Smile Asymmetry and Eyelid Closure Following Temporalis Muscle Transfer for Facial Reanimation: A Systematic Review and Meta-Analysis.

Abstract

To evaluate temporalis muscle transfer (TMT) in restoring smile and eyelid outcomes in patients with facial nerve paralysis (FNP), emphasizing surgical techniques and clinician-graded outcomes. MEDLINE (Ovid), Embase (Ovid), CINAHL, and Web of Science were searched from inception to December 19, 2025. Two independent reviewers completed screening and data extraction. Planned primary outcomes included reduction in smile asymmetry, improvement in oral commissure displacement, and reduction in lagophthalmos, assessed using objective measurements or clinician-graded outcome scales. Secondary outcomes were surgical techniques and complications. Risk of bias was assessed using the Joanna Briggs Institute Checklist and the Newcastle-Ottawa Scale. This review protocol was not registered on PROSPERO. Fifty-three studies (n = 1354) were included. Temporalis muscle transfer significantly reduced smile asymmetry (mean difference [MD]: 9.61 mm; 95% CI 7.16-12.06), improved oral commissure displacement (MD: 7.30 mm; 95% CI 5.92-8.68), and reduced lagophthalmos (MD: 5.62 mm; 95% CI 4.71-6.53). Orthodromic temporalis transfer with multi-point fixation was the most common surgical technique in 31 studies, with the emergence of minimally invasive, intra-oral approaches in recent literature. A balanced smile was achieved in 71% of cases and complete eyelid closure in 56%. Complications (n = 161) included infections, hematomas, flap issues, and aesthetic deformities. TMT can provide dual eyelid and smile improvement in a single-stage procedure. As the surgical landscape continues to evolve, future research should standardize clinician graded outcome measures and assess long-term results to improve patient-centered care.