Rates of revision and device failure in cochlear implant surgery: a 30-year experience

Abstract

Objectives/hypothesis: To characterize revision cochlear implant surgery and quantify rates of revision and device failure.

Study design: Retrospective review of 235 cases of revision cochlear implant surgery performed at the Sydney Cochlear Implant Center over a period of 30 years, between January 1982 and June 2011.

Methods: Patient demographics and characteristics of revision surgery were retrospectively extracted from a centralized database. Analyses of overall and cumulative rates were performed.

Results: During the study period, 2,827 primary cochlear implantations were performed in 2,311 patients, with 201 primary implants in 191 patients of this cohort (109 children and 82 adults) undergoing 235 revision surgeries. The most common indication for revision surgery was device failure (57.8%), followed by migration/extrusion (23.4%), infection/wound complication (17.0%), and poor outcome/secondary pathology (6.4%). The majority of revision surgeries were reimplantations. Overall revision and device failure rates were 8.3% and 4.8%, respectively. The cumulative revision rate for primary implants at all ages increased linearly by 1% per year. The cumulative revision rate was significantly higher in children, and decreased with more recently performed implantations and with newer generations of implants.

Conclusions: The cumulative revision rate for primary implants suggests an ongoing linear relationship between the time of postprimary implantation and the need for revision surgery. We have formed an evidence base that characterizes the nature and frequency of revision surgery in a high-volume setting, allowing clinicians to effectively counsel prospective patients and clinics to understand the burden of revision surgery and device failure.

Keywords: Cochlear implant; device failure; device failure rate; explantation; hard failure; reimplantation; revision rate; revision surgery; soft failure.