Risk factors for deterioration of bone conduction hearing in cases of labyrinthine fistula caused by middle ear cholesteatoma.

OBJECTIVES

We evaluated the risk factors and outcomes of bone conduction (BC) hearing in cases of labyrinthine fistulas treated under the basic principle of complete removal of the cholesteatoma matrix.

METHODS

A total of 47 patients with labyrinthine fistulas were analyzed. The fistulas were classified into smaller (no more than 3 mm) and larger fistulas (more than 3 mm). The fistulas were classified by depth into 3 stages. Preoperative symptoms and postoperative results with special reference to BC hearing were analyzed.

RESULTS

Total preoperative loss of BC hearing was found in 3 of 36 ears (9%) in the smaller-fistula group and 4 of 11 ears (36%) in the larger-fistula group; this was a statistically significant difference. The BC hearing was preserved after operation in 30 of 31 ears (97%) in the smaller-fistula group and 5 of 7 ears (71%) in the larger-fistula group; this difference was also significant. The stage (depth) of the fistula did not correlate with the postoperative BC hearing.

CONCLUSIONS

In smaller labyrinthine fistulas, complete removal of the cholesteatoma matrix can be relatively safely performed. However, in patients with larger fistulas, there is a potential for a complete loss of BC hearing.