Cochlear implant revisions: a 10-year review of the victorian cochlear implant program

Background: Cochlear implantation is an established and effective intervention for individuals with severe to profound sensorineural hearing loss, restoring auditory perception and improving communication outcomes and quality of life. Despite improvements in implant design and surgical technique, a subset of recipients require cochlear implant revision (CIR) due to device or medically related issues. Understanding contemporary revision patterns provides valuable insight into implant reliability, patient outcomes, and evolving indications for revision surgery. This study aimed to evaluate the incidence, indications and characteristics of CIR surgery over a 10-year period at the Royal Victorian Eye and Ear Hospital.

Methods: A retrospective, single-centre cohort study was conducted at the Royal Victorian Eye and Ear Hospital, Melbourne, Australia, including all CIR procedures performed between 2015 and 2025. CIR was defined as any procedure involving explantation (with or without immediate or staged reimplantation) or device repositioning. Demographic, surgical, and device data were extracted from institutional records. Indications for revision were classified as hard failure, soft failure, or medical failure according to current consensus statements.

Results: Over the 10-year period, 1,820 cochlear implant (CI) procedures were performed on 1,668 patients, including 63 revision surgeries, corresponding to an overall revision rate of 3.8% (63/1,668). Revision rates were 2.6% (10/389) among paediatric and 4.1% (53/1,279) among adult recipients. The mean interval from primary implantation to revision was 8.6 years [standard deviation (SD) 8.8] overall and shorter in paediatric (5.2 years with SD of 3.9) than adult (9.3 years with SD of 9.4) cases. Medical failure was the leading indication for CIR (47/63, 74.6%), followed by hard failure (15/63, 23.8%) and soft failure (1/63, 1.6%). Among hard failures, insulation failure (8/15, 53.3%), hermeticity failure (2/15, 13.3%) and electrode array failure (2/15, 13.3%) were the most frequent underlying causes. Device failure predominated among primary reimplantation cases (16/27, 59.3%), whereas medical causes were more common overall. Tip fold-overs were observed exclusively in perimodiolar arrays.

Conclusions: CIR remains an uncommon but clinically relevant occurrence within contemporary practice. Medical failures increasingly account for the majority of overall revisions, while device failure continues to represent the primary indication among reimplantation cases. These findings highlight a shift in revision indications from hardware malfunction toward medical and patient-related causes. Sustained surveillance, structured outcome auditing, and multidisciplinary follow-up are essential to maintaining device reliability and optimising long-term outcomes across Australian CI programs.