Clinical presentation of intralabyrinthine schwannomas: a multicenter study of 110 cases

A Case Report Demonstrating Preservation of Vestibular Receptor Function after Transcochlear Removal of an Intracochlear Schwannoma with Extension to the Fundus of the Internal Auditory Canal

Preservation of function is an important goal during surgical management of cochleovestibular schwannomas. We here demonstrate the relief of vertigo and the preservation of function of all five vestibular receptors after removal of an intracochlear schwannoma with extension to the fundus of the internal auditory canal. A 61-year-old male with a five-year history of left-sided deafness, tinnitus, vertigo attacks, and an MRI consistent with an intracochlear schwannoma with limited extension through the modiolus to the fundus of the internal auditory canal (IAC) underwent transcanal, transcochlear total tumor removal and-due to a cerebrospinal fluid leak from the fundus of the IAC-revision surgery with lateral petrosectomy and blind sac closure of the external auditory canal. Despite complete removal of the cochlear partition of the inner ear (total cochlectomy), the patient's vestibular receptors remained functional, and the vertigo symptoms disappeared. These results show that vestibular labyrinthine function may not only be preserved after partial or subtotal cochlectomy but also after complete cochlear removal. This further confirms the vestibular labyrinth's robustness and encourages surgical management of transmodiolar schwannomas with limited extension to the fundus of the IAC.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1854-1860, 2024.

Does Location of Intralabyrinthine Vestibular Schwannoma Determine Objective and Subjective Vestibular Function?

BACKGROUND AND OBJECTIVE

The incidence of intralabyrinthine schwannomas is increasing, and a growing attention is given to the detrimental effects on hearing function. On the contrary, the vestibular profile of intralabyrinthine vestibular schwannomas (VSs) is still not well understood. We aimed to investigate and report the observed relationships between the intralabyrinthine location of the schwannomas and objective and subjective vestibular profile of the patients.

METHODS

Retrospective cohort study of 20 consecutive individuals with sporadic intralabyrinthine schwannomas and grouped according to the intralabyrinthine location of the schwannomas. Vestibular testing consisted of the video head impulse test of all three semicircular canals, the caloric test, cervical and ocular vestibular evoked myogenic potentials, and the dizziness handicap inventory. A nonparametric unpaired t test was performed to compare groups, and Fisher's exact test was used for categorical data.

RESULTS

The median video head impulse test gains (lateral, anterior, posterior) were 0.40, 0.50, and 0.75 for intravestibular schwannomas and 0.93, 1.52, and 0.91 for intracochlear schwannomas ( p = 0.0001, p = 0.009, p = 0.33), respectively. Caloric unilateral weakness had a median of 100% for intravestibular schwannomas and 14% for intracochlear schwannomas ( p = 0.0001). The mean dizziness handicap inventory was 21 for intravestibular schwannomas and 1 for cochlear schwannomas ( p = 0.02). There were no significant differences in vestibular evoked myogenic potentials according to intralabyrinthine location.

CONCLUSION

By both objective and subjective measures, intralabyrinthine schwannomas with an intravestibular component has significantly worse vestibular function than schwannomas with purely cochlear involvement.

Cochlear Implantation in Sporadic Intralabyrinthine Schwannomas with Single-Sided Deafness: Implications for Binaural Hearing

BACKGROUND AND OBJECTIVE

Intralabyrinthine schwannomas (ILSs) may have detrimental effects on ipsilateral hearing, commonly leading to single-sided deafness (SSD). Cochlear implantation in patients with ILSs is an option to partly restore ipsilateral hearing; however, the available literature fails to account for the binaural hearing benefits of a cochlear implant (CI) for ILSs.

METHODS

We prospectively evaluated SSD patients with sporadic ILS undergoing cochlear implantation with simultaneous tumor resection (n = 10) or with tumor observation (n = 1). Patients completed the Speech, Spatial and Qualities Questionnaire (SSQ12) and the Nijmegen Cochlear Implant Questionnaire (NCIQ) pre- and postoperatively, as well as the Bern Benefit in Single-Sided Deafness (BBSSD) questionnaire postoperatively. Patients were also tested postoperatively with and without their CI to measure the effect on localization ability and binaural summation, squelch, and head shadow.

RESULTS

Evaluation was completed for nine and six patients (subjective and objective data, respectively). The CI significantly improved the speech reception threshold (SRT) in the head shadow condition where the target signal was presented to the CI side and the noise to the front (SCIN0). On the other hand, the SRTs in the colocated condition (S0N0) and the condition where the target signal was presented to the front and the noise to the CI side (S0NCI) were unaffected by the CI. The mean localization error decreased significantly from 102° to 61° (p = 0.0031) with the addition of a CI. The scores from SSQ12 demonstrated nonsignificant changes. For NCIQ, the self-esteem and the social interaction domains increased significantly but insignificantly for the remaining domains. The BBSSD responses ranged from +0.5 to +3.5 points.

CONCLUSION

After implantation, patients achieved significantly better scores across some of the patient-reported and objective parameters. In addition to reporting on a number of ILS cases where implantation was performed, the study is the first of its kind to document patient-reported and objective binaural hearing improvement after cochlear implantation in patients with ILS and, thereby, lends support to the active management of ILS.

Bilateral intracochlear schwannomas: histopathological confirmation and outcomes following tumour removal and cochlear implantation with lateral wall electrodes

Intracochlear schwannomas (ICS) are very rare benign tumours of the inner ear. We present histopathological proof of the extremely rare bilateral occurrence of intracochlear schwannomas with negative blood genetic testing for neurofibromatosis type 2 (NF2). Bilateral schwannomas are typically associated with the condition NF2 and this case is presumed to have either mosaicism for NF2 or sporadic development of bilateral tumours. For progressive bilateral tumour growth and associated profound hearing loss, surgical intervention via partial cochleoectomy, tumour removal, preservation of the modiolus, and simultaneous cochlear implantation with lateral wall electrode carrier with basal double electrode contacts was performed. The right side was operated on first with a 14-month gap between each side. The hearing in aided speech recognition for consonant-nucleus-consonant (CNC) phonemes in quiet improved from 57% to 83% 12 months after bilateral cochlear implantation (CI). Bilateral intracochlear schwannomas in non-NF2 patients are extremely rare but should be considered in cases of progressive bilateral hearing loss. Successful tumour removal and cochlear implantation utilizing a lateral wall electrode is possible and can achieve good hearing outcomes.

Surgical Outcomes of Simultaneous Cochlear Implantation and Intracochlear Schwannoma Removal

OBJECTIVE

Intracochlear schwannoma is very rare, and complete loss of hearing is inevitable after the removal of this tumor. Here, we discuss cochlear implantation (CI) performed simultaneously with the removal of an intracochlear schwannoma.

STUDY DESIGN

Retrospective single-center study.

SETTING

Tertiary medical institute.

METHODS

Simultaneous CI and intracochlear schwannoma removal were performed in 4 subjects. After subtotal cochleostomy, the tumors were removed meticulously, with preservation of the modiolus. A new slim modiolar electrode (Nucleus CI632) was placed in a manner that hugged the modiolus. The surgical outcomes of functional gain, word recognition score (WRS), sound localization, and hearing in noise and speech intelligibility tests were investigated.

RESULTS

Intracochlear schwannomas were removed successfully from the 4 patients, with no remnant tumor. The mean aided hearing threshold 6 months after surgery was 25.0 ± 1.8 dB, and the mean-aided WRS with a 60 dB stimulus was 36.0 ± 18.8% (range 16%-60%). The Categorical Auditory Performance (CAP) score of the 3 single-sided deafness patients under contralateral ear masking was 7. The CAP score of the patient with bilateral sensorineural hearing loss was 6, which improved from a preoperative score of 0.

CONCLUSION

When an intracochlear schwannoma does not completely invade the modiolus, CI with simultaneous tumor removal can be performed successfully, resulting in good hearing performance. A slim modiolar electrode can be placed stably at the modiolus after schwannoma removal.

Full Endoscopic Resection of Intralabyrinthine Schwannomas: A Case Series

Objective: To investigate the technique and efficacy of fully endoscope resection of intralabyrinthine schwannomas (ILS) by transcanal transpromontorial endoscopic approach (TTEA). Study Design: Retrospective case review. Setting: Hospital. Patients: All patients who were affected by ILS, without extension to the internal auditory canal and underwent surgery with TTEA in our hospital in 2020. Intervention(s): Therapeutic. Main Outcome Measure(s): Recovery status, postoperative complications and remaining symptoms after surgery. Results: Three patients were included, all of which underwent gross total resections. The follow-up period was from 10 months to 2 years. No intraoperative and postoperative major complications were observed. There was no facial paralysis or cerebrospinal fluid leakage postoperatively. The hospitalization time of TTEA was 5 days. Three patients' vertigo was relieved after 1 week without receiving vestibular therapy. Only 1 patient complained of transient episodes of vertigo when climbing or holding heavy objects. Conclusions: TTEA has the advantages of clear vision to identify the anatomical structure, enabling complete tumor resection, reduced operation time, and faster postoperative recovery.Level of Evidence: IV.

Cochlear Implantation in Intralabyrinthine Schwannoma: Case Series and Systematic Review of the Literature

Intralabyrinthine schwannomas (ILS) are rare benign tumours arising from the peripheral branches of the cochlear or vestibular nerves in the membranous labyrinth, intracochlear schwannomas being the most frequent ones. When hearing is no longer feasible on the affected side, surgical removal along with simultaneous cochlear implantation can be proposed to the patient. We hereby present a systematic review of the literature on the topic, as well as two original cases from our centre (Ospedale Università degli Studi di Padova). Cochlear implantation in intracochlear schwannomas is feasible, with overall satisfactory hearing outcomes in accordance with the evidence found in the literature.

Intralabyrinthine schwannomas: a two-case series and literature review with a focus on hearing rehabilitation

PURPOSE

Intralabyrinthine schwannomas (ILSs) are an uncommon finding. Diagnosis is challenging and no gold standard treatment exists yet. In this article, we present a two-cases series and review the latest available literature to assess the best diagnostic and therapeutic scheme.

METHODS

We reviewed the latest available literature assessing most frequent and relevant sets of symptoms, clinical features of the disease, diagnostic tests and imaging, possible treatments and after-surgery hearing rehabilitation techniques. We then compared literature data to our own series ones.

RESULTS

ILSs clinical presentation and development may overlap with other, more common otological conditions. Full audiometric battery test, electrophysiological study of VEMPS and MRI with contrast enhancement all appear to be critical to correctly diagnose these tumors. Several treatments exist: radiological follow-up, radiation therapy, full or partial surgical excision. Hearing rehabilitation is mostly accomplished through simultaneous cochlear implantation.

CONCLUSIONS

Our case-series data matches the available literature. ILSs are a rare type of vestibular schwannomas. Diagnosis in challenging and delayed in time as all the diagnostic tests, yet sensitive, are not specific for ILSs. The most suitable treatment seems to be surgical excision of these tumors followed by simultaneous cochlear implantation to restore hearing.

The Natural History of Primary Inner Ear Schwannomas: Outcomes of Long-Term Follow-Up

OBJECTIVE

To describe the natural history of primary inner ear schwannomas over a long follow-up period.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary referral center.

PATIENTS

Patients with primary inner ear schwannomas with serial audiometric and radiologic follow-up.

MAIN OUTCOME MEASURES

Patterns of hearing loss, rate of hearing decline, presence of vestibular symptoms, and rate of tumor growth.

RESULTS

A total of 12 patients with 13 tumors were identified. The mean duration of follow-up was 7 years. Forty-six percent of tumors were intracochlear, 15% were intravestibular, 23% were transmodiolar, and 15% were intravestibular-cochlear. Hearing loss was the most common presenting symptom, occurring in all patients. Among patients with serviceable hearing (American Academy of Otolaryngology-Head and Neck Surgery Class A or B) at the time of presentation, the average time to decline to a nonserviceable hearing level was 57.3 months (range, 21-117 mo). Hearing loss was sudden in 31% of patients, progressive in 61% and fluctuating in 8%. No patients had intractable vertigo; however, two required vestibular physiotherapy. On initial magnetic resonance imaging, the mean largest tumor dimension was 3.1 mm (standard deviation, 1.2 mm), and the mean largest dimension on most recent magnetic resonance imaging was 4.4 mm (standard deviation, 1.1 mm). Two tumors exhibited no growth over a follow-up of 11.3 and 2.8 years, respectively. Overall, the mean growth was 0.25 mm per year followed. Two patients underwent cochlear implantation with simultaneous tumor resection and had favorable outcomes.

CONCLUSION

Long-term follow-up suggests a conservative approach, with possible hearing rehabilitation at the time of deterioration, is a safe management strategy for primary inner ear schwannomas.

Case report: Concurrent intravestibular schwannoma mimicking Ménière's disease and cochlear hydrops detected via delayed three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging

Objective

To present a case of intralabyrinthine schwannoma (ILS) presenting as Ménière's disease diagnosed via 4-h delayed gadolinium-enhanced three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging (3D-FLAIR MRI) and treated successfully using the translabyrinthine approach.

Patient

A patient who was diagnosed with intravestibular ILS.

Interventions

The patient underwent comprehensive preoperative neurological examinations and MRI. The tumor was resected using the translabyrinthine approach and was pathologically confirmed as schwannoma based on the surgical specimen.

Main outcome measures

Preoperative audiogram and vestibular test findings and MRI images.

Results

Preoperatively, pure-tone audiogram showed progressive sensorineural hearing loss only on the affected side. The video head impulse test and vestibular evoked myogenic potential test showed vestibular dysfunction on the affected ear. Immediate gadolinium-enhanced T1-weighted MRI revealed an enhanced region in the vestibule. Meanwhile, magnetic resonance cisternography showed a filling defect. Delayed 3D-FLAIR MRI revealed a signal void in the scala media of the cochlea indicative of cochlear hydrops, and a strong signal in the perilymph at the basal cochlea suggestive of impaired blood–labyrinthine barrier.

Conclusion

Delayed 3D-FLAIR MRI is useful in diagnosing concurrent ILSs and endolymphatic hydrops.

MRI characteristics of intralabyrinthine schwannoma on post-contrast 4 h-delayed 3D-FLAIR imaging

PURPOSE

The purpose of this study was to describe the MRI characteristics of intralabyrinthine schwannoma (ILS) on post contrast three-dimensional (3D) fluid-attenuation-inversion-recovery (FLAIR) images obtained four hours after intravenous administration of a gadolinium-based contrast agent (4h-3D-FLAIR).

MATERIALS AND METHODS

This IRB-approved retrospective multi-center study included patients presenting with typical ILS from January 2016 to October 2020. All medical charts were systematically collected. All MRI examinations, including 4h-3D-FLAIR images, were reviewed by two board-certified neuroradiologists. Main outcome measures were location, signal intensity and associated anomalies of ILS.

RESULTS

Twenty-seven out of 8730 patients (0.31%) referred for the investigation of a cochleovestibular disorder had a final diagnosis of ILS. There were 13 men and 14 women with a mean age of 52 ± 17 (SD) years (age range: 20-86 years). The most common clinical presentation was unilateral progressive sensorineural hearing loss (16/27; 59%). All ILS were unilateral and 15 (15/27; 55%) were intracochlear. All ILS presented as a hypointense filling defect within the labyrinth on T2-weighted images that enhanced on post-contrast T1-weighted images. On 4h-3D-FLAIR images, all ILS presented as a hypointense filling defect, associated with diffuse perilymphatic hyperintensity. Two patients (2/27; 7%) presented with ipsilateral endolymphatic hydrops.

CONCLUSION

ILS displays consistent features on post-contrast 4h-3D-FLAIR images. ILS should not be confused with endolymphatic hydrops and requires a systematic analysis of the corresponding T2-weighted images.

Microsurgical resection of an intravestibular schwannoma: a review of surgical technique and management considerations

Intravestibular schwannomas are rare tumors within the intralabyrinthine region and involve different management considerations compared to more common vestibular schwannomas. In this report, the authors review a case of a 52-year-old woman who presented with hearing loss and vestibular symptoms and was found to have a left intravestibular schwannoma. Given her debilitating vestibular symptoms, she underwent microsurgical resection. In this video, the authors review the relevant anatomy, surgical technique, and management considerations in these patients.

The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID2187

Challenges of Cochlear Implantation in Intralabyrinthine Schwannoma Patients: Surgical Procedures and Auditory Outcome

Intralabyrinthine schwannoma (ILS) is a rare benign tumor of the inner ear potentially causing unilateral sensorineural hearing loss and vertigo. This study evaluated the outcome of one surgical session comprising microsurgical ILS resection and cochlear implantation in terms of surgical feasibility, complications, and auditory outcome. Ten clinically and histologically confirmed ILS patients included in this study (three women and seven men; mean age 56.4 ± 8.6) underwent surgery between July 2015 and February 2020. Eight patients had intracochlear tumor location; the remaining two had vestibulocochlear and intravestibular ILS. One of the three following methods was used for tumor removal: an extended cochleostomy, subtotal cochleoectomy, or a translabyrinthine approach. Although negligible improvement was observed in two of the patients, two patients were lost to follow-up, and one opted out from using CI, the speech perception of the five remaining ILS patients improved as per the Freiburg Monosyllable Test (FMT) from 0% before surgery to 45– 50% after the implantation. Our study supports the presented surgical approach’s feasibility and safety, enabling tumor removal and hearing restoration shortly after surgery.

Management of vestibular dysfunction and hearing loss in intralabyrinthine schwannomas

PURPOSE

Intralabyrinthine schwannomas (ILS) are rare, benign, slow-growing tumors arising from schwann cells of the cochlear or vestibular nerves within the bony labyrinth. This study provides insight into the management of this rare tumor through a large case series.

MATERIALS AND METHODS

After Institutional Review Board approval, a retrospective chart review was performed of all ILS patients treated at our institution between 2007 and 2019.

RESULTS

20 patients (9 male, 11 female) with ILS were managed at our institution. The right ear was affected in 9 patients (45%) and the left in 11 (55%). Subjective hearing loss was endorsed by all 20 patients. Average pure tone average at presentation was 72 dB nHL. Nine tumors (45%) were intravestibular, 6 (30%) were intracochlear, 4 (20%) were transmodiolar and 1 (5%) was intravestibulocochlear. Hearings aids were used in 3 patients (15%), BiCROS in 2 (10%), CI in 2 (10%), and bone conduction implant in 1 (5%). Vestibular rehabilitation was pursued in 5 patients. Surgical excision was performed for one patient (5%) via translabyrinthine approach due to intractable vertigo. No patients received radiotherapy or intratympanic gentamicin injections.

CONCLUSION

ILS presents a diagnostic and management challenge given the similarity of symptoms with other disorders and limited treatment options. Hearing loss may be managed on a case-by-case basis according to patient symptoms while vestibular loss may be mitigated with vestibular therapy. Surgical excision may be considered in patients with intractable vertigo, severe hearing loss with concurrent CI placement, or in other case-by-case situations.

Reduced Spread of Electric Field After Surgical Removal of Intracochlear Schwannoma and Cochlear Implantation

OBJECTIVE

The primary aim of the study was to explore whether reduced spread of electrical field is observed after partial or subtotal cochleoectomy and cochlear implantation compared with standard cochlear implantation. Secondarily, the influence on speech perception was explored comparing both groups.

STUDY DESIGN

Nonconcurrent cohort study.

SETTING

Monocentric study at a tertiary referral center.

PATIENTS

Twenty adult cochlear implant (CI) users after tumor resection with cochleoectomy of varying extent and 20 electrode-matched CI users with standard electrode insertion.

INTERVENTIONS

Partial and subtotal cochleoectomy for tumor removal and CI.

OUTCOME MEASURES

Trans-impedance, electrically evoked compound action potentials, and word recognition were measured. Relative impedance was computed as a function of distance between the stimulation and recording electrode.

RESULTS

Trans-impedance was smaller and more homogeneous in patients with partial or subtotal cochleoectomy than in the control group. In the tumor group, the mean relative impedance decreased to 0.20 (standard deviation [SD] = 0.03) at a distance of 1 electrode and to 0.25 (SD = 0.04) in the control group. After excluding seven patients with a second tumor in the internal auditory canal or cerebellopontine angle, with transmodiolar tumors, after near total cochleoectomy, or only extended cochleostomy, word recognition was 61% (SD = 19%) at 3 months and 75% (SD = 19%) at 12 months after activation of the audio processor in the tumor group. At 12 months, it was significantly (p < 0.05) better than in the control group (3 mo: 45%, SD = 25%; 12 mo: 53%, SD = 26%). A smaller trans-impedance is associated with a better word recognition.

CONCLUSION

We conclude that the surgical technique used for CI surgery after subtotal cochleoectomy reduces the spread of the electric field and overcomes the potential drawbacks in structure preservation associated with that technique.

Cochleo-facial corridor to the vestibule and fundus of the internal auditory canal through oval window: a minimal invasive and cochlea sparing approach

PURPOSE

This cadaveric work aimed to test the effectiveness of a modified surgical corridor (ExpTSA: expanded transcanal supracochlear approach) developed for anatomic cochlear preservation in selected vestibular schwannoma patients necessitating to perform cochlear implantation for appropriate cases to achieve the best outcome.

METHODS

The ears of 10 cadavers (at mean age 75.70 ± 13.75 years, range 45-92 years) were dissected from the external auditory canal (EAC) to the internal auditory canal by ExpTSA under the guidance of a microscope and endoscope. All stages of the surgical process were recorded step by step and evaluated morphometrically.

RESULTS

The vestibular base was successfully reached in all ears without damaging the cochlear morphology and facial nerve. The vestibular base was 23.33 ± 2.02 mm away from the entrance (external orifice) and 10.26 ± 1.33 mm from the exit (internal orifice) of EAC. The oval window and vestibular base were measured to be 2.94 ± 1.05 mm and 5.87 ± 1.24 mm deep from the facial nerve, respectively. The normal areas of the oval window, the exit and entrance of EAC were found as 2.90 ± 0.81 mm², 42.52 ± 13.66 mm², and 110.73 ± 25.32 mm², respectively. After ExpTSA procedure, the areas of the oval window (11.04 ± 2.83 mm²), the exit (122.45 ± 20.41 mm²) and entrance (167.49 ± 30.94 mm²) of EAC were expanded approximately 280%, 188%, and 50%, respectively.

CONCLUSION

The ExpTSA may be performed for accessing to the vestibule and fundus of IAC for tumor removal of intravestibular schwannoma patients (with or without fundus involvement) with unserviceable hearing, preserving the cochlear morphology.

Management of transmodiolar and transmacular cochleovestibular schwannomas with and without cochlear implantation

Introduction

Hearing rehabilitation with cochlear implants has attracted increasing interest also for patients with cochleovestibular schwannoma. The authors report their experience with the surgical management of tumors with rare transmodiolar or transmacular extension and outcomes after cochlear implantation (CI).

Methods

This retrospective case series included nine patients with either primary intralabyrinthine tumors or secondary invasion of the inner ear from the internal auditory canal. The primary endpoint with CI, performed in six patients, was word recognition score at 65 dB SPL (sound pressure level). Secondary endpoints were intra- and postoperative electrophysiological parameters, impedance measures, the presence of a wave V in the electrically evoked (via the CI) auditory brainstem responses, the specifics of postoperative CI programming, and adverse events.

Results

Hearing rehabilitation with CI in cases of transmodiolar tumor growth could be achieved only with incomplete tumor removal, whereas tumors with transmacular growth could be completely removed. All six patients with CI had good word recognition scores for numbers in quiet conditions (80–100% at 65 dB SPL, not later than 6 to 12 months post CI activation). Four of these six patients achieved good to very good results for monosyllabic words within 1–36 months (65–85% at 65 dB SPL). The two other patients, however, had low scores for monosyllables at 6 months (25 and 15% at 65 dB SPL, respectively) with worsening of results thereafter.

Conclusions

Cochleovestibular schwannomas with transmodiolar and transmacular extension represent a rare entity with specific management requirements. Hearing rehabilitation with CI is a principal option in these patients.

Video online

The online version of this article (10.1007/s00106-020-00919-9) includes a video (2D and 3D versions) of the described surgical technique. Article and supplementary material are available at www.springermedizin.de. Please enter the title of the article in the search field, the supplementary material can be found under “Ergänzende Inhalte”.

Endolymphatic Hydrops in Patients With Intralabyrinthine Schwannomas

Purpose: The presence of endolymphatic hydrops (EH) in patients with intralabyrinthine schwannomas (ILSs) is poorly understood. This study aims to determine whether there is a correlation between endolymphatic hydrops and clinical presentations of ILS.

Methods: Data from nine patients with ILSs were retrospectively reviewed between 2007 and 2020. Temporal bone MRI with intratympanic or intravenous injection of gadolinium was applied to detect ILSs and EH.

Results: 3D real inversion recovery (IR) sequence MRI of the temporal bone confirmed ipsilateral EH in four patients (4/6). All four patients with EH on MRI presented with vertigo similar to Meniere's disease. Among these patients with EH, one patient with EH in the cochlea showed moderate sensorineural hearing loss, while three patients with EH in both the vestibule and cochlea showed profound hearing loss. MRI demonstrated a transmacular tumor (TMA) in one patient, intravestibular (IV) in four patients, and vestibulocochlear (VC) in four patients. Two IV cases showed moderated hearing loss, while the TMA and VC cases showed profound hearing loss. Transotic resection of the tumor was applied in five patients; translabyrinthine resection was applied in one patient; two patients were under observation; and one patient was given intratympanic injection of gentamicin (ITG). During follow-up, all of the treated patients reported relief of vertigo, and postoperative MRI was performed in two patients, which showed no tumor recurrence. The two patients under observation showed no deterioration of hearing loss or vertigo. One patient was lost to follow-up.

Conclusion: EH concurrent with ILSs has been underestimated previously. With the extensive application of temporal bone MRI paradigms, such as 3D-real IR sequence MRI, more cases of potential EH in patients with ILS will be identified. The severity of hearing loss may be associated with the location of the tumor and the degree of EH.

Histopathologic Evaluation of Intralabyrinthine Schwannoma

OBJECTIVES

The aim of this study is to perform a histopathologic analysis of temporal bones with an intralabyrinthine schwannoma (ILS) in order to characterize its extension.

METHODS

Archival temporal bones with a diagnosis of sporadic schwannoma were identified. Both symptomatic and occult nonoperated ILS were included for further analysis.

RESULTS

A total of 6 ILS were identified, with 4 intracochlear and 2 intravestibular schwannomas. All intracochlear schwannomas involved the osseous spiral lamina, with 2 extending into the modiolus. The intravestibular schwannomas were limited to the vestibule, but growth into the bone next to the crista of the lateral semicircular canal was observed in 1 patient.

CONCLUSIONS

Complete removal of an ILS may require partial removal of the modiolus or bone surrounding the crista ampullaris as an ILS may extend into these structures, risking damage of the neuronal structures. Due to the slow growth of the ILS, it remains unclear if a complete resection is required with the risk of destroying neural structures hindering hearing rehabilitation with a cochlear implant.

Cervical and Ocular Vestibular-Evoked Myogenic Potentials in Patients With Intracochlear Schwannomas

Objective: To evaluate ocular and cervical vestibular evoked myogenic potentials (oVEMPs and cVEMPs) in patients with solely intracochlear localization of an intralabyrinthine schwannoma (ILS).

Study Design: Retrospective analysis of a series of cases.

Setting: Monocentric study at a tertiary referral center.

Patients: Patients with intracochlear schwannoma (ICS) and VEMP measurements.

Outcome Measures: Signed asymmetry ratio (AR) of cVEMPs and oVEMPs to air conducted sound with AR cut-offs considered to be asymmetrical when exceeding ±30% for cVEMPs and ±40% for oVEMPs with respect to the side affected by the tumor (reduced amplitudes on the affected side indicated by negative values, enhanced amplitudes by positive values); VEMP amplitudes and latencies; tumor localization in the cochlear turn and scala.

Results: Nineteen patients with a solely intracochlear tumor (ICS patients) [10 males, 9 females, mean age 57.1 (SD: 13.4) years] were included in the study. On the affected side, cVEMPs were absent or reduced in 47% of the patients, normal in 32%, and enhanced in 21%. Ocular VEMPs on the affected side were absent or reduced in 53% of the patients, normal in 32% and enhanced in 15%. Latencies for cVEMPs and oVEMPs were not significantly different between the affected and non-affected side. In all patients with enhanced VEMPs, the tumor was located in the scala tympani and scala vestibuli.

Conclusions: As a new and unexpected finding, VEMP amplitudes can be enhanced in patients with intracochlear schwannoma, mimicking the third window syndrome.

[Management of transmodiolar and transmacular cochleovestibular schwannomas with and without cochlear implantation. German version]

INTRODUCTION

Hearing rehabilitation with cochlear implants has attracted increasing interest also for patients with cochleovestibular schwannoma. The authors report their experience with the surgical management of tumors with rare transmodiolar or transmacular extension and outcomes after cochlear implantation (CI).

METHODS

This retrospective case series included nine patients with either primary intralabyrinthine tumors or secondary invasion of the inner ear from the internal auditory canal. The primary endpoint with CI, performed in six patients, was word recognition score at 65 dB SPL (sound pressure level). Secondary endpoints were intra- and postoperative electrophysiological parameters, impedance measures, the presence of a wave V in the electrically evoked (via the CI) auditory brainstem responses, the specifics of postoperative CI programming, and adverse events.

RESULTS

Hearing rehabilitation with CI in cases of transmodiolar tumor growth could be achieved only with incomplete tumor removal, whereas tumors with transmacular growth could be completely removed. All six patients with CI had good word recognition scores for numbers in quiet conditions (80-100% at 65 dB SPL, not later than 6 to 12 months post CI activation). Four of these six patients achieved good to very good results for monosyllabic words within 1-36 months (65-85% at 65 dB SPL). The two other patients, however, had low scores for monosyllables at 6 months (25 and 15% at 65 dB SPL, respectively) with worsening of results thereafter.

CONCLUSIONS

Cochleovestibular schwannomas with transmodiolar and transmacular extension represent a rare entity with specific management requirements. Hearing rehabilitation with CI is a principal option in these patients.

MRI of endolymphatic hydrops in patients with intralabyrinthine schwannomas: a case-controlled study using non-enhanced T2-weighted images at 3 T

OBJECTIVE

Like other vestibular schwannomas developing in the internal auditory canal, intralabyrinthine schwannomas (ILS) may present with similar symptoms as in endolymphatic hydrops. Two different studies have described MR saccular hydrops in ~ 30% of internal auditory canal vestibular schwannomas, but this association has never been studied in ILS before. The aim of this work is to study the prevalence of a saccular dilation in ILS, on a T2-weigthed sequence at 3 T, compared to a control group.

MATERIAL AND METHODS

All patients presenting with typical ILS between January 2008 and October 2018 were included (n = 28, two patients with bilateral tumors) and compared to a control group (n = 53). All underwent a high-resolution T2-weighted 3D sequence (FIESTA-C). The height and width of the saccule were measured on a coronal plane by two radiologists.

RESULTS

The saccule was dilated on the side of the schwannoma in 47% of the cases (p = 0.0006 for the height, p = 0.0487 for the width). Bilateral saccular dilation was observed in 37% of the cases. There was a statistically significant correlation between the presence of a saccular hydrops and balance disorders (p = 0.02) as 50% of the patients with an intralabyrinthine schwannoma who presented with such symptoms had a saccular dilation.

CONCLUSION

Forty-seven percent of ILS are associated with homolateral saccular dilation, which is an MR sign of endolymphatic hydrops (bilateral in 37%) and it appears related to the presence of balance disorders. This opens new therapeutic potentialities with the possible use of anti-vertiginous drugs, which could have a beneficial effect on their clinical symptomatology.

[Bilateral intracochlear schwannomas in a patient with no genetic or clinical features of neurofibromatosis type 2. German version]

Schwannomas of the eighth cranial nerve are benign tumours commonly found in the internal auditory meatus or in the cerebellopontine angle. In most cases, they arise from the inferior or vestibular portion of the vestibular nerve. Rarely, these tumours present in the inner ear and are then called intralabyrinthine schwannomas. Bilateral schwannomas are known in neurofibromatosis type 2 (NF2). Bilateral and ipsilateral, multilocular sporadic schwannomas of the eighth cranial nerve have been described as extremely rare findings. This report describes the first case of bilateral sporadic intracochlear schwannomas in a patient with no genetic or clinical features of NF2.

Cochlear Implantation After Partial or Subtotal Cochleoectomy for Intracochlear Schwannoma Removal-A Technical Report

To describe the technique for surgical tumor removal, cochlear implant (CI) electrode placement and reconstruction of the surgical defect in patients with intracochlear schwannomas.

Intralabyrinthine Schwannoma: Distinct Features for Differential Diagnosis

Objectives: The aim of this study was to delineate the clinical and laboratory features suggestive of intralabyrinthine schwannoma (ILS). Methods: We compared the clinical features of 16 patients with ILS, who had been diagnosed at the Seoul National University Bundang Hospital from 2003 to 2018, with those of 18 patients with symptomatic unilateral intracanalicular schwannoma and randomly selected 20 patients with definite or probable unilateral Meniere's disease (MD). Results: Patients with ILS presented with either recurrent spontaneous dizziness/vertigo combined with auditory symptoms (n = 8), isolated auditory symptoms without dizziness/vertigo (n = 7), or recurrent spontaneous dizziness/vertigo without auditory symptoms (n = 1). Most patients reported no improvement (n = 11) or worsening (n = 1) of the symptoms despite medical treatments including intratympanic (n = 5) or intravenous steroids (n = 2). Conventional brain MRIs failed to detect ILS in about a half of the patients (7/16, 44%). However, ILS showed a filling defect on 3-dimensional (3D) heavily T2-weighted MRIs (n = 12), and nodular enhancement on 3D contrast-enhanced T1 (n = 15) or FLAIR MRIs (n = 13) targeted for the inner ear. Compared to MD or intracanalicular schwannoma, ILS showed mostly abnormal head-impulse tests (HITs, p = 0.001). In contrast, the incidence of canal paresis did not differ among the groups (p = 0.513). Conclusion: ILS may mimic MD by presenting recurrent dizziness/vertigo and auditory symptoms. ILS should be suspected in patients with recurrent audiovestibulopathy especially when (1) the duration of the dizziness is not typical for MD, (2) the patients do not respond to medical treatments, or (3) HITs are abnormal.

[Intracochlear schwannoma : Tumor removal via subtotal cochleoectomy and partial cochlear reconstruction with preservation of semicircular canal function. German version]

We report about a patient who in 2005, aged 37 years, experienced sudden mild to moderate, mid-frequency sensorineural hearing loss in the right ear along with tinnitus and mild dizziness. MRI of the temporal bone revealed a very small (1 mm) contrast-enhancing lesion in the second turn of the right cochlea. Hearing gradually deteriorated with complete hearing loss in 2015. At this time, an MRI scan showed a lesion completely filling the cochlea.The tumor was removed via transmeatal subtotal cochleoectomy. The cochlea was partially reconstructed with cartilage and fascia. A cochlea implant dummy electrode was inserted as a placeholder in order to prevent complete fibrosis of the "neocochlea" during follow-up MRI examinations.Vestibular function tests 2 months postoperatively showed preserved caloric excitability and a normal vestibulo-ocular reflex (vHIT) in all three planes. The patient is free of vertigo.Intralabyrinthine schwannomas (ILS) are a rare differential diagnosis of sudden hearing loss, which should be specifically checked for in MRI. Surgical removal of an intracochlear ILS through partial or subtotal cochleoectomy with preservation of vestibular function is possible in principle.

Intralabyrinthine Schwannomas: Disease Presentation, Tumor Management, and Hearing Rehabilitation

Intralabyrinthine schwannomas (ILS) are rare tumors that frequently cause sensorineural hearing loss. The development and increased use of magnetic resonance imaging in recent years have facilitated the diagnosis of these tumors that present with otherwise nondiscriminant symptoms such as tinnitus, vertigo, and hearing loss. The following is a review of the presentation, pathophysiology, imaging, and treatment with a focused discussion on auditory rehabilitation options of ILS.

Endoscope-assisted resection of intravestibular Schwannoma: A video case report

Intravestibular schwannomas are a rare cause of unilateral sensorineural hearing loss. Management of these tumors involves translabyrinthine resection, for which complete visualization around the angles of the vestibule may be limited under an operating microscope. We present the first reported case of an endoscope-assisted resection of an intravestibular schwannoma, along with the operative video recording. Using additional information gained from endoscopic examination of the tumor and its resection site, we also propose a mechanism by which this patient's intravestibular schwannoma caused hearing loss. Use of the endoscope in resection of intravestibular schwannomas may have advantages over the traditional operating microscope in improving visualization of the narrow and angled vestibule, confirming the integrity of surrounding structures, and ensuring complete tumor removal. Laryngoscope, 129:986-988, 2019.

Diagnostics and therapy of sudden hearing loss

This article reviews recent aspects of diagnostics, differential diagnostics, and evidence in systemic and local therapy of idiopathic sudden sensorineural hearing loss (ISSHL). Since a number of disorders can be accompanied by sudden hearing loss, a meaningful and targeted diagnostic strategy is of utmost importance. An important differential diagnosis of sudden hearing loss are intralabyrinthine schwannomas (ILS). The incidence of ILS is probably significantly underestimated. This may be due to the lack of awareness or lack of explicit search for an intralabyrinthine tumor on MRI or an inappropriate MRI technique for the evaluation of sudden hearing loss ("head MRI" instead of "temporal bone MRI" with too high slice thicknesses). Therefore, the request to the radiologist should specifically include the question for (or exclusion of) an ILS. With special MRI techniques, it is possibly today to visualize an endolymphatic hydrops. The evidence in the therapy of ISSHL is - with respect to the quality and not quantity of studies - unsatisfying. The value of systemically (low dose) or intratympanically applied corticosteroids in the primary treatment of ISSHL is still unclear. In order to investigate the efficacy and safety of high dose corticosteroids as primary therapy for ISSHL, a national, multicenter, three-armed, randomized, triple-blind controlled clinical trial is currently performed in Germany (http://hodokort-studie.hno.org/). After insufficient recovery of the threshold with systemic therapy of ISSHL, intratympanic corticosteroid therapy appears to be associated with a significantly higher chance of an improved hearing threshold than no therapy or placebo. Both, hearing gain and final hearing threshold, however, appear to be independent from the onset of secondary therapy. Based on currently available data from clinical studies, no recommendation can be made with respect to the type of corticosteroid and specifics of the intratympanic application protocol.

[The tumors of the ear]

Any cutaneous lesion of the outer ear must be managed jointly by a dermatologist and an ENT, regardless of the age of the patient. The presence of a malignant cutaneous carcinoma (Squamous cell carcinoma or melanoma) of the pavilion requires a minimum extension assessment by a cervical ultrasound, CT-scan and MRI will be prescribed according to the degree of infiltration and the presence of clinics signs (lymphadenopathy, facial paralysis, cognitive impairment). A polyp of the external auditory meatus must be systematically biopsied in consultation and, if necessary, in the operating room with fresh anatomopathological analysis. Any "otitis externa", which does not progress favorably under local treatment, must lead to eliminate a tumoral pathology of the external acoustic meatus or of the middle ear. Any suspicion of cholesteatoma should lead to an ENT consultation to confirm the diagnosis and consider its treatment to limit the auditory dysfunction. Any unilateral neurosensorial hearing loss or unilateral vestibular involvement with normal otoscopy should lead to eliminate a inner ear tumor by an MRI of the inner ear and the ponto-cerebellar angle in millimeter sections.

Intralabyrinthine schwannomas : Surgical management and hearing rehabilitation with cochlear implants

Intralabyrinthine schwannomas (ILS) are a rare differential diagnosis of sudden hearing loss and vertigo. In an own case series of 12 patients, 6 tumors showed an intracochlear, 3 an intravestibular, 1 a transmodiolar including the cerebellopontine angle (CPA), 1a transotic including the CPA, and 1 a multilocular location. The tumors were removed surgically in 9 patients, whereas 3 patients decided for a "wait-and-test-and-scan" strategy. Of the surgical patients, 3 underwent labyrinthectomy and cochlear implant (CI) surgery in a single-stage procedure; 1 patient had extended cochleostomy with CI surgery; 3 underwent partial or subtotal cochleoectomy, with partial cochlear reconstruction and CI surgery (n = 1) or implantation of electrode dummies for possible later CI after repeated MRI follow-up (n = 2); and in 2 patients, the tumors of the internal auditory canal and cerebellopontine angle exhibiting transmodiolar or transmacular growth were removed by combined translabyrinthine-transotic resection. For the intracochlear tumors, vestibular function could mostly be preserved after surgery. In all cases with CI surgery, hearing rehabilitation was successful, although speech discrimination was limited for the case with subtotal cochleoectomy. Surgical removal of intracochlear schwannomas via partial or subtotal cochleoectomy is, in principle, possible with preservation of vestibular function. In the authors' opinion, radiotherapy of ILS is only indicated in isolated cases. Cochlear implantation during or after tumor resection (i. e., as synchronous or staged surgeries) is an option for hearing rehabilitation in cartain cases and represents a therapeutic approach in contrast to a "wait-and-test-and-scan" strategy.

Clinical comparison of two subtypes of cystic vestibular schwannoma: surgical considerations and outcomes

Cystic vestibular schwannoma (CVS) is classified as Type A and Type B based on the overall cyst location and cyst wall thickness in magnetic resonance imaging. A retrospective analysis was performed to compare surgical considerations and outcomes between Type A and Type B groups of CVS. We selected 188 patients diagnostic for CVS with surgical resection, and divided them into Type A and Type B groups. General information, preoperative symptoms, the result of neuroimaging, and audiological tests were recorded. Surgical approach, completeness of tumor resection, and intraoperative facial nerve (FN) integrity were taken down. After operation, the short-term and long-term FN functions, complications, and recurrence rate were evaluated. The total tumor removal rate in Type A group was higher than that in Type B group (86.1 vs 72.5 %, p = 0.021). Anatomical FN integrity was preserved in 173 patients (92.0 %), with no significant differences between Type A and Type B. FN function was better in Type A group at hospital discharge. Besides, a good FN function rate was inversely proportional to the tumor size. The long-term FN function and all of the complications had no significant differences between the two groups. Patients in the Type B group are prone to have a lower total tumor removal rate and transient FN dysfunction. The long-term FN function was similar in both groups. Tumor size is another important indication of FN function. All postoperative complications occurred in patients with a tumor larger than grade 3, regardless of the subtypes of CVS.

Meta-analysis on the clinical outcomes in patients with intralabyrinthine schwannomas: conservative management vs. microsurgery

The objective of this review is to compare the symptomatological evolution following conservative management (CM) or microsurgery (MS) in patients with intralabyrinthine schwannomas (ILS). A thorough systematic review of the English and French literature from 1948 to February 2014 was performed using Ovid Medline. An ancestor search was also completed. The major inclusion criterion consisted of a diagnosis of ILS with magnetic resonance imaging. Patients with a classic vestibular schwannoma, cases of incidentaloma during surgery or an autopsy were the main exclusion criteria. Thirty-one studies met our selective criteria. Descriptive data were collected from the articles. Clinical outcomes regarding the hearing loss, tinnitus, vertigo, dizziness and aural fullness were stated as improved, unchanged or worse at the last follow-up. All data were then separated into two different groups according to the management option: CM and MS. The data were analyzed using a Pearson χ (2) test and Fisher's exact test. This meta-analysis suggests that MS has a statistically significant favorable outcome regarding symptom relief compared to CM in patients with ILS suffering from tinnitus, vertigo and dizziness. Hearing level was not compared between treatment groups, as MS leads to anacusis. An indicative bias was the main limitation of this study, as patients suffering from intractable vertigo with moderate-to-severe hearing loss were referred to MS. Therefore, in the presence of a serviceable hearing, we suggest that CM should be the treatment of choice.