Sensorineural Hearing Loss Following Stapedectomy

Abstract

Profound sensorineural hearing losses have occurred in 20 of 750 stapedecto-mies for an incidence of 2.66 %. Nineteen of the 20 losses can be related to surgical technique. Eleven of the losses are probably related to extensive drilling of bony growth, other factors being previous traumatic mobilization, hemorrhage and instrumental trauma. Surgical exploration performed on five ears following sensorineural hearing losses after stapedectomy revealed in one an excessively long prosthesis and, in four, fibrous tissue proliferation in the oval window and vestibule associated with resorption of the free graft. This reaction is identical with the serofibrinous type of labyrinthitis which is readily produced in animals by trauma or by creating a perilymphatic fistula in the oval or round window. The five types of inner ear reaction to traumatic stapes surgery are: hyd-rops, hypotonic atrophy, acoustic trauma, serofibrinous labyrinthitis and suppurative labyrinthitis. A set of human temporal bones acquired from a patient with ot osclerosis revealed secondary atrophic changes in the membranous labyrinth. It is possible that these alterations create a fragility which predisposes the cochlea to surgical injury. Most of the sensorineural hearing losses following stapedectomy appear related to surgical factors which probably can be controlled.