Facial nerve canal dehiscence in chronic otitis media without cholesteatoma.

The information on incidence of the facial nerve canal dehiscence in chronic otitis media is important for surgeons. The purpose of this study is to disclose the histopathologic findings of facial nerve canal dehiscence in human temporal bones with chronic otitis media. We divided the human temporal bones into two groups (age 4 years, and under 4 years of age). We evaluated the incidence and the area of the facial nerve canal dehiscence in chronic otitis media under light microscopy. Age-matched normal control temporal bones were also examined. In the age group of 4 years, 68.9 % of temporal bones with chronic otitis media and 71.9 % of controls had the facial nerve canal dehiscence. There was no significant difference between them (P = 0.61). The area of the dehiscence in temporal bones with chronic otitis media was not statistically different from controls (P = 0.53). In the age group under 4 years, 88.2 % of temporal bones with chronic otitis media and 76.5 % of controls had the dehiscence. No significant difference was found between them (P = 0.66). The area of the dehiscence in temporal bones with chronic otitis media was not statistically different from controls in the age group under 4 years (P = 0.43). In chronic otitis media, the incidence of facial nerve canal dehiscence was high and was not statistically different from controls. These results suggest that there is no association between chronic otitis media and the presence of facial nerve canal dehiscence.