A Retrospective Study: Good Functional Outcomes are Independent of Pre-Operative Factors in Stapes Surgery for Otosclerosis

Context: Stapes surgery is the mainstay of treatment for otosclerosis. Reported success rates of stapes surgery for otosclerosis vary widely, ranging from 63.6% to 94%. The pre-operative prognostic factors of hearing outcomes after surgery are not well studied. Objective: To determine the hearing results after stapes surgery and analyze the prognostic role of pre-operative factors on hearing outcomes. Design: Retrospective study. Setting: Tertiary referral center. Patients: 90 cases of otosclerosis operated on in our institute from 2006 to 2016 were included into the study. Interventions: Stapes surgery was performed for 90 cases of otosclerosis (77 stapedotomies, 13 stapedectomies). Main outcome measures: Audiograms performed just before and six months after operation were used. We selected several pre-operative variables for analysis- age, gender, unilateral/bilateral disease, air (AC) and bone conduction (BC) thresholds, air-bone gap (ABG). Our outcomes measured were post-operative AC, ABG and percentage improvement in air-bone gap (ABGi). The associations between these pre-operative predictors and outcomes were then analyzed. Results: We report 80% (n=72) and 84.7% (n=76) of cases achieving ideal ABG (≤ 10 dB) and AC outcomes (gain in ≥ 20 dB), respectively. The mean post-operative ABG was 8.8 dB. The mean ABGi, was 78.8% with 78.9% (n=71) of cases attaining ideal ABGi (≥ 70%). Pre-operative variables did not significantly influence post-operative AC and ABG results. However, patients with larger pre-operative ABG (>30 dB) had greater ABGi (85.7 vs. 72.5%, p<0.001). Conclusion: Stapes surgery provides good and predictable results independent of disease severity or patient profile. Consequently, patients with larger hearing impairment are likely to benefit relatively more from surgery.