Int. Adv. Otol. 2011; 7(1) 35-40

Cochlear implantation in far advanced otosclerosis. A surgical, audiological and quality of life review of 35 cases in a single unit.
Edward P. Flook , Stephen J Broomfield, Iain A. Bruce, Kevin M. Green
ENT Registrar, Manchester  edflook@yahoo.com

Objective: This is a review of our experience of implanting patients with far advanced otosclerosis, specifically reviewing pre-operative predictors of differences in audiological outcome, complications (including facial nerve stimulation (FNS)) and patient satisfaction.

Materials and Methods: A retrospective case review including audiology assessments was undertaken.

Results: Thirty-five patients were identified as having far advanced otosclerosis from the Manchester Cochlear Implant programme database. Twenty-seven patients had good outcomes (PTA threshold mean of 39dB, AB phonemes mean of 67%, BKB mean of 80%, CUNY mean of 93%). The remaining 8 had reasonable PTA thresholds but poorer audiological test scores. Analysis of these 8 cases showed that incomplete electrode insertion and electrode “switch off”, to reduce FNS, are likely to have had the most effect. Six patients had FNS, all of which resolved with altered electrode mapping. Fourteen patients had implant devices with a straight, lateral wall lying electrode, and 6 (43%) of these had FNS.  None of the 21 patients implanted with a perimodiolar electrode had any FNS.

Conclusion: Results for cochlear implantation of patients with far advanced otosclerosis generally have good surgical success, good audiological outcomes and high satisfaction rates. Tinnitus is improved in most patients. The main factor leading to poorer outcome was in the use of only a limited number of electrode channels due to FNS or partial electrode insertion. Electrode design has a key role in facial nerve stimulation