Cochlear Implantation in Vestibular Schwannoma: A Systematic Literature Review

Cochlear implantation in vestibular schwannoma: A game changer? A narrative review

OBJECTIVES

In recent years, indications for Cochlear Implants (CIs) have been on the rise, with Vestibular Schwannoma (VS) patients among these emerging indications. On the other hand, there is growing evidence in favor of the 'wait and see' approach as opposed to surgery or irradiation for most small VS. The aim of this paper is to discuss the current role of CIs in patients with VS, addressing the most controversial topics such as the variability of outcomes, the emerging clinical scenarios, the lack of consistent prognostic factors, and the need for an intraoperative tool to aid decision-making in challenging cases.

METHODS

A Pubmed search was performed, with a selection of relevant citations, and critical appraisal of selected studies. Articles written in English on VS and cochlear implantation were eligible for inclusion. Pictures of illustrative cases from a tertiary center were included.

RESULTS

The discussed topics were the following: (1) Variability in audiological outcomes; (2) Prognostic factors including tumor size, preoperative hearing, previous irradiation, extent of resection, and Neurofibromatosis type II (NF2) status; (3) Postoperative imaging; (4) The role of intraoperative testing; and (5) The current indication of CIs in different clinical scenarios.

CONCLUSIONS

CIs have become a useful solution for certain patients with VS. Audiological outcomes are variable, but worse than those of conventional CI candidates. Small and medium-sized tumors and those with a better preoperative hearing are more likely to benefit from a CI. The effect of irradiation is uncertain. Outcomes in NF2 patients may decrease in the long term. The auditory nerve test system is a useful intraoperative tool in most scenarios. The variability of the outcomes still precludes routine CI in VS with normal contralateral hearing. In addition to VS undergoing surgical resection and CI placement, some observed and irradiated VS cases also benefit from a CI.

LEVEL OF EVIDENCE: 5

Cochlear Implantation in Vestibular Schwannoma Surgery: Diagnostic Accuracy Analysis of Intraoperative Monitoring with Intracochlear Electrode

OBJECTIVE

To investigate the role of intraoperative cochlear nerve (CN) electric monitoring with MED-EL intracochlear test electrode (ITE) in assessing the CN functional integrity.

SETTING

Tertiary referral center.

PATIENTS

Patients with intrameatal or 2 to 13 mm in the cerebello-pontine angle vestibular schwannoma (VS), not suitable for hearing preservation surgery but eligible for tumor resection via translabyrinthine approach and simultaneous cochlear implant (CI) rehabilitation.

INTERVENTION

ITE was used to register electrically evoked auditory brainstem response (eABR) before and after VS resection. All patients with anatomical preservation of CN underwent CI, regardless of eABR results, which served as the index test and was compared with postoperative sound perception by CI stimuli (gold standard test).

RESULTS

Twelve of seventeen cases allowed anatomical preservation of CN and were considered for the study. Seven of twelve cases demonstrated sound detection with CI, and six of twelve showed some degree of speech discrimination. eABR test with ITE achieved an accuracy of 66.7%, a sensitivity of 42.9%, and a specificity of 100%. Positive and negative predictive values were 100% and 55.6%, respectively.

CONCLUSION

When eABR can be evoked with ITE, the attempt of CI was likely to be successful, whereas in cases of eABR absence, other factors should be considered to reduce unsuccessful CI and not preclude rehabilitation in patients who would benefit from CI. Further studies and longer follow-up are needed to analyze the role of ITE in VS surgery with CI.

Psychological factors and long-term tinnitus handicap in vestibular schwannoma patients after retrosigmoid microsurgery - a cross-sectional study

OBJECTIVE

This study aimed to investigate the connection between psychological factors and postoperative tinnitus in vestibular schwannoma (VS) patients following retrosigmoid microsurgery.

DESIGN

Cross-sectional study.

STUDY SAMPLE

Ninety-three VS patients participated, completing questionnaires on demographics, tinnitus severity (THI-12), personality traits (TIPI-G), dizziness impact (DHI), perceived health benefits (GBI), somatisation tendencies (SOMS-2), and psychological distress (HADS-D). Our analysis involved Mann-Whitney U-tests, Spearman's rank-order correlations, and false discovery rate correction.

RESULTS

Most participants reported postoperative tinnitus (77/93), with 41 experiencing it preoperatively. Emotional stability correlated negatively with tinnitus presence, while tinnitus severity was associated with emotional distress. Preoperative somatisation tendencies were also positively linked to tinnitus severity. Postoperative Tinnitus was further linked to reduced perceived health benefits and increased anxiety and depression levels. Notably, age and gender showed no significant associations.

CONCLUSION

This study uncovers the interplay between postoperative tinnitus and psychological factors in VS patients, highlighting emotional and cognitive dimensions. Tailored psychological interventions addressing tinnitus's psychosomatic impact may enhance patients quality of life.

Cochlear Implantation With Sporadic Inner Ear Schwannomas: Outcomes in 106 Patients From an International Multi-Institutional Study

OBJECTIVE

To evaluate cochlear implant speech perception among patients with sporadic inner ear schwannoma who underwent ipsilateral implantation.

STUDY DESIGN

Retrospective multi-institutional cohort study.

SETTING

Eleven tertiary academic medical centers across Germany, Denmark, and the United States.

PATIENTS

One hundred six patients with sporadic inner ear schwannoma who received an ipsilateral cochlear implant from 2011 to 2022.

INTERVENTIONS

Ipsilateral cochlear implantation with observation, stereotactic radiosurgery, or microsurgery for tumor management.

MAIN OUTCOME MEASURES

Monosyllabic speech perception testing scores and rates of open-set speech perception.

RESULTS

Among 106 patients studied, 101 (95%) achieved open-set speech perception with a median of 24 months (interquartile range [IQR] 12-42 mo) of audiometric follow-up. Median ipsilateral monosyllabic speech perception testing achieved was 72% (IQR 54-85%), and median ipsilateral AzBio in quiet was 75% (IQR 46-90%). Most (91 of 106 [86%]) underwent microsurgery for tumor control, with cochlear implantation performed simultaneously in 98% (89 of 91) of these patients. The ability to achieve gross total resection significantly differed by tumor complexity, with 97% of low-complexity tumors, 100% of intermediate complexity, and 0% of high-complexity tumors undergoing gross total resection (p < 0.001). However, among patients managed with microsurgery, there was not a statistically significant difference in post-cochlear implantation monosyllabic speech perception scores across complexity groupings, with median scores of 75 and 70% for patients with tumors of low or intermediate complexity and those with tumors of high complexity, respectively (p = 0.5). Eight of 102 patients (8%) assessed experienced deterioration in cochlear implant performance over time. Among the subset of 39 patients with available MRI to review, the region of surveillance interest could be visualized postoperatively on MRI in all cases.

CONCLUSIONS

Open-set speech perception is achieved in most patients with inner ear schwannoma undergoing ipsilateral cochlear implantation. Although cochlear implantation in high-complexity inner ear schwannomas is only possible with incomplete tumor resection, long-term open-set speech perception outcomes are similar to lower-complexity tumors.

Brazilian Society of Otology task force - single sided deafness - recommendations based on strength of evidence

OBJECTIVE

To make evidence-based recommendations for the treatment of Single-Sided Deafness (SSD) in children and adults.

METHODS

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

RESULTS

The topics were divided into 3 parts: (1) Impact of SSD in children; (2) Impact of SSD in adults; and (3) SSD in patients with temporal bone tumors.

CONCLUSIONS

Decision-making for patients with SSD is complex and multifactorial. The lack of consensus on the quality of outcomes and on which measurement tools to use hinders a proper comparison of different treatment options. Contralateral routing of signal hearing aids and bone conduction devices can alleviate the head shadow effect and improve sound awareness and signal-to-noise ratio in the affected ear. However, they cannot restore binaural hearing. Cochlear implants can restore binaural hearing, producing significant improvements in speech perception, spatial localization of sound, tinnitus control, and overall quality of life. However, cochlear implantation is not recommended in cases of cochlear nerve deficiency, a relatively common cause of congenital SSD.

Brazilian Society of Otology task force - cochlear implant ‒ recommendations based on strength of evidence

OBJECTIVE

To make evidence-based recommendations for the indications and complications of Cochlear Implant (CI) surgery in adults and children.

METHODS

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

RESULTS

The topics were divided into 2 parts: (1) Evaluation of candidate patients and indications for CI surgery; (2) CI surgery - techniques and complications.

CONCLUSIONS

CI is a safe device for auditory rehabilitation of patients with severe-to-profound hearing loss. In recent years, indications for unilateral hearing loss and vestibular schwannoma have been expanded, with encouraging results. However, for a successful surgery, commitment of family members and patients in the hearing rehabilitation process is essential.

Intraoperative Electrical Stapedius Reflex Testing to Monitor Cochlear Nerve Integrity during Simultaneous Vestibular Schwannoma Resection and Cochlear Implantation

OBJECTIVE

To compare the utility of intraoperative electrically evoked auditory brainstem response (eABR) and electrically evoked stapedial reflex testing (eSRT) for cochlear nerve integrity monitoring during simultaneous translabyrinthine resection of vestibular schwannoma (VS) and cochlear implantation.

STUDY DESIGN

Historical cohort study.

SETTING

Tertiary academic referral center.

PATIENTS

Eleven patients (12 cases) who underwent translabyrinthine tumor resection with simultaneous placement of a standard, unmodified cochlear implant (CI).

INTERVENTION

A CI placed at the beginning of the operation before tumor resection to facilitate intraoperative cochlear nerve monitoring through a CI-delivered electrical stimulus.

MAIN OUTCOME MEASURE

Correlation of intraoperative monitoring outcomes with postoperative CI performance.

RESULTS

Among the 12 cases (median age, 47 years), eABR waveforms were present at the conclusion of tumor resection in 10, including 6 that achieved open set speech perception. Of the 2 cases with negative eABR, 1 achieved open set speech perception. By contrast, of the 8 cases with a positive eSRT response, 7 achieved open set speech perception. Of the 4 cases with a negative eSRT response, none achieved open set speech perception. The 3 cases that did not receive auditory stimulation included 2 with positive and 1 with negative eABR; all 3 had a negative eSRT response.

CONCLUSIONS

Intraoperative eSRT using an unmodified CI is a promising new method for monitoring the integrity of the cochlear nerve during simultaneous VS resection. eSRT response at the conclusion of tumor resection strongly correlated with CI open set speech capacity. Although still useful, eABR was less reliable at predicting postoperative hearing outcomes in this series.

Comparing Cochlear Implant Outcomes in 100 Patients With Sporadic Vestibular Schwannoma Managed With Observation, Radiosurgery, or Microsurgery: A Multi-Institutional Review

OBJECTIVE

To compare cochlear implant (CI) speech perception outcomes in patients with sporadic vestibular schwannoma (VS) managed with observation, radiosurgery, or microsurgery.

STUDY DESIGN

Retrospective review.

SETTING

Eleven tertiary academic medical centers.

PATIENTS

One hundred patients with sporadic VS who received an ipsilateral CI.

INTERVENTIONS

Ipsilateral cochlear implantation.

MAIN OUTCOME MEASURES

Pure-tone thresholds, monosyllabic speech perception testing scores, and rates of open-set speech acquisition.

RESULTS

Of the 100 patients studied, 54 underwent microsurgery, 26 underwent radiosurgery, 19 continued observation, and 1 underwent multimodal therapy. Among all patients, the median post-implantation pure-tone average was 31 dB (interquartile range [IQR] 25-39 dB) and the median monosyllabic speech perception score was 30% (IQR 0-60%) at a median of 12 months (IQR 5-25 months) post-implantation. Patients who were managed with microsurgery (median speech perception score 11%, IQR 0-52%) exhibited poorer implant outcomes overall compared with those managed with observation (median speech perception score 52%, IQR 40-72%) or radiosurgery (median speech perception score 30%, IQR 16-60%). Open-set speech perception was achieved in 61% of patients managed with microsurgery, 100% with observation, and 80% with radiosurgery. In a multivariable setting, those managed with observation (p = 0.02) or who underwent radiosurgery (p = 0.04) were significantly more likely to achieve open-set speech perception compared with patients who underwent microsurgery.

CONCLUSIONS

Cochlear implants offer benefit in selected patients with sporadic VS. Although achieved in over half of people after microsurgery, open-set speech perception is more reliably attained in patients who are treated with observation or radiosurgery compared with microsurgical resection. These data may inform patient counseling and VS tumor management in people who may benefit from implantation.

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 Neurofibromatosis Type 2-Related Schwannomatosis: Long-Term Hearing Outcomes

OBJECTIVE

To evaluate long-term hearing outcomes following cochlear implantation in patients with neurofibromatosis type 2 and ipsilateral vestibular schwannoma.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary general hospital.

METHODS

Twenty-two patients undergoing cochlear implantation between 2004 and 2018 with at least 1 year of follow-up were included. Patients were categorized as "users" or "nonusers" of their cochlear implant (CI). For users, speech perception (disyllabic words) without lip-reading was assessed in quiet conditions 1-year postimplantation, and annually thereafter. CI users were classified into 2 groups on the basis of speech intelligibility (≥40% or <40%). Demographic data, treatment options, and tumor size were also recorded.

RESULTS

One year after implantation, 16 (73%) patients used their CI daily. Twelve of these patients had a speech intelligibility ≥40% (mean: 74 ± 21.9%). Three had a Koos stage IV tumor. At the last visit (mean duration of follow-up: 6 ± 5 years), 12 of these 16 patients were still using their implant daily, and 6 had a speech intelligibility ≥40%. No predictive factors for good performance at 1 year or performance stability were identified.

CONCLUSION

Neurofibromatosis type 2 is a complex disease profoundly affecting patient quality of life, and cochlear implantation should always be considered on a case-by-case basis. In some individuals, cochlear implantation can provide good speech intelligibility for extended periods, even posttreatment or in cases of large tumors.

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.

Longitudinal Performance of Cochlear Implants in Neurofibromatosis Type 2

OBJECTIVE

Cochlear implants (CIs) are a well-established treatment modality for hearing loss due to neurofibromatosis type 2 (NF2). Our aim is to investigate variables that affect longitudinal performance of CIs among patients with NF2.

STUDY DESIGN

Retrospective review at a single academic institution consisting of patients who have received cochlear implants following hearing loss due to NF2.

METHODS

The primary outcome examined was CI disuse or explantation. Associated clinical and surgical variables were analyzed using descriptive statistics. These included postoperative pure tone average (PTA) at 500, 1000, and 2000 Hz, tumor size, previous surgery, and comorbid depression.

RESULTS

A total of 12 patients and 14 cochlear implants received at our institution from 2001 to 2022 were included. Notably, 35.7% of CIs (5 out of 14 cases) resulted in disuse or explantation. The average interval until explant was 9.4 years (range 3-14 years). In explanted CI cases, 20% had previous surgery and 80% had a diagnosis of comorbid depression as compared to 22.2% and 22.2%, respectively, in intact CI cases. Maximum tumor diameter was the only variable found to impact CI usage outcome (p = 0.028). Long-term data showed that on average, patients benefit from 13.85 years of CI utility and a maximum PTA improvement of 45.0 ± 29.0 dB.

CONCLUSION

Despite the recurrent nature of NF2, patients continue to receive audiological benefit from cochlear implants. We found that larger tumor size may be associated with longitudinal CI failure.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1847-1853, 2024.

Comparing Speech Recognition Outcomes Between Cochlear Implants and Auditory Brainstem Implants in Patients With NF2-Related Schwannomatosis

OBJECTIVE

To compare cochlear implant (CI) and auditory brainstem implant (ABI) performance in patients with NF2-related schwannomatosis (NF2).

STUDY DESIGN

Historical cohort.

SETTING

Tertiary academic center.

PATIENTS

A total of 58 devices among 48 patients were studied, including 27 ABIs implanted from 1997 to 2022 and 31 CIs implanted from 2003 to 2022. Three patients had bilateral ABIs, three had bilateral CIs, three had an ABI on one side and a CI on the other, one had a CI that was later replaced with an ipsilateral ABI, and one had an ABI and CI concurrently on the same side.

INTERVENTIONS

CI or ABI ipsilateral to vestibular schwannoma.

MAIN OUTCOME MEASURES

Open-set speech perception, consonant-nucleus-consonant word scores, and AzBio sentence in quiet scores.

RESULTS

Among all patients, 27 (47%) achieved open-set speech perception, with 35 (61%) daily users at a median of 24 months (interquartile range [IQR], 12-87 mo) after implantation. Comparing outcomes, CIs significantly outperformed ABIs; 24 (77%) CIs achieved open-set speech perception compared with 3 (12%) ABIs, with median consonant-nucleus-consonant and AzBio scores of 31% (IQR, 0-52%) and 57% (IQR, 5-83%), respectively, for CIs, compared with 0% (IQR, 0-0%) and 0% (IQR, 0-0%), respectively, for ABIs. Patients with ABIs were younger at diagnosis and at implantation, had larger tumors, and were more likely to have postoperative facial paresis.

CONCLUSION

Many patients with NF2-associated vestibular schwannoma achieved auditory benefit with either a CI or an ABI; however, outcomes were significantly better in those patients who were able to receive a CI. When disease and anatomy permit, hearing rehabilitation with a CI should be considered over an ABI in these patients. Tumor management strategies that increase the ability to successfully use CIs should be strongly considered given the high risk of losing bilateral functional acoustic hearing in this population.

Middle Ear Cholesteatoma and Vestibular Schwannoma Resection Followed by Cochlear Implant: Surgical Challenges and Audiological Outcomes

(1) Background: The occurrence of vestibular schwannoma (VS) associated with cholesteatoma is rare. A hearing impairment is one of the most significant issues in such cases. Moreover, the presence of middle and inner ear pathologies combined may represent a surgical challenge. No studies have described a combined surgical approach for these coexisting conditions (VS and cholesteatoma), nor the hearing rehabilitation outcomes of using cochlear implants for these patients. (2) Case Report: This paper is on a female patient who underwent simultaneous surgical treatments for VS and middle ear cholesteatoma in the right ear followed by a cochlear implant, describing the technique and the audiological results. (3) Conclusions: The surgical approach was successful and enabled the resection of lesions with the auditory nerve and cochlea preservation. Cochlear implantation in the right ear showed positive postoperative results, with an improvement in the results with the CI in silent and noisy environments.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Hearing Rehabilitation in Patients With Neurofibromatosis Type 2: The Quebec's Experience With Auditory Implants

OBJECTIVE

To review a single-center experience with hearing rehabilitation in patients with neurofibromatosis type 2 (NF2) and to describe the auditory outcomes of cochlear implants (CIs) and auditory brainstem implants (ABI) in this population.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary referral center.

PATIENTS

Twelve adult patients with NF2 who received a CI (n = 10) and/or an ABI (n = 5) between 2000 and 2021.

INTERVENTIONS

Insertion of a CI and/or an ABI in NF2 patients with bilateral vestibular schwannomas (VSs).

MAIN OUTCOME MEASURES

Patients' demographic data, treatment history, hearing evolution, hearing rehabilitation methods, implant details, and auditory outcomes after implantation.

RESULTS

Among those who received a CI, five patients had a stable untreated VS, one patient underwent a cochlear nerve preserving surgery, and four patients received radiotherapy treatments. Six patients became regular users of their device. The median open-set sentence recognition scores were as follows: 0.5% preoperatively, 60% at 1 year postoperatively, and 80% on the most recent audiological evaluation. All patients with an ABI were implanted concomitantly with VS surgical excision, and three of them also received radiotherapy treatments. The median open-set sentence recognition scores were as follows: 4% preoperatively, 26% at 1 year postoperatively, and 0% on the most recent evaluation. Three patients became regular ABI users.

CONCLUSION

Despite major technological advances, auditory outcomes with ABIs remain deceiving. Considering the overall improvement in postoperative auditory performances provided by CIs compared with ABIs, cochlear implantation standouts as a primary mean of hearing rehabilitation in NF2 patients.

Cochlear Implant Outcomes between Patients with Sporadic and Neurofibromatosis Type 2-Associated Vestibular Schwannoma

OBJECTIVE

Compare cochlear implant (CI) performance between patients with ipsilateral sporadic vestibular schwannoma (VS) and NF2-related schwannomatosis (NF2). Compare CI performance according to VS management modality.

STUDY DESIGN

Historical cohort.

SETTING

Tertiary academic center.

PATIENTS

Forty-nine patients (52 ears) undergoing cochlear implantation in the setting of ipsilateral sporadic (n = 21) or NF2-associated VS (n = 28).

INTERVENTIONS

CI ipsilateral to VS.

MAIN OUTCOME MEASURES

Auditory thresholds, consonant-nucleus-consonant (CNC) word scores, and AzBio sentences in quiet scores.

RESULTS

Among all patients, median post-CI pure tone average was 28 dB HL (interquartile range [IQR], 21-38), CNC word score was 39% (IQR, 6-62), and AzBio sentences in quiet score was 60% (IQR, 11-83) at a median of 12.5 months postimplantation. Despite the NF2 cohort having larger tumors, when comparing patients with sporadic versus NF2-associated VS, there were no statistically significant differences in CNC word (49% [30-70] vs. 31% [0-52]) or AzBio sentences in quiet (66% [28-80] vs. 57% [5-83]) scores. Regardless of NF2 status, all patients managed with observation, and radiosurgery achieved open-set speech. In patients who underwent microsurgery, 6 (46%) of 13 with NF2 achieved open-set speech recognition compared with 4 (67%) of 6 with sporadic disease.

CONCLUSION

Select patients with VS achieve successful hearing rehabilitation with a CI. In this cohort, tumor management strategy significantly influenced CI performance, whereas differences in NF2 status exhibited less effect. Specifically, all patients managed with observation or radiosurgery achieved open-set speech perception, whereas approximately half of people with NF2-related VS and two-thirds of people with sporadic VS achieved this outcome after tumor microsurgery. When disease permits, observation and radiosurgery should be considered in patients who may later pursue a CI.

Cochlear Implantation in Sporadic Vestibular Schwannoma and Neurofibromatosis Type II

Cochlear implantation offers significantly better hearing outcomes than auditory brainstem implantation in patients with vestibular schwannoma. Neither the primary treatment modality nor the cause of the tumor (neurofibromatosis type 2 related or sporadic) seems to have a significant effect on hearing outcome with cochlear implantation. Some uncertainty remains regarding long-term hearing outcomes; however, cochlear implantation in vestibular schwannoma serves to offer patients, with a functioning cochlear nerve, the probability of open set speech discrimination with a consequent positive impact on quality of life.

How Cochlear Implant Rehabilitation Impacts the Therapeutic Strategy for Vestibular Schwannoma

BACKGROUND

Since both surgery and more conservative treatments show long-term outcomes in patients with VS, the current challenge in its therapeutic strategy is to offer a cure with lower functional morbidity in terms of facial and hearing preservation or the possibility of hearing rehabilitation with a cochlear implant.

METHODS

PubMed and Scopus databases were searched from 2017 to November 2022. Fifteen articles met our selection criteria: (1) patients with a diagnosis of VS, either sporadic or NF2-related; (2) simultaneous or sequential cochlear implantation; (3) specified audiological test results and follow-up timing.

CONCLUSIONS

Although the level of evidence for the presently included studies is low due to either the study design or the lack of treatment consensus, CI rehabilitation is a promising option, especially in small VS with compromised hearing and as a salvage option after a failed attempt at hearing preservation surgery.

Functional Outcome After Simultaneous Vestibular Schwannoma Resection and Cochlear Implantation With Intraoperative Cochlear Nerve Monitoring

OBJECTIVE

Electrically evoked auditory brainstem response audiometry has emerged as a suitable option to intraoperatively assess cochlear nerve function during vestibular schwannoma resection. This study aimed to analyze the functional outcome and implant usage of patients with preserved auditory nerve responses after simultaneous translabyrinthine schwannoma resection and cochlear implantation.

STUDY DESIGN

Prospective study.

SETTING

Tertiary referral center.

METHODS

Patients with unilateral sporadic vestibular schwannoma underwent translabyrinthine tumor resection. Intraoperatively, electrically evoked auditory brainstem response audiometry was performed before and after tumor removal. Cochlear implantation was carried out if positive responses were detected after tumor removal indicating cochlear nerve function. Postoperatively, patients were biannually followed-up to assess aided sound field audiometry and word recognition as well as implant usage.

RESULTS

Overall, 26 patients with vestibular schwannoma underwent translabyrinthine schwannoma resection. Out of these patients, 15 had positive cochlear nerve responses after tumor removal and concurrently received a cochlear implant. In 13 patients with histologically confirmed vestibular schwannoma, hearing improved by 23.7 ± 33.2 decibels and word recognition by 25.0 ± 42.4% over a mean follow-up period of 18 months. Overall, 12 included patients were regular cochlear implant users.

CONCLUSION

Patients with vestibular schwannoma can benefit substantially from cochlear implantation. Intraoperative assessment of cochlear nerve function using electrically evoked auditory brainstem response audiometry can help to better identify individuals eligible for simultaneous vestibular schwannoma resection and cochlear implantation.

Cochlear Implantation Outcomes in Patients With Retrocochlear Pathology: A Systematic Review and Pooled Analysis

OBJECTIVE

To review the current literature regarding cochlear implantation in patients with retrocochlear pathologies and extract speech perception scores between 6 months and 1 year after surgery.

DATABASES REVIEWED

PubMed/MEDLINE, Embase and Cochrane CENTRAL via Ovid, CINAHL Complete via Ebsco, and Web of Science.

METHODS

The review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Search strategies included keywords and subject headings to maximize retrieval and reflect cochlear implants and retrocochlear pathologies. Patients with previously resected vestibular schwannoma (VS) were excluded.

RESULTS

There were 2,524 abstracts screened against inclusion criteria, and 53 studies were included, with individual data available for 171 adult patients. Pathologies included were either observed or irradiated VS (previously operated tumors were excluded) (n = 99, 57.9%), superficial siderosis (n = 39, 22.8%), neurosarcoidosis (n = 11, 6.4%), and previous central nervous system or skull base radiation (n = 22, 12.9%). Mean (standard deviation) postoperative consonant-nucleus-consonant (CNC) word scores were 45.4% (24.2) for observed VS, 44.4% (20.8) for irradiated VS, 43.6% (21.0) for superficial siderosis, 89.5% (3.0) for neurosarcoidosis, and 30.0% (30.2) in patients with previous central nervous system or skull base irradiation. Irradiated compared with observed VS had similar postoperative CNC word scores (effect size, 0.06; p = 0.71). Age, sex, maximal tumor dimension, and neurofibromatosis type 2 status did not significantly impact cochlear implant performance in patients with VS. Eighty-two percent of patients with reported device usage were daily users, and overall, 82% of cases benefitted from cochlear implantation.

CONCLUSION

Cochlear implantation in patients with concomitant retrocochlear pathology generally results in improved speech discrimination scores sustained over time.