INTACT CANAL WALL DRILL-OUT PROCEDURE FOR IMPLANTATION OF THE TOTALLYOSSIFIED 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. Study Design: Description of a new surgical technique and case report. Setting: Temporal bone disse ction laboratory and tertiary referral center. Patients: Adult and ped iatric cochlear implant (CI) recipients. Main Outcome Measures: Access for circum-modular drill-out and electrode insertion without radical mastoidectomy and adequate function of multichannel CI. Results: Disse ction of 10 cadaver temporal bones demonstrated feasibility of this te chnique. 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 carot id canal and use of facial nerve monitor, A case report of an 11-year- year old child with total cochlear ossification and previous failure o f a short (8 electrode) CI electrode insertion is presented. Complete insertion of a 22-channel electrode was successful and open-set word r ecognition is commencing. Conclusions: The canal wall-up drill-out pro cedure allows complete electrode insertion without mastoid obliteratio n in patients with obliterated cochleas. Appropriate attention to the carotid artery and facial nerve is essential.