A Comprehensive Radioanatomical Analysis of the Facial Nerve Canal

To conduct a detailed radioanatomical assessment of the facial nerve or fallopian canal (FNC or FC) in a Greek adult population, focusing on segmental morphometry, prevalence of bony dehiscence, and morphologic variations with clinical significance.

Fifty temporal bone computed tomography (CT) scans (100 sides) were retrospectively evaluated using Horos software. Measurements included the length and width of the labyrinthine, tympanic, and mastoid segments of the FNC, as well as the prevalence of bony dehiscence and jugular bulb (JB) contact. Statistical comparisons were made between sexes using standard tests.

The tympanic segment exhibited the highest dehiscence rate (68%), followed by the mastoid segment (18%) and the labyrinthine segment (8%). Sexual dimorphism was observed in the segment lengths of the tympanic and mastoid portions ( P <0.001). JB contact with the FNC was identified in 3% of cases. No significant differences in dehiscence prevalence were found between sexes.

The high occurrence of tympanic segment dehiscence observed in this study highlights its vulnerability during middle ear and skull base surgeries. This segment should be prioritized in preoperative imaging assessments. Anatomic variations, such as contact between the FNC and the JB, although rare, present additional surgical risks and should be identified during surgical planning. Sex-based differences in segment length emphasize the need for personalized approaches in otologic procedures. High-resolution CT imaging is essential for detecting dehiscence, segmental variations, and reducing intraoperative risks. Routine use of advanced imaging is recommended for diagnosing and managing the FNC surgically.