ObjectiveFacial paralysis can occur after surgery for cholesteatoma. The risk of facial nerve injury is great when the nerve is not covered by its normal bony Fallopian canal. The objective of this study was to identify the incidence of facial nerve dehiscence in patients undergoing surgery for cholesteatoma.Study DesignRetrospective chart review.SettingTertiary referral hospital.Patient PopulationAn assessment of all cases performed by the senior author from 1991 to 1999 revealed 59 patients with adequate data available for analysis. These patients ranged in age from 3 to 92 years. In all, 67 surgical procedures.InterventionSurgery for cholesteatoma, including tympanoplasty and mastoidectomy.Main Outcome MeasureThe presence of facial nerve bony dehiscence after exenteration of disease, and postoperative facial nerve function.ResultsIn 33% of the total procedures analyzed, 30% of the initial procedures, and 35% of the revision procedures, the patients were found to have facial nerve bony dehiscence. The dehiscence was present in the tympanic portion of the facial nerve in the vast majority of patients. Of the 97% of patients with normal preoperative facial nerve function, all retained normal function postoperatively.ConclusionsFacial nerve dehiscence in our series was far greater than that reported in the literature, underscoring the fact that this is an under-appreciated condition. These findings suggest that surgeons should be highly vigilant when dissecting near the facial nerve. Intraoperative facial nerve monitoring has been shown to be of value in facial nerve preservation during acoustic neuroma resections, and may have a role during surgery for cholesteatoma.