Labyrinthine fistulae caused by cholesteatoma. Improved bone conduction by treatment.

In five cases of labyrinthine fistulae caused by extensive cholesteatoma, more than 30-dB improvement in bone conduction was observed in four postoperative cases and in one case after preoperative administration of antibiotics. In each case, a fistula of more than 2 mm in length was present at the lateral semicircular canal, and membranous labyrinthine wall was exposed when the cholesteatoma membrane was removed. These five cases were considered to be in the stage of serous labyrinthitis. The experience with these cases shows that emergent antibiotic treatment and surgery are appropriate for cases with reduced bone conduction in which labyrinthine fistula caused by cholesteatoma is suspected. In addition, as the reduction of bone conduction does not necessarily preclude the possibility of good postoperative hearing, tympanoplasty may be appropriate even for cases with markedly reduced bone conduction due to labyrinthine fistulae.