Evaluating Outcomes of Selective Myectomy of Depressor Anguli Oris, Buccinator and Platysma in Facial Synkinesis

Introduction: Selective myectomy has gained popularity for treating facial synkinesis. Objectives & Hypotheses: We examined the combined effectiveness of depressor anguli oris (DAO), partial buccinator, and platysma myectomies. Study Design: Retrospective case series. Methods: Pre- and post-operative botulinum toxin-A (BTX-A) treatments of selective myectomy patients were collected. Facial photographs were analyzed using Emotrics+. Facial Asymmetry Index (FAI) and electronic facial paralysis assessment (eFACE) scores were calculated. Results: Twenty patients underwent myectomies. Improvements (mean ± standard error) were seen in several smile metrics, including FAI by 2.80 mm ± 0.68, nasolabial fold angle by 4.78° ± 1.83, and smile angle by 4.43° ± 1.18 (all p<0.05). Postoperative FAI was 2.79 mm. Total BTX-A decreased by 10.85 units ± 4.48 (p=0.03). eFACE revealed improved oral commissure movement and platysmal synkinesis (p<0.05 for both). Conclusions: Combined myectomies of the DAO, partial buccinator, and platysma clinically and statistically improve smile in facial synkinesis.