Structural Phenotype of High-Frequency Recurrent Facial Palsy.

Abstract

High-frequency recurrence of peripheral facial palsy suggests an underlying structural predisposition. We aimed to identify the anatomical phenotype associated with ≥ 3 recurrences using high-resolution CT (HRCT). We retrospectively analyzed 63 patients with high-frequency recurrence (mean 3.5 episodes) and 62 normal controls. Four HRCT parameters were quantified: geniculate ganglion (GG) enlargement, labyrinthine segment (LS) constriction, intracanalicular bony exostosis, and greater superficial petrosal nerve (GSPN) thickening. Inter-parameter correlations were also evaluated. The mean age at the first attack was young (22.1 years). Intracanalicular bony exostosis was identified as the most potent predictor of recurrence (39.7% vs. 9.7%; OR: 7.39, p < 0.001). GG enlargement and GSPN thickening were significantly more prevalent in the recurrent group (p < 0.01) and showed a strong positive correlation (ρ = 0.58, p < 0.001), supporting a retrograde inflammatory spread mechanism. Overall, 63.5% of the recurrent group exhibited at least one structural or secondary finding (p < 0.001). High-frequency recurrent facial palsy is associated with a structural phenotype, where fixed bony constraints like exostosis exacerbate chronic secondary inflammatory changes in the GG and GSPN. Recognizing these features on HRCT may help predict individuals at risk for recurrence and assist in planning targeted surgical decompression.