Hearing restoration after resection of an intracanalicular vestibular schwannoma: a role for emergency surgery? Case report and review of the literature

Treated large posterior fossa vestibular schwannoma and meningioma: Hearing outcome and willingness-to-accept brain implant for unilateral deafness

Background/Objective

To compare functional hearing and tinnitus outcomes in treated large (~ 3 cm) vestibular schwannoma (VS) and posterior fossa meningioma cohorts, and construct willingness-to-accept profiles for an experimental brain implant to treat unilateral hearing loss.

Methods

A two-way MANOVA model with two independent variables (tumor type; time from treatment) and three dependent variables (hearing effort of tumor ear; abbreviated Speech, Spatial, and Qualities of Hearing scale (SSQ12); Tinnitus Functional Index (TFI)) was used to analyze data from VS (N = 32) and meningioma (N = 50) patients who were treated at a tertiary care center between 2010 and 2020. A query to probe acceptance of experimental treatment for hearing loss relative to expected benefit was used to construct willingness-to-accept profiles.

Results

Tumor type was statistically significant on the combined dependent variables analysis (F[3, 76] = 19.172, p < .0005, Wilks' Λ = 0.569). Meningioma showed better outcome for hearing effort (F[1, 76] = 14.632, p < .0005) and SSQ12 (F[1, 76] = 16.164, p < .0005), but not for TFI (F[1, 76] = 1.247, p = .268) on univariate two-way ANOVA analyses. Superior hearing effort and SSQ12 indices in the short-term (< 2 years) persisted in the long-term (> 2 years) (p ≤ .017). At the 60% speech understanding level, 77% of respondents would accept an experimental brain implant.

Conclusion

Hearing outcome is better for posterior fossa meningioma compared to VS. Most patients with hearing loss in the tumor ear would consider a brain implant if the benefit level would be comparable to a cochlear implant.

Level of Evidence

2.

Impact of Social Determinants of Health on Stereotactic Radiotherapy for Vestibular Schwannoma

OBJECTIVES/HYPOTHESIS

Linear accelerator (LINAC) and Gamma Knife (GK) are common stereotactic radiation therapies for treating vestibular schwannoma (VS). There is currently limited literature examining specific demographic and socioeconomic factors, which influence the type of stereotactic radiation therapy a patient with VS receives.

STUDY DESIGN

Retrospective database review.

METHODS

The National Cancer Database was queried for cases of VS between 2004 and 2016. Patient demographic characteristics were compared using chi-squared and t-tests between GK and LINAC treated groups. Multivariate regression analysis was performed to assess predictors of stereotactic radiation therapy received.

RESULTS

Of the 6,208 included patients, 5,306 (85.5%) received GK and 902 (14.5%) received LINAC. The mean age of GK patients was significantly lower than that of LINAC patients (58.0 vs. 59.7, P < .001). Individuals treated with GK had greater proportions of private insurance (P < .001) and incomes greater than $63,332 (P = .003). A greater proportion of GK patients were treated in academic centers (P < .001), in high-volume facilities (P < .001), in metropolitan areas (P < .001), and in the Northeastern United States (P < .001). On multivariate logistic regression analysis, region, metropolitan area, facility type, tumor size, and distance traveled by patients independently predict receipt of GK versus LINAC.

CONCLUSION

Differences in patient demographics and other social determinants of health influence choice of GK versus LINAC therapy for VS patients. Future studies focused on addressing barriers to care, which may influence postprocedural quality of life and clinical outcomes associated with these two treatments are necessary to better understand the impact of these social differences.

LEVEL OF EVIDENCE

4 Laryngoscope, 2022.

Hearing improvement after vestibular schwannoma surgery in the era of the hearing preservation rule - case report and literature review

OBJECTIVES

Hearing preservation after vestibular schwannoma (VS) surgery remains a surgical challenge. In some patients with preserved inner ear function, hearing improvement is achievable. As it is currently impossible to determine which patients will present this outcome, predictions must rely on previously published reports. Our case report describes a patient who experienced hearing improvement from an unuseful level to a useful one after vestibular schwannoma surgery.

METHODS

Surgery was performed via suboccipital retrosigmoid approach. The patient underwent a basic audiovestibular protocol before and after the surgery - pure tone and speech audiometry, otoacoustic emissions, auditory brainstem responses, electronystagmography - together with a detailed questionnaire study. Usefulness of hearing was evaluated using the AAO-HNS guidelines, supplemented by a frequency of 4 kHz.

RESULTS

Hearing was preserved and even improved from an unuseful level to a useful one. Based on the available literature, the most informative predictive factors for such a result seem to be: sudden sensorineural hearing loss prior to surgery, elicitable otoacoustic emissions and the origin from the superior vestibular nerve.

CONCLUSION

There are a limited number of studies on this topic and it is still impossible to regularly improve hearing in properly selected patients. Furthermore, the importance of postoperative hearing quality compared to other symptoms and complications remains debatable.

Preservation of facial nerve function after resection of vestibular schwannoma

OBJECTIVE

Most data regarding facial nerve function in patients undergoing microsurgical resection of vestibular schwannomas predominantly include series performed at a single institution. In an effort to minimise individual surgeon or institutional bias, we performed an analysis of the published literature on facial nerve outcomes following microsurgical resection of vestibular schwannomas. The objective of this study was to provide a comprehensive assessment of reported outcomes for facial nerve preservation after VS surgery.

MATERIALS AND METHODS

We identified a total of 296 studies involving over 25,000 patients that included outcome data for facial nerve function of vestibular schwannoma patients treated surgically. Data regarding surgical approach, tumour size, patient age, and use of intra-operative monitoring were extracted and correlated with facial nerve function after surgery. Patients with preoperative facial nerve dysfunction (House-Brackmann score 3 or higher) were excluded and 'facial nerve preservation' was defined as grade I or II House-Brackmann function at last follow-up visit.

RESULTS

A total of 79 articles reporting on 11,873 patients met our inclusion criteria contributing to our analysis. Patients treated with the middle cranial fossa approach had a trend towards higher overall facial nerve preservation rate (85%), compared to the translabyrinthine approach (81%, p = 0.07) , and did statistically better than the retrosigmoid approach (78%, p < 0.0001). Patients with an average tumour size <20 mm had significantly improved facial nerve preservation rates, compared to larger tumours (90% vs. 67%, p < 0.0001). Patients under 65 years of age had a lower facial nerve preservation rate (71% vs. 84%, p < 0.001). Finally, the use of intra-operative monitoring improved the facial nerve preservation rate (76% vs. 71%, p < 0.001).

CONCLUSION

Factors that appear to be associated with facial nerve preservation after microsurgical resection of a vestibular schwannoma include tumour size <20 mm, use of the middle fossa approach and use of neuromonitoring during surgery. These data provide a summary assessment of the published literature regarding facial nerve preservation after microsurgical resection of vestibular schwannoma.

Suggested response criteria for phase II antitumor drug studies for neurofibromatosis type 2 related vestibular schwannoma

Neurofibromatosis type 2 (NF2) is a tumor suppressor gene syndrome characterized by multiple schwannomas, especially vestibular schwannomas (VS), and meningiomas. Anticancer drug trials are now being explored, but there are no standardized endpoints in NF2. We review the challenges of NF2 clinical trials and suggest possible response criteria for use in initial phase II studies. We suggest two main response criteria in such trials. Objective radiographic response is defined as a durable 20% or greater reduction in VS volume based on post-contrast T1-weighted MRI images collected with 3 mm or finer cuts through the internal auditory canal. Hearing response is defined as a statistically significant improvement in word recognition scores using 50-word recorded lists in audiology. A possible composite endpoint incorporating both radiographic response and hearing response is outlined. We emphasize pitfalls in response assessment and suggest guidelines to minimize misinterpretations of response. We also identify research goals in NF2 to facilitate future trial conduct, such as identifying the expectations for time to tumor progression and time to measurable hearing loss in untreated NF2-related VS, and the relation of both endpoints to patient prognostic factors (such as age, baseline tumor volume, and measures of disease severity). These data would facilitate future use of endpoints based on stability of tumor size and hearing, which might be more appropriate for testing certain drugs. We encourage adoption of standardized endpoints early in the development of phase II trials for this population to facilitate comparison of results across trials of different agents.

Sudden deafness as a presenting symptom of acoustic neuroma: case report

Vestibular schwannoma, also known as acoustic neurinoma, is the most frequent tumor of the cerebellopontine angle, and represents 9% of all intracranial tumors. Case Report: The authors report a case of sudden deafness with unilateral tinnitus. The patients responded to therapy with Prednisone and Pentoxifylline after the diagnosis of acoustic neurinoma by imaging exams. Discussion: Sudden deafness can be described as an intense and abrupt sensorineural loss. Usually it is higher than 30 dB at three or more frequencies and develops in less than three days. Conclusion: Investigation of the etiology of sudden deafness is extremely important to establish the adequate strategy for the case.