Ipsilateral Cochlear Implantation Research Articles

MRI surveillance after translabyrinthine vestibular schwannoma resection and cochlear implantation: is it feasible?

PurposeCochlear implantation in patients with vestibular schwannomas is of increasing importance and interest. Two remaining challenges are the assessment of conduction of the cochlear nerve and the possibility of postoperative surveillance with magnetic resonance imaging. The aim of the current study was to assess follow-up imaging and determine the visibility of the internal auditory canal after vestibular schwannoma resection and cochlear implantation as well as in patients with persistent vestibular schwannomas and cochlear implants in place. Visibility of the internal auditory canal, cerebellopontine angle, and labyrinth were evaluated and graded.MethodsFor this retrospective study, 15 MR examinations of 13 patients after translabyrinthine vestibular schwannoma resection and ipsilateral cochlear implantation were included. All patients had been implanted with an MED-EL cochlear implant. Magnetic resonance imaging was carried out on a 1.5T device. All patients were prepped according to the manufacturer’s recommendations.ResultsAll 15 examinations were carried out without any adverse event during imaging, such as pain, magnet dislocation, or malfunction. The internal auditory canal and the cerebellopontine angle were sufficiently visible in all cases to allow for vestibular schwannoma follow-up.ConclusionMagnetic resonance imaging surveillance of the internal auditory canal following vestibular schwannoma resection and cochlear implantation is feasible and safe with modern implants with a 1.5T magnetic resonance imaging device using metal artifact reduction sequences. Necessary follow-up imaging should not be a contraindication for cochlear implantation in patients with vestibular schwannomas.

Is the intra-operative morphology of the cochlear nerve a good predictor of the results of simultaneous ipsilateral cochlear implantation in vestibular schwannoma surgery?

There are currently no guidelines for simultaneous vestibular schwannoma surgery and cochlear implantation. This paper therefore provides our experience and our results regarding predictive parameters of good hearing. Morphological appearance of the cochlear nerve after tumour resection was used as the main criterion for implantation in the case series. Patients were then divided into responders and non-responders to cochlear implantation, and potential outcome predicting factors were evaluated in the two groups. Nine of the 16 patients showed a response to cochlear implantation. Pre-surgery serviceable hearing was significantly more common in the responder group, while no difference was found in the two groups for other variables. This study highlights how the morphological appearance of the cochlear nerve can be useful to predict the hearing outcome and indicates that satisfactory hearing results are closely related to pre-surgery serviceable hearing.

Cochlear Implantation in Adults With Single-Sided Deafness: A Systematic Review and Meta-analysis.

To determine the clinical outcomes of adult patients with single-sided deafness (SSD) undergoing ipsilateral cochlear implantation. An electronic search of Medline and Embase articles. A systematic review was performed with a search strategy developed by a licensed librarian to identify studies of adult patients with SSD who underwent ipsilateral cochlear implantation. Articles were managed in Covidence and evaluated by 2 independent reviewers. Risk of bias was assessed and data were extracted, including patient demographics, etiology of deafness, duration of deafness, and postoperative change in speech recognition, tinnitus, sound localization, and quality of life (QoL). A meta-analysis was performed, and pooled mean differences were calculated for each outcome of interest via random effects models by each outcome, as well as subgroup analyses by the individual clinical score used. Of 2309 studies identified, 185 full texts were evaluated, and 50 were ultimately included involving 674 patients. Speech perception scores in quiet and noise, tinnitus control, sound localization, and QoL all significantly improved after implantation. Pooled outcomes demonstrated score improvements in speech perception (standardized mean difference [SMD], 2.8 [95% CI, 2.16-3.43]), QoL (SMD, 0.68 [95% CI, 0.45-0.91]), sound localization (SMD, -1.13 [95% CI, -1.68 to -0.57]), and tinnitus score reduction (SMD, -1.32 [95% CI, -1.85 to -0.80]). Cochlear implantation in adults with SSD results in significant improvements in speech perception, tinnitus control, sound localization, and QoL.

Cochlear Implantation in Vestibular Schwannoma: A Systematic Literature Review.

Objective Ipsilateral cochlear implantation (CI) in vestibular schwannoma (VS) has been an emerging trend over the last two decades. We conducted the first systematic review of hearing outcomes comparing neurofibromatosis 2 (NF2) and sporadic VS undergoing CI. A comparison of the two populations and predictor of outcome was assessed. This is an update to a previously presented study. Data Sources Systemic data searches were performed in PubMed NCBI and Scopus by an academic librarian. No restrictions based on the year of publication were used. Study Selection Studies were selected if patients had a diagnosis of NF2 and a CI placed in the affected side with reports of hearing outcome. Two independent reviewers screened each abstract and full-text article. Data Extraction Studies were extracted at the patient level, and the assessment of quality and bias was evaluated according to the National Institutes of Health Quality Assessment Tool. Main Outcome Measures Outcome predictors were determined by using the chi-square test and Student's t -test. Results Overall, most CI recipients functioned in the high-to-intermediate performer category for both sporadic and NF2-related VS. Median AzBio (Arizona Biomedical Institute Sentence Test) was 72% (interquartile range [IQR]: 50) in NF2 patients and 70% (IQR: 7.25) in sporadic patients. Larger tumor size predicted a poorer final audiometric outcome. Conclusions Categorization of hearing outcome into superior performance and inferior performance based on sentence recognition revealed a generally good hearing outcome regardless of treatment or patient population. Select patients with sporadic and NF2 VS may benefit from CI.

Ipsilateral Cochlear Implantation in the Presence of Observed and Irradiated Vestibular Schwannomas.

Historically, eventual loss of cochlear nerve function has limited patients with neurofibromatosis type 2 (NF2) to auditory brainstem implants (ABI), which in general are less effective than modern cochlear implants (CI). Our objective is to evaluate hearing outcomes following ipsilateral cochlear implantation in patients with NF2 and irradiated vestibular schwannomas (VS), and sporadic VS that have been irradiated or observed. Multi-center retrospective analysis of ipsilateral cochlear implantation in the presence of observed and irradiated VS. MESH search in NCBI PubMed database between 1992 and 2019 for reported cases of cochlear implantation with unresected vestibular schwannoma. Seven patients underwent ipsilateral cochlear implantation in the presence of observed or irradiated vestibular schwannomas. Four patients had sporadic tumors with severe-profound contralateral hearing loss caused by presbycusis/hereditary sensorineural hearing loss, and three patients with NF2 lost contralateral hearing after prior surgical resection. Prior to implantation, one VS was observed without growth for a period of 7 years and the others were treated with radiotherapy. Mean post-operative sentence score was 63.9% (range 48-91) at an average of 28 (range 2-84) months follow up. All patients in this cohort obtained open set speech perception. While analysis of the literature is limited by heterogenous data reporting, 85% of implants with observed schwannomas achieved some open set perception, and 67% of patients previously radiated schwannomas. Furthermore, blending literature outcomes for post implantation sentence testing in quiet without lip-reading show 59.0 ± 35% for patients with CI and observed tumors and 55.7 ± 35% for patients with radiated tumors, with both groups ranging 0 to 100%. This retrospective series and literature review highlight that hearing outcomes with CI for VS patients are superior to those achieved with ABI. However, important considerations including imaging, delayed hearing loss, and observation time cannot be ignored in this population.

Analysis of the effect of cochlear implant for the patients with acoustic neuroma in the only hearing ear

To discuss the method as well as effect of hearing restoration for patients with acoustic neuroma (AN) in the only hearing ear. A retrospective study was conducted in three patients with AN in the only hearing ear. Ipsilateral cochlear implantation (CI) was performed in case 1 and contralateral CI was performed in case 2 without tumor resection. In case 3, CI was performed 6 months after tumor removal by the retrosigmoid approach. Dynamic changes in the audiological tests was recorded regularly. In case 1 and case 2, no matter which side CI was performed, pure tone average (PTA) was improved clearly, and speech discrimination score (SDS) was slightly increased. In case 3, hearing loss was observed after tumor removal. Simultaneous bilateral CI after 12 months was performed in this case. PTA on both sides was largely lower than that before CI, and SDS was slightly improved. With bilateral CI, SDS was improved, especially in noise, compared with unilateral CI on either side. For patients with AN in the only hearing ear, CI can significantly improve PTA, and SDS can be slightly increased. Bilateral CI should improve the outcome of hearing restoration compared with unilateral CI.

Ipsilateral cochlear implantation in patients with sporadic vestibular schwannoma in the only or best hearing ear and in patients with NF2.

The aim of this study was to evaluate the cochlear implant (CI) performances in neurofibromatosis type 2 (NF2) patients with bilateral vestibular schwannoma (VS) and in patients with sporadic VS in the only or better hearing ear. All patients with bilateral VS or sporadic VS in the only or better hearing ear who underwent cochlear implantation, either simultaneous to VS surgery or staged after treatment for VS, in the tumor side were chosen for the study. Postimplantation audiometric scores (sound detection, closed-set and open-set discrimination scores) and device use patterns were the main outcome measures. 15 patients were implanted. Eight patients (53 %) were NF2 and seven patients had VS in the only or better hearing ear. One patient was explanted for cerebrospinal fluid leak. In the CI-only condition, the other 14 patients obtained sound detection, 64 % of them achieving open-set discrimination (mean 70 ± 38 %) and 85 % achieving closed-set discrimination (mean 41 ± 33 %). At the last follow-up 10 patients (67 %) were using the CI. Cochlear implantation provides hearing in particular cases of patients with bilateral VS or VS in the only or better hearing ear. As long as anatomic preservation of the cochlear nerve is achieved, cochlear implantation may offer improvement in communication skills for most patients.

Vestibular and taste disorders after bilateral cochlear implantation

The objective of this study was to investigate the occurrence of vestibular receptor deficiency and taste disorders after bilateral cochlear implantation in postlingually deafened patients and to find out whether the risk for these complications is higher for the second implantation. In a retrospective cohort study, we examined 20 patients (11-58 years, mean age 41.5 years), implanted sequentially between 2000 and 2007 (mean period between cochlear implantation 32.9 ± 25 months). Pre- and postoperative vestibular testing was performed by subjective rating [Dizziness Handicap Inventory (DHI)], caloric irrigation [vestibuloocular reflex (VOR)] and by vestibular-evoked myogenic potential (VEMP) recordings for saccular function. The sense of taste was evaluated pre- and postoperatively by a questionnaire and testing (sour/sweet/bitter/salty bilaterally on the tongue). DHI evaluation showed a moderate not significant mean increase by 2.7 ± 7.7 SD points after the first and a significant increase by 9.4 ± 16.6 SD points after the second implantation. Ipsilateral VEMP responses disappeared in three ears (27.3%) after the first and in two ears (18.2%) after the second operation. VOR disappeared only once (5.9%) after the first implantation. One (5%) patient complained of a persisting disturbance of taste in the questionnaire after unilateral and 3 (15%) after bilateral implantation. Specific testing showed in one case (5%) a unilateral taste disorder after ipsilateral cochlear implantation. Our data show that there is a higher risk for subjective vertigo after the second implantation. The occurrence of unilateral and/or bilateral vestibular dysfunction and the potential risk of taste disorder should be included in the risk counseling before bilateral cochlear implantation to increase patients' and medicolegal safety in the decision-making process.