Predictors of Facial Synkinesis Severity.

Background: There is a lack of studies exploring factors influencing synkinesis severity. This study aims to identify factors that may contribute to variations in severity of facial synkinesis.

Methods: Patients with a diagnosis of facial synkinesis presenting between 2009 and 2024 were reviewed. The synkinesis score of the eFACE Facial Nerve Clinician-Graded Scale was analyzed for associations with patient characteristics and facial palsy history using univariable and multivariable analysis.

Results: Two-hundred-forty-nine synkinesis patients were included in the study. The etiology of facial palsy was infectious or idiopathic in 185 patients (74%), tumor resection in 40 patients (16%), trauma in 17 patients (7%), and compression of the facial nerve by a benign tumor in seven patients (3%). Factors independently associated with more severe synkinesis scores included age of facial palsy onset over 50 years (-7.4, 95% CI, [-10.9, -3.9]; p < 0.001), diabetes (-8.6, 95% CI, [-14.9, -2.3]; p = 0.007), smoking (-4.9; 95% CI, [-8.0, -1.8]; p = 0.003), and intratemporal facial nerve injury (-19.4; 95% CI, [-27.8, -10.8]; p < 0.001). Other variables including sex, race, hypertension, and etiology were not found to be independently associated with synkinesis severity.

Conclusions: Older age at facial palsy onset, diabetes, smoking, and intratemporal facial nerve injury were found to be independently associated with more severe synkinesis. These findings are novel and may aid in prognostication and treatment selection.