Middle ear and mastoid obliteration for cochlear implant in adults: indications and anatomical results.

Abstract

To review indications, anatomical results, and complications of cochlear implant (CI) surgery in adults for which middle ear and mastoid obliterations were performed. Thirty cases (26 patients, 4 bilaterally implanted) of 837 CI surgeries (3.5%) performed between January 2009 and December 2013 have been included in this retrospective study. The mean follow-up was 21 ± 18 months (mean ± SD, range 3-58). There were 11 males and 15 females. The mean age was 59 ± 19 years (range 35-82). All surgeries were performed with a single-stage technique including a canal wall down mastoidectomy with external auditory canal closure and mastoid obliteration with fat. A postoperative CT scan was performed in all cases. Etiologies of hearing loss were mainly chronic otitis with or without cholesteatoma in 24 cases. Other etiologies were meningitis with cochlear ossification in one case, progressive hearing loss in two cases, enlarged vestibular aqueduct in one case, temporal bone fracture with CSF leak in one case, and congenital aural atresia in one case. Four of those 30 cases were revision CI surgery for electrode array misplacement (one case with cochlear ossification) or extrusion from an open cavity (one case) and recurrent cholesteatomas (two cases). All surgeries were uneventful and performed in a single stage. The electrode array was inserted in the basal turn (29 cases) or in the middle turn (one case) of the cochlea. No complications were observed. Two cases of postoperative abdominal hematoma were drained under local anesthesia. A major failure of the CI device occurred 5 months after surgery. CI with mastoid and middle ear obliteration is a safe and effective technique for selected cases of cochlear implantation. Mastoid obliteration prevents from recurrent disease and lowering the facial ridge allows more space to manage extensive cochlear ossification or malformation.