Cochlear otosclerosis: does bone formation affect cochlear implant surgery?

This study aimed to demonstrate that new bone formation in the scala tympani of patients deaf from otosclerosis does not preclude cochlear implant surgery. In seven temporal bones from patients with otosclerosis, we measured the extent of new bone from the round window to the distal part of the new growth. We compared results to surgical data on the extent of drilling and depth and ease of placement of the electrode in 20 patients deaf from otosclerosis. We also examined clinical performance and voltage requirements for long-term implant use in patients with and patients without ossification of the scala tympani. Findings in our limited sample of patients and bones show that obstruction of the basal turn, which occurs in some otosclerotic patients, does not preclude implant surgery. The dynamic range in the studied sample was relatively stable long-term and clinical performance did not differ between groups with and without an ossified scala tympani.