Cochlear Implants in Canal Wall-Down Mastoidectomies.

Hunter et al summarized their 10 years’ experience of only 7 patients undergoing cochlear implant (CI) surgery after previous canal wall-down mastoidectomy using a single-layer external auditory canal overclosure technique. The authors seem to be surprised that their findings of 2 ear canal failures contradict the experience of 303 patients reported in the literature—including our own study. Interestingly, both failures were revised using the same technique and redeveloped ear canal dehiscences. The key principles of subtotal petrosectomy (SP) as described by Fisch include (1) water-tight double-layer closure of the external ear canal, (2) removal of the external auditory canal to the level of the facial nerve, (3) detailed and thorough removal of all pneumatized cells and mucosa from the mastoid and middle ear, (4) sealing of the eustachian tube, and (5) obliteration of the cavity with fat and muscle, including suturing of a portion of the temporalis muscle to the sternocleidomastoid muscle. When revising open cavities, special care with the elevation of the skin flaps is necessary. Additional details of our technique and references about SP are available in our article. Open cavities in chronic ears without thorough removal of pneumatized cells retain the potential for infection. Given the potential for electrode migration and infection in open cavities, we feel that the authors’ experience of 2 patients with successful canal wall-down CI implantations (follow-up 6 months and 22.8 months) using 4 distinct layers to cover the electrode groove (cartilage, fascia, bone pate, and perichondrium) is not enough evidence to recommend this technique. The proper conclusion should be the following: shortcuts lead to failures, but accurately performed SP with double layer closure of the external ear canal has proven to be safe and effective.