Disparities in Sporadic Vestibular Schwannoma Initial Presentation Between a Public Safety Net Hospital and Tertiary Academic Medical Center at the Same Zip Code 2010 to 2020.

INTRODUCTION: Treatment of vestibular schwannoma (VS) has been extensively studied, but a gap in knowledge exists demonstrating how racial and socioeconomic status influence VS presentation. Our institution has a unique setting with a public safety net hospital (PSNH) and tertiary academic medical center (TAMC) in the same zip code, which we study to evaluate initial VS presentation disparities in patient populations presenting to these hospital settings. METHODS: Retrospective chart review was performed of all adult patients (n = 531) presenting 2010 to 2020 for initial VS evaluation at TAMC (n = 462) and PSNH (n = 69). Ethnicity, insurance, maximum tumor size, audiometry, initial treatment recommendation, treatment received, and follow up were recorded and statistical analysis performed to determine differences. RESULTS: Average age at diagnosis (51.7 ± 13.6 TAMC vs 52.3 ± 12.4 PSNH) and gender (58.4% TAMC vs 52.2% PSNH female) were similar. Patients' insurance (TAMC 75.9% privately insured vs PSNH 82% Medicaid) and racial/ethnic profiles (TAMC 67.7% White and 10.0% Hispanic/Latinx, vs PSNH 4.8% White but 59.7% Hispanic/Latinx) were significantly different. Tumor size was larger at PSNH (20.2 ± 13.3 mm) than TAMC (16.6 ± 10.0 mm). Hearing was more impaired at PSNH than TAMC (mean pure tone average 58.3 dB vs 43.9 dB, word recognition scores 52.3% vs 68.2%, respectively). Initial treatment recommendations and treatment received may include more than 1 modality. TAMC patients were offered 66.7% surgery, 31.2% observation, and 5.2% radiation, while PSNH patients offered 50.7% observation, 49.3% surgery, and 8.7% radiation. TAMC patients received 62.9% surgery, 32.5% observation, and 5.3% radiation, while PSNH patients received 36.2% surgery, 59.4% observation, and 14.5% radiation. Follow up and treatment at the same facility was not significantly different between hospitals. CONCLUSIONS: Hearing was worse and tumor size larger in patients presenting to PSNH. Despite worse hearing status and larger tumor size, the majority of PSNH patients were initially offered observation, compared to TAMC where most patients were initially offered surgery.

Socioeconomic determinants impact quality of life at vestibular schwannoma diagnosis.

BACKGROUND: Socioeconomic variables including race, education, and income have been shown to affect vestibular schwannoma incidence, treatment, and outcomes. We sought to determine the impact of socioeconomic factors on quality of life at the time of vestibular schwannoma diagnosis. METHODS: Retrospective cohort study conducted at a tertiary academic center. All patients evaluated for vestibular schwannoma from March 1, 2010 to December 31, 2021 who completed at least one Penn Acoustic Neuroma Quality of Life (PANQOL) questionnaire at presentation or prior to any intervention were included. PANQOL scores were compared across income quintiles, racial groups, and health insurance categories. RESULTS: Two-hundred and ninety-six patients who had non-missing information on variables of interest were included. Compared to White/Caucasian patients (84.5 %), Black/African American patients (4.7 %) had significantly lower PANQOL total scores (b = -12.8[-21.7, -4.0], p = 0.005). Compared to patients with Commercial insurance (53 %), patients who were Uninsured/ Self-pay (1.7 %) had significantly lower PANQOL total scores (b = -16.7[-31.4, -1.9], p = 0.027). Patients in higher income quintiles had significantly higher PANQOL total scores (b = 11.7[3.9, 19.5], p = 0.004 comparing highest income quintile to lowest). After controlling for potential confounders, income quintile (b = 9.6[1.3, 17.9], p = 0.023 comparing highest quintile to lowest) and insurance (b = -17.0[-31.9, -21], p = 0.025 comparing Uninsured/Self-pay to Commercial insurance) remained predictors of total PANQOL score. CONCLUSIONS: Socioeconomic factors including race, health insurance, and income appear to contribute to quality of life at the time of vestibular schwannoma diagnosis. These variables are interrelated and the effects of race may be mediated in part by differences in income and health insurance coverage.

CLINICAL-AND-FUNCTIONAL ASSESSMENT OF THE EARLY POSTOPERATIVE OUTCOME OF SURGICAL TREATMENT OF PATIENTS WITH VESTIBULAR SCHWANNOMA.

The incidence of vestibular schwannoma (VS) increased largely within the last 50 years from 1,5 cases per 100 thousand persons to 4,2 (for the last decade). The approaches to the management of VS patients vary significantly in different medical centers and different countries. The search for the consensus in selecting strategy of VS treatment based on systemic clinical-and-functional assessment of treatment outcome is topical nowadays. The aim of study - to analyze the clinical-and-functional early postoperative outcome of the surgical treatment of vestibular schwannoma depending on the stage of the disease. The findings of the examination and the outcomes of the surgical treatment of 27 VS patients were retrospectively analyzed. The patients were treated at the Department of Subtentorial Neurosurgery of the State Institution "Romodanov Institute of Neurosurgery of the NAMS of Ukraine" in 2018-2019. According to Koos classification, three groups of the patients were delineated for the analysis of the results of the study, namely, group 1 (Koos II) - 8 (29,6 %) patients; group 2 (Koos III) - 6 (22,2 %); and group 3 (Koos IV) - 13 (48,2 %). The complex clinical examination, in particular clinical-and-instrumental otoneurological examination and the evaluation of the neurological status according to the Scale for the assessment of the functional treatment outcome were performed preoperatively and early postoperatively. The data were statistically processed. In the patients with small tumors (group 1, Koos II), the socially useful hearing on the affected side was preserved preoperatively necessitating the caution for selecting the treatment strategy in these patients. When pre- and postoperative clinical symptoms were compared in group 1, the statistically significant worsening of the hearing to the socially non-useful, the unilateral subjective tinnitus, the dysfunction of the facial nerve, the decreased sense of taste/loss of taste on the anterior 2/3 of the tongue on the affected side were found. Upon the surgical treatment, the rate of the neurological deficit increased, and the severity grade of the neurological deficit increased by about 10 points. The overall preoperative score in group 3 (Koos IV) was significantly different from that in other groups. The progression of the disease to the stage of Koos IV results in the neurological deficit that is equivalent by the set of the neurological symptoms and their severity to that in early postoperative period in patients with Koos III. In group 3, the rate of the dysfunction of the facial nerve and the caudal group of the cranial nerves increased postoperatively with concomitant decreased sense of taste/loss of taste on the anterior 2/3 of the tongue on the affected side and statocoordinatory impairments. The overall preoperative score differed significantly between all groups. In group 3, the postoperative overall score did not differ from preoperative one, although the postoperative overall score in group 3 (Koos ІV) differed significantly from that in other two groups. The proposed scale for the assessment of the functional outcome of the VS treatment is versatile and represents the integral element of the systemic assessment of the clinical-and-functional status of VS patient. There are good reasons to integrate proposed scale into the general scheme of the medical care for VS patients allowing for the objective assessment of the otoneurological patterns in the patients in the dynamics of the treatment. The analysis of our own findings and the literature data proved the relevance of the problem requiring further task-oriented scientific inquiry. The important aspects of the problem relate to the optimization and improvement of the diagnostic and treatment strategy according to the principles of individualization and multimodality allowing for increasing the level of consensus and improving the functional outcome of the treatment.

Quantitative assessment of brainstem distortion in vestibular schwannoma and its implication in occurrence of hydrocephalus.

PURPOSE: Anatomical distortion directly affects the clinical status of patients with vestibular schwannomas (VSs). It may vary for a given tumor size due to variability in posterior fossa anatomy. We aimed to quantitatively assess brainstem distortion (BSD) and review its role in occurrence of hydrocephalus associated with VSs. METHODS: Sixty-six patients with small (<3 cm, n= 8; 12.1%); large (3-4 cm; n= 26; 39.4%) and giant (>4 cm; n= 32; 48.5%) VSs were included. Cystic VSs were excluded. Tumor size, tumor-extent, linear displacement (LD; distance between line bisecting pons (line 1) and posterior fossa midline (line 2)) and angular distortion (AD; angle subtended between lines 1 and 2) in axial-T2-MRI section through pons, and their effect on hydrocephalus were assessed. RESULTS: Significant BSD occurred in a younger age (p value = .004/.003), larger-sized tumor (p value = .001/.002), hydrocephalus (p value = .001/.001), trigeminal (V) nerve palsy (p value = .004/.003) and long tract signs (p value = .001/.034). Tumors crossing midline had significant association with hydrocephalus (p value = .003). LD increased progressively even for 4-5 cm-sized tumors while AD stabilized. Receiver operating characteristic (ROC) curve revealed that diagnostic accuracy of LD (area under the ROC curve (AUROC): 78.9% (95% CI: 67.2%, 90.5%, p < .001)), AD (AUROC:77.6% (95% CI:65.8%, 89.5%, p < .001)) and LD × AD (AUROC:80.3% (95% CI: 69.2%, 91.2%, p < .001)) for predicting occurrence of hydrocephalus was better than tumor size (AUROC: 66.7% (95% CI: 53.5%, 79.9%, p < .05). Cut-off values of LD and AD for predicting occurrence of hydrocephalus were 6.25 mm and 14.6°, respectively. Hydrocephalus was significantly more when both LD was greater than  6.25 mm and AD was greater than 14.5° (p value = .034). The role of LD and AD in influencing hydrocephalus was greater than categorization based on tumor size (Spearman's correlation coefficient: 0.535 and 0.248, respectively). Hydrocephalus occurred at a lesser cut-off value of LD and AD when compared to long tract signs. CONCLUSIONS: LD and AD values in VSs have a significantly greater influence in the development of hydrocephalus compared to tumor size, and may aid, more reliably, in the prediction of hydrocephalus.

Auditory brainstem response prior to MRI compared to standalone MRI in the detection of vestibular schwannoma: A modelling study.

OBJECTIVES: To determine the cost-effectiveness of auditory brainstem response prior to MRI (ABR-MRI) compared to standalone MRI to diagnose vestibular schwannoma. DESIGN: A state transition model was developed to simulate costs and effects (quality-adjusted life years [QALY]) for both diagnostic strategies for patients suspected of a vestibular schwannoma. Model input was derived from literature, hospital databases and expert opinions. Scenario and sensitivity analyses addressed model uncertainty. RESULTS: Over a lifetime horizon, ABR-MRI resulted in a limited cost-saving of €68 or €98 per patient (dependent on MRI sequence) and a health loss of 0.005 QALYs over standalone MRI. ABR-MRI, however, did miss patients with other important pathology (2% of the population) that would have been detected when using standalone MRI. In total, €14 203 or €19 550 could be saved per lost QALY if ABR-MRI was used instead of standalone MRI. The results were sensitive to the detection rate of vestibular schwannoma and health-related quality of life of missed patients. CONCLUSION: The cost-saving with ABR-MRI does not seem to outweigh the number of missed patients with VS and other important pathologies that would have been detected when using standalone MRI.

Preoperative Differences in Intracranial Facial Versus Vestibular Schwannomas: A Four Nerve Assessment.

OBJECTIVES: Assesses whether preoperative functional testing can distinguish vestibular schwannomas from facial nerve schwannomas medial to the labyrinthine segment. STUDY DESIGN: Retrospective cohort. METHODS: Retrospectively review surgically managed intracranial facial and vestibular schwannomas between January 2015 and December 2019 at two tertiary care centers. Patients with neurofibromatosis 2 and surgery for recurrence were excluded. Preoperative functional testing to include House-Brackmann scores, electroneuronography (ENoG), cervical vestibular evoked myogenic potentials (cVEMP), caloric testing, acoustic brainstem responses (ABRs), acoustic reflexes, and audiograms was compared between the two groups of schwannomas. RESULTS: Twelve facial and 128 vestibular schwannomas met inclusion criteria. In only one case was a facial schwannoma diagnosed preoperatively from imaging. No statistically significant difference was found in preoperative House-Brackmann scores, ENoG, cVEMP, caloric testing, ABRs, or acoustic reflexes. Pure tone average was worse in the vestibular schwannoma group (63 dB [95% CI: 58-68 dB] vs. 46 dB [95% CI: 34-58 dB], P = .01), and the difference was more apparent in the lower frequencies. Word recognition score was better in the facial schwannoma group (66% [95% CI: 45-86%] vs. 41% [95% CI: 34-47%], P = .02). CONCLUSION: Specialized preoperative functional evaluation of the nerves of the internal auditory canal cannot reliably predict the presence of an intracranial facial schwannoma. Hearing is better in facial schwannomas, particularly in the lower frequencies. This should raise the index of suspicion for an intracranial facial schwannoma, especially in candidates for hearing preservation vestibular schwannoma surgery. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:2098-2105, 2021.

The prevalence and clinical characteristics of vestibular schwannoma among patients treated as sudden sensorineural hearing loss: A 10-year retrospective study in southern China.

PURPOSE: To review the prevalence and clinical characteristics of vestibular schwannoma (VS) in patients with sudden sensorineural hearing loss (SSNHL) in southern China. MATERIALS AND METHODS: This study examined the medical records and MRI findings of all the 1249 patients diagnosed with SSNHL between May 2009 and April 2019 in the Division of Otolaryngology at Peking University Shenzhen Hospital. RESULTS: Among the 1249 patients with SSNHL, VS was found in 14 (1.12%). Among 14 patients, 11 (78.6%) complained of tinnitus and 3 patients (21.4%) complained of dizziness as accompanying symptoms. There was one patient with SSNHL in right ear who had an incidental finding of VS in the contralateral ear. 2 patients (14.3%) had normal auditory brainstem response (ABR) test and 3 patients (21.4%) had hearing recovery. The size of tumors ranged from 6.1 mm to 24.2 mm, with 7 grade 1 tumors, 4 grade 2 tumors, and 3 grade 3 tumors. The total MRI screening cost was $130,857 and the average MRI cost for identifying a VS patient was $9346. CONCLUSION: The prevalence of VS among patients treated as SSNHL was 1.12%. Predicting the risk of VS in SSNHL by the audiogram patterns, pure tone audiometry or hearing recovery is not relivable. Compared with ABR, MRI is more suitable for the assessment of VS in patients with SSNHL in China.

A Retrospective Cohort Study of Longitudinal Audiologic Assessment in Single and Fractionated Stereotactic Radiosurgery for Vestibular Schwannoma.

BACKGROUND: Fractionated stereotactic radiosurgery (SRS) for vestibular schwannomas (VS) has been theorized to allow for tumor control with higher rates of hearing preservation in selected patients with useful hearing. However, there is a paucity of literature with formal audiologic measures of hearing preservation to support the standard use of fractionated SRS in VS. We hypothesized that fractionation would diminish the amount of hearing damage. OBJECTIVE: To evaluate the relationship between audiologic performance and SRS fractionation scheme. METHODS: We performed an IRB-approved retrospective review of patients treated with 1, 3, or 5 fraction SRS for VS at our institution from 1998 to 2016. Pre- and post-SRS audiograms with speech awareness threshold (SAT) in treated and contralateral ears were obtained. Contralateral ear measurements were used for hearing normalization to account for presbycusis. RESULTS: Fifty-six patients with median audiologic follow-up 2.0 yr (mean 2.66 yr, min-max 0.50-9.45 yr) were included. Patients treated with single fractionation had a significantly worsened SAT (dB) compared to patients treated with 5 fractions (P = .008) and compared to all multifraction patients (P = .009) at 12 to 24 mo follow-up. CONCLUSION: This retrospective analysis supports the use of fractionated SRS to preserve hearing in patients with VS. SAT can be used as an objective metric of hearing response to radiosurgery.

To Scan or Not to Scan-A Cross-Sectional Analysis of the Clinical Efficacy and Cost-Effectiveness of Audiometric Protocols for Magnetic Resonance Imaging Screening of Vestibular Schwannomas.

INTRODUCTION: Vestibular schwannomas (VS) are a rare cause of asymmetrical hearing loss, and routine screening with magnetic resonance imaging (MRI) can be costly. At present, no consensus exists on what qualifies as "asymmetrical sensorineural hearing loss" (ASNHL) and when a patient should be referred for screening. OBJECTIVES: 1) Evaluation of published audiometric protocols on the basis of sensitivity and specificity when applied to local clinical cohort of patients with ASNHL; 2) determination of clinical risks of missing VS and potential wastes in screening "radiologically normal" cases; 3) assessment of the cost of MRI screening. METHODS: Cross-sectional study with chart review in a 2-year (2015-2016) cohort of 1059 patients who underwent MRI screening and audiometry indicating sensorineural hearing loss. Fourteen previously published audiometric protocols were assessed for their sensitivity and specificity in guiding radiological diagnosis of VS, and cost analysis was performed. RESULTS: 6/14 audiometric protocols had a sensitivity greater than 85%. Diagnostic specificity ranged from 22.91 to 82.76%, clinical risks from 0 to 50%, and potential wastes from 17.24 to 77.09%. Average annual cost of screening was £64,069. Application of proposed local screening protocol had a projected cost saving of 32.19%. Cost of screening patients that benefit from treatment was compared with a utility function that quantified expected benefit. CONCLUSIONS: Development of an easy-to-apply algorithm incorporating high-sensitivity audiometric protocols may result in significant cost saving, with minimal clinical risk of missing cases. There was disparity between screening costs and monetary "benefit" of hearing.

Management of Vestibular Schwannomas for the Radiologist.

Vestibular schwannomas are the most common tumor of the cerebellopontine angle. The history of their management has driven advances in imaging, lateral skull base surgery, as well as radiosurgery. With these advances, a shift has occurred from life-saving treatment for late-stage disease to quality of life focused management of smaller tumors. The complicated treatment paradigms involving observation, stereotactic radiosurgery and surgery require close communication between the treatment and neuroradiology teams.

[Is the current level of investigation for vestibular schwannoma reasonable?] / Utredningsnivån av vestibulära schwannom måste bli rimlig - Nationella riktlinjer behövs.

The main aim of this study was to evaluate if the level of investigation with MRT or BRA (Brainstem Response Audiometry) is adequate in relation to the number of vestibular schwannomas (VS) found in a county like  Dalarna (277 000 inhabitants) in Sweden. The reason to investigate was asymmetrical sensorineural hearing loss (ASHL) defined as a one-sided hearing loss exceeding 10 dB compared to the contralateral side. Between 2007-2014 a total of 55 patients (incidence 2.5/100 000) were diagnosed with a VS in the county. The local ENT department found two thirds of these patients. In the year of 2010, MRT was advocated by SBU (Swedish Agency for Health Technology Assessment and Assessment of Social Services) as the primary step of investigation. During 2011-2014, 981 patients underwent MRT and 482 patients BRA, because of ASHL. Seventeen VS were found, meaning that 58 MRT and 29 BRA were conducted to find one VS. According to earlier studies, only one third of VS show growth tendency. Taking this into consideration, 174 (58 × 3) investigations with MRT will only diagnose approximately 1 patient with a growing VS. We therefore question today's level of investigation and ask for new uniform recommendations on how to investigate for VS in cases of ASHL.

Potential savings in the diagnosis of vestibular schwannoma.

INTRODUCTION: Magnetic resonance imaging (MRI) is used to screen patients at risk for vestibular schwannoma (VS). These MRIs are costly and have an extremely low yield; only 3% of patients in the screening population has an actual VS. It might be worthwhile to develop a test to predict VS and refer only a subset of all patients for MRI. OBJECTIVE: To examine the potential savings of such a hypothetical diagnostic test before MRI. DESIGN: We built a decision analytical model of the diagnostic strategy of VS. Input was derived from literature and key opinion leaders. The current strategy was compared to hypothetical new strategies, assigning MRI to the following: (i) all patients with pathology, (ii) all patients with important pathology and (iii) only patients with VS. This resulted in potential cost savings for each strategy. We conducted a budget impact analysis to predict nationwide savings for the Netherlands and the United Kingdom (UK), and a probabilistic sensitivity analysis to address uncertainty. RESULTS: Mean savings ranged from €256 (95%CI €250 - €262) or approximately US$284 (95%CI US$277 - US$291) per patient for strategy 1 to €293 (95%CI €290 - €296) or approximately US$325 (95%CI US$322 - US$328) per patient for strategy 3. Future diagnostic strategies can cost up to these amounts per patient and still be cost saving. Annually, for the Netherlands, €2.8 to €3.2 million could be saved and €10.8 to €12.3 million for the UK. CONCLUSIONS: The model shows that substantial savings could be generated if it is possible to further optimise the diagnosis of VS.

Auditory brainstem response - a valid and cost-effective screening tool for vestibular schwannoma?

CONCLUSION: Contemporary auditory brainstem response (ABR) is not valid as a screening tool for VS, when considering the sensitivity of 80%, the specificity of 77%, and the positive predictive value of 3.4%, MRI screening is superior to ABR in Denmark when considering cost-effectiveness. OBJECTIVES: The aim of this study is to assess the sensitivity, specificity, and cost-effectiveness of ABR vs MRI, when screening for VS in a clinical setting. METHOD: Data was collected on all patients subjected to an ABR during a 3-year period (2005-2008) at a tertiary referral center. The data were compared to results of MRI and with data from The Danish National VS Database. In total, 1447 adults underwent ABR, of whom 349 were referred for a subsequent MRI. Sensitivity and specificity were calculated. To assess the cost-effectiveness of ABR vs MRI, procedure costs for ABR and MRI were retrieved from the National Board of Health. RESULTS: Twelve (3.4%) of 349 patients were diagnosed with a VS. Of the 1098 patients not referred for MRI, three (0.3%) were later diagnosed with a VS. The sensitivity and specificity of ABR in diagnosing a VS were 80% and 77%, respectively. Procedure costs were 326 EURO for the ABR and 319 EURO for the MRI.

Cost analysis of vestibular schwannoma screening with contrast-enhanced magnetic resonance imaging in patients with asymmetrical hearing loss.

BACKGROUND: Vestibular schwannomas are a rare cause of asymmetrical hearing loss, and routine screening with magnetic resonance imaging can be costly. This paper reports results on vestibular schwannoma screening at our institution and compares the cost of screening to a utility of hearing benefit. METHOD: All screening examinations with magnetic resonance imaging performed for asymmetrical hearing loss between 2006 and 2011 were retrospectively reviewed. The cost per new vestibular schwannoma diagnosis was calculated. The cost per patient for those who benefitted from intervention was estimated based on rates of hearing preservation reported in the literature. RESULTS: Forty-five (4.3 per cent) of 1050 screening examinations with magnetic resonance imaging performed for asymmetrical hearing loss were positive for vestibular schwannoma, and the cost per new diagnosis was $11,436. The estimated screening cost per patient for those who benefitted from surgery or radiation was $147,030, while US federal compensation for unilateral hearing loss was $44,888. CONCLUSION: Although we achieved a lower screening cost per new diagnosis than reported in the current literature, there remains disparity between the screening cost per benefitted patient and the 'benefit' of hearing.

Cost-effective analysis of unilateral vestibular weakness investigation.

OBJECTIVES: To evaluate the cost-effectiveness of obtaining a magnetic resonance imaging (MRI) in patients with abnormal electronystagmography (ENG) or videonystagmography (VNG) results. STUDY DESIGN: Retrospective chart review. SETTINGS: Academic specialty center. PATIENTS: Patients presenting with vertigo between January 1, 2010, and August 30, 2013. METHODS: Patients who fit the following abnormal criteria were included in the study: unilateral caloric weakness (≥20%), abnormal ocular motor testing, and nystagmus on positional testing. Patients with abnormal findings who then underwent MRI with gadolinium were evaluated. RESULTS: Of the 1,996 charts reviewed, there were 1,358 patients who met the inclusion criteria. The average age of these patients was 62 years (12-94 yr). The male:female ratio was approximately 1:2. Of the 1,358 patients, 253 received an MRI with the following pathologies: four vestibular schwannomas, three subcortical/periventricular white matter changes suspicious for demyelinating disease, four acute cerebellar/posterior circulation infarct, two vertebral artery narrowing, one pseudomeningocele of internal auditory canal, and two white matter changes indicative of migraines. The positive detection rate on MRI was 5.5% based on MRI findings of treatable pathologies causing vertigo. Average cost of an MRI is $1,200, thereby making the average cost of identifying a patient with a positive MRI finding $15,180. CONCLUSION: In our study, those patients with a positive MRI had a constellation of symptoms and findings (asymmetric sensorineural hearing loss, tinnitus, vertigo, and abnormal ENG/VNG). Cost-effectiveness can be improved by ordering an MRI only when clinical examination and VNG point toward a central pathology. Clinical examination and appropriate testing should be factored when considering the cost-effectiveness of obtaining an MRI in patients with abnormal ENG/VNG findings.

Stereotactic radiosurgery for facial nerve schwannomas: A preliminary assessment and review of the literature.

OBJECTIVE: Facial nerve schwannomas (FNS) are rare tumors, and their appropriate management remains the subject of considerable debate. This report details the results of a series of patients with FNS treated with stereotactic radiosurgery (SRS) at the University of Virginia. METHODS: We performed a retrospective review of the clinical and imaging outcomes of 5 patients who underwent Gamma Knife RS (GKRS) for small-to-medium-sized (<5 mL) FNS at our institution. The study population consisted of 3 males and 2 females with a median age of 35 years. All patients presented with varying degrees of facial palsy and/or hearing dysfunction. Tumor volumes at GKRS ranged from 0.1 to 5 (median=0.8) mL. The median maximum radiosurgical dose and tumor margin dose were 24 Gy and 12 Gy, respectively. RESULTS: After a median follow-up period of 12 (range, 6-36) months, three tumors were radiographically smaller and two remained stable. Facial function improved in three patients, remained stable in one patient, and slightly declined from House-Brackmann grade I to II in one patient. Hearing function was preserved in three patients and deteriorated in two patients, one from Gardner-Robertson grade I to II and the other from serviceable hearing grade II to III. CONCLUSION: SRS appears to offer a reasonable rate of facial nerve preservation and tumor control for patients with small-to-medium-sized FNS. Considering the published outcomes achieved with resection, RS may be the preferred first-line treatment for these tumors.

The role of cervical and ocular vestibular evoked myogenic potentials in the assessment of patients with vestibular schwannomas.

OBJECTIVES: To investigate the clinical utility of VEMPs in patients suffering from unilateral vestibular schwannoma (VS) and to determine the optimal stimulation parameter (air conducted sound, bone conducted vibration) for evaluating the function of the vestibular nerve. METHODS: Data were obtained in 63 patients with non-operated VS, and 20 patients operated on VS. Vestibular function was assessed by caloric, cervical and ocular VEMP testing. 37/63 patients with conclusive ACS ocular VEMPs responses were studied separately. RESULTS: In the 63 non-operated VS patients, cVEMPs were abnormal in 65.1% of patients in response to AC STB and in 49.2% of patients to AC clicks. In the 37/63 patients with positive responses from the unaffected side, oVEMPs were abnormal in 75.7% of patients with ACS, in 67.6% with AFz and in 56.8% with mastoid BCV stimulation. In 16% of the patients, VEMPs were the only abnormal test (normal caloric and normal hearing). Among the 26 patients who did not show oVEMP responses on either side with ACS, oVEMPs responses could be obtained with AFz (50%) and with mastoid stimulation (89%). CONCLUSIONS: The VEMP test demonstrated significant clinical value as it yielded the only abnormal test results in some patients suffering from a unilateral vestibular schwannoma. For oVEMPs, we suggest that ACS stimulation should be the initial test. In patients who responded to ACS and who had normal responses, BCV was not required. In patients with abnormal responses on the affected side using ACS, BCV at AFz should be used to confirm abnormal function of the superior vestibular nerve. In patients who exhibited no responses on either side to ACS, BCV was the only approach allowing assessment of the function of the superior vestibular nerve. We favor using AFz stimulation first because it is easier to perform in clinical practice than mastoid stimulation.

Incidence of vestibular schwannoma and incidental findings on the magnetic resonance imaging and computed tomography scans of patients from a direct referral audiology clinic.

OBJECTIVE: To identify the incidence of vestibular schwannoma amongst patients referred from a direct referral audiology clinic, and also the number of incidental findings, as seen on magnetic resonance imaging or computed tomography scans. METHOD: Prospective data collection for patients referred from a direct referral audiology clinic due to audiological evidence of asymmetrical hearing loss. The audiograms, magnetic resonance imaging and computed tomography scans of patients with diagnosed vestibular schwannoma were subsequently reviewed. RESULTS: A total of 4100 patients were seen during the study period, with 396 scans performed. Six (1.5 per cent) patients had vestibular schwannoma, while 12 (3 per cent) had significant incidental findings. CONCLUSION: Patients referred from the direct referral audiology clinic had a low incidence of vestibular schwannoma detection. Their detection rate for significant incidental findings was similar to previous reports. If the current protocol had not been in place, over 300 patients would have been needlessly added to the ENT clinic list. Thus, general practitioner referral to direct referral audiology clinics provides a cost-effective way of managing asymmetrical sensorineural hearing loss in older patients. The number of such clinics could be expanded.