Title: Labyrinthine Fistula during Chronic Ear Surgery.
Abstract: Twenty cases of labyrinthine fistula have been reviewed. From 1988 to 1993, surgery was performed on 384 ears with chronic otitis media, and 20 of these cases had a labyrinthine fistula (incidence 5.2%). All twenty cases had a lateral semicircular canal fistula and one case had an additional superior semicircular canal fistula. There was no relationship between the size of the labyrinthine fistula and the incidence of vertigo or fistula symptoms. Also there was no relationship between the size of the labyrinthine fistula and preoperative bone conduction thresholds. All twenty cases were characterized by chronic otitis media with cholesteatoma, and the matrix of the cholesteatoma was completely removed in all patients with the exception one case where the cholesteatoma was enormous. Preoperative bone conduction hearing was preserved after removal of the cholesteatoma matrix in all cases except the latter.These results suggest that lesions over the lateral semicircular canal fistula should be completely removed, at best with care, when they are discovered during chronic ear surgery. This policy rarely causes lateral semicircular canal fistula bone conduction hearing to become worse.