Long-term hearing preservation in vestibular schwannoma

Analysis of the association between vestibular schwannoma and hearing status using a newly developed radiomics technique

PURPOSE

Vestibular schwannoma is a benign tumor originating from Schwann cells surrounding the eighth cranial nerve and can cause hearing loss, tinnitus, balance problems, and facial nerve disorders. Because of the slow growth of the tumor, predicting the hearing function of patients with vestibular schwannoma's is important to obtain information that would be useful for deciding the treatment modality. This study aimed to analyze the association between magnetic resonance imaging features and hearing status using a new radiomics technique.

METHODS

We retrospectively analyzed 115 magnetic resonance images and hearing results from 73 patients with vestibular schwannoma. A total of 70 radiomics features from each tumor volume were calculated using T1-weighted magnetic resonance imaging. Radiomics features were classified as histogram-based, shape-based, texture-based, and filter-based. The least absolute shrinkage and selection operator method was used to select the radiomics features among the 70 features that best predicted the hearing test. To ensure the stability of the selected features, the least absolute shrinkage and selection operator method was repeated 10 times. Finally, features set five or more times were selected as radiomics signatures.

RESULTS

The radiomics signatures selected using the least absolute shrinkage and selection operator method were: minimum, variance, maximum 3D diameter, size zone variance, log skewness, skewness slope, and kurtosis slope. In random forest, the mean performance was 0.66 (0.63-0.77), and the most important feature was Log skewness.

CONCLUSIONS

Newly developed radiomics features are associated with hearing status in patients with vestibular schwannoma and could provide information when deciding the treatment modality.

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.

Evolution in the management of vestibular schwannoma: a single-center 15-year experience

PURPOSE

To highlight the changes in the management of vestibular schwannoma (VS) since 2004 with a focus on small- to middle-size VS.

METHODS

Retrospective analysis of the decisions made in skull base tumor board between 2004 and 2021.

RESULTS

1819 decisions were analyzed (average age 59.25, 54% females). Overall, 850 (47%) cases were allocated to a Wait and Scan (WS) approach, 416 (23%) received radiotherapy and 553 (30%) were treated surgically (MS). All stages considered WS increased from 39% before 2010 to 50% after 2010. Similarly, Stereotactic Radio Therapy (SRT) increased from 5 to 18%. MS decreased from 46 to 25%. It was more commonly proposed to younger patients and larger tumors, p < 0.001. For Koos stages 1, 2, and 3 there was a statistically significant increase in SRT, and a decrease in MS, p < 0.001. WS also increased for stages 1 and 2. However, such a trend was not observed for stage 3. MS remained the primary treatment modality for stage 4 tumors throughout the study period, p = 0.057. The significance of advanced age as a factor favoring SRT decreased over time. The opposite is true for serviceable hearing. There was also a decrease in the percentage of the justification "young age" in the MS category.

CONCLUSION

The is a continuing trend towards non-surgical treatment. Small- to medium-sized VS witnessed an increase in both WS and SRT. There is only an increase in SRT for moderately large VS. Physicians are less and less considering young age as a factor favoring MS over SRT. There is a tendency towards favoring SRT when hearing is serviceable.

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.

Vestibular Impairment in Patients with Vestibular Schwannoma: A Journey through the Pitfalls of Current Literature

Vestibular Schwannoma is the most common tumour of Ponto Cerebellar Angle and is capable of strongly impacting the patient's quality of life. In recent decades, the proposals for the management of the disease have multiplied, just as the diagnostic capacity has improved. While in the past, the primary objective was the preservation of the facial function, and subsequently also of the auditory function, the attention to the vestibular symptomatology, which appears to be one of the main indicators of deterioration of quality of life, is still unsatisfactory. Many authors have tried to provide guidance on the best possible management strategy, but a universally recognized guideline is still lacking. This article offers an overview of the disease and the proposals which have advanced in the last twenty years, evaluating their qualities and defects in a critical reading.

Natural History of Hearing Loss in Sporadic Vestibular Schwannoma

Hearing loss is the most common and earliest symptom of sporadic vestibular schwannoma (VS). The most common pattern of hearing loss is asymmetric sensorineural hearing loss. Throughout its natural history, patients with serviceable hearing (SH) maintain SH at 94% to 95% after 1 year, 73% to 77% after 2 years, 56% to 66% after 5 years, and 32% to 44% after 10 years. For patients newly diagnosed with VS, it is likely their hearing will worsen despite small initial tumor size or lack of tumor growth.

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.

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.

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.

[Cochlear nerve continuity preservation during retrosigmoid ablative osteotomy of the internal auditory canal for advanced vestibular schwannomas]

The data of 86 patients with retrosigmoid microsurgical resection of vestibular schwannoma in tumor stage Koos II-IV were evaluated. In more than two thirds of the cases it was shown that the cochlear nerve followed the facial nerve, which is easily identified by electroneurography, in recurrent similar patterns in the region of the internal auditory canal. Starting from the fundus, this facilitated early identification and thus preservation of continuity of the cochlear nerve in the course of the internal auditory canal. This was of particular importance when safe functional preservation could not be guaranteed due to tumor size or formation despite intraoperative derivation of somatosenoric potentials, but when the possibility of subsequent hearing rehabilitation with a cochlear implant should be granted. Preoperative MRI sequences gave an indication of the possible nerve courses in some cases, but intraoperative imaging in the internal auditory canal was superior to MRI.

Analysis of Hearing Preservation in Middle Cranial Fossa Resection of Vestibular Schwannoma

OBJECTIVE

Describe the effect of preoperative hearing on the likelihood of hearing preservation after middle cranial fossa (MCF) approach for resection of vestibular schwannoma (VS) and the effect of hearing preservation on disease-specific quality of life (QOL).

STUDY DESIGN

Retrospective chart review.

SETTING

Academic tertiary care skull base surgery program.

PATIENTS

Sixty three adult patients with preoperative word recognition score (WRS) ≥50% who underwent MCF resection of VS between 2017 and 2020.

INTERVENTIONS

All patients underwent MCF VS resection with attempted hearing preservation.

MAIN OUTCOME MEASURES

Hearing preservation (postoperative WRS ≥50%), hearing-related Penn Acoustic Neuroma Quality of Life (PANQOL) score.

RESULTS

Sixty three patients with mean age 47.4 (±9.6) years and tumor size 11.5 (±0.5) mm were analyzed. Hearing was preserved (+HP) and lost (-HP) in 37 (58.7%) and 26 (41.3%) patients, respectively. Preoperatively, pure tone average audiometry was significantly lower among the +HP group (20.0 dB) versus -HP (31.0 dB, p < 0.003). WRS was higher among +HP versus -HP (94% vs. 84%, respectively; p < 0.002). Linear regression showed that intra- versus extra-canalicular tumor location, sudden hearing loss history, fundal fluid cap thickness, and tumor size had no relationship to hearing preservation outcomes. When evaluating postoperative QOL data (n = 37) hearing-related PANQOL score differed between +HP and -HP (t35 = 2.458, p = 0.0191) groups.

CONCLUSIONS

In this cohort of patients undergoing MCF resection of VS, rates of HP were higher for patients with excellent preoperative hearing. Postoperatively, +HP patients reported improved hearing-related PANQOL scores compared to -HP patients.

Evolution in Surgical Treatment of Vestibular Schwannomas

Purpose of Review

Management of vestibular schwannomas (VSs) is multimodal and include watchful observation, radiation treatment, and surgery. Over the past decades, a shift in treatment strategy toward radiation treatment has gradually displaced surgery from the main treatment option for VS. In recent years, however, surgery has been further refined by developments of microsurgical and endoscopic techniques and advances in intraoperative application of neuroprotective drugs. This article presents outcomes of modern surgical treatment of VS in the era of radiosurgery and reviews recent published advancements relevant to VS management.

Recent Findings

Following VS surgery, excellent tumor resection rates and cranial nerve outcomes were achieved in a consecutive series of 572 adult patients with mean postoperative follow up of 4 years. Innovations in surgical technique include endoscopic technique as additional tool to microsurgery, exploration of semi-sitting position for large tumors, and intraoperative use of vasoactive agents as neuroprotective strategy.

Summary

Despite great developments in radiation treatment of VS, surgery remains the key solution for the majority of the cases in order to achieve cure of the disease, long-term tumor control, and preservation of cranial nerve function at long-term.

Beyond the ABCs: Hearing Loss and Quality of Life in Vestibular Schwannoma

OBJECTIVE

To assess the impact of differential hearing loss on QOL in sporadic unilateral vestibular schwannoma.

PATIENTS AND METHODS

Cross-sectional observational multicenter study including 422 patients with vestibular schwannoma and formal audiometry within 1 year of survey administration, analyzed using multivariable regression.

RESULTS

Among 422 patients included, the median age was 57 (range, 18-81) years; 223 (53%) were women. Among 390 patients with complete audiometric data, American Academy of Otolaryngology-Head and Neck Surgery class was A in 134 (34%), B in 69 (18%), C in 26 (7%), and D in 161 (41%). A total of 335 of 390 (86%) reported subjective ipsilateral hearing loss (median severity, 6/10 [1 = normal, 10 = deaf]), 166 (43%) reported ipsilateral inability to use the telephone, 155 (37%) reported that hearing loss had affected personal relationships, and 213 (51%) reported difficulty with conversations. After adjusting for age and sex, the odds ratio (OR) for hearing loss adversely affecting relationships was 4.4 for class B hearing vs class A (95% CI, 2.1-9.4; P<.0001). The OR for difficulty with conversations was 2.7 for class B vs class A (95% CI, 1.4-5.3; P=.003). The OR for lost ipsilateral telephone use was 6.3 for class B vs class A (95% CI, 3.2-13.0; P<.0001). Differences between class B and class C were not significant. WRS outperformed PTA as a predictor of hearing-related QOL. The optimal threshold for predicting a significant adverse impact on QOL was WRS less than 72% to 76%.

CONCLUSION

Hearing loss adversely affects QOL after only modest audiometric disability. The WRS alone appears to be a much more reliable predictor of hearing-related QOL than PTA or American Academy of Otolaryngology-Head and Neck Surgery class.

Long-Term Outcomes of Sporadic Vestibular Schwannomas Treated with Recent Stereotactic Radiosurgery Techniques

PURPOSE

Vestibular schwannomas (VSs) are benign; thus, understanding long-term tumor control and late adverse radiation effects of stereotactic radiosurgery (SRS) through current radiosurgical techniques is important to inform treatment decisions. Our aim was to clarify long-term tumor control rates and incidence of late adverse radiation effects in patients with VSs followed for 5 years or longer after SRS.

METHODS AND MATERIALS

Altogether, 615 patients with VSs (excluding neurofibromatosis type 2 and partially treated tumors) followed for 5 years or longer after SRS using recent radiosurgical techniques were evaluated. All patients were treated at a margin dose of less than 14 Gy. All tumors were classified into 4 categories: type A (intracanalicular tumor, 87 patients [14%]), type B (cerebellopontine angle [CPA] tumor, 325 patients [53%]), type C (CPA tumor compressing the brain stem, 138 patients [22%]), and type D (CPA tumor compressing the brain stem with a deviation of the fourth ventricle, 65 patients [11%]). Median tumor volume was 2.0 cm³ and median marginal dose was 12 Gy.

RESULTS

Median follow-up period was 158 months. Actuarial 5-, 10-, and 15-year or longer local control (LC) rates were 93%, 91%, and 89%, respectively. Tumor type (P < .001, hazard ratio 2.389) and number of prior surgeries (P = .007, hazard ratio 1.698) were significant for LC. Depending on the tumor type, the actuarial 10-year LC rates were 100%, 93%, 88%, and 70% in type A, B, C, and D tumors, respectively. No patient developed persistent facial palsy. Twenty patients (3.3%) developed delayed cysts. One patient developed malignant transformation (0.2%).

CONCLUSIONS

SRS is a safe and effective treatment for VSs in the long term, excluding VSs compressing the brain stem with a deviation of the fourth ventricle. Delayed cysts such as cyst formation, enlarged preexisting cysts or extratumoral cysts, and malignant transformation should be considered possible causes of long-term treatment failures.

MRI monitoring of small and medium-sized vestibular schwannomas: predictors of growth

Background: Vestibular schwannomas are among the most common intracranial tumours. Their growth is difficult to predict.Objectives: To study the evolution of small and medium-sized vestibular schwannomas (VSs) and identify factors predictive of growth.Material and methods: This was a retrospective longitudinal study at a tertiary referral centre from January 2011 to January 2018. The inclusion criteria were radiological diagnosis of sporadic unilateral VS of stage I or II. Radiological and clinical data were analysed descriptively and by multivariate logistic regression to identify factors predictive of growth.Results: A total of 1105 cases were discussed in multidisciplinary meetings and 336 patients were included with a mean age of 57.8 years and a mean follow-up time of 24 months. Around two thirds of these patients (62.8%) had non-progressive tumours. Factors identified as predictive of VS growth were the size at diagnosis (OR = 2.622, 95% CI, 1.50-4.66; p = .001) and internal auditory canal filling (OR = 7.672; 95% CI, 4.52-13.43; p < .001).Conclusions and significance: Monitoring is the primary treatment modality for small or medium-sized VSs. As reported here for the first time, internal auditory canal filling is significantly associated with VS growth.

Surgery of the lateral skull base: a 50-year endeavour

Disregarding the widely used division of skull base into anterior and lateral, since the skull base should be conceived as a single anatomic structure, it was to our convenience to group all those approaches that run from the antero-lateral, pure lateral and postero-lateral side of the skull base as “Surgery of the lateral skull base”. “50 years of endeavour” points to the great effort which has been made over the last decades, when more and more difficult surgeries were performed by reducing morbidity. The principle of lateral skull base surgery, “remove skull base bone to approach the base itself and the adjacent sites of the endo-esocranium”, was then combined with function preservation and with tailoring surgery to the pathology. The concept that histology dictates the extent of resection, balancing the intrinsic morbidity of each approach was the object of the first section of the present report. The main surgical approaches were described in the second section and were conceived not as a step-by-step description of technique, but as the highlighthening of the surgical principles. The third section was centered on open issues related to the tumor and its treatment. The topic of vestibular schwannoma was investigated with the current debate on observation, hearing preservation surgery, hearing rehabilitation, radiotherapy and the recent efforts to detect biological markers able to predict tumor growth. Jugular foramen paragangliomas were treated in the frame of radical or partial surgery, radiotherapy, partial “tailored” surgery and observation. Surgery on meningioma was debated from the point of view of the neurosurgeon and of the otologist. Endolymphatic sac tumors and malignant tumors of the external auditory canal were also treated, as well as chordomas, chondrosarcomas and petrous bone cholesteatomas. Finally, the fourth section focused on free-choice topics which were assigned to aknowledged experts. The aim of this work was attempting to report the state of the art of the lateral skull base surgery after 50 years of hard work and, above all, to raise questions on those issues which still need an answer, as to allow progress in knowledge through sharing of various experiences. At the end of the reading, if more doubts remain rather than certainties, the aim of this work will probably be achieved.

Long-Term Hearing Outcomes Following Stereotactic Radiosurgery in Vestibular Schwannoma Patients-A Retrospective Cohort Study

BACKGROUND

An understanding of the hearing outcomes is needed for treatment counseling for patients with vestibular schwannomas (VS).

OBJECTIVE

To determine long-term hearing results following stereotactic radiosurgery (SRS) for VS and identify any influential variables.

METHODS

Tertiary hospital retrospective cohort.

RESULTS

There were 579 tumors (576 patients) treated with SRS. Eighty-two percent (473) of tumors had ≥1 yr and 59% (344 ≥3 yr follow-up. In the 244 tumor ears, with measurable hearing before SRS who were followed ≥1 yr, 14% (31) had improved hearing, 13% (29) unchanged hearing, and 74% (158) had worsened hearing. In 175 patients with ≥3 yr follow-up and who had measurable hearing pretreatment, 6% (11 ears) improved hearing, 31% (54 ears) unchanged hearing, and 63% (110 ears) had worsened hearing. Patients with tumors with larger target volumes (P = .040) and with neurofibromatosis type 2 (NF2; P = .017) were associated with poorer hearing (P = .040). Patients with word recognition scores (WRS) of 50% or poorer had tumors with a larger volume (P = .0002), larger linear size (P = .032), and NF2 (P = .045). Traditionally reported hearing outcomes using the Gardner Robertson maintenance of PTA ≤50 db or WRS ≥50% were 48% at 3 yr, which overestimates hearing outcomes compared to the above reporting standards.

CONCLUSION

Hearing declines over time in VS treated with SRS in a high proportion of cases. The frequency and magnitude of long-term hearing decline following SRS argues against prophylactic radiation for small tumors in hearing ears with undetermined growth behavior.

Long-Term Hearing Preservation Outcomes for Small Vestibular Schwannomas: Retrosigmoid Removal Versus Observation

OBJECTIVE

Management of small vestibular schwannomas (VSs) consists of three options: serial observation, radiosurgery, and microsurgery. The authors reported the long-term hearing outcomes after retrosigmoid tumor removal in 110 patients and hearing follow-up outcomes in 160 serial observation patients with small VSs to explore the appropriate management strategy and predictive factors of hearing preservation for small VSs.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary referral center.

PATIENTS

In this study, 110 patients with small VS (purely intracanalicular/cerebellopontine angle tumor ≤15 mm) during a 15-year period, from January 2001 to December 2015, were candidates for hearing preservation surgery through retrosigmoid approach, while 160 patients were candidates for serial observation. The main outcome measure was preservation of hearing under different hearing levels, assessed with the classification of American Academy of Otolaryngology-Head and Neck Surgery.

RESULTS

Preoperative hearing levels of the 110 study patients were Class A in 49 patients, Class B in 43 patients, and Class C in 18 patients. In all surgery patients (n = 110), 97.3% (107/110) patients maintained the same level during postoperative follow-up (mean follow-up time was 49.1 ± 28.2 mo) and 86 (78.2%) had complete radiologic and audiometric data at least 4 years follow-up for review. In the 4 years follow-up surgery group (n = 86), postoperative hearing levels were Class A, B, C, and D for 22, 11, 18, and 35 patients, and postoperative rates of preservation of serviceable and useful hearing were 59.3% (51/86) and 47.1% (33/70), respectively. In serial observation group, mean follow-up time was 35.2 ± 33.1 months; mean tumor size at presentation was 8.6 ± 4.3 mm; overall mean tumor growth rate was 1.08 ± 2.3 mm/yr; serviceable hearing preservation rate of 98 patients was 54.1% (53/98) at the 5-year end point and 48.7% (37/76) at the 7-year end point.

CONCLUSION

Tumor removal should be the first treatment option for patients with small VSs and preserved hearing, especially for young patients with good hearing; retrosigmoid approach is an effective and safe approach for small VSs removal with excellent functional outcomes; better preoperative hearing predicted a higher rate of postoperative hearing preservation; patients without fundal extension were more likely to achieve hearing preservation than those with fundal extension, but no difference had been detected when retrosigmoid removal assisted with endoscope was performed; patients with small tumors originating from SVN were more likely to achieve hearing preservation compared with those with IVN-originating tumors.

Systematic Review of Hearing Preservation After Radiotherapy for Vestibular Schwannoma

OBJECTIVE

To determine the long-term hearing preservation rate for spontaneous vestibular schwannoma treated by primary radiotherapy.

DATA SOURCES

The MEDLINE/PubMed, Web of Science, Cochrane Reviews, and EMBASE databases were searched using a comprehensive Boolean keyword search developed in conjunction with a scientific librarian. English language papers published from 2000 to 2016 were evaluated.

STUDY SELECTION

Inclusion criteria: full articles, pretreatment and posttreatment audiograms or audiogram based scoring system, vestibular schwannoma only tumor type, reported time to follow-up, published after 1999, use of either Gamma Knife or linear accelerator radiotherapy.

EXCLUSION CRITERIA

case report or series with fewer than five cases, inadequate audiometric data, inadequate time to follow-up, neurofibromatosis type 2 exceeding 10% of study population, previous treatment exceeding 10% of study population, repeat datasets, use of proton beam therapy, and non-English language.

DATA EXTRACTION

Two reviewers independently analyzed papers for inclusion. Class A/B, 1/2 hearing was defined as either pure tone average less than or equal to 50 db with speech discrimination score more than or equal to 50%, American Academy of Otolaryngology-Head & Neck Surgery (AAO-HNS) Hearing Class A or B, or Gardner-Robertson Grade I or II. Aggregate data were used when individual data were not specified.

DATA SYNTHESIS

Means were compared with student t test.

CONCLUSIONS

Forty seven articles containing a total of 2,195 patients with preserved Class A/B, 1/2 hearing were identified for analysis. The aggregate crude hearing preservation rate was 58% at an average reporting time of 46.6 months after radiotherapy treatment. Analysis of time-based reporting shows a clear trend of decreased hearing preservation extending to 10-year follow-up. This data encourages a future long-term controlled trial.

Decision Making in the Wait-and-Scan Approach for Vestibular Schwannomas: Is There a Price to Pay in Terms of Hearing, Facial Nerve, and Overall Outcomes?

BACKGROUND

The wait-and-scan modality has emerged as an important strategy in the management of vestibular schwannoma (VS) as it has been demonstrated that many tumors grow slowly or do not show any growth over long periods.

OBJECTIVE

To analyze long-term outcomes of wait-and-scan in the treatment of patients with VS, discuss the factors contributing to the decision making, determine the inherent risks of the policy, and compare our results with literature.

METHODS

In total, 576 patients with sporadic unilateral VS who were managed with wait-and-scan were reviewed retrospectively. Of these, a subset of 154 patients with 5-yr follow-up was separately analyzed. The tumor characteristics including patterns of growth, rate of growth, hearing outcomes, and likely factors affecting the above parameters were analyzed.

RESULTS

The mean period of follow-up was 36.9 ± 30.2 mo. The mean age was 59.2 ± 11.6 yr. Thirteen different patterns of tumor growth were observed. Eighty-four (54.5%) of 154 tumors with 5-yr follow-up showed no growth throughout 5 yr. Fifty-six (36.4%) tumors showed mixed growth rates. Only 57 (37%) patients had serviceable hearing at the start of follow-up, but 32 (56.1%) maintained it at the end of follow-up. One hundred fifty (26%) of the 576 patients who failed wait-and-scan had to be taken up for surgery.

CONCLUSION

While there may be no price to pay in wait-and-scan as far as hearing is concerned, this may not be the case for facial nerve outcomes, wherein the results may be better if the patients are taken earlier for surgery.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines on Hearing Preservation Outcomes in Patients With Sporadic Vestibular Schwannomas

Question 1

What is the overall probability of maintaining serviceable hearing following stereotactic radiosurgery utilizing modern dose planning, at 2, 5, and 10 yr following treatment?

Recommendation

Level 3: Individuals who meet these criteria and are considering stereotactic radiosurgery should be counseled that there is moderately high probability (>50%-75%) of hearing preservation at 2 yr, moderately high probability (>50%-75%) of hearing preservation at 5 yr, and moderately low probability (>25%-50%) of hearing preservation at 10 yr.

Question 2

Among patients with AAO-HNS (American Academy of Otolaryngology-Head and Neck Surgery hearing classification) class A or GR (Gardner-Robertson hearing classification) grade I hearing at baseline, what is the overall probability of maintaining serviceable hearing following stereotactic radiosurgery, utilizing modern dose planning, at 2, 5, and 10 yr following treatment?

Recommendation

Level 3: Individuals who meet these criteria and are considering stereotactic radiosurgery should be counseled that there is a high probability (>75%-100%) of hearing preservation at 2 yr, moderately high probability (>50%-75%) of hearing preservation at 5 yr, and moderately low probability (>25%-50%) of hearing preservation at 10 yr.

Question 3

What patient- and tumor-related factors influence progression to nonserviceable hearing following stereotactic radiosurgery using ≤13 Gy to the tumor margin?

Recommendation

Level 3: Individuals who meet these criteria and are considering stereotactic radiosurgery should be counseled regarding the probability of successful hearing preservation based on the following prognostic data: the most consistent prognostic features associated with maintenance of serviceable hearing are good preoperative word recognition and/or pure tone thresholds with variable cut-points reported, smaller tumor size, marginal tumor dose ≤12 Gy, and cochlear dose ≤4 Gy. Age and sex are not strong predictors of hearing preservation outcome.

Question 4

What is the overall probability of maintaining serviceable hearing following microsurgical resection of small to medium-sized sporadic vestibular schwannomas early after surgery, at 2, 5, and 10 yr following treatment?

Recommendation

Level 3: Individuals who meet these criteria and are considering microsurgical resection should be counseled that there is a moderately low probability (>25%-50%) of hearing preservation immediately following surgery, moderately low probability (>25%-50%) of hearing preservation at 2 yr, moderately low probability (>25%-50%) of hearing preservation at 5 yr, and moderately low probability (>25%-50%) of hearing preservation at 10 yr.

Question 5

Among patients with AAO-HNS class A or GR grade I hearing at baseline, what is the overall probability of maintaining serviceable hearing following microsurgical resection of small to medium-sized sporadic vestibular schwannomas early after surgery, at 2, 5, and 10 yr following treatment?

Recommendation

Level 3: Individuals who meet these criteria and are considering microsurgical resection should be counseled that there is a moderately high probability (>50%-75%) of hearing preservation immediately following surgery, moderately high probability (>50%-75%) of hearing preservation at 2 yr, moderately high probability (>50%-75%) of hearing preservation at 5 yr, and moderately low probability (>25%-50%) of hearing preservation at 10 yr.

Question 6

What patient- and tumor-related factors influence progression to nonserviceable hearing following microsurgical resection of small to medium-sized sporadic vestibular schwannomas?

Recommendation

Level 3: Individuals who meet these criteria and are considering microsurgical resection should be counseled regarding the probability of successful hearing preservation based on the following prognostic data: the most consistent prognostic features associated with maintenance of serviceable hearing are good preoperative word recognition and/or pure tone thresholds with variable cut-points reported, smaller tumor size commonly less than 1 cm, and presence of a distal internal auditory canal cerebrospinal fluid fundal cap. Age and sex are not strong predictors of hearing preservation outcome.

Question 7

What is the overall probability of maintaining serviceable hearing with conservative observation of vestibular schwannomas at 2, 5, and 10 yr following diagnosis?

Recommendation

Level 3: Individuals who meet these criteria and are considering observation should be counseled that there is a high probability (>75%-100%) of hearing preservation at 2 yr, moderately high probability (>50%-75%) of hearing preservation at 5 yr, and moderately low probability (>25%-50%) of hearing preservation at 10 yr.

Question 8

Among patients with AAO-HNS class A or GR grade I hearing at baseline, what is the overall probability of maintaining serviceable hearing with conservative observation at 2 and 5 yr following diagnosis?

Recommendation

Level 3: Individuals who meet these criteria and are considering stereotactic radiosurgery should be counseled that there is a high probability (>75%-100%) of hearing preservation at 2 yr, and moderately high probability (>50%-75%) of hearing preservation at 5 yr. Insufficient data were available to determine the probability of hearing preservation at 10 yr for this population subset.

Question 9

What patient and tumor-related factors influence progression to nonserviceable hearing during conservative observation?

Recommendation

Level 3: Individuals who meet these criteria and are considering observation should be counseled regarding probability of successful hearing preservation based on the following prognostic data: the most consistent prognostic features associated with maintenance of serviceable hearing are good preoperative word recognition and/or pure tone thresholds with variable cut-points reported, as well as nongrowth of the tumor. Tumor size at the time of diagnosis, age, and sex do not predict future development of nonserviceable hearing during observation.  The full guideline can be found at: https://www.cns.org/guidelines/guidelines-manage-ment-patients-vestibular-schwannoma/chapter_3.

Recent Trends in Vestibular Schwannoma Management: An 11-Year Analysis of the National Cancer Database

Objective

A better understanding of the natural history of vestibular schwannoma (VS) has resulted in a change in treatment paradigms. It has also been proposed that increased use of high-resolution magnetic resonance imaging has allowed for an increased identification of small tumors. The aim of this study was to evaluate recent trends in the presentation and primary management of VS in the United States.

Study Design

Retrospective analysis of the National Cancer Database (NCDB).

Setting

NCDB database.

Subjects and Methods

All patients with a diagnosis of VS between 2004 and 2014 were included. Data were analyzed with univariable and multivariable logistic regression.

Results

In total, 28,190 patients (mean age 55 years, 52.9% female) with VS were analyzed. Linear regression showed a small decrease in average tumor size over time (–0.06 mm/year, P = .03). Overall, 11,121 patients (40%) received surgery, 8512 (30%) radiation, and 7686 (27%) observation. Controlling for patient, tumor, and treatment center factors, the odds ratio (OR) for receiving surgery in 2014 was 0.60 (confidence interval [CI], 0.50-0.71) while the OR for receiving radiation was 0.75 (CI, 0.64-0.87) as compared to those diagnosed in 2004. The largest increases in observation rates occurred among tumors ≤2 cm ( P < .001).

Conclusion

There was not a clinically significant change in the average tumor size at diagnosis. Although surgery remained the most common treatment modality in the United States, there was a strong shift in the management of VS away from primary surgery and radiation and toward a “wait-and-scan” approach.

Systematic Review of Hearing Preservation in Observed Vestibular Schwannoma

Objective  This is a systematic review of the literature on the spontaneous course of hearing in patients observed with a vestibular schwannoma. Included studies are appraised using the Grading of Recommendations Assessment, Development and Evaluation system. Design  PubMed, Embase, Medline, Cochrane library, and CINAHL (Cumulative Index to Nursing and Allied Health Literature) were searched for literature on hearing in patients observed with a vestibular schwannoma. Participants  Of 217 evaluated papers, 15 were included, representing a total of 2,142 patients. Main Outcome Measures  Hearing according to the AAO-HNS (American Academy of Otorhinolaryngology- Head and Neck Surgery) classification system. Weighted average of the proportion of patients preserving good hearing (>70% discrimination score and pure tone audiometry [PTA] < 30dB) and serviceable hearing (>50% discrimination score and PTA < 50dB) was determined. Results  Fifty percent of patients presenting with good hearing at diagnosis had preserved this after a mean of 5 years of observation, whereas serviceable hearing was preserved in 54%. Patients with normal discrimination at diagnosis preserve their hearing very well. Very few studies exist on long-term hearing preservation. Conclusions  After 5 years of observation, around half of patients will have preserved good or serviceable hearing. Patients with normal discrimination at diagnosis are more likely to preserve good hearing.

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.

Audiovestibular Loss of Function Correlates in Vestibular Schwannomas

OBJECTIVES

The aim of the present study was to investigate the relationships between tumor size, hearing, and vestibular outcomes in patients with vestibular schwannomas (VSs).

MATERIALS AND METHODS

Adult patients (n=124) with unilateral extrameatal VS prior to surgery were included in the study. This was a retrospective cohort study of preoperative audiovestibular investigations including audiometry, discrimination test, caloric test, cervical vestibular evoked myogenic potential (c-VEMP), and ocular vestibular evoked myogenic potential (o-VEMP).

RESULTS

The difference between lesioned and non-lesioned ear was significant for all audiovestibular outcomes. The mean caloric deficit was 74%. No tumor sided o-VEMPs were elicited. Caloric deficit correlated with hearing loss measured with pure tone average and discrimination score. c-VEMP deficit was significantly associated with severe hearing loss and larger tumors.

CONCLUSION

The presence of VS leads to a significant deterioration of audiovestibular function in all objective measures. Caloric test and o-VEMPS are sensitive though unspecific measures of VSs. Increasing tumor size is not directly associated with hearing loss and only somewhat to vestibular deficit. However, audiovestibular findings are correlated.

The Feasibility of a Modified Exclusive Endoscopic Transcanal Transpromontorial Approach for Vestibular Schwannomas

Objective  We evaluated the feasibility of an exclusive endoscopic transcanal transpromontorial approach (EETTA) for the treatment of small vestibular schwannomas (VSs) limited to the internal auditory canal (IAC), and introduced a modification without external auditory canal closure.

Methods  Between June 2016 and June 2017, seven patients with VS underwent surgery using a modified EETTA. Treatment outcomes, including efficacy of tumor resection, preservation of function, operation time, and quality of life (QOL), were evaluated.

Results  The patients preoperatively exhibited Koos Grade I/II tumors and severe-to-profound hearing loss. Gross total resection was accomplished in all cases. There were no major complications, and all patients exhibited normal facial nerve function immediately after surgery. The mean follow-up period was 12.9 months. The operation time (average 196.3 ± 64.9 minutes) and hospitalization period (average 7.4 ± 1.0 days) were favorable. Short Form-36 scores for QOL showed unremarkable results compared with previous reports.

Conclusions  The modified EETTA was effective in the removal of VSs in the IAC. It can be an alternative surgical option for small VSs.

Translabyrinthine microsurgical resection of small vestibular schwannomas

OBJECTIVE

Translabyrinthine resection is one of a number of treatment options available to patients with vestibular schwannomas. Though this procedure is hearing destructive, the authors have noted excellent clinical outcomes for patients with small tumors. The authors review their experience at a tertiary acoustic neuroma referral center in using the translabyrinthine approach to resect small vestibular schwannomas. All operations were performed by a surgical team consisting of a single neurosurgeon and 1 of 7 neurotologists.

METHODS

Data from a prospectively maintained clinical database were extracted and reviewed. Consecutive patients with a preoperative diagnosis of vestibular schwannoma that had less than 1 cm of extension into the cerebellopontine angle, operated on between 2008 and 2013, were included. Patents with neurofibromatosis Type 2, previous treatment, or preexisting facial weakness were excluded. In total, 107 patients were identified, 74.7% of whom had poor hearing preoperatively.

RESULTS

Pathologically, 6.5% of patients were found to have a tumor other than vestibular schwannoma. Excluding two malignancies, the tumor control rates were 98.7%, as defined by absence of radiographic disease, and 99.0%, as defined by no need for additional treatment. Facial nerve outcome was normal (House-Brackmann Grade I) in 97.2% of patients and good (House-Brackmann Grade I–II) in 99.1%. Complications were cerebrospinal fluid leak (4.7%) and sigmoid sinus thrombosis (0.9%), none of which led to long-term sequelae.

CONCLUSIONS

Translabyrinthine resection of small vestibular schwannomas provides excellent results in terms of complication avoidance, tumor control, and facial nerve outcomes. This is a hearing-destructive operation that is advocated for selected patients.

Prospective Evaluation of Patients Undergoing Translabyrinthine Excision of Vestibular Schwannoma with Concurrent Cochlear Implantation

OBJECTIVE

Translabyrinthine (TL) vestibular schwannoma (VS) resection may be accomplished with preservation of the cochlear nerve, permitting successful, concurrent cochlear implantation. In this single institution, Food and Drug Administration-approved feasibility study, we wished to determine the success and outcomes of concurrent cochlear implantation at the time of TL resection of VS.

STUDY DESIGN

Prospective cohort.

SETTING

Tertiary referral center.

PATIENTS

Patients with small VS less than 1.5 cm in size.

INTERVENTION

Concurrent TL VS resection and cochlear implantation.

MAIN OUTCOME MEASURE

Sound localization and speech understanding.

RESULTS

All cochlear nerves were anatomically preserved. Five out of seven patients had auditory precepts at the time of activation. At 1 month following surgery, AzBio scores (0 dB SNR, with sound front, noise to normal ear) were improved by an average of 10% with implant on, persisting to 6 months out from surgery. Localization 1 month after surgery was markedly improved with root mean square 78 degrees ±13 in the "implant off" condition and 41 ± 9 degrees in the "implant on" condition. Average tinnitus severity was reduced in subjects and speech and spatial hearing was improved on speech, spatial and qualities of hearing scale (SSQ).

CONCLUSIONS

These data demonstrate preservation of electrical hearing in TL VS surgery is consistently possible, and although speech outcomes do not achieve the same levels seen with other etiologies of hearing loss, excellent improvement in sound localization, improved speech understanding, and substantial reductions in tinnitus are achieved.

Long-term Hearing Preservation After Resection of Vestibular Schwannoma: A Systematic Review and Meta-analysis

OBJECTIVE

The objective is to perform a systematic review and meta-analysis of the literature on the long-term results of hearing preservation after vestibular schwannoma resection.

DATA SOURCES

Ovid/Medline, PubMed, Embase, and the Cochrane library from January 1980 to January 2015.

STUDY SELECTION

Inclusion criteria: age ≥18 years, minimum 10 patients in the treatment group, hearing preserving microsurgery, no previous radiation treatment, serviceable hearing at immediate postop follow-up, hearing outcomes reported using Gardner Robinson or the American Academy of Otolaryngology-Head and Neck Surgeons hearing grading scales, and average follow-up of 5 years. Preoperative, immediate postoperative, and last follow-up audiograms were required. Exclusion criteria included neurofibromatosis type 2 patients and surgery for salvage therapy or decompression.

DATA EXTRACTION

Quality evaluated using Methodological Index for Non-Randomized Studies.

DATA SYNTHESIS

Meta-analysis was performed using R v3.2.2, Metafor package v 1.9-7. Cohen's D was used to determine effect size. Ten reports had at least 5-year follow-up and used standardized hearing grading scales. The systematic review found that if hearing was preserved at Class A or B at early postop visit, the chance of preserving hearing at 5 years was excellent. Those who maintained speech discrimination score ≥ 89% at the early postoperative follow-up had better long-term hearing preservation. The meta-analysis reveals that only preoperative and postoperative pure-tone average was associated with long-term hearing preservation.

CONCLUSION

Long-term (>5 yr) hearing durability rates are generally very good. Most studies do not report patient and tumor characteristics, therefore precluding combining studies for meta-analysis. Only preoperative and postoperative postoperative pure-tone average was associated with long-term hearing durability.

Audiovestibular Handicap and Quality of Life in Patients With Vestibular Schwannoma and "Excellent" Hearing

BACKGROUND

Studies examining patient-reported outcomes in subjects with vestibular schwannoma (VS) and "excellent" hearing are lacking.

OBJECTIVE

To assess patient-reported audiovestibular handicap and overall quality of life (QoL) in VS patients with class A hearing in both ears.

METHODS

Among 539 VS patients treated during 1998 to 2008, we identified 296 patients with either bilateral class A (AA) hearing or 1 good ear and 1 deaf ear (AD) according to the American Academy of Otolaryngology-Head and Neck Surgery classification. Patients responded to validated hearing, tinnitus, and dizziness handicap inventories and 2 QoL questionnaires, and the 2 groups were compared. A reference group of 103 adults filled out the same questionnaires.

RESULTS

Forty-nine patients (16.6%) had class AA and 247 patients (83.4%) had class AD hearing. AA patients scored poorer than control subjects without tumor on all handicap questionnaires ( P < .001) and a VS-specific QoL instrument ( P = .006). Con-versely, AA patients scored significantly better than patients with AD on the hearing inventory and the disease-specific QoL instrument ( P < .001), but no difference was found between these groups with regard to tinnitus and dizziness. The hearing disability score was approximately 3 times poorer for AA patients compared with control subjects without tumor; a third of AA patients reported a hearing handicap.

CONCLUSION

Patients with VS and bilateral class A hearing report significantly poorer hearing handicap than control subjects without tumor but better hearing than those with unilateral deafness. When patients with bilateral class A hearing are counseled, it should be noted that one-third of patients experience self-perceived hearing handicap.

Ten-Year Follow-up on Tumor Growth and Hearing in Patients Observed With an Intracanalicular Vestibular Schwannoma

BACKGROUND

Reports on the natural history of tumor growth and hearing in patients with a vestibular schwannoma (VS) are almost exclusively short-term data. Long-term data are needed for comparison with results of surgery and radiotherapy.

OBJECTIVE

To report the long-term occurrence of tumor growth and hearing loss in 156 patients diagnosed with an intracanalicular VS and managed conservatively.

METHODS

In this longitudinal cohort study, diagnostic and follow-up magnetic resonance imaging and audiometry were compared.

RESULTS

After a follow-up of 9.5 years, tumor growth had occurred in 37% and growth into the cerebellopontine angle had occurred in 23% of patients. Conservative treatment failed in 15%. The pure tone average had increased from 51- to 72-dB hearing level, and the speech discrimination score (SDS) had decreased from 60% to 34%. The number of patients with good hearing (SDS > 70%) was reduced from 52% to 22%, and the number of patients with American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) class A hearing was reduced from 19% to 3%. Hearing was preserved better in patients with 100% SDS at diagnosis than in patients with even a small loss of SDS. Serviceable hearing was preserved in 34% according to AAO-HNS (class A-B) and in 58% according to the word recognition score (class I-II). Rate of hearing loss was higher in patients with growing tumors.

CONCLUSION

Tumor growth occurred in only a minority of patients diagnosed with an intracanalicular VS during 10 years of observation. The risk of hearing loss is small in patients with normal discrimination at diagnosis. Serviceable hearing is preserved spontaneously in 34% according to AAO-HNS and in 58% according to the word recognition score.

Predictors of hearing outcomes following low-dose stereotactic radiosurgery in patients with vestibular schwannomas: A retrospective cohort review

OBJECTIVES

Hearing deterioration is a major concern for hearing-preserved patients with vestibular schwannomas who are treated with stereotactic radiosurgery (SRS). Thus, determining which patients are more likely to have worse hearing outcomes following SRS may facilitate clinicians in deciding whether conservative policy should be applied in the interest of hearing preservation. This study aimed to define the predictors of hearing outcomes following SRS.

PATIENTS AND METHODS

This retrospective study included 100 patients who underwent low-dose SRS (12- to 13-Gy marginal dose) for vestibular schwannomas between January 2004 and January 2014. Clinical factors and hearing outcomes following radiosurgery were reviewed.

RESULTS

All patients had serviceable hearing at diagnosis and prior to SRS. The median follow-up period was 6.5years (range, 3-10years). The hearing preservation rate in the first, third, and fifth year after radiosurgery was 89%, 68%, and 63%, respectively. A mean cochlear dose lower than 4Gy was a favorable predictor of hearing outcome. Maximal cochlear dose, patient age, pre-treatment pure-tone average, and imaging characteristics were not associated with post-treatment hearing preservation. Our study showed an accelerated rate of deterioration of serial pure-tone average in the first 3years, followed by a more gradual decline after radiosurgery.

CONCLUSION

Our results suggest that cochlear dose constraint is the most crucial factor for hearing preservation. This study provides insight into the rate of hearing preservation and the pattern of hearing deterioration following radiosurgery and can help clinicians advise patients of hearing outcomes following SRS.

CyberKnife for Treatment of Vestibular Schwannoma: A Meta-analysis

Objectives (1) Perform a meta-analysis of the available data on the outcomes of CyberKnife radiosurgery for treatment of vestibular schwannomas (VSs) in the published English-language literature and (2) evaluate the collective outcomes of CyberKnife treatment with respect to tumor control and hearing preservation. Data Sources A thorough literature search of published English-language articles was performed in the PubMed, Ovid, and Cochrane databases. Review Methods A database search was conducted with the keywords "CyberKnife" and "vestibular schwannoma" or "acoustic neuroma." A total of 25 papers were found and reviewed. Data were extracted for patient demographics, number of patients with neurofibromatosis type 2, pretreatment hearing status, tumor size, margin dose, and follow-up duration. The primary outcome variables evaluated were tumor control and hearing preservation. Results After careful review of the published articles, 11 papers reported data on outcomes of CyberKnife treatment for VS and were included in the analysis, comprising 800 patients studied during 1998 to 2012. The reported mean tumor volume ranged from 0.02 to 19.8 cm³, and the follow-up duration ranged from 6 to 120 months. Margin dose varied from 14 to 25 Gy. The collective mean tumor control rate was 96.3% (95% CI: 94.0%-98.5%). The collective hearing preservation rate was 79.1% (95% CI: 71.0%-87.3%) in 427 patients with measurable hearing. Conclusion Clinical data on outcomes of CyberKnife radiosurgery for treatment of VSs are sparse and primarily limited to single-institution analyses, with considerable variation in tumor volume and follow-up time. This meta-analysis not only provides an in-depth analysis of available data in the literature but also reviews reported outcomes and complications.

Audiovestibular Function Deficits in Vestibular Schwannoma

Introduction. Vestibular schwannomas (VS) are benign tumours of the vestibular nerve and can lead to hearing loss, tinnitus, vertigo, facial palsy, and brainstem compression. Audiovestibular diagnostic tests are essential for detection and treatment planning. Methods. Medline was used to perform a systematic literature review with regard to how audiovestibular test parameters correlate with symptoms, tumour size, and tumour location. Results. The auditory brainstem response can be used to diagnose retrocochlear lesions caused by VS. Since hearing loss correlates poorly with tumour size, a retrocochlear lesion is probably not the only cause for hearing loss. Also cochlear mechanisms seem to play a role. This can be revealed by abnormal otoacoustic emissions, despite normal ABR and new MRI techniques which have demonstrated endolymphatic hydrops of the inner ear. Caloric and head impulse tests show frequency specific dynamics and vestibular evoked myogenic potentials may help to identify the location of the tumour regarding the involved nerve parts. Conclusion. In order to preserve audiovestibular function in VS, it is important to stop the growth of the tumour and to avoid degenerative changes in the inner ear. A detailed neurotological workup helps to diagnose VS of all sizes and can also provide useful prognostic information.

Peripheral Vestibular System Disease in Vestibular Schwannomas: A Human Temporal Bone Study

INTRODUCTION

Dizziness is a common symptom in patients with vestibulo-cochlear schwannoma (VS), and several recent studies have identified this symptom as the single most important concerning the quality of life. Clinical and histological observations regarding hearing loss have suggested that this may be caused by both cochlear and retrocochlear mechanisms. Multiple mechanisms may also be at play in the case of dizziness, which may broaden perspectives of therapeutic approach. This study presents a systematic and detailed assessment of vestibular histopathology in temporal bones from patients with VS.

METHODS

Retrospective analysis of vestibular system histopathology in temporal bones from 17 patients with unilateral VS. The material was obtained from The Copenhagen Temporal Bone Collection.

RESULTS

Vestibular schwannomas were associated with atrophy of the vestibular ganglion, loss of fiber density of the peripheral vestibular nerve branches, and atrophy of the neuroepithelium of the vestibular end organs. In cases with small tumors, peripheral disease occurred only in the tissue structures innervated by the specific nerve from which the tumor originated.

CONCLUSION

Vestibular schwannomas are associated with distinctive disease of the peripheral vestibular tissue structures, suggesting anterograde degeneration and that dizziness in these patients may be caused by deficient peripheral vestibular nerve fibers, neurons, and end organs. In smaller tumors, a highly localized disease occurs, which opens perspectives of differentiated clinical assessment and subsequent, targeted therapy.

Vestibular Schwannoma: The Evolution of Hearing and Tumor Size in Natural Course and after Treatment by LINAC Stereotactic Radiosurgery

OBJECTIVE

To review the natural course of tumor size and hearing during conservative management of 151 patients with unilateral vestibular schwannoma (VS), and to evaluate the same parameters for the part of the group (n = 84) who were treated by LINAC stereotactic radiosurgery (SRS).

METHODS

In prospectively collected data, patients underwent MRI and complete audiovestibular tests at inclusion, during the conservative management period and after SRS. Hearing was graded according to the Gardner-Robertson (GR) scale and tumor size according to Koos. Statistics were performed using Kaplan-Meier survival analysis and multivariate analyses including linear and logistic regression. Specific insight was given to patients with serviceable hearing.

RESULTS

During the conservative management period (mean follow-up time: 24 months, range: 6-96), the annual risk of GR class degradation was 6% for GRI and 15% for GR II patients. Hearing loss as an initial symptom was highly predictive of further hearing loss (p = 0.003). Tumor growth reached 25%. For SRS patients, functional hearing preservation was 51% at 1 year and 36% at 3 years. Tumor control was 94 and 91%, respectively.

CONCLUSION

In VS patients, hearing loss at the time of diagnosis is a predictor of poorer hearing outcome. LINAC SRS is efficient for tumor control. Patients who preserved their pretreatment hearing presented less hearing loss per year after SRS than before treatment, suggesting a protective effect of SRS when cochlear function can be preserved.

Internal Auditory Canal Decompression for Hearing Maintenance in Neurofibromatosis Type 2 Patients

BACKGROUND:

In neurofibromatosis type 2 (NF2), multiple therapeutic options are available to prevent bilateral hearing loss that significantly affects the quality of life of patients.

OBJECTIVE:

To evaluate the morbidity and functional results of internal auditory canal (IAC) decompression in NF2 patients with an only hearing ear.

METHODS:

Twenty-one NF2 patients operated on for IAC decompression in a 3-year period with a minimum follow-up of 1 year were included in this retrospective study. They presented unilateral deafness due to previous contralateral vestibular schwannoma removal in 16 patients or contralateral hearing loss due to the tumor in 5 patients. Hearing level was of class A (American Academy of Otolaryngology-Head and Neck Surgery classification) in 7 patients, B in 8 patients, C in 1 patient, and D in 5 patients. Pure-tone average and speech discrimination score evaluations were performed at 6 days, 1 year, and during the follow-up. Eight patients had postoperative chemotherapy.

RESULTS:

No case of facial nerve palsy was observed. In the early postoperative period; all patients maintained the hearing class of the preoperative period. At 1-year follow-up, all but 3 patients maintained their hearing scores; at last follow-up (mean follow-up, 23 + 8 months; range, 12-44 months), hearing classes remained stable with only 1 patient worsening from class B to C and 1 patient improving from class D to B.

CONCLUSION:

Decompression of IAC seems to be a useful procedure for hearing maintenance in NF2 patients, with very low morbidity. Ideal timing and association with chemotherapy should be evaluated in the future.