Intact canal wall drill-out procedure for implantation of the totally ossified cochlea.

Objective: To describe a simplified drill-out technique for insertion of a multichannel electrode in the completely ossified cochlea without radical mastoidectomy and obliteration.

Methods: Description of a new surgical technique and case report. Methods: Temporal bone dissection laboratory and tertiary referral center. Methods: Adult and pediatric cochlear implant (CI) recipients. Methods: Access for circum-modular drill-out and electrode insertion without radical mastoidectomy and adequate function of multichannel CI.

Results: Dissection of 10 cadaver temporal bones demonstrated feasibility of this technique. Highlights include facial recess cochleostomy and 8 mm tunnel; elevation of superiorly based tympanomeatal flap; removal of incus, cochleariform process, and tensor tympani; and identification of carotid canal and use of facial nerve monitor. A case report of an 11-year-year old child with total cochlear ossification and previous failure of a short (8 electrode) CI electrode insertion is presented. Complete insertion of a 22-channel electrode was successful and open-set word recognition is commencing.

Conclusions: The canal wall-up drill-out procedure allows complete electrode insertion without mastoid obliteration in patients with obliterated cochleas. Appropriate attention to the carotid artery and facial nerve is essential.