S George Lesinski1. 1. Otology Associates, Inc, Midwest Ear Foundation, 10550 Montgomery Road, Suite 34, Cincinnati, OH 45242, U.S.A.
Abstract
OBJECTIVE: To analyze the causes for residual or recurrent conductive hearing loss following stapedectomy or stapedotomy and then propose surgical techniques to avoid these complications. STUDY DESIGN: Prospective study of 279 consecutive stapedectomy or stapedotomy revisions performed by the author. SETTING: Tertiary referral center. PATIENTS: The study included 260 patients who presented with a 20 dB or greater average air-bone gap in the speech frequencies 1 month to 35 years following stapedectomy or stapedotomy (19 patients were explored for possible oval window perilymph fistula). INTERVENTION: Stapedectomy (stapedotomy) surgical revision. MAIN OUTCOME MEASURES: Microscopic inspection and palpation assessed the mobility and continuity of the malleus, incus, and prosthesis. Infrared laser vaporization thinned the oval window neomembrane to identify the precise depth and margins of the oval window, the presence of residual stapes footplate, and finally, the relationship of the prosthesis to the fenestra into the vestibule. RESULTS: Prosthesis displacement out of the oval window fenestration with fixation of the prosthesis against the residual stapes footplate or otic capsule margin was demonstrated in 81% (211/260) of the patients. Of these patients, 31% had complete incus erosion, and an additional 60% demonstrated partial incus erosion, usually on the undersurface of the incus. Residual fixed stapes footplate was found in 14%, and malleus fixation in 4%. Incus dislocation was found in 4%, and incus fixation in 2%. CONCLUSIONS: Prosthesis migration and subsequent fixation caused the majority of stapedectomy failures. Collagen contracture of the oval window neomembrane lifts the prosthesis out of the oval window fenestration. Prosthesis displacement then results from adhesions pulling the prosthesis or mechanical forces further tilting the prosthesis. Incus erosion results from vibration against the fixed prosthesis. Six specific stapedotomy recommendations are made to minimize postoperative prosthesis migration.
OBJECTIVE: To analyze the causes for residual or recurrent conductive hearing loss following stapedectomy or stapedotomy and then propose surgical techniques to avoid these complications. STUDY DESIGN: Prospective study of 279 consecutive stapedectomy or stapedotomy revisions performed by the author. SETTING: Tertiary referral center. PATIENTS: The study included 260 patients who presented with a 20 dB or greater average air-bone gap in the speech frequencies 1 month to 35 years following stapedectomy or stapedotomy (19 patients were explored for possible oval window perilymph fistula). INTERVENTION: Stapedectomy (stapedotomy) surgical revision. MAIN OUTCOME MEASURES: Microscopic inspection and palpation assessed the mobility and continuity of the malleus, incus, and prosthesis. Infrared laser vaporization thinned the oval window neomembrane to identify the precise depth and margins of the oval window, the presence of residual stapes footplate, and finally, the relationship of the prosthesis to the fenestra into the vestibule. RESULTS: Prosthesis displacement out of the oval window fenestration with fixation of the prosthesis against the residual stapes footplate or otic capsule margin was demonstrated in 81% (211/260) of the patients. Of these patients, 31% had complete incus erosion, and an additional 60% demonstrated partial incus erosion, usually on the undersurface of the incus. Residual fixed stapes footplate was found in 14%, and malleus fixation in 4%. Incus dislocation was found in 4%, and incus fixation in 2%. CONCLUSIONS: Prosthesis migration and subsequent fixation caused the majority of stapedectomy failures. Collagen contracture of the oval window neomembrane lifts the prosthesis out of the oval window fenestration. Prosthesis displacement then results from adhesions pulling the prosthesis or mechanical forces further tilting the prosthesis. Incus erosion results from vibration against the fixed prosthesis. Six specific stapedotomy recommendations are made to minimize postoperative prosthesis migration.