Abstract

OBJECTIVE: This study aims to evaluate the facial canal diameter and length and mastoid bone pneumatization on the affected side, compared to the contralateral side, in patients with unilateral Bell’s palsy (BP).

METHODS: Between January 2014 and November 2016, a total of 30 patients (16 males, 14 females; mean age 42.3±12.7 years; range, 18 to 65 years) who were admitted to our outpatient clinic with unilateral BP were retrospectively analyzed. The temporal bone computed tomography images of the patients were examined by multislice and three-dimensional (3D) reconstruction method and the facial canal diameters were measured in the mastoid segment, labyrinthine segment, and foramen stylomastoideum level in both temporal bones. The length of the facial canal was also measured along the mastoid segment. Using the 3D images, each mastoid cell volume was measured separately to calculate the total cell surface area and to identify the level of mastoid pneumatization.

RESULTS: The mean facial canal diameter was statistically significantly narrower in the mastoid segment, labyrinthine segment, and foramen stylomastoideum level on the affected side (p=0.001). The mean facial canal length was also statistically significantly longer along the mastoid segment on the affected side (p=0.043). There was no statistically significant difference in the level of mastoid bone pneumatization between the two sides (p=0.359).

CONCLUSION: Our study results suggest that the diameter of the facial canal is particularly relevant in BP etiology as a risk factor. The length of the facial canal course along the mastoid segment may be also considered a risk factor. However, there is no significant relationship between the mastoid pneumatization level and BP.