Does the Diameter of the Stapes Prosthesis Really Matter? A Prospective Clinical Study

Objectives/Hypothesis: To evaluate the influence of the diameter of stapes prosthesis on functional outcomes in stapes surgery. Study Design: Prospective cohort study. Methods: Fifty consecutive small fenestra stapedotomies performed using a 0.4-mm-diameter prosthesis were compared with 50 consecutive small fenestra stapedotomies carried out using a 0.6-mm-diameter piston. Audiological assessment following the recommendations of the Committee on Hearing and Equilibrium was performed 1 month after surgery. Postoperative complications between the two groups were noted. Results: There were no statistically significant differences in demographic data between the two groups, and no differences in preoperative bone-conduction (BC) or air-conduction (AC) hearing thresholds for all frequencies (analysis of variance [ANOVA] and chi(2) tests). No differences were found in the mean preoperative BC and AC pure-tone average and air-bone gap (ABG). In the postoperative evaluation, a statistically significant difference was found for the mean AC gain (20 +/- 8.7 vs. 24 +/- 11.5, P = .042, ANOVA) as well as for the postoperative AC threshold at 0.125 and 0.25 kHz and the postoperative BC threshold at 0.25 kHz (P < .01, ANOVA). A postoperative ABG <= 10 dB was obtained in 90% and 94% of patients in the 0.4-mm- and 0.6-mm-diameter piston groups, respectively (difference not significant, chi(2) test). No postoperative dead ear and/or sensorineural hearing loss was noted in either group. Conclusions: The 0.6-mm piston allowed a statistically significant higher AC gain compared with the 0.4-mm diameter piston. A larger diameter piston may be preferable if there are no anatomical or technical reasons that would favor a smaller prosthesis.