Failure and Revision Surgery After Cochlear Implantation in the Adult Population: A 10-year Single-institution Retrospective and Systematic Review of the Literature

Objective: To characterize failure rate and etiology after cochlear implantation; to identify predictors and describe outcomes after implant failure. Study Design: Retrospective chart review and systematic review of the literature using PubMed and Embase. Setting: Academic Cochlear Implant Center. Subject Population: Four hundred ninety-eight devices in 439 distinct adult patients. Interventions: Unilateral or bilateral cochlear implantation. Main Outcome Measures: Implant failure rate and etiology. Results: A total of 32 devices (5.9%) failed in 31 patients encompassing the following failure types in accordance with the European Consensus Statement of Cochlear Implants: 17 device failures (53.1%), 11 failures due to performance decrement/adverse reactions (34.4%), and 4 medical reasons (12.9%). There was no significant difference in age, sex, or manufacturer between patients with and without failures. Twenty-five percent of patients with failure leading to explantation had childhood onset of deafness compared to 12.1% of patients with adult-onset hearing loss (OR = 2.42; p = 0.04). Performance decrement/adverse reaction patients had an older average age at implantation compared to device failure patients (mean 68.5 yr 95% CI: 59.9–77.1 vs mean 47.6 yr, CI: 39.9–55.3, p < 0.01). There was no significant difference in time to failure, sex, or device manufacturer between the different types of failures. Twenty-nine patients who experienced CI failure underwent a revision surgery, while the remaining two opted for explantation without reimplantation. One patient who underwent revision surgery subsequently presented with a second failure and underwent a second revision, which was successful. In our systematic review, 815 citations were reviewed, and 9 studies were selected for inclusion. Overall failure rate across all studies was 5.5%. Device failure was the leading cause of failure in the majority (6/9) of studies, accounting for 40.8% of all failures. Medical reasons were the second leading cause at 33.6%, followed by performance decrement/adverse reaction (20.9%) and other (4.8%). Conclusions: Cochlear implant failure is a rare phenomenon. Childhood-onset of hearing loss appears to be associated with an increased risk of overall failure. Older patients are at increased risk for performance decrement/adverse reaction. Revision surgery success rates remain very high and patients with failure of any cause should be offered explantation with concurrent reimplantation.