Analysis of fifty-six cochlear implant device failures

Our aim was to present a failure analysis after cochlear implant revision surgery in a large series of children and adults and to assess the outcome and audiologic performance.

Fifty-six cochlear implant failures that occurred in 422 devices implanted between 1990 and 2007 at the Department of Otolaryngology, Head and Neck Surgery at the University of Mainz, Germany, were retrospectively analyzed. The causes of failure were reviewed evaluating the individual history, telemetric and intraoperative findings and manufacturer's investigation reports.

We performed 56 surgical revisions in a series of 422 consecutive implants (overall revision rate: 13.27%). The most frequent causes for revision were hard failures (58.9%), most commonly caused by traumatic impact (37.5%), especially in the pediatric population. Soft failures were less frequent (21.4%). Surgical reimplantations, although challenging in some cases, were performed without complications and with an electrode insertion depth comparable to that at the time of the initial implantation in all patients. The average audiologic performance improved by 2.4 dB in pure-tone perception levels after reimplantation.

The cochlear implant failure rates vary between children and adults as well as between different implant manufactures. However, cochlear reimplantation is safe with excellent and predictable results in audiologic performance.