Recurrent extrusion of cochlear implant at an interval of 5 years

To describe two different types of device extrusion occurring in the same patient 1 and 6 years after cochlear implantation and to discuss the relation between the two extrusions and problems of cochlear implantation in patients with chronic suppurative otitis media.

Retrospective case review.

Tertiary referral center. PATIENT AND INTERVENTIONS: The patient was a 52-year-old man with profound hearing loss in the right ear caused by chronic otitis media and deafness in the left ear caused by removal of an acoustic neuroma. Surgery for cleaning the tympanic cavity and reconstruction of the bony canal after previous radical mastoidectomy was performed in the right ear first. One year later, cochlear implantation was performed in this ear.

One year after implantation, the anterior edge of the internal device of cochlear implant was exposed along the skin incision. This site was stable after corrective surgery. Five years after this operation, however, the posterior edge of the internal device extruded, accompanied by infection around the device.

The two extrusions occurred with a long interval in between and at two different sites. The first extrusion occurred along the skin incision, and the second extrusion occurred away from the skin incision with infection around the device. The authors assumed that the first and the second extrusion occurred independently; the first extrusion was caused by insufficient blood supply resulting from scar formation from repeated mastoid operations and by pressure on the skin from the internal and external devices, and the second extrusion was caused by proliferated tissue pushing the device upward and against the skin as a result of chronic middle ear infection. The clinical course indicates that sufficiently long follow-up periods are needed to determine the usefulness of the prevention techniques for cochlear implantation in patients with chronic suppurative otitis media.