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

The Benefits of Cochlear Implantation for Adults: A Systematic Umbrella Review

OBJECTIVES

The uptake of cochlear implants among adults who could benefit (based on pure-tone audiometry) in developed countries is estimated to be less than 10%. Concerns about potential surgical complications, fear of losing residual hearing, and limited awareness about the benefits of this intervention contribute to the low adoption rate. To enhance quality of life and improve the uptake of cochlear implants, it is essential to have a clear understanding of their benefits.

DESIGN

This umbrella review aims to summarize the major benefits of cochlear implant usage in adults, by synthesizing findings from published review articles. A comprehensive search of databases including MEDLINE, EMBASE, PsycINFO, and Google Scholar, was conducted. The search was limited to English-language review articles published between 1990 and 2022, focusing on cochlear implant outcomes in at least 5 adults (aged ≥18 years). Two independent reviewers screened titles, abstracts, and full-text articles, and conducted a quality assessment using the Joanna Briggs Checklist for Systematic Reviews and Research Syntheses.

RESULTS

Forty-two articles were included in this review. There were 15 systematic reviews with meta-analysis, 25 systematic reviews without meta-analysis, and 2 systematic scoping reviews. All 42 articles underwent quality assessment using the Joanna Briggs Institute Checklist for Systematic Reviews and Research Syntheses, of which 40% (n = 17) satisfied 9 out of 11 quality criteria. This umbrella review shows that cochlear implants are associated with improvements in speech perception and recognition as well as improved quality of life and cognition. These benefits are observed in a significant proportion of adults undergoing the procedure, highlighting its effectiveness as a viable intervention for individuals with severe to profound hearing loss.

CONCLUSIONS

The potential benefits of cochlear implantation appear to outweigh the risks and complications associated with the procedure. It is recommended that adults with severe to profound hearing loss in particular, engage in informed discussions with healthcare professionals to consider cochlear implantation as a viable treatment option.

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.

Cochlear Implantation After Head and Neck Radiation: A Case Series, Systematic Review, and Meta-analysis

OBJECTIVE

To determine if cochlear implant (CI) is safe and effective in patients with radiation therapy (XRT)-induced sensorineural hearing loss and to discuss considerations in this population through a retrospective cohort review, systematic review, and meta-analysis.

DATABASES REVIEWED

PubMed, Cochrane Library, and Embase.

METHODS

We retrospectively reviewed all CI cases after head and neck (HN) XRT at our institution, noting intraoperative findings, postoperative complications, and hearing outcomes. Change in speech discrimination scores (SDSs) was the primary outcome measure. Systematic review was performed to identify all cases of CI after HNXRT. A meta-analysis was performed to assess SDS change.

RESULTS

The retrospective cohort review identified 12 patients who underwent CI after HNXRT. One patient with HN cancer (HNC) and one with central nervous system pathology (CNSP) received bilateral implants. Six had HNC, three had CNSP, and one had Langerhans cell histiocytosis. Eleven had abnormal findings during CI. There were no postoperative complications. Twenty articles with an additional 97 patients were suitable for systematic review inclusion. Of the 109 patients, 67 (61.5%) had HNC and 18 (16.5%) had CNSP. Abnormal intraoperative findings were common (30.3%), most frequently in the mastoid (66.7%). Postoperative complications, including wound dehiscence and infection with some requiring explantation, occurred in 10.1% of patients. Sixty-six patients were included in the meta-analysis. All demonstrated SDS improvement (mean increase, 56.2%).

CONCLUSION

Patients with prior HNXRT benefit from CI. Paying careful attention to surgical planning and technique, postoperative care, and patient expectations is imperative, as complications are not uncommon.

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.