Cochlear implantation in cochlear otosclerosis

The objective was to correlate implant performance in cochlear otosclerosis to 1) matched control samples, 2) severity of otic capsule involvement, 3) prior ipsilateral surgery, and 4) programming issues.

Retrospective case controlled study.

Study cohort comprised 30 individuals. Diagnosis was based on prior ear surgery (stapedectomy [n = 18] or fenestration [n = 2]) and/or pathognomonic radiological findings. High-resolution computed tomography images of the temporal bones were assessed by two radiologists and graded (range, 0-3) for the extent of otosclerosis. Operative records were reviewed. Performance, programming visits, and the number of electrode deactivations at 6 months and at 1 year after implantation were determined for the individuals with otosclerosis and compared with a group of matched control subjects. A within-group comparison correlating severity of otosclerosis to the above was carried out.

Implant performance in individuals with cochlear otosclerosis was not significantly different from those without. Previous surgery on the side of implantation did not alter performance. Programming difficulty as reflected in the number of visits and electrode deactivation for sound quality reasons were comparable. Deactivation for facial nerve stimulation occurred exclusively in otosclerotics with the most severe radiological disease (grade 3) and was only with non-modiolar hugging electrodes (n = 5). There was no observed difference between the radiological extent of otosclerosis and implant performance.

Individuals with severe otosclerosis considering cochlear implantation can be counseled to expect similar benefit to those without, regardless of whether prior surgery occurred on the side of implantation or of severity of otic capsule involvement. There is a significant risk of facial nerve stimulation in otosclerotics with grade 3 disease.