Successful revision of failed cochlear implants in severe labyrinthitis ossificans

Abstract

Labyrinthitis ossificans may complicate the insertion of a multichannel cochlear implant in patients deafened after meningitis. Two children who initially underwent partial insertion of a 22-channel cochlear implant because of severe cochlear ossification required revision surgery after several months of unsuccessful device use. At the time of revision, resection of the car canal, tympanic membrane, malleus, and incus provided access to the lateral wall of the cochlea, permitting extensive drilling of the basal turn and a circumodiolar placement of the electrode. Functional integrity of the electronic components of the original device was documented intraoperatively, avoiding the expense of a new receiver-stimulator. Complete insertion of the active electrodes was accomplished in both cases, and electrophysiologic responsiveness to the implant was documented using intraoperative electrically evoked auditory brainstem response recordings. Postoperative performance has been similar to that of cochlear implant patients with nonossified ears. Experience with these two cases suggests that efforts to optimize electrode insertion at the original surgical procedure are appropriate and may help to avoid the disappointment of an unsuccessful cochlear implant.