Vestibular schwannomas occur in schwannomatosis and should not be considered an exclusion criterion for clinical diagnosis.

Schwannomatosis is a recently delineated inherited condition that has clinical overlap with neurofibromatosis type 2 (NF2). Diagnostic criteria have been developed to distinguish schwannomatosis from NF2, but the existence of mosaic NF2, which may closely mimic schwannomatosis, makes even these criteria problematic. In particular, it is not clear why there is a relative sparing of the cranial nerves from schwannomas in schwannomatosis. We have identified two individuals with schwannomatosis and a unilateral vestibular schwannoma (VS), where a diagnosis of NF2 has been excluded. A third case with an identified SMARCB1 mutation was reported by two radiologists to have a VS, but this was later confirmed as a jugular schwannoma. These cases question whether the current exclusion of a VS from the clinical diagnosis of schwannomatosis is justified.

Cranial meningiomas in 411 neurofibromatosis type 2 (NF2) patients with proven gene mutations: clear positional effect of mutations, but absence of female severity effect on age at onset.

BACKGROUND: Meningiomas have been reported to occur in approximately 50% of neurofibromatosis type 2 (NF2) patients. The NF2 gene is commonly biallelically inactivated in both schwannomas and meningiomas. The spectrum of NF2 mutations consists mainly of truncating (nonsense and frameshift) mutations. A smaller number of patients have missense mutations, which are associated with a milder disease phenotype. METHODS: This study analysed the cumulative incidence and gender effects as well as the genotype-phenotype correlation between the position of the NF2 mutation and the occurrence of cranial meningiomas in a cohort of 411 NF2 patients with proven NF2 mutations. RESULTS AND CONCLUSION: Patients with mutations in exon 14 or 15 were least likely to develop meningiomas. Cumulative risk of cranial meningioma to age 50 years was 70% for exons 1-3, 81% for exons 4-6, 49% for exons 7-9, 56% for exons 10-13, and 28% for exons 14-15. In the cohort of 411 patients, no overall gender bias was found for occurrence of meningioma in NF2 disease. Cumulative incidence of meningioma was close to 80% by 70 years of age for both males and females, but incidence by age 20 years was slightly increased in males (male 25%, female 18%; p=0.023). Conversely, an increased risk of meningiomas in women with mosaic NF2 disease was also found.

Empirical development of improved diagnostic criteria for neurofibromatosis 2.

PURPOSE: Four sets of clinical diagnostic criteria have been proposed for neurofibromatosis 2, but all have low sensitivity at the time of initial clinical assessment for the disease among patients with a negative family history who do not present with bilateral vestibular schwannomas. We have empirically developed and tested an improved set of diagnostic criteria that uses current understanding of the natural history and genetic characteristics of neurofibromatosis 2 to increase sensitivity while maintaining very high specificity. METHODS: We used data from the UK Neurofibromatosis 2 Registry and Kaplan-Meier curves to estimate frequencies of clinical features at various ages among patients with or without unequivocal neurofibromatosis 2. On the basis of this analysis, we developed the Baser criteria, a new diagnostic system that incorporates genetic testing and gives more weight to the most characteristic features and to those that occur before 30 years of age. RESULTS: In an independent validation subset of patients with unequivocal neurofibromatosis 2, the Baser criteria increased diagnostic sensitivity to 79% (9-15% greater than previous sets of criteria) while maintaining 100% specificity at the age at onset of the first characteristic sign of neurofibromatosis 2. CONCLUSION: The Baser criteria permit early diagnosis in a greater proportion of patients with neurofibromatosis 2 than previous sets of diagnostic criteria.

Brain stem responses evoked by stimulation of the mature cochlear nucleus with an auditory brain stem implant.

OBJECTIVES: The Nucleus auditory brain stem implant (ABI) has been used in the hearing rehabilitation of totally deaf individuals for whom a cochlear implant is not an option such as in the case of neurofibromatosis type 2 (NF2). Intraoperative electrically evoked auditory brain stem responses (EABRs) are recorded to assist in the placement of the electrode array over the dorsal and ventral cochlear nuclei in the lateral recess of the IVth ventricle of the brain stem. This study had four objectives: (1) to characterize EABRs evoked by stimulation with an ABI in adolescents and adults with NF2, (2) to evaluate how the EABR morphology relates to auditory sensations elicited from stimulation by an ABI, (3) to establish whether there is evidence of morphology changes in the EABR with site of stimulation by the ABI, and (4) to investigate how the threshold of the EABR relates to behavioral threshold and comfortably loud sensations measured at initial device activation. DESIGN: Intraoperative EABRs were recorded from 34 subjects with ABIs: 19 male and 15 female, mean age 27 yrs (range 12 to 52 yrs). ABI stimulation was applied at seven different sites using either wide bipolar stimulation across the array or in subsections of the array from medial to lateral and inferior to superior. The EABRs were analyzed with respect to morphology, peak latency, and changes in these characteristics with the site of stimulation. In a subset of eight subjects, additional narrow bipolar sites were stimulated to compare the intraoperative EABR threshold levels with the behavioral threshold (T) and comfortably loud (C) levels of stimulation required at initial device activation. RESULTS: EABRs were elicited from 91% of subjects. Morphology varied from one to four vertex-positive peaks with mean latencies of 0.76, 1.53, 2.51, and 3.64 msecs, respectively. The presence of an EABR from stimulation by electrodes across the whole array had a high predictive value for the presence of auditory electrodes at initial device activation. When examining subsections of the array, the absence of an EABR was a poor predictor for the absence of auditory electrodes. The morphology of the EABRs varied with site of stimulation in 16 cases, but there was no consistent pattern of change with stimulation site. There was a trend for more auditory electrodes to be present in stimulation sites that evoked EABRs with a higher number of peaks in the waveform. The EABR threshold was closer to the behavioral C level than the T level, but there was no overall correlation between the intraoperative EABR threshold level and the behavioral T and C levels. CONCLUSIONS: The presence of an intraoperative EABR corresponded well to the presence of auditory electrodes. The absence of an EABR from stimulating subsections of the array was not; however, a good indicator for the absence of auditory electrodes and the EABR from such stimulation would not be of assistance in identifying the nonauditory sections of the array to exclude in behavioral fitting of the device. The morphology of the EABR did not relate to site of stimulation. More peaks in the EABR was associated with a greater number of electrodes with auditory sensations, suggesting that correct positioning of the ABI activated more auditory subsystems within the cochlear nucleus. The intraoperative EABR thresholds did not correlate with the behavioral T and C levels and could not be used to assist in device fitting.

Brain stem responses evoked by stimulation with an auditory brain stem implant in children with cochlear nerve aplasia or hypoplasia.

OBJECTIVES: The inclusion criteria for an auditory brain stem implant (ABI) have been extended beyond the traditional, postlingually deafened adult with Neurofibromatosis type 2, to include children who are born deaf due to cochlear nerve aplasia or hypoplasia and for whom a cochlear implant is not an option. Fitting the ABI for these new candidates presents a challenge, and intraoperative electrically evoked auditory brain stem responses (EABRs) may assist in the surgical placement of the electrode array over the dorsal and ventral cochlear nucleus in the brain stem and in the postoperative programming of the device. This study had four objectives: (1) to characterize the EABR by stimulation of the cochlear nucleus in children, (2) to establish whether there are any changes between the EABR recorded intraoperatively and again just before initial behavioral testing with the device, (3) to establish whether there is evidence of morphology changes in the EABR depending on the site of stimulation with the ABI, and (4) to investigate how the EABR relates to behavioral measurements and the presence of auditory and nonauditory sensations perceived with the ABI at initial device activation. DESIGN: Intra- and postoperative EABRs were recorded from six congenitally deaf children with ABIs, four boys and two girls, mean age 4.2 yrs (range 3.2 to 5.0 yrs). The ABI was stimulated at nine different bipolar sites on the array, and the EABRs recorded were analyzed with respect to the morphology and peak latency with site of stimulation for each recording session. The relationship between the EABR waveforms and the presence or absence of auditory electrodes at initial device activation was investigated. The EABR threshold levels were compared with the behavioral threshold (T) and comfortably loud (C) levels of stimulation required at initial device activation. RESULTS: EABRs were elicited from all children on both test occasions. Responses contained a possible combination of one to three peaks from a total of four identifiable peaks with mean latencies of 1.04, 1.81, 2.61, and 3.58 msecs, respectively. The presence of an EABR was a good predictor of an auditory response; however, the absence of the EABR was poor at predicting a site with no auditory response. The morphology of EABRs often varied with site of stimulation and between EABR test occasions. Postoperatively, there was a trend for P1, P3, and P4 to be present at the lateral end of the array and P2 at the medial end of the array. Behavioral T and C levels showed a good correlation with postoperative EABR thresholds but a poor correlation with intraoperative EABR thresholds. CONCLUSIONS: The presence of an intraoperative EABR was a good indicator for the location of electrodes on the ABI array that provided auditory sensations. The morphology of the EABR was often variable within and between test sessions. The postoperative EABR thresholds did correlate with the behavioral T and C levels and could be used to assist with initial device fitting.

Outcome from surgery for vestibular schwannomas in children.

OBJECT: A review of sporadic and NF2-related vestibular schwannoma surgery in children (under 18 years of age) with a specific interest in resection rates, recurrence, facial nerve outcomes, hearing preservation, hearing rehabilitation and genetic analysis. METHODS: A retrospective analysis of prospectively collected data of 35 consecutively operated vestibular schwannomas in 29 paediatric patients that underwent 38 operations between 1992 and 2007. Pre- and post-operative radiology, facial nerve function, pure tone audiogram and speech discrimination tests were performed with a mean follow-up of 4.5 years. Tumour and blood mutations were analysed in 86% of patients. RESULTS: Total resection was achieved in all sporadic cases and 68% of NF2 cases. Near total resection led to tumour recurrence in 5 out of 10 cases. The facial nerve was anatomically preserved in 92%. Facial nerve function was excellent to good (Grades 1-3) in 88% with outcome related to tumour size. Hearing preservation was successful in 3 of 11 cases. CONCLUSIONS: Surgery with complete resection results in excellent tumour control, but it is more difficult to attain total resection in NF2 with a relatively high recurrence rate of persistently growing tumours. A better facial outcome is associated with smaller tumours, near-total resection and first time surgery. Hearing preservation is possible in a minority. Hearing rehabilitation can be successful by utilising cochlear implants and auditory brain stem implants (ABI) as appropriate. Overall there is a low complication rate and results are comparable with adult series.

What are the implications in individuals with unilateral vestibular schwannoma and other neurogenic tumors?

OBJECTIVES: Individuals who develop a unilateral vestibular schwannoma (VS) and other neurogenic tumors are at high risk of having the inherited condition neurofibromatosis Type 2 (NF2). The risk of bilateral disease and transmission risk to offspring are important in surgical planning and counseling. The authors have attempted to resolve these risks. METHODS: A large NF2 dataset was interrogated for individuals who had initially presented with a unilateral VS and other tumors before developing bilateral disease, to assess the contralateral and offspring risks. RESULTS: Ninety-six patients with a unilateral VS and additional neurogenic tumors had a bilaterality rate of 48% at 20 years in those initially diagnosed when > 18 years of age and 82% if presenting earlier. Constitutional NF2 mutations were found in blood in 25 (27%) of 92, but 13 (76%) of 17 patients presenting with unilateral VS at < or = 18 years of age. Tumor analysis suggests that the vast majority of the remainder are mosaic for an NF2 mutation. CONCLUSIONS: Patients with unilateral VS and other NF2-related tumors who fulfill Manchester criteria have a high risk of developing a contralateral tumor, especially if presenting in childhood. Transmission risks are reduced for offspring, particularly in the older patients who are likely to be mosaic.

Cochlear implantation in the neurofibromatosis type 2 patient: long-term follow-up.

OBJECTIVE: To evaluate the long-term hearing outcomes of neurofibromatosis type 2 (NF2) patients with cochlear implants. METHODS: Retrospective analysis of cochlear implant performance in NF2 patients using open- and closed-set speech perception testing. RESULTS: Patients with NF2-associated bilateral vestibular schwannomas frequently become profoundly deaf. The aim of surgical resection should be to preserve serviceable hearing in at least one ear; however, this goal can be difficult to achieve. Frequently, tumor size or poor preoperative hearing status can require a surgical approach that leaves the patient with a profound, bilateral sensorineural hearing loss. If the cochlear nerve is preserved anatomically after vestibular schwannoma surgery, and if promontory stimulation confirms the functionality of the cochlear nerve, then cochlear implantation is an excellent option to restore hearing. We present six cochlear implant patients with NF2 who attained a significant improvement in open- and closed-set speech understanding with a mean follow-up of 7.9 (range: 5-13) years after surgery. In all but one case, the hearing results did not deteriorate over the follow-up period. CONCLUSION: Early surgical intervention for vestibular schwannomas in NF2 patients when the cochlear nerve can be spared is an important consideration to allow for possible cochlear implantation. A 6- to 8-week recovery period for the anatomically intact cochlear nerve may be necessary to obtain a positive promontory stimulation response following tumor resection and should be performed prior to cochlear implantation.

Does Meningitis Stop CSF Rhinorrhea following Lateral Skull Base Surgery?

In cases of cerebrospinal fluid (CSF) rhinorrhea following lateral skull base surgery, fibrosis and fibrin formation resulting from meningitis has been postulated as a mechanism of spontaneously resolving the CSF leak. This study was undertaken to explore any possible relationship between the cessation of CSF leak and meningitis. A retrospective study at a tertiary referral center of 232 consecutive patients was performed. Out of a total of 232 procedures, 29 patients developed CSF rhinorrhea, of whom 7 subsequently developed meningitis. Bacteria were isolated in CSF obtained at lumbar puncture in 5 cases, with the CSF analysis in the remaining 2 cases suggesting aseptic meningitis. Conservative treatment failed to stop the CSF rhinorrhea in 6 of 7 cases. In this study, the development of meningitis did not appear to aid in the resolution of the CSF rhinorrhea. We conclude that surgical intervention should not be delayed in the expectation that meningitis and conservative interventions may promote CSF leak resolution.

Long-term Quality of Life Following Vestibular Schwannoma Excision Via the Translabyrinthine Approach.

OBJECTIVE: To assess postoperative quality of life (QOL) and other patient-reported outcomes following surgery for vestibular schwannoma. STUDY DESIGN: Cross-sectional retrospective case review using postal questionnaires. SETTING: Tertiary referral center. PATIENTS: Five hundred consecutive patients undergoing surgery for vestibular schwannoma. INTERVENTION(S): Patients undergoing surgery via the translabyrinthine approach (excluding neurofibromatosis type 2) under the senior author, with a minimum of 5 years follow-up, were included. MAIN OUTCOME MEASURE(S): QOL was assessed using the Short Form 36 (SF-36) questionnaire and a disease-specific survey to assess patients' subjective outcomes. RESULTS: The SF-36 scores in this group were significantly lower than the general UK population, though 24% of respondents reported a subjective improvement in overall QOL. Tumors larger than 4 cm were related to a reduced SF-36 total mental component score (p = 0.037). Increased age at time of surgery correlated with a reduced physical component of QOL (correlation coefficient = -0.26) and an improved mental component (correlation coefficient = 0.26). Subjective reports of postoperative symptoms and return to work, driving and social activities were similar to other published studies. 35% of patients reported vivid dreams or nightmares following surgery; the first reported incidence of this phenomenon in a large group of vestibular schwannoma patients. CONCLUSIONS: Generic measures of QOL in patients following translabyrinthine surgery for vestibular schwannoma do not always match subjective reports, reflecting the complexity of QOL assessment and the range of outcomes in this group. Increased time since surgery appears to be associated with an improvement in mental health.

Auditory cortical activation and speech perception in cochlear implant users: effects of implant experience and duration of deafness.

This study aimed to investigate the relationship between outcome following cochlear implantation and auditory cortical activation. It also studied the effects of length of implant use and duration of deafness on the auditory cortical activations. Cortical activity resulting from auditory stimulation was measured using [(18)F]FDG positron emission tomography. In a group of 18 experienced adult cochlear implant users, we found a positive correlation between speech perception and activations in both the primary and association auditory cortices. This correlation was present in a subgroup of experienced implant users but absent in a group of new implant users with similar speech perception abilities. There was a significant negative correlation between duration of deafness and auditory cortical activation. This study gives insights into the relationship between implant speech perception and auditory cortical activation and the influence of duration of preceding deafness and implant experience.

Size and growth rate of sporadic vestibular schwannoma: predictive value of information available at presentation.

BACKGROUND: The current study examines the hypothesis that tumor growth rate in sporadic vestibular schwannoma could be in part predicted by data available at diagnosis, such as tumor volume, patient age, laterality, and sex. METHODS: Tumor volumes and growth rates were calculated from serial magnetic resonance imaging data in a cohort of 50 patients (26 men and 24 women; mean age at presentation, 64.1 +/- 12.8 yr). Tumor volumes were measured using an algorithm that corrects for partial volume averaging errors and provides accurate estimates of tumor volume with known errors. RESULTS: Examination of presentation data showed no relationship between tumor size at diagnosis and patient age, sex, or tumor laterality. Two measurements of tumor growth--absolute growth per annum and tumor volume doubling time--were studied, and neither showed any relationship with tumor size at presentation, patient age, tumor laterality, or sex. CONCLUSION: The study represents a typical spectrum of patient ages and is of sufficient size in view of the distribution pattern of the variables to give a calculated statistical power in excess of 90% for each variable. This indicates that the clinical features available at presentation and diagnosis have no power to predict the expected behavior of sporadic vestibular schwannoma.

A comparison of surgical techniques used in dynamic reanimation of the paralyzed face.

OBJECTIVES: To compare the outcomes of three surgical techniques used in the rehabilitation of the paralyzed face. STUDY DESIGN: Retrospective study. SETTING: University-based tertiary referral center. PATIENTS: Between 1976 and 2000, rehabilitative facial nerve surgery was performed on 70 adult patients with varying underlying diseases. INTERVENTION: Three methods of facial nerve rehabilitative surgery were performed: end-to-end anastomosis, cable nerve graft interposition, and classic faciohypoglossal transposition. MAIN OUTCOME MEASURES: The House-Brackmann grade was scored at 6, 12, 24, and 36 months by the two senior authors. A favorable outcome was defined as House-Brackmann Grade

Cochlear implantation in adolescents: Factors influencing compliance.

OBJECTIVES: To quantify rates of non- and partial-use of cochlear implants (CIs) in adolescent patients implanted in adolescence and childhood and identify factors influencing compliance. METHODS: A retrospective case note review undertaken at The Manchester Auditory Implant Centre. Adolescents were defined as young people aged 11-18 years. Individuals implanted in adolescence were defined as Group 1, individuals implanted in childhood under the age of 3 years and currently adolescents were defined as Group 2 and individuals implanted between the age of 3 and11 years and currently adolescents were defined as Group 3. Non-use was defined as not using the CI at all and partial use was defined as consistently using the CI less than full-time, or fluctuating periods of full and less than full-time use. RESULTS: In Group 1 there was 1 non-user (1.3%) and 11 partial-users (13.9%), with an overall non-compliance rate of 15.2%. In Group 2 there was one non-user (1.9%) and one partial-user (1.9%) with an overall non-compliance rate of 3.8%. In Group 3 there were no non-users and eight partial-users (9%), with an overall non-compliance rate of 9%. The factors influencing compliance differed between groups with the most common factor in Group 1 being a preference for the auditory input gained from the contralateral hearing aid (50%). In Groups 2 and 3 the main factors influencing compliance were behavioural and related to wearing the implant only at school (50 and 75%, respectively). CONCLUSIONS: Patients implanted during adolescence have higher rates of non- and partial-use compared with their adolescent counterparts who have been implanted during childhood. It is important to investigate factors influencing non-compliance so appropriate support may be provided to the patient and their family.

Using Bayesian tissue classification to improve the accuracy of vestibular schwannoma volume and growth measurement.

BACKGROUND AND PURPOSE: True 3D measurements of tumor volume are time-consuming and subject to errors that are particularly pronounced in cases of small tumors. These problems complicate the routine clinical assessment of tumor growth rates. We examined the accuracy of currently available methods of size and growth measurement of vestibular schwannomas compared with that of a novel fast partial volume tissue classification algorithm. METHODS: Sixty-three patients with unilateral sporadic vestibular schwannomas underwent imaging. Thirty-eight of these patients underwent imaging two or more times at approximately 12-month intervals. Contrast-enhanced 3D T1-weighted images were used for all measurements. An experienced radiologist performed standard size estimations, including maximal diameter, elliptical area, perimeter, manually segmented area, intensity thresholded seeding volume, and manually segmented volume. A method for calculating volume was also used, incorporating Bayesian probability statistics to estimate partial volume effects. Manually segmented volume was obtained as a baseline standard measure. A computer-generated phantom exhibiting the intensity and partial volume characteristics of brain tissue, CSF, and intracanalicular vestibular schwannoma tissue was used to measure absolute accuracy of the standard technique and Bayesian partial volume segmentation. RESULTS: The Bayesian partial volume segmentation method showed the highest correlation (R(2) = 0.994) with the standard method, whereas the commonly used method of maximal diameter measurement showed poor correlation (R(2) = 0.732). Accuracy of Bayesian segmentation was shown to be more than twice that of manual segmentation, with an absolute accuracy of 5% (cf, 13%) and a remeasurement accuracy of 70 mm(3) (cf, 150 mm(3)). For the 38 patients who underwent imaging twice, definite tumor growth was shown for 12, potential growth for seven, no growth for 17, and definite shrinkage for two. CONCLUSION: Commonly used methods such as maximal diameter measurements do not provide adequate statistical accuracy with which to monitor tumor growth in patients with small vestibular schwannomas. Bayesian partial volume segmentation provides a more accurate and rapid method of volume and growth estimation. These differences in measurement accuracy translated into a significant improvement in clinical assessment, allowing identification of tumor growth in 10 of 12 cases that appeared to be static in size when manual segmentation techniques are used. The technique is quick to perform and suitable for use in routine clinical practice.

Cochlear implantation in 53 patients with otosclerosis: demographics, computed tomographic scanning, surgery, and complications.

OBJECTIVES: To collect data from a large number of cochlear implant recipients with otosclerosis and to make an assessment of these patients' clinical characteristics, computed tomographic scans, surgical findings, and complications, and to quantify the occurrence of postoperative facial nerve stimulation. STUDY DESIGN: Retrospective multicenter study. PATIENTS: Fifty-three patients with otosclerosis from four cochlear implant centers in the United Kingdom and The Netherlands were reviewed. Sixty surgical procedures were performed in these patients: 57 devices were placed in 56 ears. RESULTS: The computed tomographic imaging demonstrated retrofenestral (cochlear) otosclerotic lesions in the majority of patients. Although not statistically significant, the extent of otosclerotic lesions on the computed tomographic scan as categorized in three types tends to be greater in patients with rapidly progressive hearing loss, in patients in whom there is surgically problematic insertion of the electrode array, and in patients with facial nerve stimulation. In four patients, revision surgery had to be performed. Twenty of 53 (38%) patients experienced facial nerve stimulation at various periods postoperatively. CONCLUSION: Cochlear implant surgery in patients with otosclerosis can be challenging, with a relatively high number of partial insertions and misplacements of the electrode array demanding revision surgery. A very high proportion of patients experienced facial nerve stimulation mainly caused by the distal electrodes. This must be discussed with patients preoperatively.

Virtual reality modelling language: freely available cross-platform visualization technique for 3-D visualization of the inner ear.

This was a study of the use of virtual reality modelling language (VRML) for cross-platform interactive three-dimensional (3-D) visualization of high-resolution magnetic resonance (MR) images of the inner ear in the assessment of cochlear implant candidates. A retrospective case review was made of cochlear implant candidates undergoing pre-operative high-resolution MR studies to determine their suitability for implantation. 3-D visualizations of MR scans of the inner ear structures were created using surface rendering and exported as portable VRML files. Case studies are presented to illustrate different points of interest. VRML reconstructions aided the interpretation of two-dimensional (2-D) source images in a variety of inner ear abnormalities. VRML is an internationally recognized standard for cross-platform 3-D visualization that creates a means of providing the implanting surgeon with a portable 3-D representation of the inner ear, aiding interpretation of the complex cross-sectional anatomy of these structures, and guiding selection of patients for implantation as well as implantation technique. The elucidation of the mechanisms behind inner ear malformations can also be aided by detailed imaging studies of the temporal bone, with VRML reconstructions providing an easily interpreted representation of deformities.

Surgical outcomes in cystic vestibular schwannoma versus solid vestibular schwannoma.

OBJECTIVE: To review the postoperative surgical outcomes of cystic vestibular schwannomas (CVSs), especially facial nerve outcomes, and compare these results with those from matched solid vestibular schwannomas (SVS) resected during the same period at a tertiary referral center. STUDY DESIGN: Retrospective case series. METHODS: One hundred thirty-one surgically managed patients with cystic vestibular schwannomas (CVSs) were age, sex, and tumor size matched to 131 surgically managed patients with solid vestibular schwannomas (SVSs). Demographics, tumor morphology, surgical approach, extent of resection, facial and nonfacial complications, and recurrence rates were compared between the 2 groups. Subtotal removal was defined as removal of at least 95% of the tumor. RESULTS: The mean maximal tumor diameter was 2.8 cm for both groups. For CVS, gross total tumor resection (GTR) was achieved in 92 patients (70.2%), and subtotal tumor resection (STR) was achieved in 39 patients (29.8%). Postoperative facial nerve outcomes at 1-year follow-up were good (HB Grade I-III) in 116 (88.5%) of 131 CVS patients. Twenty-three patients developed nonfacial nerve-related complications (17.6%). For SVS, GTR was achieved in 102 patients (77.9%), and STR was achieved in 29 patients (22.1%). Postoperative facial nerve outcomes at 1-year follow-up were good (HB Grade I-III) in 118 (90.1%) of 131 SVS patients. Nonfacial nerve related complications occurred in 14 patients (10.7%). None of the differences in outcome between the 2 groups were statistically significant. CONCLUSION: The difference in surgical outcomes is minimal between patients with CVS and those with SVS, not reaching statistical significance. We think, with judicious surgical management, similar outcomes can be achieved in cystic tumors and solid tumors.