Facial canal dehiscence rate: a retrospective analysis of 372 chronic otitis media cases.

Purpose: This study aimed to investigate the rate and location of facial canal dehiscence (FCD) observed during surgery for chronic otitis media (COM) with or without cholesteatoma.
Material and Method: Operative details of 1296 patients who underwent chronic otitis media surgery from January 2000 to January 2017 by the same surgeon were included in this retrospective study focusing on intraoperative observations of FCD.
Results: Because of the type of the surgery, the Fallopian canal could not be seen completely, so 924 of the cases which only involved performing a tympanoplasty were not included in the study. A total of 372 patients (196 males and 176 females) who had a canal wall down (CWD) or canal wall up (CWU) mastoidectomy were included in the study. A CWD mastoidectomy was performed on 250 patients, while 122 patients underwent a CWU mastoidectomy. The prevalence of FCD was 11.29% (42/372 patients). The dehiscence was more common in patients with cholesteatoma (n = 37; 88.1%) than those with non-cholesteatoma (n = 5; 11.9%). The tympanic segment (n = 32; 76.19%) was the most common location for FCD. When we compared the ossicular erosion results of the cases that had FCD, erosion in three ossicles together was more statistically significantly frequent than the other possibilities.
Conclusion: It is possible to see FCD because of COM, especially with cholesteatoma. FCD is most commonly seen around the oval window. If stapes or all three ossicles are eroded, the surgeons must be more careful regarding FCD to be more effective in preventing facial nerve damage.