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

A Novel Imaging Grading Biomarker for Predicting Hearing Loss in Acoustic Neuromas

PURPOSE

The aim of this study was to investigate an imaging biomarker based on contrast enhanced T1-weighted and T2-weighted magnetic resonance imaging (MRI) to determine the hearing loss related to acoustic neuromas (AN).

METHODS

In this retrospective study, 441 acoustic neuromas treated with microsurgery were included. The diagnostic and follow-up MRI and audiometry of these patients were compared.

RESULTS

We discovered a new MRI grading biomarker based on the percentage of tumor filling the inner auditory canal (TFIAC classification). The area under the receiver operating characteristics (AUROC) curve was highest for TFIAC (0.675), followed by period of observation (0.615) and tumor size (0.6) (P < 0.001). The percentage of patients in TFIAC grade III (90.1%) experiencing hypoacusis prior to microsurgery was significantly higher than that in TFIAC grade I (72.7%, P = 0.037) and TFIAC grade IV patients had a higher rate of non-serviceable hearing compared to TFIAC grade III patients (P < 0.001). During the follow-up, TFIAC grade IV patients experienced a significantly higher rate of non-serviceable hearing than TFIAC grade III patients in all ANs (P < 0.001) and in serviceable hearing acoustic neuroma cases prior to surgery (TFIAC grade IV 55.4%, TFIAC grade III 69.0%, P = 0.045). The TFIAC grade IV patients experienced a significantly higher rate of facial nerve dysfunction than TFIAC grade III patients after surgery (grade IV 48.0%, grade III 26.1%, P < 0.001).

CONCLUSION

The TFIAC classification serves as a potential imaging biomarker for preoperative and postoperative hearing prediction in ANs, which may aid neurosurgeons in predicting hearing loss and selecting optimal surgical strategies.

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.

Magnetic Resonance Imaging Surveillance for Vestibular Schwannoma After Microsurgical Resection Using a Retrosigmoid Transmeatal Approach

BACKGROUND

Vestibular schwannoma (VS) is a benign, usually slow-growing tumor. The drawback of radical microsurgical VS resection is the increased likelihood of neurologic injury, forcing surgeons to leave a tumor remnant in some cases. We evaluated the prognostic value of magnetic resonance imaging (MRI) enhancement patterns to determine the risk of tumor regrowth.

METHODS

This clinical study included 30 patients (20 women and 10 men) with VS who underwent surgery via a retrosigmoid transmeatal approach. The extent of resection was assessed by MRI 6 months after surgery. Two subtypes of intracanalicular linear enhancement were defined: linear enhancement of the walls of the internal auditory canal (IAC) or in the cerebellopontine angle (CPA) and linear enhancement covering the end of the IAC. All patients included in the study underwent follow-up MRI every year for at least 6 years.

RESULTS

Intracanalicular nodular enhancement suggestive of a tumor remnant was seen in the IAC in 11 patients (36.7%). Volume of nodular enhancements was <0.5 cm³ when measurable. The enhancement remained stable throughout follow-up except in 2 cases that showed a slight decrease in size and in 1 case with an initial tumor remnant of 0.5 cm³ showing a slight increase over the years. Eighteen patients (60%) had linear enhancement in the IAC or in the CPA. No patients with linear enhancement showed nodular enhancement.

CONCLUSIONS

Although specific monitoring protocols can be designed based on MRI findings 6 months after microsurgical VS resection, follow-up should be maintained indefinitely given the slight possibility of very late regrowth.

Location of Small Intracanalicular Vestibular Schwannomas Based on Magnetic Resonance Imaging

Vestibular schwannomas (VSs) were proposed to arise from the glial-Schwann cell junction within the internal auditory canal (IAC). However, otopathology studies indicate that VS may arise anywhere along the course of the vestibular nerve. Recent studies suggested that the majority of tumors are located centrally within the IAC with an equal distribution near the porus acusticus and the fundus. However, these studies analyzed tumors of all sizes, obscuring their precise origin. Herein, we aim to quantify the position of small intracanalicular tumors (<5 mm), assessing hearing outcomes and growth patterns in relation to tumor position. Of the 38 small intracanalicular tumors analyzed, 61% originated closest to the fundus, 34% at the midpoint, and only 5% closest to the porus acusticus. Tumors were observed with serial magnetic resonance imaging for 3.37 ± 2.65 years (mean ± SD) without intervention. Our findings indicate a lateral predominance of small VS within the IAC, an independence between tumor location and hearing outcomes, and further support the slow natural progression of VS.

Screening for vestibular schwannoma in the context of an ageing population

Objective

To review the literature regarding screening for vestibular schwannoma in the context of demographic changes leading to increasing numbers of elderly patients presenting with asymmetric auditory symptoms.

Methods

A systematic review of the literature was performed, with narrative synthesis and statistical analysis of data where appropriate.

Results

Vestibular schwannomas diagnosed in patients aged over 70 years exhibit slower growth patterns and tend to be of smaller size compared to those tumours in younger age groups. This fact, combined with reduced life expectancy, renders the probability of these tumours in the elderly requiring active treatment with surgery or stereotactic radiotherapy to be extremely low. Vestibular schwannomas in the elderly are much more likely to be managed by serial monitoring with magnetic resonance imaging. The weighted yield of magnetic resonance imaging in the diagnosis of vestibular schwannoma in all age groups is 1.18 per cent, with almost 85 scans required to diagnose 1 tumour.

Conclusion

An evidence-based approach to the investigation of asymmetric hearing loss and tinnitus in the elderly patient can be used to formulate guidelines for the rational use of magnetic resonance imaging in this population.

Long-term Effects of Conservative Management of Vestibular Schwannoma on Dizziness, Balance, and Caloric Function

Objectives

To study the development of dizziness, caloric function, and postural sway during long-term observation of untreated vestibular schwannoma patients.

Study Design

Retrospective review of a prospectively maintained longitudinal cohort.

Setting

Tertiary referral hospital.

Subjects and Methods

Patients with vestibular schwannoma undergoing wait-and-scan management were included—specifically, those who did not require treatment during a minimum radiologic follow-up of 1 year. Baseline data and follow-up included magnetic resonance imaging, posturography, bithermal caloric tests, and a dizziness questionnaire. Main outcomes were prevalence of moderate to severe dizziness, canal paresis, and postural instability at baseline and follow-up, as compared with McNemar’s test.

Results

Out of 433 consecutive patients with vestibular schwannoma, 114 did not require treatment during follow-up and were included. Median radiologic follow-up was 10.2 years (interquartile range, 4.5 years). Age ranged from 31 to 78 years (mean, 59 years; SD, 10 years; 62% women). Median tumor volume at baseline was 139 mm3(interquartile range, 314 mm3). This did not change during follow-up ( P = .446). Moderate to severe dizziness was present in 27% at baseline and 19% at follow-up ( P = .077). Postural unsteadiness was present in 17% at baseline and 21% at follow-up ( P = .424). Canal paresis was present in 51% at baseline and 56% at follow-up ( P = .664).

Conclusions

There was no significant change in the prevalence of dizziness, postural sway, or canal paresis during conservative management of vestibular schwannoma, while tumor volume remained unchanged. This indicates a favorable prognosis in these patients with regard to vestibular symptoms.

How to radiologically identify a spontaneous regression of sporadic vestibular schwannoma?

Background

The natural history of sporadic vestibular schwannoma is unpredictable, with tumors growing, non-growing and even showing spontaneous regression in some rare cases.

Objective

This retrospective study aims to describe the radiologic signs characterizing and identifying the shrinking vestibular schwannoma.

Methods

Involution was considered to have occurred if tumor size had decreased by 2 mm or more on its largest diameter. All magnetic resonance imaging scans were reviewed for tumor size, internal auditory meatus size, and tumor characteristics. Volumetric measurements were performed on the first and last scan. Audiometric data were collected at the first and last visit.

Results

Fourteen patients with a confirmed spontaneous regression were included, with a mean follow-up of 5 ± 2.6 years. The mean shrinkage rate was 0.9 ± 0.59 mm/year on 2D measurements, and 0.2 ± 0.17 cm³/year on volumetric measurements, with a relative shrinkage of 40 ± 16.9%. Two remarkable radiologic features were observed: First, a festooned aspect, defined by multiple curves in the tumor outline, noticed in 12 cases (86%); second, the appearance of cerebrospinal fluid filling the internal auditory meatus, associated with an enlargement of the internal auditory meatus compared to the contralateral side, and observed in 10 out of 13 cases with internal auditory meatus invasion (77%). Those two aspects were associated in 64% of cases.

Conclusion

These two newly reported radiologic features could help neurosurgeons, oto-neurosurgeons and neuroradiologists to identify a spontaneous vestibular schwannoma involution at first visit. This could allow any treatment to be postponed, monitoring to be more widely spaced, and patients to be reassured.

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.

De Novo Vestibular Schwannoma: A Report of Three Cases

The reported growth rate of vestibular schwannoma varied widely in the literature. However, emergence of vestibular schwannoma remains unsolved. We presented three patients who had undergone previous magnetic resonance imaging (MRI) confirming the absence of tumor and were diagnosed with a unilateral vestibular schwannoma with a diameter of 18–30 mm, 6–9 years after the initial MRI. One patient had solid tumor and experienced stereotactic radiosurgery. Following stereotactic radiosurgery, continuous tumor growth led to hydrocephalus and trigeminal dysfunction, resolved by surgical removal. Other two patients had the tumor with cystic component and experienced surgical removal as first treatment. All tumors were pathologically diagnosed as schwannomas without evidence of high potential of proliferation. This is the first report of three patients with de novo vestibular schwannoma, showing tumor emergence and rapid growth in a short period. Considering a de novo aspect, the “wait and scan” policy may not be appropriate for the subset of VS such as de novo VS.

Multi-option therapy vs observation for small acoustic neuroma: hearing-focused management

The current treatment options for acoustic neuromas (AN) – observation, microsurgery and radiotherapy – should assure no additional morbidity on cranial nerves VII and VIII. Outcomes in terms of disease control and facial function are similar, while the main difference lies in hearing. From 2012 to 2016, 91 of 169 patients (54%) met inclusion criteria for the present study, being diagnosed with unilateral, sporadic, intrameatal or extrameatal AN up to 1 cm in the cerebello-pontine angle; the remaining 78 patients (46%) had larger AN and were all addressed to surgery. The treatment protocol for small AN included observation, translabyrinthine surgery, hearing preservation surgery (HPS) and radiotherapy. Hearing function was assessed according to the Tokyo classification and the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) classification. Sixty-one patients (71%) underwent observation, 19 (22%) HPS and 6 (7%) translabyrinthine surgery; 5 patients were lost to follow-up. Median follow-up was 25 months. In the observation group, 24.6% of patients abandoned the wait-and-see policy for an active treatment; the risk of switching from observation to active treatment was significant for tumour growth (p = 0.0035) at multivariate analysis. Hearing deteriorated in 28% of cases without correlation with tumour growth; the rate of hearing preservation for classes C-D was higher than for classes A-B (p = 0.032). Patients submitted to HPS maintained an overall preoperative hearing class of Tokyo and AAO-HNS in 63% and 68% of cases, respectively. Hearing preservation rate was significantly higher for patients presenting with preoperative favourable conditions (in-protocol) (p = 0.046). A multi-option management for small AN appeared to be an effective strategy in terms of hearing outcomes.

Outcomes of large vestibular schwannomas following subtotal resection: early post-operative volume regression and facial nerve function

INTRODUCTION

Subtotal resection (STR) of vestibular schwannoma (VS) tumors remains controversial and little is known regarding post-operative volume changes.

METHODS

Authors retrospective reviewed the medical records from January 1st 2002 to January 1st 2018, for all patients who had undergone primary STR of large VS at a single tertiary academic institution.

RESULTS

Our series consists of 34 patients with a mean age of 53.9 (median 53; range 21-87) years that had STR of their VS tumor. The mean pre-operative tumor diameter and volume was 3.9 cm (median 3.0 cm; range 1.6-6.0 cm) and 11.7 cm³ (median 9.6 cm³; range 2.8-44.3 cm³), respectively, with a mean extent of resection of 86% (median 90%; range 53-99%). The mean radiographic and clinical follow-up was 40 months (range 6-120 months) and 51 months (range 7-141 months), respectively. 85% of patients had optimal House-Brackmann (HB) scores (Grade 1 & 2) immediately post-operatively, and 91% at 1 year; 94% of patients had normal (HB 1) at last follow-up. There was significant regression of residual tumor volume at 1 year (p = 0.006) and 2 years (p = 0.02), but not at 3 years (p = 0.08), when compared to the prior year. There was significant regression of size over time, with a mean slope estimate of - 0.70 units per year (p < 0.001).

CONCLUSION

Excellent clinical facial nerve outcomes can be obtained with STR of large VS tumors. Maximal reduction in tumor size occurs at 2-year post-operatively. Thus, in patients undergoing surgery for large VS, STR and a "watch and wait" strategy is a reasonable treatment option that may optimize facial nerve outcomes.

The natural history of incidental retroperitoneal schwannomas

The natural history of asymptomatic retroperitoneal schwannomas is poorly understood. This study aimed at investigating the natural history of incidental retroperitoneal schwannomas. The medical charts and imaging studies of 22 asymptomatic patients under observation for at least 12 months for retroperitoneal schwannomas were reviewed. The duration of follow-up ranged between 13 and 176 months (mean 48 months). In the 22 patients managed by the “wait and see” approach, the average tumor size at initial presentation was 51 mm, which increased to 57 mm at final follow-up. During the final follow-up, 2 patients required surgical treatment for tumor enlargement, while the remaining patients remained asymptomatic without surgery. The average growth rate of the tumors was 1.9 mm/year (range: -1.9 to 8.7 mm/year). The majority of asymptomatic retroperitoneal schwannomas demonstrate minimal growth and may be suitable for management with the “wait and see” approach.

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 small acoustic neuroma: observation or active therapy? Literature review and institutional experience

BACKGROUND

Current imaging modalities enable early diagnosis of a large number of small acoustic neuromas in patients with well-preserved hearing, whose best management is still a debatable matter.

METHODS

Comparing the hearing outcome of the various therapeutical approaches, including observation, radiosurgery, or resective surgery, is not easy because of the numerous classifications measuring hearing in different ways. In this review, a literature review was performed and papers selected dealing with small tumors, short- and long-term hearing, tumor control or radical resection, and effect of pre-treatment hearing and size on outcome. Two different surgical institutional series of sporadic vestibular schwannomas provided us comparative data on the outcome of observation alone.

RESULTS AND CONCLUSIONS

Our experience suggests that active treatment with hearing preservation surgery, unlike observation alone, offers a better chance of hearing preservation, also enabling a more effective treatment of the tumor and an appropriate rehabilitation with hearing aids or cochlear implants.

When Should We Stop Scanning Older Patients with Vestibular Schwannomas?

Objective  Observation is a well-accepted management for small- to medium-sized vestibular schwannomas (VSs). Although there are good data on the natural history of this disease within adults, no studies have looked specifically at those aged over 70 years. Thus, there is a need for a surveillance protocol to determine if and when we can stop imaging safely patients aged 70 years and over with a new diagnosis of VSs when managed with observation. Design  Over a 13-year period, we retrospectively analyzed all skull base unit patients with a sporadic unilateral VSs managed with an imaging surveillance protocol. All data were collected prospectively with a minimum follow-up of 5 years. Setting  Tertiary referral skull base unit Participants  Patients aged 70 years and over with sporadic VSs at diagnosis Main Outcome Measures  Main outcome measures Results  A total of 112 patients met inclusion criteria. The median age at diagnosis was 74 years (range: 70-87 years). The mean follow-up was 82 months (range: 60-144). The size of the VSs at diagnosis was intracanalicular (IC) in 46%, small in 41%, medium in 12%, and large in 2%. Growth was more likely where tumors were extracanalicular (EC) rather than IC at presentation ( p  = 0.036) and within the first 18 months after diagnosis ( p  < 0.001). Twenty-nine percent of VSs displayed growth (6% continued surveillance, 23% received active treatment). Good hearing at diagnosis did not predict tumor stability for IC or EC tumors ( p  = 0.162 and p  = 0.536). Conclusions  Since no VSs grew after 42 months from diagnosis, our data support an initial magnetic resonance imaging (MRI) at 6 months after diagnosis followed by an annual MRI for 3 years. At this point, consideration could be given to discussing discontinuation or further imaging with patients.

An international comparison of diagnostic and management strategies for vestibular schwannoma

Objective

To compare international diagnostic and management strategies for vestibular schwannoma (VS).

Methods

A web-based questionnaire was sent to 130 otolaryngologists, mainly identified through the European Skull Base Society. It contained questions on general information including guideline usage as well as questions on diagnosis (focussing on selection of patients for MRI) and management of VS, including case scenarios. Descriptive statistics were reported.

Results

Thirty-six otolaryngologists working in 11 different countries completed the questionnaire (response rate: 28%). Guidelines for diagnosis and management of VS are used by 44% and 42% of respondents, respectively. In the diagnostic strategy for VS, different types and combinations of audiovestibular function tests are used when deciding whether a patient should undergo an MRI. Respondents apply 18 different definitions of asymmetrical hearing loss. Variation was also apparent from reported considerations on management of VS. Most respondents (84%) prefer a wait-and-scan strategy in case of a small intrameatal VS (Koos 1). Variety in management strategies increases for patients with a medium to large sized VS (Koos 2, 3 and 4). The details of each management strategy (wait-and-scan, microsurgery, stereotactic radiosurgery and fractionated radiotherapy) also differ among respondents.

Conclusions

A large variation in diagnostic and management strategies for VS was identified between respondents. More evidence and/or consensus seem warranted to reduce uncertainties for patients, and differences in outcome and costs that might result from the variety of strategies currently being applied.

Electronic supplementary material

The online version of this article (10.1007/s00405-018-5199-6) contains supplementary material, which is available to authorized users.

Surgical outcome in smaller symptomatic vestibular schwannomas. Is there a role for surgery?

BACKGROUND

Currently, there is no consensus in the initial management of small vestibular schwannomas (VSs). They are routinely watched and/or referred for radiosurgical treatment, although surgical removal is also an option. We hereby evaluate clinical outcomes of patients who have undergone surgical removal of smaller symptomatic VSs.

METHODS

Patients with vestibular schwannomas (grade T1-T3b according to Hannover classification) were reviewed. Patients with symptomatic tumors who underwent surgery were evaluated. Their preoperative hearing status was based on the guideline of the committee on hearing and equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) foundation. Their postoperative facial nerve function, hearing status, vestibular symptoms, and degree of tumor resection were assessed.

RESULTS

Thirty patients were selected for surgery via a retrosigmoid approach based on their age, symptoms, and their own decision-making after discussion of management options. Most patients presented with hearing loss. Seventeen patients had useful hearing preoperatively. Among them, 10 patients (59%) preserved useful hearing (class A or B) postoperatively. MRI at 1-year follow-up confirmed complete resection in 26/29 patients. Also, 29 patients (97%) had HB grade I-II, and 1 patient had HB III at 1-year follow-up. Except for 1 patient with CSF leak, 1 patient with delayed facial nerve palsy, and 2 patients with asymptomatic sigmoid sinus occlusion, there were no other new morbidities.

CONCLUSION

Although both observation and radiosurgery are valid options in the management of smaller size vestibular schwannomas, surgical treatment seems to offer a high rate of facial nerve preservation, a reasonable rate of hearing sparing, and a high total resection rate. Clinicians should consider surgical treatment as a valid option in the initial management of symptomatic small vestibular schwannomas in younger patients.

Audiologist-led screening of acoustic neuromas in patients with asymmetrical sensorineural hearing loss and/or unilateral tinnitus: our experience in 1126 patients

OBJECTIVE

To determine whether patients within an otolaryngology department presenting with asymmetrical sensorineural hearing loss and/or unilateral tinnitus can be safely and cost-efficiently screened for acoustic neuroma by audiologists as a first or only point of contact.

METHODS

A prospective case series and cost analysis were conducted at a tertiary referral centre. Between April 2013 and March 2017, 1126 adult patients presented to the audiology department with asymmetrical sensorineural hearing loss and/or unilateral tinnitus. All were screened for acoustic neuroma with magnetic resonance imaging, based on pre-determined criteria. The main outcome measure was the presence of acoustic neuroma or other pathology on magnetic resonance imaging.

RESULTS

Twenty-five patients (2.22 per cent) were found to have an acoustic neuroma (size range: 3-20 mm) and were referred to the otolaryngologist for further assessment. The remaining patients were appropriately managed and discharged by the audiologists without ENT input. This resulted in an overall cost saving of £164 850.

CONCLUSION

Patients with asymmetrical sensorineural hearing loss and/or unilateral tinnitus can be safely screened for acoustic neuroma and independently managed by audiologists as a first or only point of contact, resulting in considerable departmental cost savings.

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.

Common Histologically Benign Tumors of the Brain

PURPOSE OF REVIEW

As a group, benign tumors account for the majority of primary neoplasms affecting the central nervous system (CNS). This article reviews the epidemiology, clinical presentation, neuroimaging features, and management of the most common of these tumors: meningiomas, schwannomas, and pituitary adenomas.

RECENT FINDINGS

Awareness of the most common nonmalignant tumors of the CNS and their management guidelines is important as many of these tumors are managed conservatively, with neurologists playing a primary role in both surveillance and symptom management. Knowledge of the varied neurologic consequences of these tumors allows optimizing interventions that improve quality of life in people living with these tumors without incurring treatment-related complications. Awareness of the clinical features that require surgery, radiation therapy, or chemotherapy is imperative. Finally, important discoveries in both germline and somatic mutations underlying some of these lesions have contributed to the launch of several novel drug trials for these tumors.

SUMMARY

As a group, nonmalignant neoplasms are the most common neoplasms affecting the CNS in adults. Because of their unique neuroanatomic location or containment within the bony skull, these histologically benign lesions can cause significant neurologic morbidity. Management with a multidisciplinary team that includes neurologists, neuro-oncologists, radiologists, neurosurgeons, radiation oncologists, otolaryngologists, pathologists, neuropsychologists, physiatrists, and others is necessary for the optimal management of these lesions.

Middle Fossa Approach for Resection of Vestibular Schwannomas: A Decade of Experience

BACKGROUND

The middle cranial fossa (MCF) approach is a challenging surgical technique for the resection of small and intermediate sized, primarily intracanalicular, vestibular schwannomas (VS), with the goal of hearing preservation (HP).

OBJECTIVE

To describe a decade-long, single institutional experience with the MCF approach for resection of VS.

METHODS

This is a retrospective cohort study of 63 patients who underwent the MCF approach for resection of VS from 2006 to 2016. Audiometric data included pure-tone average (PTA), low-tone pure-tone average (LtPTA), word recognition score, and American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) hearing classification at presentation and follow-up. Patients with postoperative serviceable (AAO-HNS class A-B) and/or useful (AAO-HNS class A-C) hearing were compared to those without HP. Facial nerve function was assessed using the House–Brackmann scale.

RESULTS

The mean age and duration of follow-up were 50 ± 13 yr and 21 ± 21 mo, respectively. The mean tumor size was 10 ± 4 mm. The serviceable and usable HP rates were 54% and 50%, respectively. Some residual hearing was preserved in 71% of patients. Large tumor size (P = .05), volume (P = .03), and extrameatal tumor extension (P = .03) were associated with poor audiometric outcomes. The presence of a fundal fluid cap (P = .01) was a favorable finding. At definitive testing, LtPTA was significantly better preserved than traditional PTA (P = .01). Facial nerve outcomes, tumor control rates, and durability of audiometric outcomes were excellent. 47% of patients pursued aural rehabilitation.

CONCLUSION

In our series, the MCF approach for VS provided excellent rates of tumor and facial nerve function, with durable serviceable HP.

The proteome of perilymph in patients with vestibular schwannoma. A possibility to identify biomarkers for tumor associated hearing loss?

BACKGROUND

Due to the surrounding bone, the human inner ear is relatively inaccessible and difficult to reach for cellular and molecular analyses. However, these types of investigations are needed to better understand the etiology, pathophysiology and progression of several inner ear disorders. Moreover, the fluid from the inner ear cannot be sampled for micro-chemical analyses from healthy individuals in vivo. Therefore, in the present paper, we studied patients with vestibular schwannoma (VS) undergoing trans-labyrinthine surgery (TLS). Our primary aim was to identify perilymph proteins in patients with VS on an individual level. Our second aim was to investigate the proteins identified at a functional level and our final aim was to search for biological markers for tumor-associated hearing loss and tumor diameter.

METHODS AND FINDINGS

Sixteen patients underwent TLS for sporadic VS. Perilymph was aspirated through the round window before opening the labyrinth. One sample was contaminated and excluded resulting in 15 usable samples. Perilymph samples were analyzed with an online tandem LTQ-Orbitrap mass spectrometer. Data were analyzed with MaxQuant software to identify the total number of proteins and to quantify proteins in individual samples. Protein function was analyzed using the PANTHER Overrepresentation tool. Associations between perilymph protein content, clinical parameters, tumor-associated hearing loss and tumor diameter were assessed using Random Forest and Boruta. In total, 314 proteins were identified; 60 in all 15 patients and 130 proteins only once in 15 patients. Ninety-one proteins were detected in at least 12 out of 15 patients. Random Forest followed by Boruta analysis confirmed that alpha-2-HS-glycoprotein (P02765) was an independent variable for tumor-associated hearing loss. In addition, functional analysis showed that numerous processes were significantly increased in the perilymph. The top three enriched biological processes were: 1) secondary metabolic processes; 2) complement activation and 3) cell recognition.

CONCLUSIONS

The proteome of perilymph in patients with vestibular schwannoma has an inter-individual stable section. However, even in a cohort with homogenous disease, the variation between individuals represented the majority of the detected proteins. Alpha-2-HS-glycoprotein, P02765, was shown to be an independent variable for tumor-associated hearing loss, a finding that needs to be verified in other studies. In pathway analysis perilymph had highly enriched functions, particularly in terms of increased immune and metabolic processes.

Long-term hearing outcomes after gamma knife surgery in patients with vestibular schwannoma with hearing preservation: evaluation in 92 patients with serial audiograms

The treatment strategy for patients with vestibular schwannoma (VS) is controversial, and data concerning the long-term hearing outcomes > 5 years after gamma knife surgery (GKS) are limited. The long-term hearing outcomes after GKS were evaluated in VS patients with hearing preservation. Ninety-two VS patients with a pure tone average (PTA) ≤ 50 dB were evaluated. The median age was 54 years; the median tumor volume was 1.5 cm³. The tumors were treated with a median margin dose of 12 Gy and a median mean cochlear dose of 4.0 Gy. At the time of GKS, 65 patients retained a PTA of 0-30 dB, and 27 had a PTA of 31-50 dB. The median follow-up period was 106 months. At the final follow-up, 2 (2%) developed tumor progression. During the median audiogram follow-up of 83 months, the PTA was ≤ 30 dB in 22 patients (24%) and 31-50 dB in 27 patients (29%); 43 patients (47%) worsened to a PTA > 50 dB. Hearing preservation rates were 66, 57, and 44% at 3, 5, and 10 years, respectively. In multivariate analysis, the mean cochlear dose (P < 0.001) and pre-GKS PTA (P = 0.045) were significant for hearing preservation. GKS was an effective treatment option for VS patients with a PTA ≤ 50 dB. As a lower cochlear dose and better pre-GKS PTA contributed to long-term hearing preservation, prophylactic GKS before hearing deterioration or tumor growth would be a treatment of choice if patients provided informed consent.

Progression of vestibular schawnnoma after GammaKnife radiosurgery: A challenge for microsurgical resection

OBJECTIVE

We aimed to evaluate the outcome of patients who underwent salvage microsurgery for vestibular schwannoma (VS) that failed primary Gammaknife radiosurgery (GKS).

PATIENTS AND METHODS

Among the 1098 patients who received GKS for the treatment of VS in our center between January 2004 and December 2012, the follow-up was organized in our institution for 290 patients who lived in our recruitment area. Tumor progression was noted in 23 patients. A salvage microsurgical resection was performed in 11 patients, who were included in our study. Grading of facial function was done according to the House & Brackman scale.

RESULTS

The mean age at diagnosis was 50.2 years (19-68 years) and the mean follow-up was 9.4 years (4-13 years). The mean dose was 11.8 Gy (11-12 Gy) and the mean volume was 922 mm3 (208-2500 mm3). The mean period between GKS and diagnosis of tumor progression was 32 months (18-72 months). Concerning salvage microsurgery, complete resection was obtained in 8 patients. Small residual tumor on the facial nerve was deliberately left in 3 patients and no tumor progression was noted with a mean follow-up of 26 months. At last follow-up, facial nerve function was grade 1 in 4 patients, grade 2 in 3 patients, grade 3 in 1 patient and grade 4 in 3 patients.

CONCLUSION

Salvage surgery of recurrent vestibular schwannoma after failed initial GKS remains a good treatment. However, facial nerve preservation is more challenging in this case and small tumor remnant could be sometimes deliberately left.

The proteome of perilymph in patients with vestibular schwannoma. A possibility to identify biomarkers for tumor associated hearing loss?

BACKGROUND

Due to the surrounding bone, the human inner ear is relatively inaccessible and difficult to reach for cellular and molecular analyses. However, these types of investigations are needed to better understand the etiology, pathophysiology and progression of several inner ear disorders. Moreover, the fluid from the inner ear cannot be sampled for micro-chemical analyses from healthy individuals in vivo. Therefore, in the present paper, we studied patients with vestibular schwannoma (VS) undergoing trans-labyrinthine surgery (TLS). Our primary aim was to identify perilymph proteins in patients with VS on an individual level. Our second aim was to investigate the proteins identified at a functional level and our final aim was to search for biological markers for tumor-associated hearing loss and tumor diameter.

METHODS AND FINDINGS

Sixteen patients underwent TLS for sporadic VS. Perilymph was aspirated through the round window before opening the labyrinth. One sample was contaminated and excluded resulting in 15 usable samples. Perilymph samples were analyzed with an online tandem LTQ-Orbitrap mass spectrometer. Data were analyzed with MaxQuant software to identify the total number of proteins and to quantify proteins in individual samples. Protein function was analyzed using the PANTHER Overrepresentation tool. Associations between perilymph protein content, clinical parameters, tumor-associated hearing loss and tumor diameter were assessed using Random Forest and Boruta. In total, 314 proteins were identified; 60 in all 15 patients and 130 proteins only once in 15 patients. Ninety-one proteins were detected in at least 12 out of 15 patients. Random Forest followed by Boruta analysis confirmed that alpha-2-HS-glycoprotein (P02765) was an independent variable for tumor-associated hearing loss. In addition, functional analysis showed that numerous processes were significantly increased in the perilymph. The top three enriched biological processes were: 1) secondary metabolic processes; 2) complement activation and 3) cell recognition.

CONCLUSIONS

The proteome of perilymph in patients with vestibular schwannoma has an inter-individual stable section. However, even in a cohort with homogenous disease, the variation between individuals represented the majority of the detected proteins. Alpha-2-HS-glycoprotein, P02765, was shown to be an independent variable for tumor-associated hearing loss, a finding that needs to be verified in other studies. In pathway analysis perilymph had highly enriched functions, particularly in terms of increased immune and metabolic processes.

Quality of life in patients with unilateral vestibular schwannoma on wait and see - strategy

OBJECTIVE

A 'wait and see' strategy is an option when managing patients with small vestibular schwannomas (VS). A risk of growth and worsening of hearing may influence a patient's daily quality of life (QOL). Therefore, the present study focused on QOL parameters in patients who are on a 'wait and see' strategy following magnetic resonance imaging (MRI)-based diagnosis of small unilateral VS.

PATIENTS AND METHODS

Sixty-five patients (mean age 64.4 years; male:female, 32:33) who suffered from a small unilateral VS (9.34 mm, range 1.5-23 mm) between 2013 and 2016 were included in a prospective single center study. During follow-up, in addition to clinical and neurological examinations and MRI imaging, all patients answered the Short Form 36 questionnaire once to characterize QOL. Additionally, the severity of tinnitus was determined by the Mini-TQ-12 from Hiller and Goebel.

RESULTS

It was found during follow-up that there was no lowering of QOL in patients with small VS who were on 'wait and see' strategy compared with Germany's general population and no tumor growth was detected in 53 patients (81.5%). Patients with a tumor diameter larger than 10 mm did not suffer from stronger tinnitus, vertigo or unsteadiness than the group with an average tumor size, which is smaller than 10 mm. Sixty-two patients (95.4%) showed ipsilateral hearing loss and three of these reported deafness (4.6%). Severe vertigo or tinnitus is connected with lower levels of mental component scale and physical component scale. These findings reduced the QOL (p = 0.05).

CONCLUSION

In our series, QOL is not influenced in patients with unilateral untreated small VS in comparison to Germany's general population. This is helpful information when advising patients during follow-up and finding out the optimal timing of individual treatment.