients retained their hearing level or lost less than 15 dB of PTA on the irradiated side, preservation of hearing remains a major concern.

Objective: We retrospectively analyzed various clinical factors to determine whether or not these factors are etiopathologically related to the development of hydrocephalus in patients with vestibular schwannomas., Methods: There were 68 patients (29 men, 39 women) in this study who underwent resection of a vestibular schwannoma. The age at the time of surgery ranged from 19 to 76 years (mean age, 51.4 yr). The maximum diameter of the tumor in the cerebellopontine cistern ranged from 0 (localized within the internal auditory canal) to 56 mm (mean, 32.0 +/- 12.9 mm). Cerebrospinal fluid (CSF) protein concentration in the cerebellomedullary cistern was measured intraoperatively in all patients., Results: Sixteen (23.5%) of the 68 patients exhibited radiographic evidence of hydrocephalus. Univariate analysis of various factors revealed that both tumor size and CSF protein concentration were positively related to development of hydrocephalus (P < 0.05 and P < 0.01, respectively). However, in multiple logistic regression analysis, only the CSF protein concentration was predictive for development of hydrocephalus (P = 0.022). There was a trend toward increased CSF protein concentration in patients with a large tumor (> or = 40 mm) compared with those with a small tumor (< 40 mm) (P = 0.06)., Conclusion: A high CSF protein concentration in fluid from the cerebellomedullary cistern is one of the most important factors contributing to hydrocephalus associated with vestibular schwannoma. It is important to judge whether or not any further treatment is required for hydrocephalus, in addition to tumor resection, especially in patients with communicating hydrocephalus.

Objective: The aim of the present study was to characterize the relation between quality of life (QOL) and the four major complaints (hearing loss, tinnitus, vertigo, and unsteadiness) caused by unilateral vestibular schwannomas (VS) in a cohort of well-characterized untreated patients., Methods: One hundred ninety-nine consecutive patients (91 men, 108 women) with a mean age of 56.9 years were studied prospectively during the 4-year period from 2001 to 2004. The average length of time from symptom onset to the radiological diagnosis was 4.2 years. The patients were subject to a standardized examination including magnetic resonance imaging, evaluation of hearing acuity, balance function by stabilimetry, and a visual analogue scale self-evaluation of tinnitus and vertigo. Furthermore, the patients responded to two questionnaires: Short-Form 36 and the Glasgow Benefit Inventory. A reference population was recruited from 80 adults who visited Haukeland University Hospital as nonpatients or nonstaff members. All data were recorded prospectively in a customized case report form. Statistical analysis was performed with SPSS software., Results: The response rates of the Short-Form 36 and Glasgow Benefit Inventory questionnaires were 91.5 and 89.9%, respectively. According to the Short-Form 36 questionnaire, the patients scored significantly below that of expected norms with the exception of physical function and mental health. Patients report negative benefit on the general and physical sections of the Glasgow Benefit Inventory questionnaire. Regression analysis showed that vertigo had a strong negative impact on QOL, whereas unilateral hearing loss and tinnitus had less impact on QOL., Conclusion: Vertigo is the symptom causing the most pronounced negative effect on QOL in patients with VS. The more frequent VS symptoms, unilateral hearing loss and tinnitus, seem to be less important in the patients' perception of QOL as evaluated by the questionnaires used in this study. If vertigo could be relieved by treatment, this symptom should be a primary focus when discussing treatment options in small- to medium-sized VS.

Objective: The best management for patients with small- to medium-sized vestibular schwannomas (VS) is controversial., Methods: : A prospective cohort study of 82 patients with unilateral, unoperated VS less than 3 cm undergoing surgical resection (n = 36) or radiosurgery (n = 46). Patients undergoing resection were younger (48.2 yr versus 53.9 yr, P = 0.03). The groups were similar with regard to hearing loss, associated symptoms, and tumor size. The mean follow-up period was 42 months (range, 12-62 mo)., Results: Normal facial movement and preservation of serviceable hearing was more frequent in the radiosurgical group at 3 months (P < 0.001), 1 year (P < 0.001), and at the last follow-up examination (P < 0.01) compared with the surgical resection group. Patients undergoing surgical resection had a significant decline in the following subscales of the Health Status Questionnaire 3 months after surgery: physical functioning (P = 0.006), role-physical (P < 0.001), energy/fatigue (P = 0.02), and overall physical component (P = 0.004). Patients in the surgical resection group continued to have a significant decline in the physical functioning (P = 0.04) and bodily pain (P = 0.04) subscales at 1 year and in bodily pain (P = 0.02) at the last follow-up examination. The radiosurgical group had no decline on any component of the Health Status Questionnaire after the procedure. The radiosurgical group had lower mean Dizziness Handicap Inventory scores (16.5 versus 8.4, P = 0.02) at the last follow-up examination. There was no difference in tumor control (100 versus 96%, P = 0.50)., Conclusion: Early outcomes were better for VS patients undergoing stereotactic radiosurgery compared with surgical resection (Level 2 evidence). Unless long-term follow-up evaluation shows frequent tumor progression at currently used radiation doses, radiosurgery should be considered the best management strategy for the majority of VS patients.

Objective: Hydrocephalus (HCP) resulting from cerebellopontine angle (CPA) tumors is not rare. This retrospective study was designed to investigate the incidence of HCP and the clinical presentations, management options, and outcomes of HCP in 284 patients with CPA tumors., Methods: A retrospective study of 284 consecutive patients with CPA tumors (mostly vestibular schwannomas) treated from 1985 to 1996 at Toronto Western Hospital managed by one surgical team consisting of a neurosurgeon and a neuro-otologist., Results: Thirty-nine patients (13.7%) had radiographic and/or clinical evidence of HCP, 37 preoperatively and 2 postoperatively. Tumor type distribution was 33 vestibular schwannomas, 5 meningiomas, and 1 cavernous hemangioma. Only five patients (12%) had obvious obstruction at the fourth ventricular level. In 36 patients (92%), symptoms were mostly chronic and mild, consistent with normal pressure hydrocephalus. Multivariate analysis confirmed the strong association of tumor size and incidence of HCP (P < .0001). Four patients underwent permanent shunting before microsurgical tumor excision, mainly because of florid symptoms of HCP. Microsurgical tumor excision without preoperative shunting was performed in 23 patients, 5 of whom required postoperative shunting in the first 2 months after tumor excision. Eighteen patients (78%) did not need shunts after tumor resection. With regard to tumor size, the postoperatively shunted group did not differ from the patients who had surgery but did not require shunt treatment (P < 0.50). The remaining 10 patients with preoperative HCP received shunts as the only treatment (3 patients), stereotactic radiosurgery (3 patients), or expectant management (4 patients). Two other patients without preoperative HCP developed postoperative HCP and required shunts. Postoperatively, we observed a significant (P < 0.001) increase in the incidence of pseudomeningocele and a nonsignificant (P < 0.1) increase in cerebrospinal fluid leaks (rhinorrhea and/or otorrhea) in patients without shunts as compared with postoperative patients without HCP. The patients were followed after any treatment for a mean of 3.2 years (range, 6 mo-10 yr). Follow-up in the patients who had surgery but did not require a shunt revealed a 61% decrease in clinical symptoms related to HCP and a 75% decrease in radiographic signs of HCP., Conclusion: In the presence of HCP, operative resection of CPA tumors can be performed without permanent cerebrospinal fluid shunting. Precautionary measures to decrease the incidence of postoperative complications related to cerebrospinal fluid leak in patients with preoperative HCP include meticulous obliteration of any exposed air cells, including those around the internal auditory canal, accurate restoration of the dural barrier, and temporary lowering of intracranial pressure with a ventricular or lumbar drain. Patients with persistent symptomatic HCP after tumor excision should be treated with a ventriculoperitoneal shunt. Delaying this decision until the postoperative period is safe and avoids unnecessary shunting in the majority of patients.

Objective: Vestibular schwannomas (VSs) affect young patients with Neurofibromatosis 2 (NF-2) and cause very serious problems for hearing, facial expression, and brain stem function. Our objective was to determine a therapy concept for the right timing and indication of neurosurgical therapy., Methods: In 1000 consecutive VS resections, 120 tumors in 82 patients with NF-2 were surgically treated by the same surgeon (MS) at the Department of Neurosurgery at Nordstadt Hospital from 1978 to 1993. The mean age of the patients was 27.5 years. Sixty tumors were surgically treated in 41 male patients, and 60 tumors were surgically treated in 41 female patients. Bilateral tumor resection was performed in 38 patients (76 operations, after previous partial surgery in 15 cases elsewhere), and unilateral operations were performed in 44 patients, 5 of whom had undergone ipsi- or contralateral surgery that was performed elsewhere. The operative and clinical findings are evaluated and compared with the data of patients without NF-2., Results: In 105 cases, complete tumor resections were achieved. In 15 cases, deliberate subtotal resections were performed. These were for brain stem decompression in 4 cases and for hearing preservation in the last hearing ear in 11 cases, with successful preservation in 8 of the 11. Pre- and postoperative hearing rates were higher in male than in female patients (70% in male versus 65% in female patients before surgery and 40.5 versus 31%, respectively, after surgery). Hearing was preserved in 29 of 81 ears (36%). The rate of preservation was 24% in cases of large tumors and 57% in cases of small tumors (<30 mm). Twenty-one of 82 patients (26%) were bilaterally deaf before surgery. Twenty-five patients had uni- or bilateral hearing after surgery (i.e., 41 % of those with preoperative hearing or 30.5% of the whole group). Anatomic facial nerve preservation was achieved in 85%. The facial nerve was reconstructed intracranially at the cerebellopontine angle by sural grafting in 17 cases and by hypoglossal-facial reanimation in 5. Two deaths occurred 1 and 3 months postsurgically as a result of malignant tumor growth with brain stem dysfunction and respiratory problems. In summary, for patients with NF-2, the presentation ages are lower, tumor progression is faster, the chances of anatomic and functional nerve preservation are lower, the chances of good outcomes are best when surgery is performed early and when there is good preoperative hearing function, and the danger of sudden hearing loss is higher. The chances and danger often differ from side to side among individual patients., Conclusion: The indication and the timing of tumor resections are in some respects different from normal VS handling and are dependent on the tumor extension and related necessity of brain stem decompression and on the auditory function. As an optimal goal, completeness of resection with functional cochlear nerve preservation is formulated, and as an acceptable compromise, subtotal microsurgical resection with functional cochlear nerve preservation in the last hearing ear is suggested.

The case of a 66-year-old man with a 3-year progressive hearing loss and a homogeneous left cerebellopontine angle mass on magnetic resonance imaging scan is described. At surgery, the major portion of the mass was a typical encapsulated, solid, acoustic schwannoma, but the most rostral portion was a distinct, flaky, cystic mass without a well-defined capsule, typical of an epidermoid cyst. The radiographic and operative findings of this unique coexistence of two different benign cerebellopontine angle masses are presented.

A case of trigeminal neuralgia caused by a contralateral acoustic neurinoma is reported. The patient's tic pain was completely alleviated after removal of the tumor. Previously reported cases of trigeminal neuralgia caused by contralateral cerebellopontine angle tumors are reviewed, and the pathophysiology of this disorder is discussed.

A 49-year-old woman presented with right facial sensory impairment due to trigeminal nerve dysfunction caused by a contralateral acoustic neuroma. The mechanism of the falsely localizing trigeminal involvement is probably displacement and distortion of the brain stem by the large mass lesion and not increased intracranial pressure. A preoperative orbicularis oculi reflex study was abnormal and indicative of right trigeminal nerve dysfunction; after surgical removal of the tumor, the orbicularis oculi reflex study was normal. We conclude that a false localizing sign of trigeminal nerve dysfunction can occur rarely on the contralateral side in patients with large posterior fossa tumors, especially tumors arising from the cerebellopontine angle, and should be considered in the differential diagnosis of hemifacial sensory disturbance.

Between 1981 and 1984, 44 patients underwent acoustic neurinoma removal by a posterior cranial fossa approach with an attempt to preserve hearing. Seven tumors were small (less than 20 mm), 28 were medium (20 to 40 mm), and 9 were large (greater than 40 mm). Preoperatively, 4 patients had normal hearing, 15 had serviceable hearing, 10 had poor hearing, and 15 had no hearing. Postoperative hearing was preserved in 11 cases. Of the 19 patients with normal or serviceable hearing, 8 (42%) had serviceable hearing preserved postoperatively. Hearing preservation was achieved in 43% of the patients with small tumors, 25% of those with medium tumors, and 11% of those with large tumors. This study confirms the value of the suboccipital approach, which can be used in an attempt to preserve hearing whenever the patient has serviceable hearing preoperatively and whenever the tumor size makes it feasible.