Success rate in revision stapes surgery for otosclerosis

Objective: The aim of this study was to evaluate the hearing results of revision stapes surgery performed because of previously failed operations and to determine the causes of failure. Study Design: Retrospective review of revision stapes operations. Setting: Tertiary referral center. Patients: Sixty-three consecutive revision stapes operations were performed in 56 patients over a period of 12 years (19922004). The indication for revision surgery was recurrent or persistent air-bone gap greater than 20 dB after primary surgical treatment of otosclerosis of the oval window. Results: All patients were operated on to improve hearing. Sixty-three revision stapes operations resulted in closure of the air-bone gap to 10 dB or less in 52.4% of cases. The average postoperative air-bone gap was 13.1 dB, and the mean pure-tone average improvement was 12.9 dB. In six patients (9.5%), revision surgery produced no change in hearing, and in four (6.3%) the hearing decreased by 5 dB or more. In one patient, the operation resulted in a profound hearing loss. Prosthesis malfunction was the most common primary cause of failure (60.3%). The original prosthesis was replaced with a new one in 48 cases. In 30 of these (62.5%), closure of the air-bone gap to within 10 dB was achieved. In 15 cases, the prosthesis was not replaced, and in only four of these (26.7%), closure of the air-bone gap within 10 dB was obtained (p < 0.022). Conclusion: Revision stapes surgery is less likely to be successful than the primary operation. Closure of the air-bone gap to within 10 dB was achieved in 52.4% of patients. The success rate was better in cases where the original prosthesis was replaced with a new one. The risk for decreased bone-conduction threshold does not seem to be higher than in primary surgery.