Indications for and outcomes of mastoid obliteration in cochlear implantation

Objective: To review the indications, efficacy, and long-term outcomes of mastoid obliteration in cochlear implant surgery. Study Design: Retrospective case review. Setting: Tertiary referral center. Patients: Seventeen patients who underwent a mastoid obliteration procedure to facilitate the insertion of a cochlear implant between 1978 and 2005. Intervention: Mastoid obliteration procedure before cochlear implantation. Main Outcome Measures: Revision rate of the mastoid obliteration and cochlear implantation, postoperative audiometric scores (consonant-nucleus-consonant words/phonemes, Central Institute for the Deaf sentences, City University New York sentences in quiet and in noise), and incidence of complications. Results: There were 17 patients with a median age of 60 years (range, 3-79 yr). Eight patients required mastoid obliteration for active chronic suppurative otitis media before cochlear implantation. Another 8 patients had existing mastoid cavities requiring obliteration (modified radical [n = 5] and fenestration cavities [n = 3]). A single patient with a sclerotic mastoid and an anterior sigmoid sinus underwent obliteration because of inadequate surgical access. The technique of obliteration was radical mastoidectomy with eustachian tube occlusion, blind sac closure of the external auditory canal, and cavity obliteration with either temporalis muscle flap (n = 15) or abdominal fat (n = 2). Cochlear implantation and mastoid obliteration were performed as a two-stage procedure in 10 patients and as a single-stage procedure in 7. Two patients required revision of the mastoid obliteration. At follow-up, all patients had stable obliterated cavities. Fifteen patients obtained significant improvement in speech discrimination scores, whereas 2 patients obtained some benefit from the cochlear implant through the perception of environmental sounds. Conclusion: For patients with chronic suppurative otitis media or existing mastoid cavities, the obliteration with temporalis muscle or abdominal fat is an effective technique to facilitate safe cochlear implantation.