Systematic Review of Hearing Preservation After Radiotherapy for Vestibular Schwannoma

Stereotactic Radiosurgery in Primary Treatment of Sporadic Small to Medium (<3 cm) Vestibular Schwannomas: A Systematic Review and Meta-Analysis

OBJECTIVE

To analyze the literature regarding the use of stereotactic radiosurgery as the primary treatment of vestibular schwannoma to further evaluate efficacy and treatment-related neurologic deficits.

METHODS

Online databases were queried to identify relevant studies from January 2001 to December 2020. Full-text articles in English for sporadic vestibular schwannoma treated primarily with radiosurgery and documented hearing preservation data were reviewed. Studies that had a minimum follow-up period of less than 36 months, did not use radiosurgery for primary treatment, or included patients with neurofibromatosis type 2 were excluded.

RESULTS

A total of 33 studies involving 4286 patients with an average follow-up of 62.5 months were included in the final analysis. All 33 studies included eligible hearing data; overall preservation of serviceable hearing was found to be 58.27%. Twenty-seven studies with 3822 eligible patients were analyzed for tumor control rates; overall, tumor control was reported in 92.98% of cases. Twenty-seven studies were analyzed for posttreatment facial nerve dysfunction, which was reported in 1.53% of cases.

CONCLUSIONS

Stereotactic radiosurgery is a safe and effective primary treatment modality for sporadic vestibular schwannoma as shown by the present analysis. Radiosurgery is effective regarding tumor control and hearing preservation and offers a low rate of posttreatment facial nerve dysfunction.

Long-Term Hearing Outcome For Vestibular Schwannomas After Microsurgery And Radiotherapy: A Systematic Review and Meta-Analysis

OBJECTIVE

Hearing loss is a common symptom associated with vestibular schwannoma (VS), either because of the tumor's effects on the cochlear nerve or due to active treatments such as surgery or stereotactic radiosurgery (SRS). Treatment decisions for VS are based on factors including tumor size, hearing status, patient symptoms, and institutional preference. The study aimed to investigate long-term auditory outcomes in VS patients undergoing active treatments with a hearing preservation intent.

DATA SOURCES

A systematic literature review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, searching Scopus, Pubmed, and Web of Science databases from inception to January 2024.

REVIEW METHODS

Studies meeting inclusion criteria, including a minimum 5-year follow-up and assessment of pre- and posttreatment hearing outcomes, were included. Pooled prevalence estimates for serviceable hearing after SRS and microsurgery were calculated using MetaXL software. Risk of bias assessment was performed with the Risk of Bias in Non-randomized Studies of Interventions tool.

RESULTS

Nine studies met the inclusion criteria, with 356 patients included for analysis. The pooled prevalence of maintaining serviceable hearing after SRS at 10 years was 18.1% (95% confidence interval [CI]: 1.7%-43.3%), with wide prediction intervals indicating variability in outcomes. Microsurgery demonstrated a higher prevalence of maintaining long-term serviceable hearing, with a pooled estimate of 74.5% (95% CI: 63.5%-84.1%).

CONCLUSION

This systematic review underscores the importance of long-term follow-up in evaluating auditory outcomes in VS treatment. Despite the biases inherent to pretreatment patients selection, hearing preservation microsurgery for sporadic VS removal demonstrated favorable and stable long-term serviceable hearing.

Hearing Function after CyberKnife for Vestibular Schwannoma: A Systematic Review

Introduction  CyberKnife (CK) radiosurgery is a treatment strategy for vestibular schwannoma (VS). Objectives  To evaluate hearing preservation (HP) after CK for VS. Data Synthesis  The study was conducted following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement, and it was registered at the International Prospective Register of Systematic Reviews (PROSPERO, under number CRD42021250300). The inclusion criteria were based on the population, intervention, comparison, outcome, timing and study design (PICOTS) strategy: population - patients with VS; intervention - CK; Comparison - none; Outcome - serviceable HP defined by Gardner and Robertson as grades I or II, or by the American Academy of Otolaryngology and Head and Neck Surgery as classes A or B; timing - mean follow-up longer than 1 year; and study design - retrospective or prospective studies. The exclusion criteria were: studies not published in English; studies published before January 2000 and after October 2021; and studies only including patients with neurofibromatosis type 2 or submitted to a previous treatment. The PubMed/MEDLINE, EMBASE, Web of Science, Cochrane Library, LILACS, and IBECS databases were used and last searched on October 27th, 2021. Statistical heterogeneity was assessed using I 2 statistics. The appraisal checklist was used to assess the risk of bias in the included studies. A total of 222 studies were analyzed, and 13 were included in the synthesis, which represents 493 participants with serviceable hearing before intervention. The mean HP rate after CK using a random effects model was of 68% (95% confidence interval [95%CI]: 59-76%) at a mean follow-up of 42.96 months. Conclusion  The longer follow-up period was associated with a lower HP rate after CK radiosurgery for VS in the qualitative synthesis.

Coordinated Same- or Next-Day Radiosurgery and Cochlear Implantation for Vestibular Schwannoma

OBJECTIVE

To describe the experience and results from coordinated and closely scheduled radiosurgery and cochlear implantation (CI) in a vestibular schwannoma (VS) cohort.

PATIENTS

Patients with VS who underwent radiosurgery followed by CI on the same or next day.

INTERVENTIONS

Interventions included sequential radiosurgery and CI.

MAIN OUTCOME MEASURES

Tumor control defined by tumor growth on posttreatment surveillance and audiometric outcomes including consonant-nucleus-consonant words and AzBio sentences in quiet.

RESULTS

In total, six patients were identified that met the inclusion criteria, with an age range of 38 to 69 years and tumor sizes ranging from 2.0 to 16.3 mm. All patients successfully underwent radiosurgery and CI on the same or immediately successive day. Postoperatively, all patients obtained open-set speech recognition. Consonant-nucleus-consonant word scores ranged from 40 to 88% correct, and AzBio scores ranged from 44 to 94% correct. During posttreatment magnetic resonance imaging surveillance, which ranged from 12 to 68 months, all tumors were noted to be adequately visualized, and no tumor progression was noted.

CONCLUSION

Coordinated radiosurgery and CI can be safely performed in patients with VS on the same or next day, serving to decrease burden on patients and increase access to this vital rehabilitative strategy.

Reported Hearing Outcome Measures Following Stereotactic Radiosurgery for Vestibular Schwannoma: A Scoping Review

Background  Evidence on hearing outcome measures when assessing hearing preservation following stereotactic radiosurgery (SRS) for adults with vestibular schwannoma (VS) has not previously been collated in a structured review. Objective  The objective of the present study was to perform a scoping review of the evidence regarding the choice of hearing outcomes and other methodological characteristics following SRS for adults with VS. Methods  The protocol was registered in the International Platform of Registered Systematic Review and Meta-Analysis Protocols (INPLASY) and reported according to the Preferred Reporting Items for Systematic Review and Meta-Analyses extension guidelines for scoping reviews. A systematic search of five online databases revealed 1,591 studies, 247 of which met the inclusion criteria. Results  The majority of studies ( n  = 213, 86%) were retrospective cohort or case series with the remainder ( n  = 34, 14%) prospective cohort. Pure-tone audiometry and speech intelligibility were included in 222 (90%) and 158 (64%) studies, respectively, often summarized within a classification scheme and lacking procedural details. Fifty-nine (24%) studies included self-report measures. The median duration of follow-up, when reported, was 43 months (interquartile range: 29, 4-150). Conclusion  Evidence on hearing disability after SRS for VS is based on low-quality studies which are inherently susceptible to bias. This review has highlighted an urgent need for a randomized controlled trial assessing hearing outcomes in patients with VS managed with radiosurgery or radiological observation. Similarly, consensus and coproduction of a core outcome set to determine relevant hearing and communication outcome domains is required. This will ensure that patient priorities, including communication abilities in the presence of background noise and reduced participation restrictions, are addressed.

Long-Term Hearing Outcome of Cochlear Implantation in Cases with Simultaneous Intracochlear Schwannoma Resection

OBJECTIVES

The aim was to analyze the long-term hearing results after simultaneous microsurgical extirpation via enlarged cochleostomy and cochlear implantation in intracochlear schwannoma as compared with non-tumor single-side deafness patients.

METHODS

Microsurgical extirpation via enlarged cochleostomy with simultaneous cochlear implantation was performed in 15 cases of intracochlear schwannoma between 2014 and 2021. Speech recognition tests in German language and impedance performances were collected over 36 months of observation and compared with an internal cohort of 52 age matched non-tumor single-side deafness patients. Retrospective cohort study in a tertiary referral center.

RESULTS

The surgery proved feasible and uneventful in all cases. In the case of intracochlear schwannoma, the hearing rehabilitation results were highly satisfactory and comparable to those of the non-tumor single-side deafness cohort. The speech recognition performance improved steadily in the first 12 months; afterward, it remained stable, providing indirect evidence against tumor recurrence during the follow-up. One patient required implant revision surgery related to device failure, but no recurrence was registered in the 36 months of observation.

CONCLUSIONS

Cochlear implantation is the strategy of choice for hearing rehabilitation in case of intracochlear schwannomas in the long term. In particular, the combination of tumor extirpation via cochleostomy with a cochlear implantation in the same surgical time offers a viable therapy for intracochlear schwannoma, granting a sufficient degree of radicality without compromising the cochlear integrity. This technique allows for revision surgery if required.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1854-1860, 2024.

Pathophysiology of Postoperative Hearing Disorders after Vestibular Schwannoma Resection: Insights from Auditory Brainstem Response and Otoacoustic Emissions

Background: In order to better understand the pathophysiology of surgically induced hearing loss after vestibular schwannoma (VS) surgery, we postoperatively analyzed the hearing status in a series of patients where hearing was at least partially preserved. Methods: Hearing was assessed through tonal audiometry, speech discrimination score, maximum word recognition score (dissyllabic word lists-MaxIS), otoacoustic emissions (OAEs), and auditory brainstem response (ABR). The magnetic resonance imaging (MRI) tumor characterization was also noted. Results: In a series of 24 patients operated on for VS over 5 years, depending on the results of this triple hearing exploration, we could identify, after surgery, patients with either a myelin alteration or partial damage to the acoustic fibers, others with a likely partial cochlear ischemia, and some with partial cochlear nerve ischemia. One case with persisting OAEs and no preoperative ABR recovered hearing and ABR after surgery. Long follow-up (73 ± 57 months) revealed a mean hearing loss of 30 ± 20 dB with a drastic drop of MaxIS. MRI revealed only 25% of fundus invasion. Conclusion: a precise analysis of hearing function, not only with classic audiometry but also with ABR and OEAs, allows for a better understanding of hearing damage in VS surgery.

Clinical practice guideline on the management of vestibular schwannoma

INTRODUCTION

Vestibular schwannoma (VS) is the most common tumour of the cerebellopontine angle. The greater accessibility to radiological tests has increased its diagnosis. Taking into account the characteristics of the tumour, the symptoms and the age of the patient, three therapeutic strategies have been proposed: observation, surgery or radiotherapy. Choosing the most appropriate for each patient is a frequent source of controversy.

MATERIAL AND METHODS

This paper includes an exhaustive literature review of issues related to VS that can serve as a clinical guide in the management of patients with these lesions. The presentation has been oriented in the form of questions that the clinician usually asks himself and the answers have been written and/or reviewed by a panel of national and international experts consulted by the Otology Commission of the SEORL-CCC.

RESULTS

A list has been compiled containing the 13 most controversial thematic blocks on the management of VS in the form of 50 questions, and answers to all of them have been sought through a systematic literature review (articles published on PubMed and Cochrane Library between 1992 and 2023 related to each thematic area). Thirty-three experts, led by the Otology Committee of SEORL-CCC, have analyzed and discussed all the answers. In Annex 1, 14 additional questions divided into 4 thematic areas can be found.

CONCLUSIONS

This clinical practice guideline on the management of VS offers agreed answers to the most common questions that are asked about this tumour. The absence of sufficient prospective studies means that the levels of evidence on the subject are generally medium or low. This fact increases the interest of this type of clinical practice guidelines prepared by experts.

Single-cell multi-omic analysis of the vestibular schwannoma ecosystem uncovers a nerve injury-like state

Vestibular schwannomas (VS) are benign tumors that lead to significant neurologic and otologic morbidity. How VS heterogeneity and the tumor microenvironment (TME) contribute to VS pathogenesis remains poorly understood. In this study, we perform scRNA-seq on 15 VS, with paired scATAC-seq (n = 6) and exome sequencing (n = 12). We identify diverse Schwann cell (SC), stromal, and immune populations in the VS TME and find that repair-like and MHC-II antigen-presenting SCs are associated with myeloid cell infiltrate, implicating a nerve injury-like process. Deconvolution analysis of RNA-expression data from 175 tumors reveals Injury-like tumors are associated with larger tumor size, and scATAC-seq identifies transcription factors associated with nerve repair SCs from Injury-like tumors. Ligand-receptor analysis and in vitro experiments suggest that Injury-like VS-SCs recruit myeloid cells via CSF1 signaling. Our study indicates that Injury-like SCs may cause tumor growth via myeloid cell recruitment and identifies molecular pathways that may be therapeutically targeted.

COX inhibitor use during definitive radiotherapy is associated with worse hearing preservation in patients with vestibular schwannoma

PURPOSE

Patients with vestibular schwannoma undergoing definitive radiotherapy commonly experience hearing loss due to tumor and treatment effects; however, there is limited data evaluating concurrent medication use and other clinicopathologic factors associated with hearing preservation during and after radiotherapy. We performed a retrospective cohort study reviewing consecutive patients from 2004 to 2019 treated with radiotherapy for vestibular schwannoma at our institution.

METHODS

Ninety four patients with concurrent medications, baseline audiograms, and post-radiotherapy audiograms available were evaluable. We performed chi-squared analyses of the frequency of various clinicopathologic factors and t-tests evaluating the degree of hearing loss based on audiograms.

RESULTS

At a median follow-up of 35.7 months (mean: 46.5 months), the baseline pure-tone average (PTA) of the ipsilateral ear worsened from 38.4 to 59.5 dB following completion of radiotherapy (difference: 21.1, 95% CI 17.8-24.4 dB, p < 0.001). 36 patients (38.3%) reported regular use of cyclooxygenase (COX) inhibitors (including acetaminophen and NSAIDs) during radiotherapy. The mean increase in PTA was significantly higher for patients taking COX inhibitors (25.8 dB vs 18.1 dB, p = 0.024) in the ipsilateral ear but not for the contralateral side. COX inhibitor use remained independently associated with worse PTA in the multivariate analysis.

CONCLUSION

COX inhibitor use during definitive radiotherapy is associated with worse hearing loss in the affected ear but not for the contralateral side. This suggests the ototoxic effects of COX inhibitors may influence the effects of radiotherapy. These results could have clinical implications and warrant further investigation.

Impact of Cochlear Dose on Hearing Preservation Following Stereotactic Radiosurgery in Treatment of Vestibular Schwannomas: A Multi-Center Study

OBJECTIVE

Stereotactic radiosurgery (SRS) is a well-established treatment for vestibular schwannomas (VS). Hearing loss remains a main morbidity of VS and its treatments, including SRS. The effects of radiation parameters of SRS on hearing remain unknown. The goal of this study is to determine the effect of tumor volume, patient demographics, pretreatment hearing status, cochlear radiation dose, total tumor radiation dose, fractionation, and other radiotherapy parameters on hearing deterioration.

METHODS

Multicenter retrospective analysis of 611 patients who underwent SRS for VS from 1990-2020 and had pre- and post-treatment audiograms.

RESULTS

Pure tone averages (PTAs) increased and word recognition scores (WRSs) decreased in treated ears at 12-60 months while remaining stable in untreated ears. Higher baseline PTA, higher tumor radiation dose, higher maximum cochlear dose, and usage of single fraction resulted in higher post radiation PTA; WRS was only predicted by baseline WRS and age. Higher baseline PTA, single fraction treatment, higher tumor radiation dose, and higher maximum cochlear dose resulted in a faster deterioration in PTA. Below a maximum cochlear dose of 3 Gy, there were no statistically significant changes in PTA or WRS.

CONCLUSIONS

Decline of hearing at one year in VS patients after SRS is directly related to maximum cochlear dose, single versus 3-fraction treatment, total tumor radiation dose, and baseline hearing level. The maximum safe cochlear dose for hearingtbrowd preservation at one year is 3 Gy, and the use of 3 fractions instead of one fraction was better at preserving hearing.

The Course of Hearing Loss in Patients With a Progressive Vestibular Schwannoma

OBJECTIVE

This study evaluates the natural course of hearing loss (HL) prior to treatment in patients with progressive tumors and an indication for active intervention. Evaluating this patient group specifically can put hearing outcomes after vestibular schwannoma therapy into an adequate context.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary referral center.

METHODS

Inclusion criteria comprised unilateral vestibular schwannomas prior to active treatment, with ≥2 mm extracanalicular (EC) tumor growth and ≥2 audiograms. We performed a comprehensive assessment of hearing using multiple outcome parameters including (the annual decrease in) pure-tone averages (PTAs; an average of 0.5, 1, 2, and 3 kHz). Predictors for HL were evaluated (patient age, tumor size/progression, follow-up duration, baseline hearing).

RESULTS

At presentation, 86% of patients suffered from sensorineural HL on the affected side (≥20 dB PTA) with a median of 39 dB (interquartile rate [IQR]: 27-51 dB). The median follow-up duration was 21 months (IQR: 13-34 months), after which 58% (187/322) of patients experienced progressive HL (≥10 dB), with a median increase of 6.4 dB/year. At the last follow-up, the median PTA was 56 dB (IQR: 37-73). Median speech discrimination scores deteriorated from 90% (IQR: 70%-100%) to 65% (IQR: 35%-100%). Tumor progression (maximal EC diameter) was significantly correlated to the progression of sensorineural HL, corrected for follow-up (F(2,228) = 10.4, p < .001, R2  = 8%).

CONCLUSION

The majority of patients (58%) with radiologically confirmed progressive vestibular schwannomas experience progressive sensorineural HL during observation. Tumor progression rate, EC tumor extension, and longer follow-up are factors associated with more sensorineural HL.

Hearing Aid in Vestibular-Schwannoma-Related Hearing Loss: A Review

(1) Background: Several types of hearing aids are available for the rehabilitation of vestibular-schwannoma (VS)-related hearing loss. There is a lack of recently published papers regarding this theme. The aim of the present work is to organize current knowledge. (2) Methods: A review of the literature regarding the topics "vestibular schwannoma", "hearing loss", and "hearing aid" was performed. Nineteen studies were thus considered. (3) Results: Conventional hearing aids, contralateral routing of signal (CROS) aids, bone anchored hearing aids (BAHA), and others are available options for hearing rehabilitation in VS patients. The speech discrimination score (SDS) is considered the best measure to assess candidacy for rehabilitation with hearing aids. The best hearing rehabilitative conditions in VS patients when using conventional hearing aid devices are a mild-moderate hearing loss degree with good word recognition (more than 50% SDS). CROS-Aid and BAHA are reported to be beneficial. CROS-Aid expands on the area of receiving hearing. BAHA aids use direct bone-conduction stimulation. Unfortunately, there are no available studies focused specifically on VS patients that compare CROS and BAHA technologies. (4) Conclusions: Hearing aids, CROS, and BAHA are viable options for rehabilitating hearing impairment in VS, but require an accurate case-by-case audiological evaluation for rehabilitating hearing impairment in VS. Further studies are needed to prove if what is currently known about similar hearing illnesses can be confirmed, particularly in the case of VS.

Upfront Radiosurgery vs a Wait-and-Scan Approach for Small- or Medium-Sized Vestibular Schwannoma: The V-REX Randomized Clinical Trial

Importance

Current guidelines for treating small- to medium-sized vestibular schwannoma recommend either upfront radiosurgery or waiting to treat until tumor growth has been detected radiographically.

Objective

To determine whether upfront radiosurgery provides superior tumor volume reduction to a wait-and-scan approach for small- to medium-sized vestibular schwannoma.

Design, Setting, and Participants

Randomized clinical trial of 100 patients with a newly diagnosed (<6 months) unilateral vestibular schwannoma and a maximal tumor diameter of less than 2 cm in the cerebellopontine angle as measured on magnetic resonance imaging. Participants were enrolled at the Norwegian National Unit for Vestibular Schwannoma from October 28, 2014, through October 3, 2017; 4-year follow-up ended on October 20, 2021.

Interventions

Participants were randomized to receive either upfront radiosurgery (n = 50) or to undergo a wait-and-scan protocol, for which treatment was given only upon radiographically documented tumor growth (n = 50). Participants underwent 5 annual study visits consisting of clinical assessment, radiological examination, audiovestibular tests, and questionnaires.

Main Outcomes and Measures

The primary outcome was the ratio between tumor volume at the trial end at 4 years and baseline (V4:V0). There were 26 prespecified secondary outcomes, including patient-reported symptoms, clinical examinations, audiovestibular tests, and quality-of-life outcomes. Safety outcomes were the risk of salvage microsurgery and radiation-associated complications.

Results

Of the 100 randomized patients, 98 completed the trial and were included in the primary analysis (mean age, 54 years; 42% female). In the upfront radiosurgery group, 1 participant (2%) received repeated radiosurgery upon tumor growth, 2 (4%) needed salvage microsurgery, and 45 (94%) had no additional treatment. In the wait-and-scan group, 21 patients (42%) received radiosurgery upon tumor growth, 1 (2%) underwent salvage microsurgery, and 28 (56%) remained untreated. For the primary outcome of the ratio of tumor volume at the trial end to baseline, the geometric mean V4:V0 was 0.87 (95% CI, 0.66-1.15) in the upfront radiosurgery group and 1.51 (95% CI, 1.23-1.84) in the wait-and-scan group, showing a significantly greater tumor volume reduction in patients treated with upfront radiosurgery (wait-and-scan to upfront radiosurgery ratio, 1.73; 95% CI, 1.23-2.44; P = .002). Of 26 secondary outcomes, 25 showed no significant difference. No radiation-associated complications were observed.

Conclusion and relevance

Among patients with newly diagnosed small- and medium-sized vestibular schwannoma, upfront radiosurgery demonstrated a significantly greater tumor volume reduction at 4 years than a wait-and-scan approach with treatment upon tumor growth. These findings may help inform treatment decisions for patients with vestibular schwannoma, and further investigation of long-term clinical outcomes is needed.

Trial Registration

ClinicalTrials.gov Identifier: NCT02249572.

Simultaneous Cochlear Implantation and Salvage Translabyrinthine Resection of Vestibular Schwannoma after Radiotherapy

OBJECTIVE

To report on the novel use of simultaneous cochlear implantation (CI) during salvage translabyrinthine resection of vestibular schwannoma (VS) after failed stereotactic radiosurgery (SRS).

PATIENT

A 52-year-old woman presented with a medium-sized right VS. She experienced continued tumor growth despite previous SRS, resulting in medial extension beyond the internal auditory canal into the cerebellopontine angle. Associated symptoms included asymmetrical right moderate to severe sensorineural hearing loss, poor word recognition, tinnitus, and dizziness.

INTERVENTION

Simultaneous CI with translabyrinthine VS resection.

MAIN OUTCOME MEASURE

CI-aided pure-tone averages.

RESULTS

After 4 months of device use, CI-aided speech audiometry revealed hearing thresholds in the normal range, with a four-tone pure-tone, average of 16.3 dB. Speech perception with consonant-nucleus-consonant testing in the CI-only condition was 46%, representing a 12% improvement compared with preoperatively. Tinnitus and dizziness burden were subjectively reduced.

CONCLUSIONS

Despite challenges inherent to second procedures after radiotherapy failure, successful CI outcomes can be achieved. The current study demonstrates the feasibility of simultaneous CI during salvage VS resection after SRS. A larger study should be undertaken to further substantiate these preliminary findings.

Single Fraction and Hypofractionated Radiation Cause Cochlear Damage, Hearing Loss, and Reduced Viability of Merlin-Deficient Schwann Cells

BACKGROUND

Vestibular schwannomas (VS) are benign intracranial tumors caused by loss of function of the merlin tumor suppressor. We tested three hypotheses related to radiation, hearing loss (HL), and VS cell survival: (1) radiation causes HL by injuring auditory hair cells (AHC), (2) fractionation reduces radiation-induced HL, and (3) single fraction and equivalent appropriately dosed multi-fractions are equally effective at controlling VS growth. We investigated the effects of single fraction and hypofractionated radiation on hearing thresholds in rats, cell death pathways in rat cochleae, and viability of human merlin-deficient Schwann cells (MD-SC).

METHODS

Adult rats received cochlear irradiation with single fraction (0 to 18 Gray [Gy]) or hypofractionated radiation. Auditory brainstem response (ABR) testing was performed for 24 weeks. AHC viabilities were determined using immunohistochemistry. Neonatal rat cochleae were harvested after irradiation, and gene- and cell-based assays were conducted. MD-SCs were irradiated, and viability assays and immunofluorescence for DNA damage and cell cycle markers were performed.

RESULTS

Radiation caused dose-dependent and progressive HL in rats and AHC losses by promoting expression of apoptosis-associated genes and proteins. When compared to 12 Gy single fraction, hypofractionation caused smaller ABR threshold and pure tone average shifts and was more effective at reducing MD-SC viability.

CONCLUSIONS

Investigations into the mechanisms of radiation ototoxicity and VS radiobiology will help determine optimal radiation regimens and identify potential therapies to mitigate radiation-induced HL and improve VS tumor control.

Radiation for Sporadic Vestibular Schwannoma

Stereotactic radiosurgery (SRS) is a valid option for most patients undergoing treatment of small- and medium-sized vestibular schwannoma. Predictors of hearing preservation are the same for observation or surgery: when pretreatment hearing is normal, the tumor is smaller, and when a cerebrospinal fluid fundal cap exists. Hearing outcomes are poor when hearing loss exists pre-treatment. Rates of facial and trigeminal neuropathy are higher post-treatment after fractionated plans than single-fraction SRS. Subtotal resection and adjuvant radiation appears to offer patients with large tumors optimal outcomes for hearing, tumor control, and cranial nerve function versus gross total resection.

Translabyrinthine Approach for Sporadic Vestibular Schwannoma: Patient Selection, Technical Pearls, and Patient Outcomes

Herein we briefly describe the translabyrinthine approach to vestibular schwannoma resection as well as a focused literature review as to the best candidates, technical recommendations, and key outcomes with respect to other approaches.

Novel Multiportal Approach to the Internal Auditory Canal for Hearing-Preserving Surgery: Feasibility Assessment in Dissections

OBJECTIVE

State-of-the-art, minimally invasive endoscopic transcanal surgery of the internal auditory canal (IAC) sacrifices the cochlea with complete hearing loss. With a combination of the transcanal infracochlear and transmastoid retrolabyrinthine approaches, we aim to preserve hearing and enable minimally invasive surgical treatment of vestibular schwannoma. In this study, we investigate the anatomical indications and the feasibility of both approaches in dissections, in human whole head specimens.

METHODS

We operated whole head anatomical specimens with a four-handed technique, using the retrolabyrinthine approach as the main surgical corridor and the infracochlear approach for endoscopic visualization. We tested 4 different powered surgical systems. We collected intraoperative data on the size of the access windows, the surgical freedom, and the exposed area of the IAC. Finally, we evaluated the outcome in postoperative computed tomography scans.

RESULTS

Six out of 14 sides were anatomically suitable and qualified for the surgery based on preoperative computed tomography. In all attempted sides, the IAC could be reached and opened, leaving the ossicular chain and the labyrinth intact. 51%-75% of the length and 22%-40% of the circumference of the IAC could be exposed. All tested instruments were beneficial at different stages of the surgery. The four-handed technique enabled good maneuverability of the instruments.

CONCLUSIONS

The combined multiportal approach to the IAC is feasible with a good surgical exposure and full anatomical preservation of hearing. State-of-the-art surgical instruments in specimens with suitable anatomy are sufficient to perform this approach.

Factors Influencing Personalized Management of Vestibular Schwannoma: A Systematic Review

Management of vestibular schwannoma (VS) is a complex process aimed at identifying a clinical indication for fractionated stereotactic radiotherapy (sRT) or microsurgical resection or wait and scan (WS). The aim of the review was to clarify which patient and tumor parameters may lead to different therapeutic choices, with a view to a personalized VS approach. A systematic review according to Preferred Reporting Items for Systematic Review and Meta-Analysis criteria was conducted between February and March 2022. The authors defined six parameters that seemed to influence decision-making in VS management: 1-incidental VS; 2-tumor size; 3-tumor regrowth after sRT; 4-subtotal resection; 5-patients' age; 6-symptoms. The initial search yielded 3532 articles, and finally, 812 articles were included. Through a qualitative synthesis of the included studies, management strategies were evaluated and discussed. An individualized proposal of procedures is preferable as compared to a single gold-standard approach in VS decision-making. The most significant factors that need to be considered when dealing with a VS diagnosis are age, tumor size and hearing preservation issues.

Hearing Preservation After Intervention in Vestibular Schwannoma

OBJECTIVE

This study aimed to assess the durability of audiological outcomes after radiation and surgery in the management of vestibular schwannoma.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary academic center.

PATIENTS

Adults with sporadic vestibular schwannoma and serviceable hearing at the time of intervention.

INTERVENTIONS

Gamma Knife, middle cranial fossa, or retrosigmoid approaches.

MAIN OUTCOME MEASURES

Pure-tone audiometry and speech discrimination scores.

RESULTS

Postintervention serviceable hearing (class A/B) was preserved in 70.4% (n = 130; mean follow-up, 3.31 yr; range, 0-15.25 yr). Of the 49 patients treated with radiation, 19 (39.6%) had serviceable hearing at last follow-up, compared with 38 (46.9% of 81) who underwent retrosigmoid (n = 36 [44.4%]) and middle cranial fossa (n = 45 [55.6%]) approaches (odds ratio [OR], 1.40; 95% confidence interval [CI], 0.67-2.82; p = 0.47). A matched analysis by age, tumor volume, and preintervention hearing (n = 38) also found no difference in hearing preservation (HP) likelihood between surgery and radiation (OR, 2.33; 95% CI, 0.24-35.91; p = 0.59). After initial HP, 4 (9.5%) surgical versus 10 (37.0%) radiated patients subsequently lost residual serviceable (A/B) hearing (OR, 0.18; 95% CI, 0.06-0.69; p = 0.01) at a mean 3.74 ± 3.58 and 4.73 ± 3.83 years after surgery and radiation, respectively. Overall, 5- and 10-year HP rates (A/B) after initially successful HP surgery were 84.4 and 63.0%, respectively. However, survival estimates declined to 48.9% at 5 years and 32.7% at 10 years when patients with immediate postoperative serviceable hearing loss were also included, which were comparable to radiation-HP rates at 5 and 10 years of 28.0 and 14.2%, respectively ( p = 0.75).

CONCLUSIONS

After vestibular schwannoma intervention, overall HP was similar between radiated and surgical cohorts. However, when successful, surgical approaches offered more durable hearing outcomes at long-term follow-up.

Early Translabyrinthine Surgery for Small- and Medium-Sized Vestibular Schwannomas: Consecutive Cohort Analysis of Outcomes

OBJECTIVE

Reappraisal of the role of translabyrinthine (TLAB) surgery in small- and medium-sized vestibular schwannomas (VSs).

STUDY DESIGN

Retrospective study.

SETTING

Tertiary referral center.

PATIENTS

A total of 330 consecutive patients diagnosed between 1973 and 2019 with small- and medium-sized VS up to 20 mm in the extrameatal portion submitted to surgical treatment.

INTERVENTIONS

VS removal through microscopic TLAB approach.

MAIN OUTCOME MEASURES

Facial nerve function according to the House-Brackmann scale at 12-month follow-up, postoperative complications and entity of tumor resection assessed with postoperative MRI. A comparative analysis of outcomes between two groups of patients was further conducted, according to tumor size: Group A, small-sized (intrameatal or ≤10 mm extrameatal tumors) and Group B, medium-sized VSs (extrameatal between 11 and 20 mm).

RESULTS

Complete tumor removal was achieved in all cases. The overall complication rate was 5.5%, being cerebrospinal fluid leak the most frequent. Patients with small-sized VS (n = 121) presented a significantly better facial nerve function than patients with medium-sized tumors (n = 209), showing House-Brackmann Grades I to II in 92.6% versus 73.6% of cases, respectively ( p < 0.001). A nearly 4.5-fold higher risk of poor facial nerve function at 12 months affects patients with medium-sized tumors (odds ratio, 4.473; 95% confidence interval, 2.122-9.430; p < 0.001).

CONCLUSION

In the current scenario of multioptional VS management, when hearing preservation is not feasible, early TLAB approach as first-line treatment for small-sized VSs showed favorable results. Factors supporting such proactive surgical treatment include long-term definitive cure, no major complications, good facial nerve outcomes, and the possibility of simultaneous hearing rehabilitation with a cochlear implant.

Wait and Scan Management of Intra-canalicular Vestibular Schwannomas: Analysis of Growth and Hearing Outcome

OBJECTIVE

To report on the results of intracanalicular vestibular schwannomas (ICVS) that were managed by wait and scan and to analyze the possible predictors of tumor growth and hearing deterioration throughout the observation period.

STUDY DESIGN

A retrospective case series.

SETTING

Quaternary referral center for skull base pathologies.

PATIENTS

Patients with sporadic ICVS managed by wait and scan.

INTERVENTION

Serial resonance imaging (MRI) with size measurement and serial audiological evaluation.

MAIN OUTCOME MEASURE

Tumor growth defined as 2 mm increase of maximal tumor diameter, further treatment, and hearing preservation either maintain initial modified Sanna hearing class, or maintain initial serviceable hearing (class A/B).

RESULTS

339 patients were enrolled. The mean follow-up was 36.5±31.7 months with a median of 24 months. Tumor growth occurred in 141 patients (40.6%) either as slow growth (SG) in 26.3% of cases or fast growth (FG) in 15.3% of cases. Intervention was performed in only 64 cases (18.8%). Out of 271 patients who underwent hearing analysis, 86 patients (33.5%) showed hearing deterioration to a lower hearing class of the modified Sanna classification. Tumor growth and older age were predictors of hearing deterioration. Of the 125 cases with initial serviceable hearing (Class A/B), 91 cases (72.8%) maintained serviceable hearing at last follow-up. Tumor growth and a worse initial pure tone average (PTA) were predictors of hearing deterioration.

CONCLUSIONS

Wait and scan management of ICVS is a viable option and only 18.8% of patients needed further treatment. Hearing tends to deteriorate over time.

Hearing Preservation in Observed Sporadic Vestibular Schwannoma: A Systematic Review

OBJECTIVE

To characterize the natural history of hearing loss for patients presenting with serviceable hearing (SH) who undergo a wait-and-scan approach for sporadic vestibular schwannoma (VS) using aggregate time-to-event survival analysis.

STUDY DESIGN

Systematic review.

SETTING

Published international English literature, January 1, 2000 to May 31, 2020.

PATIENTS

Patients with sporadic VS entering a wait-and-scan approach with SH at diagnosis.

INTERVENTIONS

Observation with serial MRI and audiometry.

RESULTS

In total, 3,652 patients from 26 studies were included for analysis. Mean age at diagnosis was 58.8 years (SD, 4.1). Mean follow-up was 49.2 months (SD, 26.5). In total, 755 patients (21%) failed conservative treatment and underwent radiosurgery or microsurgery at the time of last follow-up. The average loss to follow-up was 6.9% (SD, 11.1). A total of 1,674 patients had SH at the time of diagnosis. Survival rates for maintaining SH were 96% at 1 year, 77% at 3 years, 62% at 5 years, and 42% at 10 years following diagnosis.

CONCLUSION

In this systematic review, aggregate data from 3,652 patients across 26 studies show consistent patterns in progression of hearing loss during observation for patients with sporadic VS as a function of time. As an easy-toremember conservative benchmark for those presenting with SH at diagnosis: approximately 75% retain SH at 3 years, 60% at 5 years, and 40% at 10 years.

Fractionated Proton Radiation Therapy and Hearing Preservation for Vestibular Schwannoma: Preliminary Analysis of a Prospective Phase 2 Clinical Trial

BACKGROUND

Local management for vestibular schwannoma (VS) is associated with excellent local control with focus on preserving long-term serviceable hearing. Fractionated proton radiation therapy (FPRT) may be associated with greater hearing preservation because of unique dosimetric properties of proton radiotherapy.

OBJECTIVE

To investigate hearing preservation rates of FPRT in adults with VS and secondarily assess local control and treatment-related toxicity.

METHODS

A prospective, single-arm, phase 2 clinical trial was conducted of patients with VS from 2010 to 2019. All patients had serviceable hearing at baseline and received FPRT to a total dose of 50.4 to 54 Gy relative biological effectiveness (RBE) over 28 to 30 fractions. Serviceable hearing preservation was defined as a Gardner-Robertson score of 1 to 2, measured by a pure tone average (PTA) of ≤50 dB and a word recognition score (WRS) of ≥50%.

RESULTS

Twenty patients had a median follow-up of 4.0 years (range 1.0-5.0 years). Local control at 4 years was 100%. Serviceable hearing preservation at 1 year was 53% (95% CI 29%-76%), and primary end point was not yet reached. Median PTA and median WRS both worsened 1 year after FPRT (P < .0001). WRS plateaued after 6 months, whereas PTA continued to worsen up to 1 year after FPRT. Median cochlea D90 was lower in patients with serviceable hearing at 1 year (40.6 Gy [RBE] vs 46.9 Gy [RBE]), trending toward Wilcoxon rank-sum test statistical significance (P = .0863). Treatment was well-tolerated, with one grade 1 cranial nerve V dysfunction and no grade 2+ cranial nerve dysfunction.

CONCLUSION

FPRT for VS did not meet the goal of serviceable hearing preservation. Higher cochlea doses trended to worsening hearing preservation, suggesting that dose to cochlea correlates with hearing preservation independent of treatment modality.

Outcome after Radiotherapy for Vestibular Schwannomas (VS)—Differences in Tumor Control, Symptoms and Quality of Life after Radiotherapy with Photon versus Proton Therapy

Background: To evaluate differences in local tumor control (LC), symptoms and quality of life (QOL) of 261 patients with VS after stereotactic radiosurgery/hypofractionated stereotactic radiotherapy (SRS/HFSRT) vs. fractionated radiotherapy (FRT) vs. fractionated proton therapy (FPT) were studied. Methods: For SRS/HFSRT (n = 149), the median fraction dose applied was 12 Gy. For FRT (n = 87) and FPT (n = 25), the median cumulative doses applied were 57.6 Gy and 54 Gy (RBE), respectively. FRT and FPT used single median doses of 1.8 Gy/Gy (RBE). Median follow-up was 38 months. We investigated dosimetry for organs at risk and analyzed toxicity and QOL by sending out a questionnaire. Results: LC was 99.5% at 12 months after RT with no statistical difference between treatment groups (p = 0.19). LC was significantly lower in NF2 patients (p = 0.004) and in patients with higher tumor extension grade (p = 0.039). The hearing preservation rate was 97% at 12 months after RT with no statistical difference between treatment groups (p = 0.31). Facial and trigeminal nerve affection after RT occurred as mild symptoms with highest toxicity rate in FPT patients. Conclusion: SRS/HFSRT, FRT and FPT for VS show similar overall clinical and functional outcomes. Cranial nerve impairment rates vary, potentially due to selection bias with larger VS in the FRT and FPT group.

Comparing Hearing Outcomes in Irradiated and Conservatively Managed Vestibular Schwannoma

OBJECTIVE

Compare hearing outcome for vestibular schwannoma patients following stereotactic radiosurgery (SRS) or conservative management.

STUDY DESIGN

Retrospective review.

SETTING

University Hospital.

PATIENTS

Patients with small- or medium-sized sporadic vestibular schwannoma (intracanalicular or with CPA component <2 cm) who were managed conservatively or underwent SRS with available clinical, radiological, and audiometric data from the time of presentation (or just before radiotherapy for the SRS group) and most recent follow-up; with the two sets of data to be compared being at least 3 years apart (minimum follow-up period).

INTERVENTIONS

SRS or observation.

MAIN OUTCOME MEASURE

Pure-tone averages, speech discrimination scores, and corresponding hearing classifications.

RESULTS

Two hundred forty-seven patients met our inclusion criteria; 140 were managed conservatively with a mean follow-up period of 5.9 ± 1.6 years and 107 underwent SRS with a mean follow-up period of 7.1 ± 1.9 years. There was significant deterioration of hearing measures for both groups; with the SRS group displaying consistently worse measures. SRS patients showed worse mean pure-tone averages and speech discrimination scores decline rates by 2.72 dB/yr and 2.98 %/yr, respectively, when compared with conservatively managed patients. Stratifying patients according to Tokyo's hearing classification revealed that 68.75% of conservatively managed patients who had baseline serviceable hearing preserved their hearing throughout the studied period compared with only 15.38% of the SRS patients.

CONCLUSION

Based on our data we conclude that patients with small- and medium-sized tumors will have a better hearing outcome if managed via an initial conservative approach with radiotherapy reserved for those demonstrating disease progression.

Hearing-Preserving Approaches to the Internal Auditory Canal: Feasibility Assessment from the Perspective of an Endoscope

OBJECTIVE

Minimally invasive transcanal transpromontorial endoscopic approaches to the internal auditory canal sacrifice the cochlea. Two hearing-preserving approaches, the exclusively endoscopic transcanal infracochlear approach and the endoscope-assisted transmastoid retrolabyrinthine approach, have been controversially discussed in the literature. In this study, we examine the feasibility of these 2 approaches by means of three-dimensional surface models, a population-based analysis of the available surgical space, and dissections in human whole-head specimens.

METHODS

We reconstructed three-dimensional surface models based on clinical high-resolution computed tomography scans of 53 adult temporal bones. For both approaches, we measured the maximal extensions and the area of the surgical access windows located between landmarks on the surrounding anatomic structures. We then identified the limiting extensions and derived the cumulative distribution to describe the available surgical space. Dissections were performed to validate the corridors and landmark selection.

RESULTS

The limiting extension for the infrachochlear approach is 7.0 ± 2.7 mm from the round window to the dome of the jugular bulb. The limiting extension for the retrolabyrinthine approach is 6.4 ± 1.5 mm from the dura of the posterior fossa to the facial nerve. The cumulative distribution shows that 80% of the cohort have access window extensions ≥3 mm for both approaches.

CONCLUSIONS

This study shows that in a high percentage of the measured cohort, the access windows are sufficiently large for endoscopic approaches to the internal auditory canal. With appropriate instrumentation, these hearing-preserving minimally invasive approaches may evolve into alternatives to surgical treatment.

Outcome and Toxicity of Proton Therapy for Vestibular Schwannoma: A Cohort Study

OBJECTIVE

To assess the efficacy and toxicity of proton radiotherapy in vestibular schwannoma.

STUDY DESIGN

Retrospective chart review and volumetric MRI-analyses.

SETTING

Tertiary referral center.

PATIENTS

Vestibular schwannoma patients treated with protons between 2003 and 2018.

INTERVENTION

Proton radiotherapy.

MAIN OUTCOME MEASURES

Tumor control was defined as not requiring salvage treatment. Progressive hearing loss was defined as a decrease in maximum speech discrimination score below the 95% critical difference in reference to the pretreatment score. Hearing assessment includes contralateral hearing and duration of follow-up. Dizziness and/or unsteadiness and facial and trigeminal nerve function were scored. Patients who had surgery prior to proton radiotherapy were separately assessed.

RESULTS

Of 221 included patients, 136 received single fraction and 85 fractionated proton radiotherapy. Actuarial 5-year local control rate was 96% (95% CI 90-98%). The median radiological follow-up was 4.5 years. Progressive postirradiation speech discrimination score loss occurred in 42% of patients with audiometric follow-up within a year. Facial paresis was found in 5% (usually mild), severe dizziness in 5%, and trigeminal neuralgia in 5% of patients receiving protons as primary treatment.

CONCLUSIONS

Proton radiotherapy achieves high tumor control with modest side effects aside from hearing loss in vestibular schwannoma patients. Limited and heterogeneous outcome reporting hamper comparisons to the literature. Potential sequelae of radiation therapy impacting vestibular function, cognitive function, and quality of life warrant further evaluation. Subgroups that benefit most from proton radiotherapy should be identified to optimize allocation and counterbalance its costs.

Long-term outcomes of rotating gamma knife for vestibular schwannoma: A 4-year prospective longitudinal study of 89 consecutive patients in Vietnam

Background:

Microsurgical total removal of vestibular schwannoma (VS) is the definitive treatment but has a high incidence of postoperative neurological deficits. Rotating Gamma Knife (RGK) is a preferred option for a small tumor. This study aims to evaluate long-term neurological outcomes of RGK for VS.

Methods:

This prospective longitudinal study was conducted at the Nuclear Medicine and Oncology Center, Bach Mai Hospital, Hanoi, Vietnam. Eighty-nine consecutive patients were enrolled from October 2011 to October 2015 and followed up to June 2017. RGK was indicated for VS measuring <2.2 cm, while RGK for tumors measuring 2.2–3 cm was considered in patients with severe comorbidities, high-risk surgery, and who denied surgery. Concurrently, VS consisted of newly diagnosed, postoperative residual, and recurrent tumors. Patients with neurofibromatosis type 2 were excluded from the study. Primary outcomes were radiological tumor control rate, vestibulocochlear functions, facial and trigeminal nerve preservation. Stereotactic radiosurgery was performed by the Rotating Gamma System Gamma ART 6000.

Results:

The tumors were measured 20.7 ± 5.6 mm at pre treatment and 17.6 ± 4.1 mm at 3-year post treatment. The mean radiation dose was 13.5 ± 0.9 Gy. Mean follow-up was 40.6 ± 13.3 months. The radiological tumor control rate was achieved 95.5% at 5-year post treatment. The hearing and vestibular functions were preserved in 70.3% and 68.9%, respectively. The facial and trigeminal nerve preservation rates were 94.4% and 73.3%, respectively.

Conclusion:

RGK is an effective and safe treatment for VS measuring ≤3 cm with no significant complications during long-term follow-up.

Primary treatment of small-to-medium (<3cm) sporadic vestibular schwannomas: A systematic review and meta-analysis on hearing preservation and tumor control rates for microsurgery versus radiosurgery

BACKGROUND

A meta-analysis of sporadic VS patients primarily treated with stereotactic radiosurgery (SRS) or microsurgery (MS) was performed, and hearing preservation outcome (HPO), tumor control (TC), and facial nerve dysfunction (FND) were analyzed.

METHODS

A systematic review was conducted (Medline and Scopus database) for the period, January 2010 to June 2020 with appropriate MeSH. English language articles for small-to-medium sporadic VS (<3cm) utilizing SRS or MS as primary treatment modality, with minimum follow-up of 3 years, were included. Studies had to report an acceptable standardized hearing metric.

RESULTS

Thirty-two studies met inclusion criteria: 10 (microsurgery); 23 (radiosurgery); (one comparative study included in both). HPO, at ∼65 months follow-up, were comparable between MS group (10 studies; 809 patients) and SRS group (23 studies; 1234 patients) (56% versus 59%, p=0.1527). TC, at ∼70 months follow-up, was significantly better in MS group (9 studies; 1635 patients) versus SRS group (19 studies; 2260 patients) (98% versus 92%, p < 0.0001). FND, at ∼ 12 months follow-up, was significantly higher in MS group (8 studies; 1101 patients) versus SRS group (17 studies; 2285 patients) (10% versus 2%, p < 0.0001).

CONCLUSION

MS and SRS are comparable primary treatments for small (<3cm) sporadic VS with respect to HPO at 5-year follow-up in patients with serviceable hearing at presentation; ∼50% patients for both modalities will likely lose serviceable hearing by that time-point. High TC rates (>90%) were seen with both modalities; MS (98%) versus SRS (92%). The post-treatment FND was significantly less with SRS group (2%) versus MS group (10%).

Lifetime Cost and Quality-Adjusted Life-Years Across Management Options for Small- and Medium-Sized Sporadic Vestibular Schwannoma

OBJECTIVE

Despite the growing emphasis on healthcare costs, limited data address this aspect of care within the vestibular schwannoma (VS) literature. We sought to determine which strategy confers the lowest lifetime cost and greatest quality-adjusted life-years (QALYs) for patients with small- to medium-sized sporadic VS tumors.

STUDY DESIGN

A Markov model was created to determine the most cost-effective management algorithm. Tumor characteristics, magnetic resonance imaging surveillance schedule, treatment outcomes, and health-related quality of life values were derived from previously published data. Cost estimates were based on CMS Fee Schedule reimbursement rates.

SETTING

Economic Evaluation Service within the Kern Center for the Science of Healthcare Delivery.

PATIENTS

Patients diagnosed with small- to medium-sized sporadic VS.

INTERVENTIONS

Upfront microsurgery following diagnosis, upfront radiosurgery following diagnosis, observation with microsurgery reserved for observed tumor growth, and observation with radiosurgery reserved for observed tumor growth.

RESULTS

Across patient ages at time of diagnosis ranging from 18 to 70 years, observation with subsequent radiosurgery used for tumor growth was the most cost-effective management algorithm while upfront microsurgery was the least. When presented with a hypothetical 50-year-old patient, the strategy with the lowest lifetime cost and highest QALYs was observation with subsequent radiosurgery reserved for tumor growth ($32,161, 14.11 QALY), followed by observation with microsurgery reserved for tumor growth ($34,503, 13.94 QALY), upfront radiosurgery ($43,456, 14.02 QALY), and lastly, upfront microsurgery ($47,252, 13.60 QALY). Sensitivity analyses varying mortality rates, estimated costs, health-related quality of life, and progression to nonserviceable hearing demonstrated consistent ranking among treatments.

CONCLUSIONS

When considering initial management of small- and medium-sized sporadic VSs, neither lifetime cost nor QALYs support upfront microsurgery or radiosurgery, even for younger patients. Initial observation with serial imaging, reserving radiosurgery or microsurgery for patients exhibiting tumor growth, confers the greatest potential for optimized lifetime healthcare cost and QALY outcomes.

Hear me out: rethinking internal auditory meatus magnetic resonance imaging in primary care. A cohort evaluation

Background

Imaging detects acoustic neuroma, a rare pathology associated with asymmetric sensorineural hearing loss and tinnitus, that is mostly managed conservatively. Scanning indication is debatable, without evaluation in primary care, despite the high burden of audiovestibular symptoms and commissioning of general practitioner imaging.

Method

Cohort evaluation of two years' internal auditory meatus magnetic resonance imaging in primary care.

Results

Of 200 scans requested by 77 general practitioners, only 33 per cent conformed to guideline indications. Most were referred to specialists, regardless of result. Only 10.5 per cent were appropriately imaged to rule out neuroma without specialist referral. One neuroma was detected (diagnostic yield 0.5 per cent) in a patient already referred. Incidental findings were shown in 44.5 per cent, triggering low-value cascades in 18 per cent. Whilst fewer than 1 in a 1000 imaged patients may improve through surgery, 1 in 5 can suffer negative imaging cascades.

Conclusion

Considering the bi-directional relationship between distress and audio-vestibular symptoms, anxiety-provoking imaging overuse should be minimised. In low-prevalence primary care, retrocochlear imaging could be limited to those with asymmetric sensorineural hearing loss. Alternatively, assessment and imaging could be shifted to audiologist-led settings, with a wider therapeutic offer, likely more beneficial and cost-effective than conventional surgical pathways.

Impact of vestibular nerve preservation on facial and hearing outcomes in small vestibular schwannoma surgery: a technical feasibility study

BACKGROUND

Management of small vestibular schwannomas (VSs) remains controversial. When surgery is chosen, the preservation of facial and cochlear nerve function is a priority. In this report, we introduce and evaluate a technique to anatomically preserve the vestibular nerves to minimize manipulation and preserve the function of the facial and cochlear nerves.

METHODS

The vestibular nerve preservation technique was prospectively applied to resect small VS tumors in patients with serviceable preoperative hearing (American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) class A or B). Clinical and radiological data were recorded and analyzed.

RESULTS

Ten patients met the inclusion criteria. The mean (SD) age was 40.4 (12.5) years. Follow-up ranged from 6 weeks to 2 years. The maximum tumor diameter parallel to the internal auditory canal ranged from 10 to 20 mm (mean, 14.9 (3.1) mm). There were three Koos grade 3 and seven Koos grade 2 tumors. Gross total resection was achieved in all cases. Both the facial and cochlear nerves were anatomically preserved in all cases. Postoperatively, 7 patients (70%) remained in the AAO-HNS class A or B hearing category. None of the patients had new vestibular symptoms, and all had House-Brackmann grade 1 facial function. Nervus intermedius dysfunction was observed in 1 patient preoperatively, which worsened postoperatively. Two patients had new nervus intermedius symptoms postoperatively.

CONCLUSION

Improvement of facial nerve and hearing outcomes is feasible through the intentional preservation of the vestibular nerves in the resection of small VSs. Longer follow-up is required to rule out tumor recurrence.

Time-based Assessment of Hearing Preservation Rates After Microsurgical Resection of Vestibular Schwannomas: A Systematic Review

OBJECTIVE

To determine short- and intermediate-term hearing preservation rates after microsurgical resection of vestibular schwannoma (VS).

DATA SOURCES

Systematic review of the Ovid, Cochrane, EMBASE, and Web of Science databases.

STUDY SELECTION

This study was restricted to full-text English-language articles detailing VS resection via the middle cranial fossa or retrosigmoid approaches. Documentation of pre- and posttreatment hearing outcomes with American Academy of Otolaryngology-Head and Neck Surgery, Gardner-Robertson, or word recognition score scales, as well as time to follow-up were required. Duplicate data sets, studies with >10% of patients with neurofibromatosis two, previous or nonsurgical VS treatment, case reports with <five patients, or studies detailing decompressive surgery were excluded.

DATA EXTRACTION

Two authors independently performed full-text reviews to determine study eligibility. Discrepancies were settled by consensus. "Class A/B, I/II" hearing was defined as AAO-HNS Class A or B, Gardner-Robertson Class 1 or 2, or PTA ≤ 50 dB with word recognition score ≥ 50% on audiogram.

DATA SYNTHESIS

Pooled estimates of preserved Class A/B, I/II hearing at last postoperative follow-up.

CONCLUSIONS

Of 1323 reports, 14 were utilized in analyses yielding data from 2,977 patients. Mean follow-up was 52.5 months (SD = 19.9). Class A/B, 1/2 hearing was preserved at last follow-up in 57% of patients. Meta-regression revealed that resection through the middle cranial fossa was associated with preservation of serviceable hearing. Moreover, when preserved in the immediate postoperative period, it seems to be stable over time.

What Genes Can Tell: A Closer Look at Vestibular Schwannoma

OBJECTIVE

Comprehensive molecular profiling of radioresistant and cystic vestibular schwannoma (VS) subtypes.

STUDY DESIGN

Our study utilized whole-exome sequencing (WES), RNA-sequencing (RNAseq), and correlated clinical data from 12 samples (2 samples of solid sporadic subtype, 8 with cystic changes, and 2 previously irradiated).

SETTING

Academic medical center.

PATIENTS

Patients diagnosed with VS who required surgical treatment. Inclusion: Cystic and radioresistant tumors matched to age and tumor volume, with solid sporadic VS samples as control; Exclusion: NF-2 patients.

INTERVENTION(S)

WES using custom probes for copy number analysis. A modified version of the Agilent Human Whole Exome sequencing hybrid capture system was used to process samples. Recurrent variants were identified and compared between groups. Leukocyte-derived DNA was utilized as internal control to reduce false-positives.

MAIN OUTCOME MEASURE(S)

Analysis of genetic landscape of VS subtypes (naive solid VS, cystic VS, and previously irradiated VS) by performing deep next-generation sequencing.

RESULTS

WES data achieved a mean coverage of 202X and RNAseq generated an average of 74 million total reads. As a group, 25% of samples had 22q loss. Somatic analysis identified previously reported genes and multiple novel mutations across samples. Differential expression analysis of RNAseq data found significantly mutated genes such as COL6A3, CLMP, ART4, Lumican that were shared by both cystic VS and irradiated VS, but not seen in sporadic VS.

CONCLUSIONS

Using WES we were able to demonstrate that cystic and irradiated samples are subtypes of VS with an increased mutation burden and a unique genetic fingerprint. We identified differences between the genomic and molecular profile of cystic VS and radioresistant VS. Our results help advance the understanding of the pathophysiology of these tumor subtypes and suggest possible molecular targets for novel treatment strategies.

Vestibular dose correlates with dizziness after radiosurgery for the treatment of vestibular schwannoma

BACKGROUND

Stereotactic radiosurgery (SRS) has been recognized as a first-line treatment option for small to moderate sized vestibular schwannoma (VS). Our aim is to evaluate the impact of SRS doses and other patient and disease characteristics on vestibular function in patients with VS.

METHODS

Data on VS patients treated with single-fraction SRS to 12 Gy were retrospectively reviewed. No dose constraints were given to the vestibule during optimization in treatment planning. Patient and tumor characteristics, pre- and post-SRS vestibular examination results and patient-reported dizziness were assessed from patient records.

RESULTS

Fifty-three patients were analyzed. Median follow-up was 32 months (range, 6-79). The median minimum, mean and maximum vestibular doses were 2.6 ± 1.6 Gy, 6.7 ± 2.8 Gy, and 11 ± 3.6 Gy, respectively. On univariate analysis, Koos grade (p = 0.04; OR: 3.45; 95% CI 1.01-11.81), tumor volume (median 6.1 cm3; range, 0.8-38; p = 0.01; OR: 4.85; 95% CI 1.43-16.49), presence of pre-SRS dizziness (p = 0.02; OR: 3.98; 95% CI 1.19-13.24) and minimum vestibular dose (p = 0.033; OR: 1.55; 95% CI 1.03-2.32) showed a significant association with patient-reported dizziness. On multivariate analysis, minimum vestibular dose remained significant (p = 0.02; OR: 1.75; 95% CI 1.05-2.89). Patients with improved caloric function had received significantly lower mean (1.5 ± 0.7 Gy, p = 0.01) and maximum doses (4 ± 1.5 Gy, p = 0.01) to the vestibule.

CONCLUSIONS

Our results reveal that 5 Gy and above minimum vestibular doses significantly worsened dizziness. Additionally, mean and maximum doses received by the vestibule were significantly lower in patients who had improved caloric function. Further investigations are needed to determine dose-volume parameters and their effects on vestibular toxicity.

Efficacy and comorbidities of hypofractionated and single-dose radiosurgery for vestibular schwannomas: a systematic review and meta-analysis

Background

Vestibular schwannomas (VS) are tumors of the cerebellopontine angle with significant morbidity, causing hearing loss, tinnitus, and trigeminal and facial nerve compromise. An effective alternative to microsurgical resection is stereotactic radiosurgery (SRS), which can be delivered in either single-fraction (SRS) or hypofractionated stereotactic radiotherapy (hSRT) (3-5 treatments) regimens. It remains unclear which fractionation regimen provides superior outcomes.

Methods

Ovid MEDLINE, EMBASE, CINAHL, and Cochrane Reviews were searched for studies either comparing hSRT with SRS or focusing on hSRT alone in treating VS. Primary endpoints included tumor control, serviceable hearing, tinnitus, and cranial nerve V and VII symptoms. A random-effects analysis was employed to compare pre- and post-treatment effects (hSRT alone) or SRS and hSRT outcomes (two-arm studies).

Results

This analysis included 21 studies focusing on hSRT alone and 13 studies comparing SRS and hSRT. Significant heterogeneity was observed. Overall, when hSRT was analyzed alone, crude tumor control was achieved in 94% (95% CI: 88%, 99%) of 1571 patients. There was no difference between pre- and post-treatment odds ratios (OR) of tinnitus, facial, or trigeminal impairment. Serviceable hearing was diminished following hSRT (OR = 0.60, 95% CI: 0.44, 0.83). Comparison with SRS showed no difference with respect to tumor control, serviceable hearing, trigeminal or facial nerve impairment.

Conclusions

hSRT achieved excellent tumor control and, with the exception of serviceable hearing, did not result in worse post-treatment cranial nerve symptomatology. Analysis of comparative studies between hSRT and SRS did not reveal any significant difference in either tumor control or treatment morbidities.

[Hearing classification in patients with vestibular schwannoma using German-language test procedures]

BACKGROUND

Hearing function in patients with vestibular schwannoma is often classified according to the Gardner and Robertson (1988) or the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS, 1995) systems. These classification systems are based on English-language test procedures, there is no German-language equivalent. The aim of the study was to investigate the influence of various target parameters on hearing classification and to derive a recommendation for the use of German-language test methods.

MATERIALS AND METHODS

The rules for speech audiometry based on English-language test procedures were applied to German speech test materials. In 91 patients with vestibular schwannoma, pure tone hearing thresholds, speech recognition thresholds, and speech discrimination at different sound pressure levels were measured. The patients were categorized according to the Gardner and Robertson and AAO-HNS classifications.

RESULTS

In both the Gardner-Robertson and the AAO-HNS classifications, the number of patients in the hearing classes with serviceable hearing function (measured as Pure Tone Average across three (3PTA) or four (4PTA) frequencies) was highest when using the 3PTA_{0,5;1;2 kHz} condition, followed by 4PTA_{0,5;1;2;3 kHz}, 4PTA_{0,5;1;2;4 kHz}, and 4PTA_{0,5;1;2;"3"kHz}. If maximum word recognition score (WRS_max) was used instead of word recognition 40 dB above the sensation level (WRS_40SL), more patients were classified into the hearing classes with serviceable hearing function, irrespective of the mean pure tone hearing threshold.

CONCLUSION

The Gardner-Robertson and AAO-HNS classifications can be used in German-speaking settings. The Freiburg monosyllabic test can be used to determine speech discrimination scores or maximum word recognition.

Health Care Utilization in Patients Undergoing Repeat Stereotactic Radiosurgery for Vestibular Schwannoma with 5-Year Follow-up: A National Database Analysis

Background Stereotactic radiosurgery (SRS) has been used as an alternative to microsurgery in patients with small vestibular schwannoma (VS). We compare health care utilization metrics in patients undergoing repeat-SRS (re-SRS) and no repeat SRS (nr-SRS) at long-term follow-up.

Materials and Methods We queried the MarketScan database using International Classification of Diseases, Ninth Revision and Current Procedural Terminology 4, from 2000 to 2016. We included adult patients who had diagnosis of VS and treatment with SRS with at least 5 years of continuous enrollment after the procedure. Outcomes were hospital admissions, outpatient services, and medication refills.

Results Of 1,047 patients, 5.1% (n = 53) had repeat SRS. Majority of re-SRS (74%, n = 39) were done within 2 years of index procedure and 51% were within 1-year of initial procedure. Patients who required re-SRS incurred higher hospital readmission rate, outpatient services, and had higher payments compared with those who did not require re-SRS at 6 months, 1 year, and 2 years following the initial procedures. Re-SRS received 3.0- and 3.1-times higher payments at 1 and 2 years compared with nr-SRS cohort. At 5 years following SRS, median combined payments for re-SRS cohort was $105286 (interquartile range [IQR] $70999, $156569) compared with $44172 (IQR $22956, $84840) for nr-SRS cohort.

Conclusion More than half of the re-SRS procedures were noted within first year of initial SRS for VS. Overall payments at 5 years for repeat SRS was more than double that for nr-SRS. Repeat SRS was also associated with more re-admissions and outpatient services at annual follow-up time points.

Hearing and Quality of Life Over Time in Vestibular Schwannoma Patients: Observation Compared to Stereotactic Radiosurgery

OBJECTIVE

To examine quality of life changes for patients with vestibular schwannoma (VS) undergoing observation or stereotactic radiosurgery (SRS).

STUDY DESIGN

Retrospective review.

SETTING

Academic medical center.

PATIENTS

Patients with VS who underwent observation or SRS and had at least two audiograms and Penn Acoustic Neuroma Quality of Life (PANQOL) surveys, a quality of life survey for patients with VS.

INTERVENTIONS

SRS or observation.

MAIN OUTCOME MEASURES

Pure-tone average (PTA), speech discrimination score (SDS), PANQOL score; controlling for tumor size, baseline hearing, and other factors.

RESULTS

One hundred twenty-three patients met inclusion criteria: 89 underwent observation and 34 SRS. There was no significant difference in the rate of decline measured by PTA (PTA worsened at a rate of 0.25 dB/yr more in the observation group compared with the SRS group, p = 0.77) and SDS (SDS worsened at a rate of 2.1%/yr more in the SRS group compared with the observation group, p = 0.82). Kaplan-Meier analysis demonstrated the SRS group had a higher probability to progress to class D hearing over observation (hazard ratio 7.1, p = 0.005). The rate of change of the SRS PANQOL scores was significantly improved in the total (p = 0.005) and hearing (p = 0.04) domain score compared with observation. However, both groups regress to a similar PANQOL total and hearing domain score over time.

CONCLUSION

PANQOL scores were higher at baseline in the observation group than in the SRS group. However, over time, PANQOL scores in the observation group decreased while PANQOL scores in the SRS group increased, resulting in PANQOL scores that were equivalent by the end of follow-up.

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.

Hearing Preservation in Stereotactic Radiosurgery for Vestibular Schwannoma

Despite no universally accepted definition of hearing preservation following vestibular schwannoma (VS) treatment, numerous variables have been identified as possible factors that may affect hearing outcomes following radiotherapy. Age, pretreatment hearing, radiation dose, tumor location and size, length of follow-up, fractionation, and timing of radiation have all been explored, among other variables, as factors related to hearing outcomes following radiation. These variables and associated hearing outcomes will be explored in detail, summarizing the literature to date to improve patient counseling for those patients who present with serviceable hearing and are considering their VS management options.

Hearing Preservation in Vestibular Schwannoma Surgery

Modern imaging techniques allow early detection of small vestibular schwannomas (VSs) with minimal or no hearing impairment. While controversy surrounds the management of these tumors, given their benign nature and unpredictable natural history, microsurgical excision is the only modality that offers the opportunity to cure the tumor and preserve hearing. Hearing preservation in VS surgery may be accomplished via the middle fossa or retrosigmoid approaches. Appropriate patient selection and surgical approach is critical in achieving the best hearing outcomes. This article highlights the preoperative assessment, patient selection and prognostic factors, intraoperative monitoring of hearing, and surgical approaches to optimize hearing preservation during VS removal.

Progression of hearing loss after LINAC-based stereotactic radiotherapy for vestibular schwannoma is associated with cochlear dose, not with pre-treatment hearing level

Background

Although stereotactic radiotherapy (SRT) for vestibular schwannoma has demonstrated excellent local control rates, hearing deterioration is often reported after treatment. We therefore wished to assess the change in hearing loss after SRT and to determine which patient, tumor and treatment-related factors influence deterioration.

Methods

We retrospectively analyzed progression of hearing loss in patients with vestibular schwannoma who had received stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT) as a primary treatment between 2000 and 2014. SRS had been delivered as a single fraction of 12 Gy, and patients treated with FSRT had received 30 fractions of 1.8 Gy. To compare the effects of SRS and FSRT, we converted cochlear doses into EQD₂. Primary outcomes were loss of functional hearing, Gardner Robertson (GR) classes I and II, and loss of baseline hearing class. These events were used in Kaplan Meier plots and Cox regression. We also calculated the rate of change in Pure Tone Average (PTA) in dB per month elapsed after radiation—a measure we use in linear regression—to assess the associations between the rate of change in PTA and age, pre-treatment hearing level, tumor size, dose scheme, cochlear dose, and time elapsed after treatment (time-to-first-audiogram).

Results

The median follow-up was 36 months for 67 SRS patients and 63 months for 27 FSRT patients. Multivariate Cox regression and in linear regression both showed that the cochlear V90 was significantly associated with the progression of hearing loss. But although pre-treatment PTA correlated with rate of change in Cox regression, it did not correlate in linear regression. The time-to-first-audiogram was also significantly associated, indicating time dependency of the rate of change. None of the analysis showed a significant difference between dose schemes.

Conclusions

We found no significant difference between SRS and FSRT. As the deterioration in hearing after radiotherapy for vestibular schwannoma was associated with the cochlea V90, restricting the V90 may reduce progression of hearing loss. The association between loss of functional hearing and baseline PTA seems to be biased by the use of a categorized variable for hearing loss.