Facial canal dehiscence in the initial operation for chronic otitis media without cholesteatoma

To evaluate the risk of the facial nerve injury during operations for chronic otitis media without cholesteatoma by analysis of the intraoperative findings of the facial canal dehiscence.

We retrospectively reviewed operative findings of 152 patients who underwent tympanoplasty with mastoidectomy for chronic otitis media. We examined every segment of the facial canal from the geniculate ganglion to the mastoid segment. Facial canal dehiscence was confirmed by palpation with a Rosen pick after inspection with a surgical microscope.

The rate of facial canal dehiscence was 8.6% (13 of 152 cases), and the tympanic segment was the most commonly found region at 84.6% (11 of 13 cases). Of the 11 cases of tympanic segment dehiscence, 9 cases were involved the lateral aspect of the facial canal in the oval window area. There was one case each of facial canal dehiscence in the geniculate ganglion and the mastoid segment, respectively.

The rate of facial canal dehiscence of 8.6% is not a low incidence rate, so even though performing a routine chronic ear operation, surgeons may encounter facial canal dehiscence at any time and should be prepared for the emergence of such a situation.