Intralabyrinthine schwannomas : Surgical management and hearing rehabilitation with cochlear implants

Cochlear Implantation Outcomes in Patients With Sporadic Inner Ear Schwannomas With and Without Simultaneous Tumor Resection

OBJECTIVES

Describe a single institution's cochlear implant outcomes for patients with inner ear schwannomas (IES) in the setting of various tumor management strategies (observation, surgical resection, or stereotactic radiosurgery [SRS]).

STUDY DESIGN

Single-institution retrospective review.

PATIENTS

Patients diagnosed with isolated, sporadic IES who underwent cochlear implantation (CI).

INTERVENTIONS

CI with or without IES treatment.

MAIN OUTCOME MEASURES

Speech perception outcomes, tumor status.

RESULTS

Twelve patients with IES underwent CI with a median audiologic and radiologic follow-up of 12 months. Six patients underwent complete resection of the tumor at the time of CI, four underwent tumor observation, and two underwent SRS before CI. At 1 year after CI for all patients, the median consonant-nucleus-consonant (CNC) word score was 55% (interquartile range, 44-73%), and the median AzBio sentence in quiet score was 77% (interquartile range, 68-93%). Overall, those with surgical resection performed similarly to those with tumor observation (CNC 58 versus 61%; AzBio in quiet 74 versus 91%, respectively). Patients who underwent tumor resection before implantation had a wider range of speech performance outcomes compared with patients who underwent tumor observation. Two patients had SRS treatment before CI (10 months previous and same-day as CI) with CNC word scores of 6 and 40%, respectively.

CONCLUSIONS

Patients with IES who underwent CI demonstrated similar speech performance outcomes (CNC 56% and AzBio 82%), when compared with the general cochlear implant population. Patients who underwent either tumor observation or surgical resection performed well after CI.

Cochlear Implant Outcomes in Patients with Intralabyrinthine Schwannoma: A Scoping Review

OBJECTIVE

To evaluate the literature and summarize cochlear implantation (CI) outcomes after intralabyrinthine schwannoma (ILS) excision and tumor observation with CI.

DATA SOURCES

OVID Medline, Embase, Web of Science; conception to 2024.

REVIEW METHODS

A literature review was performed using subject headings, MeSH terms, and keywords. Abstracts and full texts were reviewed by two independent reviewers and adjudicated by a third. Inclusion criteria included studies with ILS and CI with reported audiologic outcomes. Subjects were analyzed into two groups, ILS resection with CI and in situ ILS with CI. Patients with NF2 were included. The main outcome of interest was CI audiometric performance level, with secondary outcomes of CI user status and open-set speech attainment.

RESULTS

There were 29 articles with a total of 93 patients who met inclusion criteria. The resection group had 17% low performers, 44% intermediate performers, and 38% high performers. The in situ group had 40% low performers, 32% intermediate performers, 27% high performers. The resection group had 69 patients with 97% maintaining user status and 92% with open-set speech recognition. The observation group had 24 patients, with 87% user rate and 86% achieving open-set speech recognition. There was a greater percentage of NF2 diagnosis seen in the in situ group.

CONCLUSION

There is a paucity of literature on CI and ILS. Patients are managed with both resection of tumor and implantation in situ. Early data are limited, with improvement in hearing outcomes and high user rates in both populations.

LEVEL OF EVIDENCE

N/A Laryngoscope, 134:3910-3920, 2024.

Cochlear implantation in patients with inner ear schwannomas: a systematic review and meta-analysis of audiological outcomes

PURPOSE

In patients with inner ear schwannomas (IES), reports on hearing rehabilitation with cochlear implants (CI) have increased over the past decade, most of which are case reports or small case series. The aim of this study is to systematically review the reported hearing results with CI in patients with IES considering the different audiologic outcome measures used in different countries.

METHODS

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline, a search of published literature was conducted. We included patients with IES (primary or with secondary extension from the internal auditory canal (IAC) to the inner ear, sporadic or NF2 related) undergoing cochlear implantation with or without tumour removal. The audiological results were divided into the categories "monosyllables", "disyllables", "multisyllabic words or numbers", and "sentences".

RESULTS

Predefined audiological outcome measures were available from 110 patients and 111 ears in 27 reports. The mean recognition scores for monosyllabic words with CI were 55% (SD: 24), for bisyllabic words 61% (SD: 36), for multisyllabic words and numbers 87% (SD: 25), and 71% (SD: 30) for sentences. Results from for multisyllabic words and numbers in general showed a tendency towards a ceiling effect. Possible risk factors for performance below average were higher complexity tumours (inner ear plus IAC/CPA), NF2, CI without tumour removal ("CI through tumour"), and sequential cochlear implantation after tumour removal (staged surgery).

CONCLUSION

Hearing loss in patients with inner ear schwannomas can be successfully rehabilitated with CI with above average speech performance in most cases. Cochlear implantation thus represents a valuable option for hearing rehabilitation also in patients with IES while at the same time maintaining the possibility of MRI follow-up. Further studies should investigate possible risk factors for poor performance. Audiological tests and outcome parameters should be reported in detail and ideally be harmonized to allow better comparison between languages.

First Clinical Experience with a New Device for the Removal of Cochlear Schwannomas

Background: In most cases, intralabyrinthine schwannoma (ILS) occurs in patients with unilateral hearing deterioration or neurofibromatosis type II (NF II). The pattern of localization of these tumors varies but mostly affects the cochlea. Extirpation of the cochlear schwannoma, if hidden by the cochlea modiolus, is difficult under the aspect of complete removal. Therefore, a tissue removal device (TRD) was designed and tested in temporal bones. The principle of handling the new device is a pushing and pipe cleaner handling inside the cochlea. This present study aimed to describe the first in vivo experience with the newly developed TRD for removing cochlear intralabyrinthine schwannomas. Methods: In three patients, the TRD was used for the tumor removal of cochlear schwannomas. In two patients with a cochlear schwannoma in combination with a cochlea implantation and one patient suffering from NF II, a cochlear schwannoma was removed with the TRD. The access was performed with a posterior tympanotomy, an enlarged round window approach and an additional second turn access. The device was inserted and extracted gradually from the second turn access until the rings were visible in the second turn access. By pushing and pipe cleaner handling, the tumors were removed. An MRI control was performed on the day postoperatively with a T1 GAD sequence. Results: Tumor removal with the TRD was performed in a 15-min procedure without any complications. An MRI control confirmed complete removal on the postoperative day in all cases. Conclusions: In vivo handling of the device confirmed straightforward handling for the tumor removal. MRI scanning showed complete removal of the tumor by the TRD.

Radiation-Induced Sensorineural Hearing Loss and Potential Management

The cochlear apparatus is one of the major organs at risk when considering radiation therapy (RT) for brain, head, and neck tumors. Radiation oncologists currently consider mean dose constraints of <35 Gy for conventionally fractioned radiation therapy (RT), <4 Gy for single fraction stereotactic radiosurgery, and <17.1 or 25 Gy for 3- or 5-fraction stereotactic radiosurgery, respectively, as the standard of care. Indeed, dose adjustments are made in the setting of concurrent platinum-based chemotherapy or when prioritizing tumor coverage during treatment planning. Despite guidelines, in many patients, RT to the cochlea may still cause sensorineural hearing loss through progressive degeneration and ossification of the inner ear. There are several audiologic and otolaryngologic interventions for incident RT-induced hearing loss, including hearing aids, cochlear implants, or, in the context of vestibular schwannoma due to neurofibromatosis type 2, auditory brain stem implantation. Cochlear implants are the most effective at restoring hearing and improving quality of life for those with an intact cochlear nerve. An early multidisciplinary approach is essential to optimally manage RT-induced hearing loss, and this topic discussion serves as a guide for radiation oncologists on cochlear dosimetric considerations as well as how to address potential RT-induced adverse effects.

Translabyrinthine Excision of a Transmodiolar Intralabyrinthine Schwannoma Mimicking Meniere's Disease: A Case Report

Intralabyrinthine schwannomas (ILSs) are rare tumors involving the otic capsule. Notably, they are often misdiagnosed because their symptoms mimic those of other, more common inner ear pathologies. Diagnosis requires high-resolution contrast-enhanced magnetic resonance imaging (MRI), which reveals filling defects (using a T2-weighted MRI sequence) or focal enhancement (using a T1-weighted MRI sequence with gadolinium enhancement) in the inner ear. A 52-year-old male patient with intractable vertigo or single-sided deafness should raise suspicion of this clinical entity as a differential diagnosis. Translabyrinthine excision of the tumor along with auditory rehabilitation using a cochlear implant can provide good outcomes with minimal morbidity in carefully selected cases. Here, we present an interesting case of a transmodiolar ILS mimicking Meniere's disease, wherein surgery using the translabyrinthine approach and an extended cochleostomy yielded favorable outcomes.

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.

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.

Resection of Intracochlear Schwannomas With Immediate Cochlear Implantation

INTRODUCTION

Intralabyrinthine schwannomas, including the intracochlear variety, are rare benign tumors. They can cause a number of symptoms and have the potential to grow to involve other critical structures of the inner ear and skull base. While surgical resection is feasible, there is typically permanent hearing dysfunction as a result of resection and subsequent fibrosis. Here, we present 2 cases of intracochlear schwannomas (ICS) that were successfully resected with simultaneous cochlear implant placement.

METHODS

Patient 1 presented with an intravestibulocochlear schwannoma. This patient underwent a translabyrinthine approach. Endoscopic assistance was used to dissect the tumor from the vestibule and basal turn of the cochlea, through an enlarged round window approach. A cochlear implant was placed via a round window cochleostomy. Patient 2 presented with an intracochlear schwannoma involving the basal and middle turns of the cochlea. The patient underwent a trans-otic approach for resection. A large portion of the cochlear promontory required unroofing for complete exposure of the tumor. A cochlear implant was then placed via a round window cochleostomy.

RESULTS

Upon cochlear implant activation, Patient 1's sound field thresholds using the implant were near the normal range of hearing, ranging from 25 to 50 dB HL from 250 to 6000 Hz. Patient 2's 6-month post-operative cochlear implant sound field testing ranged from 20 to 30 dB HL from 250 to 6000 Hz and speech recognition testing revealed 59% on AZ Bio sentences compared to 0% pre-operatively.

CONCLUSION

Simultaneous cochlear implantation after resection of intracochlear schwannomas is safe and successful in restoring hearing. Attention to adequate exposure and endoscopic assistance, when required, allow for gross total resection while minimizing trauma to cochlear structures. In such cases, immediate cochlear implantation allows for hearing rehabilitation before likely cochlear fibrosis can occur.

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.

A new device for the removal of cochlear schwannoma: A temporal bone study

Background

Intralabyrinthine schwannoma (ILS) is a rare, mostly unilateral disease that causes deafness. Different intralabyrinthine sites of ILS can occur and can be removed by different surgical approaches. Cochlear ILSs are frequently partially hidden by the modiolus and therefore difficult to extirpate. Surgical techniques can be traumatic, offer limited surgical control during removal, and are time-consuming. The aim of this present study was to demonstrate the performance and handling of a newly developed device for the removal of cochlear intralabyrinthine schwannoma in the temporal bone.

Methods

In a temporal bone study with a prepared posterior tympanotomy, an enlarged round window approach, and additional second turn access, a stiffened device with silicone rings was inserted and extracted gradually from the second turn access until the rings were visible in the second turn access.

Results

Insertion and extraction of the second cochlear access were easily performed. Pulling and pushing the silicone rings through the modiolus and hidden parts of the basal turn was possible and worked like a pipe cleaner.

Conclusion

This newly developed tissue removal device in combination with the proposed surgical handling offers a new and less traumatic way to remove cochlear ILS.

Twelve-Month Outcomes of Simultaneous Translabyrinthine Resection and Cochlear Implantation

OBJECTIVE

Audiometric outcomes at 12 months following simultaneous translabyrinthine (TL) resection of vestibular schwannoma (VS) and cochlear implantation (CI).

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary referral center.

METHODS

Adult patients undergoing TL resection of sporadic, unilateral VS ≤ 2 cm were prospectively enrolled. Preoperative testing included binaural AZBio in noise and quiet and unilateral Consonant-Nucleus-Consonant (CNC). Tinnitus Handicap Index (THI) and Speech, Spatial, and Qualities of Hearing (SSQ) questionnaires were also completed. Patients underwent TL resection with simultaneous CI. The preoperative test battery was repeated at 1, 3, 6, and 12 months after activation. Statistical analysis was performed to characterize short-term outcomes (preoperative to 3 months), longer-term outcomes (3-12 months), and overall changes during the preoperative to 12-month period.

RESULTS

AZBio, CNC, and THI improved at 3 months with no significant changes thereafter and showed durable improvement at 12 months compared to preoperative testing. While SSQ did not improve at 12 months, a subset of patients showed either recovery or improvement of SSQ-spatial subscores. Patients with cerebellopontine angle tumors had poorer performance, although the impact of tumor size and location could not be deduced based on the small sample size.

CONCLUSION

Patients undergoing simultaneous CI and TL resection of VS had durable improvements in speech perception and tinnitus severity 12 months following surgery. Subjective improvements in localization were not observed. Additional studies are needed to determine which VS patients are optimal candidates for CI.

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.

Cochlear Implant in Patients with Intralabyrinthine Schwannoma without Tumor Removal

(1) Background: Schwannomas of the vestibulocochlear nerve are benign, slow-growing tumors, arising from the Schwann cells. When they originate from neural elements within the vestibule or cochlea, they are defined as intralabyrinthine schwannomas (ILSs). Cochlear implant (CI) has been reported as a feasible solution for hearing restoration in these patients. (2) Methods: Two patients with single-sided deafness (SSD) due to sudden sensorineural hearing loss and ipsilateral tinnitus were the cases. MRI detected an ILS. CI was positioned using a standard round window approach without tumor removal. (3) Results: The hearing threshold was 35 dB in one case and 30 dB in the other 6 mo after activation. Speech audiometry with bisillables in quiet was 21% and 27% at 65 dB, and the tinnitus was completely resolved or reduced. In the localization test, a 25.9° error azimuth was obtained with CI on, compared to 43.2° without CI. The data log reported a daily use of 11 h and 14 h. In order to not decrease the CI’s performance, we decided not to perform tumor exeresis, but only CI surgery to restore functional binaural hearing. (4) Conclusions: These are the sixth and seventh cases in the literature of CI in patients with ILS without any tumor treatment and the first with SSD. Cochlear implant without tumor removal can be a feasible option for restoring binaural hearing without worsening the CI’s performance.

Quality Control after Intracochlear Intralabyrinthine Schwannoma Resection and Cochlear Implantation

Background: The combination of intralabyrinthine schwannoma (ILS) removal and cochlear implantation is the standard of care after surgical resection for audiological rehabilitation. Intracochlear ILS is not only the most frequent tumor in this group of schwannomas, but it is also, to some degree, surgically the most challenging because of its position behind the modiolus. Recent developments in the knowledge of implant position, implant magnet choice, and magnetic resonance imaging (MRI) sequences make an MRI follow-up after surgical removal possible. Thus far, no results are known about the surgical success and residual rate of these kind of tumors. The aim of the present study was to perform an early MRI follow-up for the evaluation of residual or recurrent intracochlear ILS after surgical removal and cochlear implantation. Methods: In a retrospective study, we evaluated seven patients after an intracochlear ILS removal and single-stage cochlear implantation with a mean period of 13.4 months post surgery with a 3T T1 GAD 2 mm sequence for a residual ILS. Patients were operated on using an individualized technique concept. Results: In six out of seven cases, 3 T T1 GAD 2 mm MRI follow-up showed no residual or recurrent tumor. In one case, a T1 signal indicated a tumor of the upper inner auditory canal (IAC) at the MRI follow up. Conclusion: MRI follow-up as a quality control tool after ILS removal and cochlear implantation is highly important to exclude residual tumors. Long-term MRI evaluation results are needed and can be obtained under consideration of implant position, implant magnet, and MRI sequence choice. A preoperative MRI slice thickness less than 2 mm can be recommended to visualize possible modiolar and IAC expansion.

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.

Embryology, Malformations, and Rare Diseases of the Cochlea

Despite the low overall prevalence of individual rare diseases, cochlear dysfunction leading to hearing loss represents a symptom in a large proportion. The aim of this work was to provide a clear overview of rare cochlear diseases, taking into account the embryonic development of the cochlea and the systematic presentation of the different disorders. Although rapid biotechnological and bioinformatic advances may facilitate the diagnosis of a rare disease, an interdisciplinary exchange is often required to raise the suspicion of a rare disease. It is important to recognize that the phenotype of rare inner ear diseases can vary greatly not only in non-syndromic but also in syndromic hearing disorders. Finally, it becomes clear that the phenotype of the individual rare diseases cannot be determined exclusively by classical genetics even in monogenetic disorders.

Early Outcomes of Simultaneous Translabyrinthine Resection and Cochlear Implantation

OBJECTIVES/HYPOTHESIS

Hearing rehabilitation after translabyrinthine resection of a vestibular schwannoma (VS) has largely been based on the transfer of acoustic stimulus to the contralateral ear, typically through a contralateral routing of signal hearing aid or bone-anchored hearing aid (BAHA). Cochlear implant, either as a subsequent surgery or simultaneously, has become a more common treatment option; however, there is still relatively limited data available on its success. The purpose of this study is to evaluate the early outcomes of simultaneous cochlear implantation in patients with sporadic VS undergoing translabyrinthine resection.

STUDY DESIGN

Prospective, nonrandomized study.

METHODS

A prospective study of nonrandomized patients was completed at a tertiary care neurotology center. Audiologic outcomes, primarily based on AzBIO in quiet and background noise, as well as consonant-nucleus-consonant (CNC) testing of the affected ears were utilized. Tinnitus, dizziness, and spatial hearing questionnaries were also completed. Audiologic outcomes and questionnaires were compared between the pre- and postoperative groups.

RESULTS

Ten patients were included in the study with 3 month follow-up data. There was statistically significant improvement in AzBO with +10 and +5 signal to noise ratio and in quiet, as well as in CNC testing (P < .05). There was a significant improvement in Tinnitus Handicap Inventory between the two groups.

CONCLUSIONS

Simultaneous cochlear implantation is a viable treatment for hearing loss after translabyrinthine approach to VS. These patients have improved hearing in background noise and tinnitus compared to their preoperative state. Further prognostic data are required to determine which patients are the best candidates.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E2312-E2317, 2021.

Endoscope-assisted Partial Cochlectomy for Intracochlear Schwannoma With Simultaneous Cochlear Implantation: A Case Report

INTRODUCTION

Intralabyrinthine schwannomas are a small subset of vestibular schwannomas which originate within the labyrinthine structures. Management typically consists of watch-and-wait strategies given that surgical intervention will sacrifice hearing. Endoscopic resection of primary intracochlear schwannoma with simultaneous cochlear implantation for a patient with progressive hearing loss and debilitating tinnitus is described.

PATIENT

A 56-year-old male presenting with asymmetric left sensorineural hearing loss (SNHL) was diagnosed with intracochlear schwannoma on MRI.

INTERVENTION

Surgery was indicated due to tumor growth on serial imaging, worsening SNHL, and severe tinnitus. Partial cochlectomy was performed via transcanal endoscopic approach. Cochlear implantation via mastoidectomy and posterior tympanotomy was simultaneously performed with a CI512 Contour Advanced implant (Cochlear, Sydney, Australia).

MAIN OUTCOME MEASURES

Post partial cochlectomy speech performance.

RESULTS

Preoperative audiometry showed left profound SNHL with 20% speech recognition score despite maximal amplification. Speech perception testing 5 months postoperatively demonstrated good unilateral discrimination when testing the implanted ear alone (BKB sentences 66%, CUNY sentences 79%), open-set comprehension, and excellent binaural performance.

CONCLUSION

The endoscope offers an additional viable approach to the otic capsule for the removal of intracochlear schwannoma and good audiologic outcomes can be achieved with simultaneous cochlear implantation even after partial cochlectomy.

Rare Diseases of the Middle Ear and Lateral Skull Base

Otalgia, otorrhea and hearing loss are the most common ear-related symptoms that lead to the consultation of an otolaryngologist. Furthermore, balance disorders and affections of the cranial nerve function may play a role in the consultation. In large academic centres, but also in primary care, the identification of rare diseases of the middle ear and the lateral skull base is essential, as these diseases often require interdisciplinary approaches to establish the correct diagnosis and to initiate safe and adequate treatments. This review provides an overview of rare bone, neoplastic, haematological, autoimmunological and infectious disorders as well as malformations that may manifest in the middle ear and the lateral skull base. Knowledge of rare disorders is an essential factor ensuring the quality of patient care, in particular surgical procedures. Notably, in untypical, complicated, and prolonged disease courses, rare differential diagnoses need to be considered.

Rare Disorders of the Vestibular Labyrinth: of Zebras, Chameleons and Wolves in Sheep's Clothing

The differential diagnosis of vertigo syndromes is a challenging issue, as many - and in particular - rare disorders of the vestibular labyrinth can hide behind the very common symptoms of "vertigo" and "dizziness". The following article presents an overview of those rare disorders of the balance organ that are of special interest for the otorhinolaryngologist dealing with vertigo disorders. For a better orientation, these disorders are categorized as acute (AVS), episodic (EVS) and chronic vestibular syndromes (CVS) according to their clinical presentation. The main focus lies on EVS sorted by their duration and the presence/absence of triggering factors (seconds, no triggers: vestibular paroxysmia, Tumarkin attacks; seconds, sound and pressure induced: "third window" syndromes; seconds to minutes, positional: rare variants and differential diagnoses of benign paroxysmal positional vertigo; hours to days, spontaneous: intralabyrinthine schwannomas, endolymphatic sac tumors, autoimmune disorders of the inner ear). Furthermore, rare causes of AVS (inferior vestibular neuritis, otolith organ specific dysfunction, vascular labyrinthine disorders, acute bilateral vestibulopathy) and CVS (chronic bilateral vestibulopathy) are covered. In each case, special emphasis is laid on the decisive diagnostic test for the identification of the rare disease and "red flags" for potentially dangerous disorders (e. g. labyrinthine infarction/hemorrhage). Thus, this chapter may serve as a clinical companion for the otorhinolaryngologist aiding in the efficient diagnosis and treatment of rare disorders of the vestibular labyrinth.

Hearing rehabilitation after subtotal cochleoectomy using a new, perimodiolar malleable cochlear implant electrode array: a preliminary report

PURPOSE

We here report about the first surgical experience and audiological outcome using a new, perimodiolar malleable cochlear implant electrode array for hearing rehabilitation after subtotal cochleoectomy for intralabyrinthine schwannoma (ILS).

METHOD

Based on a cochlear implant with MRI compatibility of the magnet in the receiver coil up to 3 T, a cochlear implant electrode array was developed that is malleable and can be placed perimodiolar after tumor removal from the cochlea via subtotal cochleoectomy. Malleability was reached by incorporating a nitinol wire into the silicone of the electrode array lateral to the electrode contacts. The custom-made device was implanted in four patients with intracochlear, intravestibulocochlear or transmodiolar schwannomas. Outcome was assessed by evaluating the feasibility of the surgical procedure and by measuring sound field thresholds and word recognition scores.

RESULTS

After complete or partial tumor removal via subtotal cochleoectomy with or without labyrinthectomy, the new, perimodiolar malleable electrode array could successfully be implanted in all four patients. Six months after surgery, the averaged sound field thresholds to pulsed narrowband noise in the four patients were 36, 28, 41, and 35 dB HL, and the word recognitions scores for monosyllables at 65 dB SPL were 65, 80, 70, and 25% (one patient non-German speaking).

CONCLUSION

The surgical evaluation demonstrated the feasibility of cochlear implantation with the new, perimodiolar malleable electrode array after subtotal cochleoectomy. The audiological results were comparable to those achieved with another commercially available type of perimodiolar electrode array from a different manufacturer applied in patients with ILS.

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.

[Effective diagnostics for vertigo, dizziness and equilibrium disorders]

Vertigo, dizziness and equilibrium disorders are symptoms with a variety of causes. First, four cardinal questions (type and duration of the vertigo, triggering factors, accompanying symptoms) must be answered. After that, the search for a spontaneous nystagmus (differentiation of peripheral and central disorder using the HINTS[head impulse, nystagmus, test of skew]-test ) and, as part of a positioning examination, the search for a benign paroxysmal positional vertigo (BPPV) are necessary. If the result is negative an instrument-based receptor-specific examination is carried out. The caloric examination (low-frequency stimulus) tests the horizontal semicircular canal and the superior vestibular nerve, whereas the 3‑D video head impulse test (vHIT, high-frequency stimulus) is used to analyze all three semicircular canals as well as the superior and inferior vestibular nerves. Analysis of the cervical vestibular evoked myogenic potential (cVEMP) checks the function of the sacculus and that of the ocular VEMP (oVEMP) checks the function of the utriculus. The final overall analysis usually gives a definitive diagnosis or at least provides a suspected diagnosis, which then determines the further diagnostic procedure (e.g. targeted radiological diagnostics if vestibular paroxysmia, superior canal dehiscence or a vestibular schwannoma are suspected).

Long-Term in vivo Release Profile of Dexamethasone-Loaded Silicone Rods Implanted Into the Cochlea of Guinea Pigs

Glucocorticoids are used intra-operatively in cochlear implant surgeries to reduce the inflammatory reaction caused by insertion trauma and the foreign body response against the electrode carrier after cochlear implantation. To prevent higher systemic concentrations of glucocorticoids that might cause undesirable systemic side effects, the drug should be applied locally. Since rapid clearance of glucocorticoids occurs in the inner ear fluid spaces, sustained application is supposedly more effective in suppressing foreign body and tissue reactions and in preserving neuronal structures. Embedding of the glucocorticoid dexamethasone into the cochlear implant electrode carrier and its continuous release may solve this problem. The aim of the present study was to examine how dexamethasone concentrations in the electrode carrier influence drug levels in the perilymph at different time points. Silicone rods were implanted through a cochleostomy into the basal turn of the scala tympani of guinea pigs. The silicone rods were loaded homogeneously with 0.1, 1, and 10% concentrations of dexamethasone. After implantation, dexamethasone concentrations in perilymph and cochlear tissue were measured at several time points over a period of up to 7 weeks. The kinetic was concentration-dependent and showed an initial burst release in the 10%- and the 1%-dexamethasone-loaded electrode carrier dummies. The 10%-loaded electrode carrier resulted in a more elevated and longer lasting burst release than the 1%-loaded carrier. Following this initial burst release phase, sustained dexamethasone levels of about 60 and 100 ng/ml were observed in the perilymph for the 1 and 10% loaded rods, respectively, during the remainder of the observation time. The 0.1% loaded carrier dummy achieved very low perilymph drug levels of about 0.5 ng/ml. The cochlear tissue drug concentration shows a similar dynamic to the perilymph drug concentration, but only reaches about 0.005–0.05% of the perilymph drug concentration. Dexamethasone can be released from silicone electrode carrier dummies in a controlled and sustained way over a period of several weeks, leading to constant drug concentrations in the scala tympani perilymph. No accumulation of dexamethasone was observed in the cochlear tissue. In consideration of experimental studies using similar drug depots and investigating physiological effects, an effective dose range between 50 and 100 ng/ml after burst release is suggested for the CI insertion trauma model.

Diagnosis and management of intralabyrinthine schwannoma: case series and review of the literature

Intralabyrinthine schwannoma (ILS) is a rare benign tumor affecting cochlear and vestibular nerves, whose symptoms are generally unspecific and frequently responsible for a late diagnosis. Radiological examinations, with particular reference to magnetic resonance imaging (MRI), represent the only diagnostic technique to identify ILS. On computed tomography ILS can only be indirectly suspected by the presence of surrounding bone remodeling, whereas MRI provides direct visualization of the neoplasm as a filling defect within the labyrinth with vivid contrast enhancement. At the same time, MRI is also helpful in defining ILS anatomical extension into adjacent structures and in planning therapeutic management. Here we report three representative cases of ILS with new pictorial imaging features to improve ILS early detection and optimize subsequent therapeutic management.

[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.

[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.

Extension patterns of vestibular schwannomas towards the middle ear: three new cases and review of the literature

OBJECTIVE

Middle ear extension of vestibular schwannomas is not a common occurrence, and only a few cases have been described so far in past publications. We report three new cases of vestibular schwannomas extending to the middle ear and reviewed the literature to specify the patterns of such an extension.

MATERIALS AND METHODS

We analysed databases of previously published articles to search for additional cases of middle ear extension of vestibular schwannomas and compared them to the cases we have documented. Extension patterns of the tumours were analysed, especially focusing on the extension through the round and oval windows.

RESULTS AND CONCLUSION

Middle ear vestibular schwannomas are uncommon tumours and only 13 cases have been published so far. The vestibular schwannoma (internal auditory canal or intralabyrinthine) has to invade the labyrinth first (complete invasion in 88% of the cases, n = 14), before reaching the middle ear. In the majority of cases (69%, n = 11/16), internal auditory canal vestibular schwannomas or intralabyrinthine schwannomas extended in the middle ear though the round window.

Translabyrinthine Excision of Vestibular Schwannoma with Concurrent Cochlear Implantation: Systematic Review

Objectives  Hearing rehabilitation is an important management aspect of patients undergoing excision of vestibular schwannomas. Studies have shown cochlear implantation (CI) is possible at the time of tumor excision via a translabyrinthine approach. Primary objectives of this report are (1) to review prospective studies pertaining to outcomes of concurrent CI and translabyrinthine tumor removal in detail and (2) perform an aggregate analysis of outcomes for case reports and series. Design  Systematic review based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Setting  Review of literature using PubMed and Cochrane databases. Participants  Eligibility included patients undergoing translabyrinthine excision of vestibular schwannoma with concurrent CI. Main Outcome Measures  Open-set speech discrimination scores, sound localization, patient-reported outcome measures. Results  Forty-one subjects were identified. Two prospective studies have been performed, which showed improvement in speech localization and patient-reported outcome measures. While the majority of patients achieved open set speech recognition, data pertaining to improvement in speech perception were variable. Approximately 85% of subjects had audibility with their CI. Of those that achieved open-set speech discrimination, 75% could be classified as either intermediate or high performers. The majority of low performers in open-set speech either endorsed subjective benefit or demonstrated improvement compared to preoperative measures. There was a high risk of selection and reporting bias. Conclusions  The majority of patients undergoing translabyrinthine excision of vestibular schwannoma with concurrent CI achieve open set speech perception, with 75% of these patients meeting criteria for being intermediate to high performers. Additional benefits include improved subjective hearing measures, decreased tinnitus, and improved sound localization.

Cochlear Implantation in Sporadic Vestibular Schwannoma: A Systematic Literature Review

Objective  This study was aimed to perform a systematic literature review by examining outcomes in patients with sporadic vestibular schwannoma (VS) undergoing ipsilateral cochlear implant (CI). Data Sources  PubMed-NCBI (National Center for Biotechnology Information) and Scopus databases were searched through October 2017. Study Selection  Studies reporting auditory outcomes for each patient when a CI was placed with an ipsilateral sporadic VS were included. Main Outcome Measures  Demographic variables, VS characteristics, preoperative hearing metrics, duration of deafness, CI type, approach to tumor resection, postoperative auditory outcomes, and postoperative tinnitus outcomes were reported for each eligible patient within studies. Each study was evaluated for quality and bias. Results  Fifteen studies and 45 patients met inclusion criteria. Mean speech discrimination score (SDS) improved from 30.0 to 56.4% after CI placement. The majority when reported had an improvement in tinnitus. Preoperative ipsilateral SDS was a negative predictor of postoperative SDS, while neither tumor resection status, tumor location, duration of deafness, ipsilateral pure tone average, nor timing of CI placement had a significant effect on patient outcome. Conclusions  Notwithstanding the challenges inherent with surveillance magnetic resonance imaging (MRI) in the setting of a cochlear implant magnet, select sporadic vestibular schwannoma patients can be considered for cochlear implantation.

Gamma Knife radiosurgery for intravestibular and intracochlear schwannomas

BACKGROUND

Schwannomas of the VIIIth cranial nerve are benign tumours, with vast majority occurring in vestibular division. Rarely, they can also arise from distal branches of cochlear, superior or inferior vestibular. We review our experience with Gamma Knife radiosurgery (GKR), as first intention treatment for intracochlear (ICS) and intravestibular (IVS) schwannomas.

METHODS

A total number of five patients were analysed, treated over 8 years, between June 2010 and September 2018, with Leksell Gamma Knife Perfexion or Icon (Elekta Instruments, AB, Sweden). The marginal dose prescribed was 12 Gy at a mean prescription isodose line of 61.4% (range 50-70). Clinical evaluation included auditory and facial function.

RESULTS

The mean age was 49.9 (range 34-63). The mean follow-up period was 52.8 months (range 12-84). The mean target volume (TV) was 0.087 ml (range 0.014-0.281). The mean maximal dose received by the cochlea was 11.2 Gy (range 2.6-20.3). The mean marginal dose received by the vestibule (e.g. utricula) was 14.2 Gy (range 3.8-17.5). No patient experienced an acute or subacute clinical adverse radiation effect after GKR. Four cases had overall symptom stability. In one patient (1/5), the vertigo, which was the main clinical complain, disappeared 1 year after GKR. However, it reappeared 3 years later, with same pretherapeutic characteristics and is currently fluctuating. One patient experienced hearing decrease after GKR, during the first 12 months. This case received 11.2 Gy to the cochlea. Follow-up MRI course showed a decrease in size in four patients, and stability in one.

CONCLUSIONS

Gamma Knife radiosurgery is a valuable first intention treatment for ICS or IVS, in selected cases. Special attention should be paid for the dose delivered to the cochlea and the vestibular apparatus. Acute and subacute clinical effects are exceptional, while tumour control was achieved in all cases in our small series.

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.