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Hearing preservation in patients with labyrinthine fistulae.

INTRODUCTION
Labyrinthine fistula is the most common complication of chronic middle ear disease with cholesteatoma. We present a series of cases of labyrinthine fistula found during the surgical procedures carried out for cholesteatoma in a district hospital setting, over 11-year period.


MATERIALS AND METHODS
This is retrospective study based on case notes and author's database for the period of 1987 to 1999. During this period 382 operations were performed and 25 (6.54%) patients found to have labyrinthine fistulae. We looked at the incidence, clinical presentation, surgical technique and hearing outcomes. A standard fistula classification system has been used in order to compare the pre and post-operative hearing.


RESULTS
Records were available in 22 cases, which were 12 men, and 10 women with mean age of 45.2 years at presentation. Only one-third had presented with vertigo. Lateral semicircular canal was the most affected site (95%). Fistulae classified as types: I = 8 (36.3%), II-a = 1 (4.5%), II-b = 5 (22.9%) and III = 8 (36.3%). All patients had a standard open technique mastoidectomy. In 5 ears the hearing was lost pre-operatively (1 type II-b and 4 type III fistulae), and in remaining 17 the bone conduction thresholds remained unchanged in 15 (88 per cent) ears. Two dead ears directly related to the surgery and both were of type III fistula.


CONCLUSIONS
One-staged mastoid surgery can be the treatment of choice in these cases. Meticulous surgical technique with adequate sealing of the fistula helps to preserve the hearing. An appropriate classification system is an essential tool in presentation and comparison of results.