The prevalence of facial canal dehiscence: first cross-sectional study in Iraq

The facial nerve is considered a crucial structure and is vulnerable to injury during middle ear and mastoid surgery. The facial canal could be dehiscent in certain populations; therefore, identifying it and avoiding injury to the nerve is an important step during otological surgeries. In this study, we assessed the rate of facial canal dehiscence (FCD) among patients undergoing surgery due to the presence of chronic suppurative otitis media (CSOM). A cross-sectional study was performed between June 2019 and May 2023. We included 102 patients (aged 8–70 years), admitted for primary tympanomastoid exploration due to the presence of CSOM with and without cholesteatoma at Azadi Teaching Hospital in Duhok/Iraq. Cases with a history of trauma or craniofacial abnormalities were excluded from the study. Also, none of the selected patients complained of facial nerve disorders. Among the 102 patients who were admitted, 11.76% (n = 12) had FCD; they were between the ages of 11 and 58 (average: 30.9) years (18.8% ≤ 18 years vs. 10.5% > 18 years, p = 0.396). The dehiscence was more common in males than females (14.3% vs. 10.0%, p = 0.545) and was also more common on the left side than the right side (13.8% vs. 9.1%, p = 0.547). Of those with the dehiscent facial nerve, 83% (n = 10) had the dehiscence on the tympanic segment. The dehiscence was statistically more common in patients with cholesteatoma than those without (25.9% vs. 6.7%, p = 0.014). Dehiscence in the facial nerve can be encountered in patients with CSOM, particularly those with cholesteatoma. In such patients, the dehiscence is most commonly found on the tympanic segment of the facial nerve, so care should be taken during surgery for such cases to avoid injury of the nerve.