Deep Dive into Denervation: Institutional Experience with Selective Denervation in Nonflaccid Facial Palsy

Background: Selective denervation of facial nerve branches ("Modified Selective Neurectomy") improves smile dynamics in patients with nonflaccid facial palsy, but functional morbidity such as oral incompetence has been reported. A comprehensive outcomes assessment of selective denervation will help clinicians educate patients regarding risks and benefits, and improve decision making as they incorporate this procedure into treatment algorithms. Methods: Retrospective review identified selective denervation cases performed by the senior author between February 2019 and February 2020. Pre- and postoperative outcomes were assessed using chart review, the facial clinimetric evaluation (FaCE), the electronic clinician-graded facial function tool (eFACE), and an automated computer-aided facial assessment tool (Emotrics). Results: Twenty consecutive selective denervation procedures were performed in 19 patients. Review of patient-reported outcome measures demonstrated mixed results. Favorably, patients reported smile improvement (13/17, 76.5%) and improvements in facial tightness/discomfort (8/17, 47.1%). Seven patients (41.2%) had worse drooling and five patients (29.4%) had increased difficulty chewing after surgery. Clinician-graded evaluation revealed statistically significant improvements in nasolabial fold depth at rest, oral commissure (OC) position at rest, and OC movement with smile. Total, static, and dynamic eFACE scores all demonstrated significant improvements. Computer-aided facial assessment revealed a significant increase in dental display, and an increase in OC excursion that trended toward significance. Conclusions: Selective denervation improves patient-reported, clinician-graded, and automated smile metrics, but some patients experience exacerbations in oral incompetence and articulation difficulties, and must be counseled regarding these possibilities.