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

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.

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.

Audiological Outcome of the Simultaneous Tumor Resection and Cochlear Implantation in Two Cases of Sporadic and Two Cases of Neurofibromatosis Type 2-Associated Intracochlear Schwannoma

Objectives: Simultaneous removal and cochlear implantation (CI) have been reported in intralabyrinthine and intracochlear schwannoma. A wide range of postoperative hearing outcomes have been reported after CI in these cases. This study evaluated the outcomes of performing a simultaneous resection of Schwannoma in cochlea and cochlear implantation (CI), aiming to assess the effectiveness of this combined surgical approach for hearing rehabilitation with CI. Methods: This retrospective case series was conducted at a tertiary care center. The study included four consecutive patients with profound sensorineural hearing loss due to a mass inside the cochlea. These patients underwent simultaneous single-sided CI and tumor resection performed by the same surgeon. Preoperative and postoperative audiological assessments were conducted to evaluate the patients' hearing outcomes before and after the surgical intervention. Results: Simultaneous CI with tumor resection was successful in all cases. Two of the four patients had a unilateral tumor, while the other two had a bilateral tumor with the involvement of the internal auditory canal and cerebellopontine angle (neurofibromatosis type 2 (NF2)). In two cases of unilateral tumor, aided free-field pure tone average (PTA) was 26 dB, and 46 dB hearing level (HL), and word recognition score (WRS) at 65 dB was 40% and 68%, respectively, 3 months after surgery. In two cases of tumor with NF2, aided free-field PTA was 36 dB and 60 dB HL, and both cases showed 0% WRS at 65 dB 3 months after surgery. Conclusions: Simultaneous schwannoma excision and CI in patients with Schwannoma inside cochlea are surgically practical and safe. Postoperatively, there was a notable improvement in hearing in cases of sporadic schwannoma, regardless of the type of CI used. However, there was 0% WRS in the two NF2 patients with a mass in the internal auditory canal.

Changing Management of Intravestibular Schwannomas in the Era of Cochlear Implantation for Single-Sided Deafness

OBJECTIVE

Intralabyrinthine schwannomas (ILSs) are a rare cause of deafness. Patients with ILS confined to the semicircular canals and the vestibule (intravestibular schwannomas) are potential candidates for cochlear implantation for hearing rehabilitation, a new option for patients with unilateral hearing loss since the 2019 FDA approval of cochlear implant (CI) for single-sided deafness. In this report, we describe an evolving management approach for ILSs causing hearing loss.

PATIENTS

Adults (≥18 years) who underwent simultaneous ILS resection and CI between January 2019 and June 2023 (n = 3).

INTERVENTION

Transmastoid labyrinthectomy with simultaneous cochlear implantation.

MAIN OUTCOME MEASURES

Hearing performance with cochlear implantation measured as CNC Word Recognition scores and AzBio Sentence scores.

RESULTS

Three patients with ILS confined to the semicircular canals and vestibule underwent simultaneous tumor resection via labyrinthectomy with CI placement. In all cases, complete tumor resection and full CI insertion were achieved. No patients experienced postoperative complications. Patients 1 and 2 underwent 6- and 9-month postactivation testing, respectively, with CNC scores 64% to 80% and AzBio 81% to 99% in the implanted ears. Patient 3 scored 0% on CNC and AzBio testing at 3 months and deferred her 6-month audiometry.

CONCLUSIONS

Patients with ILS confined to the vestibule and semicircular canals can be considered for simultaneous tumor resection and CI placement.

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.

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.

Hearing Rehabilitation in Vestibular Schwannoma

The most common complaint among patients with vestibular schwannoma (VS) is hearing loss. This significantly affects the quality of life before, during, and after treatment for patients with VS. Untreated hearing loss in VS patients may even lead to depression and feelings of social isolation. A variety of devices are available for hearing rehabilitation for patients with vestibular schwannoma. These include contralateral routing of hearing signals (CROSs), bone-anchored hearing devices, auditory brainstem implants (ABI), and cochlear implants. In the United States, ABI is approved for patients 12 years of age and older with neurofibromatosis type 2. In the past few years, cochlear implantation has been offered simultaneously or sequentially with tumor resection or irradiation, or even to patients whose VS have been monitored with serial imaging. However, determining the functional integrity of the auditory nerve in patients with vestibular schwannoma is a challenge. This review article consists of (1) the pathophysiology of vestibular schwannoma (VS), (2) hearing loss in VS, (3) treatment of VS and associated hearing loss, (4) options for auditory rehabilitation in patients with VS with their individual benefits and limitations, and (5) challenges in hearing rehabilitation in this cohort of patients to determine auditory nerve functionality. (6) Future directions.

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.