[The incidence of facial nerve dehiscence at mastoidectomy and its risk factors].

Objective: To study the incidence and locations of facial nerve dehiscence (FND) in mastoidectomy for the patients with cholesteatoma and chronic otitis media, and to determine its relevance as pre-operative prediction.

Method: Three hundred and fifteen ears (217 ears with cholesteatoma and 98 with chronic otitis media) undergoing mastoidectomy with or without tympanoplasties were selected for retrospective study, in which the incidence and locations of FND was studied, and the relevance for FND were analyzed by univariate test following by multivariate stepwise logistic regression.

Result: The presence of FND was 22.9% of total surgical procedures and the locations of FND were 93.1% in the tympanic segment, which was significantly higher than in the mastoid segment. The factors as otogenic facial paralysis, pathologic style (cholesteatoma or chronic otitis media) and lateral semicircular canal (LSC) fistula were related to FND, while others factors as sex, age, revision operations, preoperative complications, dural exposure, sigmoid sinus exposure were not risk factors for FND.

Conclusion: The incidence of FND was 22.9% in this study, the most common location for FND was in the tympanic segment, therefore, the facial nerves should be especially taken care in mastoidectomy for patients with presence of otogenic facial paralysis, cholesteatoma and LSC fistula.