Symptom Timeline Preceding Cochlear Implant Failure

Objective: 1) Review cochlear explants and determine the incidence of device and medical failures. 2) Develop a pattern of symptoms indicating probable implant failure. Method: This is a retrospective chart review at a tertiary referral center. Subjects were selected if they underwent cochlear explantation. A total of 847 implants were performed from 1988 to 2008, with 128 devices explanted. Data were reviewed to determine initial symptom and symptom timeline preceding implant failure. Results: Of total implants, 72% were Advanced Bionic devices, 28% were Nucleus. Overall failure rate was 128 out of 847 (15%). Patients with Advanced Bionic devices underwent 102 explants (16.7% failure rate), with 35% medical failures and 65% device failures. Patients with Nucleus devices underwent 26 explants (11% failure rate), with 58% medical failures and 42% device failures. Medical failures included infected devices and wound dehiscence, the pattern averaging 4.5 months to explantation. Hard device failures included sudden malfunction and slow decline in function, with pattern of failure over 4.2 months. Soft failures included tinnitus and discomfort, with failure over 8 months. Conclusion: There were common patterns when evaluating both medical and device failures. By recognizing patterns of symptoms that may indicate probable implant failure, otolaryngologists can better counsel patients on what to expect with their implants when they present with certain symptoms.