Vestibular schwannoma: 825 cases from a 25-year experience

Plasticity of the auditory cortex and brainstem in surgically induced unilaterally deaf adult humans with and without tinnitus

OBJECTIVE

Cortical auditory evoked potentials (CAEPs) and auditory brainstem responses (ABRs) were compared between surgically induced unilaterally deaf (UD) adult humans with tinnitus (UD+T), without tinnitus (UD-T), and with binaurally hearing controls (CO). We hypothesised increased CAEP amplitudes from UD+T individuals, and increased ABR amplitudes from all UD individuals.

METHODS

Data were gathered from 34 individuals (8 UD-T, 13 UD+T, 13 CO) using a 64-channel BioSemi device. Stimuli were delivered monaurally at 60 dB nHL. Evoked potential amplitudes and scalp topographies were compared between groups.

RESULTS

Only UD+T individuals showed higher N1 amplitude compared to the controls (1.48 versus 1.04 μV) over the ipsilateral hemisphere (relative to intact ear). Higher ABR wave III/V ratios were revealed in both UD groups (UD-T 0.426 and UD+T 0.317) compared with the CO group (0.213), regardless of channel.

CONCLUSIONS

Tinnitus is thought to be a perceptual correlate of deafferentation-induced activity increase within the central auditory system (CAS) and the present findings support this. However, increased CAEP amplitude was observed amongst UD+T individuals, while altered ABR amplitude was observed in all UD listeners, suggesting deafferentation alone is insufficient for tinnitus.

SIGNIFICANCE

Deafferentation and associated increased brainstem activity may be necessary but insufficient for triggering tinnitus.

Angiotensin-Receptor Blockers Prevent Vestibular Schwannoma-Associated Hearing Loss

BACKGROUND INTRODUCTION

Vestibular schwannoma (VS) tumors typically present with sensorineural hearing loss (SNHL). Losartan has recently demonstrated prevention of tumor-associated SNHL in a mouse model of VS through suppression of inflammatory and pro-fibrotic factors, and the current study investigates this association in humans.

METHODS

This is a retrospective study of patients with unilateral VS and hypertension followed with sequential audiometry at a tertiary referral hospital from January 1994 to June 2023. Patients were stratified into subgroups by anti-hypertensive medication class. SNHL progression was assessed using Kaplan-Meier analysis to account for variable follow-up times.

RESULTS

Two hundred thirty-six patients were identified with diagnosis of both VS and hypertension, and with sequential audiometry. Of these, 186 were taking anti-hypertensive therapy at the time of initial VS diagnosis, and 23 were taking losartan or another angiotensin receptor blocker (ARB). Patients taking an ARB were both more likely to have normal baseline hearing and no progressive hearing loss with 36.5 total patient-years of follow-up. Patients taking other anti-hypertensives all showed expected declines in hearing consistent with natural history of VS tumors.

DISCUSSION CONCLUSION

This study represents the first statistically significant association between ARB intake and hearing preservation in a real-world VS patient population. Significant confounding factors, such as concomitant hypertension in these patients, could still cloud the full effect of ARB medications' interaction with SNHL progression. Given that ARBs are well tolerated and safe, the results advocate for a prospective clinical trial to validate this effect.

Audiological Characteristics of Vestibular Schwannoma Patients With Normal Pure-Tone Audiometry

OBJECTIVE

To investigate the audiological characteristics of vestibular schwannoma (VS) patients with normal pure-tone audiometry (PTA) results.

STUDY DESIGN

A retrospective study.

SETTING

Forty-two VS patients with normal PTA results from October 2016 to October 2022 were included.

METHODS

Normal PTA was defined when the hearing threshold is ≤25 dB hearing loss (HL) in each test frequency and the PTA is ≤25 dB HL. Results of multiple audiological tests such as the auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), multiple auditory steady-state responses threshold (ASSR), and speech discrimination score were retrospectively reviewed. Demographic data of these patients were also been collected.

RESULTS

According to our results, the ABR and average ASSR threshold of the affected side were statistically significantly higher in VS patients with normal PTA. ABR waveforms on the affected side also showed more abnormalities. The DPOAE pass rates of the affected side were lower than the unaffected side while the amplitude and signal-to-noise ratio rate was also lower. In addition, we used magnetic resonance imaging 3-dimensional reconstruction images to measure the volume of tumors in these patients. We also found that higher ABR threshold means lager tumor size in patients with normal PTA.

CONCLUSION

VS patients with normal PTA result cannot be assumed to have no impairment of hearing function. ABR, DPOAE, and ASSR results showed the characteristic changes in the affect ear. ABR threshold has the highest sensitivity for hearing abnormalities and is strong relative with tumor size in patients with normal PTA.

Navigating Uncharted Waters: Comparative Analysis of Clinical Progression and Outcomes in Vestibular Schwannoma Patients with Papilledema and without Hydrocephalus, Versus Those without Papilledema and Hydrocephalus: A Comprehensive Institutional Insight

BACKGROUND

Papilledema's association with hydrocephalus (HCP)-linked larger vestibular schwannoma (VS) is established but cases lacking concurrent HCP require further investigation.

METHODS

This retrospective comparative observational study, conducted from July 2018 to July 2023, examined 120 VS patients undergoing surgery. Patients were categorized into Group 1 (papilledema without HCP) and Group 2 (no papilledema or HCP), with comprehensive data analyzed.

RESULTS

In this study, Group 1 (14 patients with papilledema) and Group 2 (106 patients without papilledema or HCP) were compared. Group 1 was younger (mean age 27.21 ± 11.73 years) than Group 2 (mean age 54.66 ± 11.44 years). Both groups had similar symptom durations and tumor detection times. Group 1 had increased vascularity (P = 0.001), elevated cisterna magna protein levels (P = 0.001), and a higher incidence of neurofibromatosis 2 (P = 0.003). They also experienced longer surgeries (P = 0.001) and more blood loss (P = 0.001), leading to extended postoperative complications. Group 2 showed improved postsurgery visual outcomes (P = 0.001), better Glasgow Outcome Scores (P = 0.001), enhanced facial nerve preservation (P = 0.002), and improved hearing on follow-up (P = 0.003). Logistic regression analysis highlighted prolonged surgery duration (P = 0.057) and papilledema (P = 0.0001) as significant factors influencing visual improvement.

CONCLUSIONS

Patients with VS require preoperative fundoscopy evaluation due to potential visual loss and papilledema, even without HCP. Early treatment initiation enhances visual and hearing outcomes. Meticulous surgery is vital given the lesion's hypervascular nature and adherence to surrounding structures. Preoperative embolization may aid in preserving neurovascular structures. In developing countries with higher blindness rates, judicious noncontrast computed tomography brain evaluation is crucial for timely detection and treatment initiation of lesions like VS.

Brazilian Society of Otology task force - Vestibular Schwannoma ‒ evaluation and treatment

OBJECTIVE

To review the literature on the diagnosis and treatment of vestibular schwannoma.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on vestibular schwannoma were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 parts: (1) Diagnosis - audiologic, electrophysiologic tests, and imaging; (2) Treatment - wait and scan protocols, surgery, radiosurgery/radiotherapy, and systemic therapy.

CONCLUSIONS

Decision making in VS treatment has become more challenging. MRI can diagnose increasingly smaller tumors, which has disastrous consequences for the patients and their families. It is important to develop an individualized approach for each case, which highly depends on the experience of each surgical team.

Comparative Transcriptomic Analysis of Archival Human Vestibular Schwannoma Tissue from Patients with and without Tinnitus

Vestibular schwannoma (VS) is an intracranial tumor that commonly presents with tinnitus and hearing loss. To uncover the molecular mechanisms underlying VS-associated tinnitus, we applied next-generation sequencing (Illumina HiSeq) to formalin-fixed paraffin-embedded archival VS samples from nine patients with tinnitus (VS-Tin) and seven patients without tinnitus (VS-NoTin). Bioinformatic analysis was used to detect differentially expressed genes (DEG; i.e., ≥two-fold change [FC]) while correcting for multiple comparisons. Using RNA-seq analysis, VS-Tin had significantly lower expression of GFAP (logFC = -3.04), APLNR (logFC = -2.95), PREX2 (logFC = -1.44), and PLVAP (logFC = -1.04; all p < 0.01) vs. VS-NoTin. These trends were validated by using real-time RT-qPCR. At the protein level, immunohistochemistry revealed a trend for less PREX2 and apelin expression and greater expression of NLRP3 inflammasome and CD68-positive macrophages in VS-Tin than in VS-NoTin, suggesting the activation of inflammatory processes in VS-Tin. Functional enrichment analysis revealed that the top three protein categories-glycoproteins, signal peptides, and secreted proteins-were significantly enriched in VS-Tin in comparison with VS-NoTin. In a gene set enrichment analysis, the top pathway was allograft rejection, an inflammatory pathway that includes the MMP9, CXCL9, IL16, PF4, ITK, and ACVR2A genes. Future studies are needed to examine the importance of these candidates and of inflammation in VS-associated tinnitus.

Systematic scoping review of papilledema in vestibular schwannoma without hydrocephalus

BACKGROUND

Vestibular schwannoma is a common pathology encountered by neurosurgeons worldwide. Often vestibular schwannoma presents with obstructive hydrocephalus. Papilledema is present in 8% of the patients with vestibular schwannoma, primarily due to obstructive hydrocephalus. Hyperproteinorrhachia is believed to be responsible for papilledema in the absence of hydrocephalus in vestibular schwannoma. However, there is a paucity of literature on the mechanism of papilledema in vestibular schwannoma patients with hydrocephalus.

OBJECTIVE

The aim of this study was to conduct a scoping review of scientific literature on papilledema in vestibular schwannoma patients without hydrocephalus.

METHODS

Design: This was a systematic scoping review and critical appraisal. Literature Search from PubMed was done following PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) and Joanna Briggs Institute guidelines for conducting and reporting scoping reviews.

RESULTS

A total of seven studies, including eight patients, were identified for inclusion in the review. The studies were heterogeneous in terms of reporting for various variables. All the included studies were case reports, with the earliest publication in 1954 and the latest publication in 2020. The mean age of the patients in the included studies was 35 years, with a minimum age of 20 years and maximum age of 64 years. Approximately 62.5% were females, and 37.5% were males in the included study. Only three studies have studied cerebrospinal fluid (CSF) proteins levels in these patients.

CONCLUSIONS

There is paucity in literature and a lack of evidence to conclusively state hyperproteinorrhachia as an antecedent to the development of papilledema in vestibular schwannoma patients without hydrocephalus. Younger age and female gender are risk factors for developing papilledema in the absence of hydrocephalus in vestibular schwannoma patients. Brainstem compression due to the large size of vestibular schwannoma can still have a patent aqueduct of Sylvius and no obstruction to CSF flow. The development of papilledema in vestibular schwannoma is a complex interplay of multiple factors that must be studied comprehensively for complete understanding.

The Diagnostic Accuracy of Pure-Tone Audiometry Screening Protocols for Vestibular Schwannoma in Patients with Asymmetrical Hearing Loss-A Systematic Review and Meta-Analysis

(1) Background: Magnetic resonance imaging (MRI) is the gold standard investigation for all patients who present with asymmetrical hearing loss (AHL) and a high index of suspicion for vestibular schwannoma (VS). However, pure-tone audiometry (PTA) is an investigation that can be used for the screening of these patients in order to reduce the costs. The aim of this systematic review and meta-analysis was to evaluate the diagnostic accuracy of different PTA protocols for VS in patients with ASHL, when compared with MRI; (2) Methods: Medline, Embase, and Cochrane databases were used to find relevant studies. All prospective and retrospective observational studies that evaluated the accuracy of PTA protocols for the screening of VS were assessed, according to the international guidelines; (3) Results: We analyzed seven studies (4369 patients) of poor-to-moderate quality. Their pooled sensitivity was good (0.73-0.93), but their specificity was low (0.31-0.60). All protocols were located in the right lower quadrant on the likelihood scattergram, and the post-test probabilities for positive and negative diagnosis of these protocols were extremely low; (4) Conclusions: PTA protocols cannot be used for a proper screening or diagnosis of vestibular schwannoma despite their good sensibility, and MRI remains the gold standard for this purpose.

Vision Deterioration and Hydrocephalus: Rare Presentations of Vestibular Schwannoma and Evolution of Management

Introduction The incidence of vestibular schwannoma is reported as 12 to 54 new cases per million per year, increasing over time. These patients usually present with unilateral sensorineural hearing loss, tinnitus, or vertigo. Rarely, these patients present with symptoms of hydrocephalus or vision changes.

Objective The study aimed to evaluate the surgical management of vestibular schwannoma at a single institution and to identify factors that may contribute to hydrocephalus, papilledema, and the need for pre-resection diversion of cerebrospinal fluid.

Patients and Methods A retrospective review examining the data of 203 patients with vestibular schwannoma managed with surgical resection from May 2008 to May 2020. We stratified patients into five different groups to analyze: tumors with a diameter of ≥40 mm, clinical evidence of hydrocephalus, and of papilledema, and patients who underwent pre-resection cerebrospinal fluid (CSF) diversion.

Results From May 2008 to May 2020, 203 patients were treated with surgical resection. Patients with tumors ≥40 mm were more likely to present with visual symptoms (p < 0.001). Presentation with hydrocephalus was associated with larger tumor size (p < 0.001) as well as concomitant visual symptoms and papilledema (p < 0.001). Patients with visual symptoms presented at a younger age (p = 0.002) and with larger tumors (p < 0.001).

Conclusion This case series highlights the rare presentation of vision changes and hydrocephalus in patients with vestibular schwannoma. We recommend urgent CSF diversion for patients with visual symptoms and hydrocephalus, followed by definitive resection. Further, vision may still deteriorate even after CSF diversion and tumor resection.

Nervus Intermedius Outcomes after Vestibular Schwannoma Surgery and Radiosurgery: A Single Institution Experience

OBJECTIVE

Nervus intermedius (NI) outcomes are under reported in the management of vestibular schwannoma (VS) and are experienced by patients undergoing stereotactic radiosurgery and surgical resection. We present our NI outcomes in our series of patients that have undergone all treatment modalities for vestibular schwannoma and a review of the existing literature.

METHODS

We performed a retrospective review of all patients with VS who were treated at our institution between January 1, 2008 and December 31, 2018. Demographic data were collected, in addition to tumor size, Koos grade, treatment modality, extent of resection (EOR), postoperative facial nerve function and hearing function. NI outcomes were determined from phone interview using a pre-existing functional questionnaire.

RESULTS

222 patients were reviewed and a total of 98 patients responded to the questionnaire. Patients were stratified into three groups: Group 1 included 54 patients who underwent radiation, Group 2 with 27 patients who underwent surgical treatment, and Group 3 with 17 patients who underwent both radiation and surgery. Twenty-eight percent of patients presented with pre-operative NI dysfunction; most commonly dry eye followed by taste dysfunction and dysfunction with lacrimation. Following treatment, 79% of patients experienced NI dysfunction most commonly dry eye. Statistical differences in dry eye and taste were observed when comparing the treatment groups.

CONCLUSION

NI dysfunction is common following treatment for VS. NI dysfunction should be included in patients' pretreatment counseling as it may impact treatment choice and quality of life. Additional studies are warranted to fully characterize NI dysfunction after treatment.

Clinical Subtypes and vHIT Parameters in a Population With Bilateral Vestibulopathy

Objective: To evaluate the different peripheral, neurological, genetic, and systemic etiologies of bilateral vestibulopathy (BVP) and the value of vHIT in the diagnostic process. Materials and methods: A retrospective case review was performed on 176 patients diagnosed with BVP in a tertiary referral center, between 2010 and 2020. Inclusion criteria comprised imbalance and/or oscillopsia during locomotion and horizontal angular VOR gain on both sides <0.8. We classified patients into different groups according to (1) their fulfillment of the Barany guideline for bilateral vestibulopathy (2) the definite etiology of BVP and (3) the four clinical subtypes distributed in our population (recurrent vertigo with BVP, rapidly progressive BVP, slowly progressive BVP, and slowly progressive BVP with ataxia). Medical history of vertigo, hypoacusis or migraine, and family background of imbalance and/or oscillopsia were assessed. Horizontal, posterior, and superior semicircular canal angular VOR gain was registered along with saccadic parameters such as velocity, and dispersion of the saccades' latency values. Results: Barany's Society diagnostic criteria for BVP was accomplished in 89 patients. Among our patients, 13.6% had migraines in their medical history and the idiopathic group accounted for 50% of the population. All four clinical subtypes were found in our population, slowly progressive bilateral vestibulopathy without vertigo was the most frequent one. A percentage of our population could not be categorized into any of the former subtypes, many of these patients were diagnosed with BVP after suffering a single vertigo episode. Lower vHIT gains were found in those patients with Barany's criteria for BVP and oscillopsia was significantly more prevalent in this group. Conclusions: Bilateral vestibulopathy manifests with very different patterns representing a very heterogeneous condition. The distribution of the clinical subtypes and Barany's criteria are a useful clinical tool to differentiate groups of patients. The vHIT can serve as an initial tool for identifying patients with BVP. The finding of bilateral vestibular involvement in a clinically suspected unilateral vestibulopathy should be considered in some patients.

Brainstem hyperintensity in patients with vestibular schwannoma is associated with labyrinth signal on magnetic resonance imaging but not vestibulocochlear tests

OBJECTIVES

Focal hyperintensity in the dorsal brainstem (HDB) has been described in large cerebellopontine angle tumours and is thought to represent vestibular nuclei degeneration, but its functional significance has not been thoroughly investigated. Our aim was to analyse its relationship to imaging characteristics of the tumour and inner-ear structures and to vestibulocochlear functional tests.

METHODS

We retrospectively reviewed 54 patients with a histological diagnosis of vestibular schwannoma (VS). Magnetic resonance imaging tumour characteristics (size, cystic composition and distance from the cochlear aperture), signal intensity ratio of the cochlea and vestibule in fluid-attenuated inversion recovery (FLAIR) and fast imaging employing steady-state acquisition (FIESTA)/fast spin-echo imaging with variable flip angles (CUBE) and vestibulocochlear function tests (audiometry, auditory brainstem response (ABR) and video head impulse testing (vHIT)) were obtained. Statistical analyses were performed to evaluate their relation to focal HDB.

RESULTS

Focal HDB was found in 22% of VS. It was significantly associated with large (p < 0.001) and cystic (p = 0.004) tumours and also with tumours located further from the cochlear aperture (p = 0.039). The signal intensity ratio of the cochlea on FLAIR was higher in patients with HDB (p < 0.014), but this difference was not observed in FIESTA/CUBE (p = 0.981). Audiometry, ABR and vHIT results did not significantly differ in patients with HDB, but ABR results were worse in patients with higher cochlear signal intensity on FLAIR sequences (p = 0.026).

CONCLUSIONS

Focal HDB in patients with VS was associated with increased signal intensity ratio of the cochlea on FLAIR in patients with VS but not directly to the results of vestibulocochlear function tests.

Papilledema secondary to vestibular schwannoma: An atypical case without intracranial hypertension

In most cases, vestibular schwannomas with papilledema are associated with intracranial hypertension secondary to hydrocephalus (obstructive or communicating). We describe the atypical case of a 39-years-old man who presented with bilateral papilledema revealing a vestibular schwannoma, but without hydrocephalus and with normal intracranial pressure. Ophtalmologic signs were completely resolved after tumor removal. The pathophysiological mechanism generally described to explain bilateral papilledema in such cases is tumor-induced hyperproteinorachia. However, in the absence of hydrocephalus or intracranial hypertension, this case raises the question of the mechanisms involved in the visual impairment related to vestibular schwannoma.

An Update on Epidemiology and Management Trends of Vestibular Schwannomas

OBJECTIVE

To determine the current epidemiology and management trends for patients with vestibular schwannomas (VS).

STUDY DESIGN

Retrospective cohort study.

SETTING

The Surveillance, Epidemiology, and End Results (SEER) tumor registry.

PATIENTS

The SEER database was queried to identify patients diagnosed with VS from 1973 to 2015. Demographics, patient and tumor characteristics, and treatment methods were analyzed.

RESULTS

A total of 14,507 patients with VS were identified. The mean age at diagnosis was 55 ± 14.9 years. Age-adjusted incidence from 2006 to 2015 was 1.4 per 100,000 per year and remained relatively stable. Incidence across age varied with sex, as younger women and older men had increased incidences comparatively. A higher percentage of patients underwent surgery alone (43%), followed by observation (32%), radiation alone (23%), and combined radiation and surgery (2%). Age 65 and older was associated with observation (odds ratio [OR] 1.417; p = 0.029) whereas age 20 to 39 and 40 to 49 were associated with surgery (OR 2.013 and 1.935; p < 0.001). Older age was associated with radiation. Larger tumor size was associated with surgery and combined treatment. African American patients and American Indian or Alaskan Native patients were more likely to undergo observation than surgery.

CONCLUSIONS

The overall incidence of VS is 1.4 per 100,000 per year and has remained relatively stable. There is a trend toward more conservative management with observation, which may be secondary to earlier diagnosis given widespread use of magnetic resonance imaging. Further studies are necessary to investigate differences in disease patterns and disparities in management.

Repeat stereotactic radiosurgery for progressive vestibular schwannomas after previous radiosurgery: a systematic review and meta-analysis

Vestibular schwannomas (VS) are slow-growing intracranial extraaxial benign tumors, developing from the vestibular part of the eight cranial nerves. Stereotactic radiosurgery (SRS) has now a long-term scientific track record as first intention treatment for small- to medium-sized VS. Though its success rate is very high, SRS for VS might fail to control tumor growth in some cases. However, the literature on repeat SRS after previously failed SRS remains scarce and reported in a low number of series with a limited number of cases. Here, we aimed at performing a systematic review and meta-analysis of the literature on repeat SRS for VS. Using PRISMA guidelines, we reviewed manuscripts published between January 1990 and October 2020 and referenced in PubMed. Tumor control and cranial nerve outcomes were evaluated with separate meta-analyses. Eight studies comprising 194 patients were included. The overall rate of patients treated in repeat SRS series as per overall series with first SRS was 2.2% (range 1.2–3.2%, p < 0.001). The mean time between first and second SRS was 50.7 months (median 51, range 44–64). The median marginal dose prescribed at first SRS was 12 Gy (range 8–24) and at second SRS was 12 Gy (range 9.8–19). After repeat SRS, tumor stability was reported in 61/194 patients, i.e., a rate of 29.6% (range 20.2–39%, I² = 49.1%, p < 0.001). Tumor decrease was reported in 83/194 patients, i.e., a rate of 54.4% (range 33.7–75.1%, I² = 89.1%, p < 0.001). Tumor progression was reported in 50/188 patients, i.e., a rate of 16.1% (range 2.5–29.7%, I² = 87.1%, p = 0.02), rarely managed surgically. New trigeminal numbness was reported in 27/170 patients, i.e., a rate of 9.9% (range 1.4–18.3%, p < 0.02). New facial nerve palsy of worsened of previous was reported in 8/183 patients, i.e., a rate of 4.3% (range 1.4–7.2%, p = 0.004). Hearing loss was reported in 12/22 patients, i.e., a rate of 54.3% (range 24.8–83.8%, I² = 70.7%, p < 0.001). Repeat SRS after previously failed SRS for VS is associated with high tumor control rates. Cranial nerve outcomes remain favorable, particularly for facial nerve. The rate of hearing loss appears similar to the one related to first SRS.

"When the Benign Bleed" Vestibular Schwannomas with Clinically Significant Intratumoral Hemorrhage: A Case Series and Review of the Literature

Vestibular schwannomas (VSs) are slow-growing benign neoplasms commonly located at the cerebellopontine angle. Although clinically significant hemorrhagic VSs are rarely encountered with only 75 patients previously reported, they could be life threatening. We discuss the presentation and outcomes of three patients with hemorrhagic VS as well as review the literature for this phenomenon. Consecutive adult patients with a histologically proven diagnosis of VS over a 9-year period were retrospectively reviewed. Fifty adult patients were identified with three (6%) having clinically significant intratumoral hemorrhage. This was defined as patients having acute to subacute symptoms with frank radiological evidence of hemorrhage. The mean age of diagnosis was 62 ± 9 years and the male-to female ratio was 2:1. The mean duration of symptoms, namely headache, vertigo, and sensorineural hearing impairment, was 26 ± 4 days with one patient presenting with acute coma. Retrosigmoid craniotomy for tumor resection was performed for all patients. Histopathological examination revealed extensive areas of microhemorrhage with considerable macrophage infiltration. All three patients were discharged with no additional neurological deficit and good functional performance. Clinically significant hemorrhagic VSs are rare, and patients may present with acute to subacute (i.e., within a month) symptoms of hearing loss headache, facial, or trigeminal nerve palsy. Macrophage infiltration is frequently encountered in tumor specimens and reflects the pivotal role of chronic inflammation in their pathophysiology. Surgical resection can lead to good outcomes with timely intervention.

Secondary stabbing headache associated with intracranial tumors, aneurysms, and arteriovenous malformation: An alarming warning sign

BACKGROUND

Stabbing headache (SH) is considered as a pure primary headache, but according to a few clinical observations it could also be secondary. Over the past decades, we have been observing the complaint of SH in patients with intracranial vascular and neoplastic lesions.

OBJECTIVE

To describe a series of patients with intracranial lesions who experienced SH.

METHODS

This is a cross-sectional, retrospective study of 34 patients with intracranial lesions associated with SH, admitted at Hospital das Clínicas, Federal University of Pernambuco, Brazil.

RESULTS

In this series of 34 patients [29 women, 44 ± 12 years (mean ± SD)] with secondary SH, the causes were intracranial neoplasms (n = 31), cerebral aneurysms (n = 2), or arteriovenous malformation (n = 1). Pituitary tumor (n = 18), meningioma (n = 6), and vestibular schwannomas (n = 4) were the most prevalent types of intracranial neoplasms. All these lesions had intimate contact with the dura mater, including an oligodendroglioma, the only intra-axial tumor in the series. A characteristic in the secondary SH is the crescendo pattern (12/34, 35%), progressing from infrequent attacks to recurrent crises occurring several times a day. The SH lasted from 5 days to 60 months (15 ± 18 months, mean ± SD) until the correct diagnosis [16/34 (47%) of the patients ≤6 months]. The SH was triggered by the movement of the head (5/34, 15%) or Valsalva maneuver (1/34). After surgery, suppression of the SH was observed. In a few of the patients to whom dexamethasone was prescribed, the SH subsided within a few days.

CONCLUSION

This study was able to identify clinical red flags associated with intracranial lesions and secondary SH, for example, recent onset of SH, exclusively unilateral (ipsilateral) at the same location, crescendo pattern, triggered by head movements, or Valsalva maneuver.

Progression of Contralateral Hearing Loss in Patients With Sporadic Vestibular Schwannoma

Background and Introduction: Vestibular schwannomas (VSs) are the most common tumors of the cerebellopontine angle, typically presenting unilaterally with ipsilateral sensorineural hearing loss (SNHL). The mechanism of tumor-induced hearing loss has recently been shown to be related to secreted tumor factors, in addition to mechanical compression of the adjacent auditory nerve, and these factors may percolate through CSF or blood to affect contralateral hearing as well.

Methods: This is a retrospective study of medical records for patients treated for VS at Mass Eye and Ear from January 1994 through October 2018. Included patients had unilateral VS and sequential audiometry allowing for longitudinal assessment of hearing over time. Mass Eye and Ear's audiology database was used to select age- and sex-matched case controls, also with sequential audiometry, from the non-VS population. Subgroup analysis was performed by age, sex, baseline hearing, and tumor size at initial diagnosis. Hearing loss progression was performed using Kaplan-Meier analysis to account for variable follow-up times.

Results: A total of 661 patients were identified with VS and sequential audiometry. The population was predominantly female vs. male (368 vs. 293, p = 0.0035), driven primarily by younger patients with Koos 4 tumors (76 female vs. 49 male, p = 0.016). Patients with normal baseline hearing bilaterally (N = 241) demonstrated no significant difference in hearing loss progression in VS-contralateral vs. control ears. Patients with abnormal baseline VS-ipsilateral hearing (N = 190), however, demonstrated significantly higher likelihood of reaching moderate SNHL in VS-contralateral ears. Subgroup analysis by age, sex, and baseline tumor size did not yield any subgroup-specific trends for hearing loss progression.

Discussion and Conclusion: This is the largest study to date tracking long-term bilateral hearing outcomes in patients with VS, and demonstrates that, in patients with abnormal hearing in the VS-ipsilateral ear, there exists a long-term risk of progression to moderate hearing loss in the contralateral ear as well. Combined with the absence of significant changes in word understanding in the affected ears, these findings may provide clues to the nature of tumor-secreted factors involved in VS-associated hearing loss. Female predominance within the VS patient population is confirmed, driven mostly by younger female patients with Koos 4 tumors.

Manual segmentation versus semi-automated segmentation for quantifying vestibular schwannoma volume on MRI

Purpose

Management of vestibular schwannoma (VS) is based on tumour size as observed on T1 MRI scans with contrast agent injection. The current clinical practice is to measure the diameter of the tumour in its largest dimension. It has been shown that volumetric measurement is more accurate and more reliable as a measure of VS size. The reference approach to achieve such volumetry is to manually segment the tumour, which is a time intensive task. We suggest that semi-automated segmentation may be a clinically applicable solution to this problem and that it could replace linear measurements as the clinical standard.

Methods

Using high-quality software available for academic purposes, we ran a comparative study of manual versus semi-automated segmentation of VS on MRI with 5 clinicians and scientists. We gathered both quantitative and qualitative data to compare the two approaches; including segmentation time, segmentation effort and segmentation accuracy.

Results

We found that the selected semi-automated segmentation approach is significantly faster (167 s vs 479 s, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$p<0.001$$\end{document}p<0.001), less temporally and physically demanding and has approximately equal performance when compared with manual segmentation, with some improvements in accuracy. There were some limitations, including algorithmic unpredictability and error, which produced more frustration and increased mental effort in comparison with manual segmentation.

Conclusion

We suggest that semi-automated segmentation could be applied clinically for volumetric measurement of VS on MRI. In future, the generic software could be refined for use specifically for VS segmentation, thereby improving accuracy.

Electronic supplementary material

The online version of this article (10.1007/s11548-020-02222-y) contains supplementary material, which is available to authorized users.

Facial nerve function and hearing after microsurgical removal of sporadic vestibular schwannomas in a population-based cohort

BACKGROUND

Vestibular schwannoma (VS) is a benign tumor originating from the vestibulocochlear nerve. The optimal treatment strategy is debated, since surgery may result in iatrogenic facial nerve injury. We report the results of VS surgery in a population-based unselected cohort in a center with access to Cyber Knife (CK) radiosurgery.

METHODS

We reviewed 117 consecutive operations and found 95 patients who had their primary operation due to vestibular schwannoma between 2001 and 2017. Facial nerve function was evaluated with the House-Brackmann (HB) scale and hearing with the EU classification.

RESULTS

The population consisted of 37 males and 58 females with a median age of 54 years (range 19-79). One year after surgery 67% of patients had a good outcome (HB 1-2). The rate of good outcome was 90% if no facial nerve damage was observed during intraoperative monitoring, the size of the tumor was under 30 mm and no hydrocephalus was present. During the study period, the treatment strategy changed from total to near-total resection after the introduction of CK radiosurgery, which could be used as a second-line treatment in case of residual tumor regrowth. This resulted in an improvement of outcomes (0% HB 5-6) despite the larger tumor sizes (25 ± 14 mm vs. 31 ± 9 mm, p < 0.05). Hearing preservation rates did not increase.

CONCLUSIONS

Near-total resection and subsequent CK radiosurgery in case of residual tumor regrowth during follow-up seems to provide a good outcome of facial nerve function even in large VSs.

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.

Increased cochlear radiation dose predicts delayed hearing loss following both stereotactic radiosurgery and fractionated stereotactic radiotherapy for vestibular schwannoma

PURPOSE

Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (fSRT) are noninvasive therapies for vestibular schwannomas providing excellent tumor control. However, delayed hearing loss after radiation therapy remains an issue. One potential target to for improving hearing rates is limiting radiation exposure to the cochlea.

METHODS

We retrospectively reviewed 100 patients undergoing either SRS with 12 Gy (n = 43) or fSRT with 50 Gy over 28 fractions (n = 57) for vestibular schwannoma. Univariate and multivariate analysis were carried out to identify predictors of hearing loss as measured by the Gardner Robertson scale after radiation therapy.

RESULTS

Deterioration of hearing occurred in 30% of patients with SRS and 26% with fSRT. The overall long term (> 2 year) progression rates were 20% for SRS and 16% for fSRT. Patients with a decrease in their Gardner Robertson hearing score and those that loss serviceable hearing had significantly higher average minimal doses to the cochlea in both SRS and fSRT cohorts. ROC analysis showed that a cut off of 5 Gy and 35 Gy, for SRS and fSRT respectively, predicted hearing loss with high sensitivity/specificity.

CONCLUSION

Our data suggests the minimal dose of radiation that the cochlear volume is exposed to is a predictor of delayed hearing loss after either SRS or fSRT. A threshold of 5 Gy/35 Gy may lead to improved hearing preservation after radiotherapy. Further prospective multi center studies can further elucidate this mechanism.

Biomarkers in Vestibular Schwannoma-Associated Hearing Loss

Vestibular schwannomas (VSs) are benign tumors composed of differentiated neoplastic Schwann cells. They can be classified into two groups: sporadic VS and those associated with neurofibromatosis type 2 (NF2). VSs usually grow slowly, initially causing unilateral sensorineural hearing loss (HL) and tinnitus. These tumors cause HL both due to compression of the auditory nerve or the labyrinthine artery and due to the secretion of different substances potentially toxic to the inner ear or the cochlear nerve. As more and more patients are diagnosed and need to be managed, we are more than ever in need of searching for biomarkers associated with these tumors. Owing to an unknown toxic substance generated by the tumor, HL in VS may be linked to a high protein amount of perilymph. Previous studies have identified perilymph proteins correlated with tumor-associated HL, including μ-Crystallin (CRYM), low density lipoprotein receptor-related protein 2 (LRP2), immunoglobulin (Ig) γ-4 chain C region, Ig κ-chain C region, complement C3, and immunoglobulin heavy constant γ 3. Besides, the presence of specific subtypes of heat shock protein 70 has been suggested to be associated with preservation of residual hearing. It has been recently demonstrated that chemokine receptor-4 (CXCR4) is overexpressed in sporadic VS as well as in NF2 tumors and that hearing disability and CXCR4 expression may be correlated. Further, the genetic profile of VS and its relationship with poor hearing has also been studied, including DNA methylation, deregulated genes, growth factors, and NF2 gene mutations. The knowledge of biomarkers associated with VS would be of significant value to maximize outcomes of hearing preservation in these patients.

Audiological Evaluation of Vestibular Schwannoma Patients with Normal Hearing

Objective: To evaluate the audiological aspects of vestibular schwannoma (VS) patients with normal hearing. Study Design: Retrospective study. Setting: Quaternary referral center for skull base pathologies. Patients: The records on 4,000 patients who had been diagnosed with VS between 1986 and December 2017 were retrospectively reviewed. The patients included in the study were the ones who complied with the strict audiological normality criteria, as follows: a pure tone hearing threshold (at the 6-octave-spaced frequencies from 250 to 8,000 Hz) ≤25 dBHL; a word recognition score >90%; and interaural differences ≤10 dB at each frequency. Interventions: Auditory brainstem response (ABR) testing and radiological imaging. Main Outcome Measures: The incidence of normal objective hearing among VS patients, and the diagnostic utility of the ABR and the effect of tumor size and site on the response. Results: The incidence of normal hearing among VS patients was 4.2%. Tinnitus and vertigo were the most common symptoms across tumor grades; 5.6% of the tumors were large and giant tumors. The ABR yielded a sensitivity of 73.6%, with a false negative rate of 26.3% using a cutoff point of 0.2 ms for interaural latency differences. Conclusions: The diagnosis of VS should not be based on audiometric thresholds alone. Alarming signs of VS should be clear to the physician in order not to miss or delay the diagnosis of the disease. The ABR is useful in the diagnosis of VS, but normal results do not exclude the occurrence of the disease in patients with normal hearing.

Vestibular Schwanomma: An Experience in a Developing World

Background

Tumors related to the acoustic nerves represent 90% of cerebellopontine angle diseases and have been in the picture for at least 200 years. Famous as acoustic neuromas and vestibular neuromas, these are usually benign, slow-growing tumors of Schwann cells of the myelin sheath. Surgery is the treatment of choice though some authors have suggested "wait and watch" policy. The aims of our study were to study the clinical presentation and management of the tumors, and to evaluate the perioperative outcomes of the surgery.

Methods

A retrospective review of the datasheet of 33 patients diagnosed with vestibular schwanomma who had undergone surgery from January 2014 to January 2017 was performed in National Academy of Medical Sciences, Bir Hospital, Kathmandu, Nepal. Analysis of the demographic data and perioperative outcomes was performed.

Results

Hearing loss was the main presenting symptom in 72% cases followed by tinnitus, dizziness, facial numbness and sudden sensorineural hearing loss. Mean tumur size was 39.7 ± 3 mm. The mean age of the patients was 46 ± 3 years with a female preponderance (1.2:1). In particular, the retrosigmoid route was preferred in all the cases since it was the most employed approach at our center and 63% of the tumors presented to us were grade 5. The surgical techniques allowed safe preservation of the facial function which was 93%. The hearing loss did not improve after the surgery in 94% while it worsened in 6% of cases. We did not find any significant relation between outcome and size, age, gender or laterality of the tumor (P > 0.05). There was no perioperative mortality.

Conclusions

The benign and slow-growing nature of vestibular schwanomma usually poses problems for the early diagnosis and treatment especially in a poor resource setting like ours. Likewise, there are very few studies so far done in the country regarding the incidence and management of the disease. Thus, this study might be helpful in providing insight into the occurrence of the disease in the present scenario and the need for much more studies in the future.

Anatomical study of presigmoid-retrolabyrinthine approach based on temporal bone high-resolution CT

BACKGROUND

The surgical approach of acoustic neuroma includes translabyrinthine, transcranial fossa, suboccipital retrosigmoid sinus, and presigmoid retrolabyrinthine approach. Aims/Objective: To provide the anatomical basis for the surgical selection of presigmoid retrolabyrinthine approach by measuring the anatomical parameters of retrolabyrinthine space of the petrous bone by high-resolution CT.

MATERIAL AND METHODS

A retrospective study of 208 high-resolution CT (HRCT) images of 104 patients examined in our hospital were analyzed retrospectively. Forty-nine males and 55 females were included in this study. Lines were drawn on the HRCT to measure the morphological data for pre-operational assessment.

RESULT

Morphological data were retracted from HRCT, for preoperational assessment.

CONCLUSION AND SIGNIFICANCE

Using the standard postprocessing images of temporal bone HRCT can predict the size of the retrolabyrinthine space and the degree of exposure to the inner auditory canal, providing an important anatomical index for the choice of presigmoid retrolabyrinthine approach.

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.

Diagnosis of retrocochlear lesions with emphasis on expansion of the cerebellopontine angle

The correct diagnosis of CPA tumours is a relatively common issue in both neurological and ENT practice, the omission of which can have serious consequences for the patient. Properly set clinical guidelines and diagnostic protocols are key aspects of good clinical practice. In the case of CPA tumours, two options are available: the first is diagnosis with the help of an ABR as the primary tool for determining the group of patients with a possible tumour; the second is an MRI scan of the posterior cranial fossa. With an appropriately set diagnostic protocol in place, and despite the 40% chance of failure of the ABR to detect tumours less than or equal to 1 cm, similar treatment results can be achieved with much higher cost efficacy in case of primary ABR testing.

Advanced Vestibular Schwannoma: A Case of Optic Disc Oedema without Hydrocephalus

A wide range of pathologies can cause papilloedema. Vestibular schwannoma is a benign and slow-growing tumour that causes symptoms and findings on ophthalmic examination when the diagnostic is delayed. The authors report a case of a 64-year-old male who presented with bilateral disc oedema secondary to a vestibular schwannoma grade 4. Obstructive hydrocephalus was not evident. The authors suggest that cerebrospinal fluid protein may have a role in the formation of optic disc oedema. A right suboccipital craniectomy was performed to remove the tumour, leading to secondary facial palsy.

Vestibular Schwannoma Presenting as Oral Dysgeusia: An Easily Missed Diagnosis

We present a case of a fifty-year-old male patient who was referred to the Oral Medicine Department with a complaint of a salty taste. History taking subsequently revealed that the patient was also experiencing intermittent numbness of his left lower lip, tinnitus, and a feeling of fullness in the left ear. Magnetic resonance imaging was performed which revealed a large vestibular schwannoma affecting the left vestibulocochlear nerve, which was treated surgically. This case shows the importance of taking a detailed history in a patient presenting with an initial complaint of oral dysgeusia. It also highlights the possibility of significant underlying pathology, presenting with initial low level, nonspecific complaints such as an altered taste, and the rationale for imaging patients who report unilateral facial hypoesthesia.