Reanimation of the Lower Lip with the Anterior Belly of Digastric Transfer: A Systematic Review.

Dynamic reanimation of the lower lip is a challenging issue for patients, with depressor asymmetry commonly addressed with chemodenervation, selective neurectomy, or myectomy. To determine whether the anterior belly of digastric transfer is an effective method of lower-lip reanimation for patients with either isolated marginal mandibular branch weakness or inadequate depressor function after hemifacial reanimation, as measured by patient satisfaction and objective symmetry evaluation. Systematic review of the literature was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Abstracts and full texts were reviewed. A Risk of Bias assessment was performed. Nine studies with 164 patients were included. Anterior belly of digastric transfer was successfully performed in 162 patients. Most patients (52%) underwent one-staged reanimation innervated by the native nerve to the mylohyoid. A two-staged approach after placement of a cross face nerve graft was performed in 46%. Patient satisfaction was excellent (90.6%), with minimal complications including revision (4/162), infection (4/162), and lipofilling (8/162). In patients seeking a permanent outcome, use of an anterior belly of digastric transfer in either a one-stage or two-stage approach appears to be a safe and effective method to restore symmetry and dynamic function.