Comparison of Outcomes of Smile Reanimation Between Dual- Versus Single-Innervation Technique in Single-Stage Latissimus Dorsi Neuromuscular Transfer in Facial Paralysis Patients

Background: Although a dual-innervation technique has emerged in single-stage functional latissimus dorsi (LD) muscle transfer for smile reanimation, its benefits over conventional techniques have not been elucidated.Objective: To compare outcomes of dual-innervation technique with those of single-innervation.Methods: Patients with facial palsy treated with single-stage functional LD muscle transfer were identified, and categorized into two groups: single and dual innervation. Outcomes were assessed using clinical examination based on the Terzis grading system and using automated software (Emotrics).Results: Fifty-nine patients (mean age 37.6 years; male/female 30/29) were analyzed, including 40 in single (35.1 years, 23/17) and 19 in dual-innervation group (43.0 years, 7/12), with a median follow-up of 34 months (range, 9-165) (single: 41.5, 12-165, dual: 23.0, 9-41). Tumor-related paralysis was the most common etiology in both groups (overall: 45.8%, single: 40.0%, dual: 57.9%). The dual group had a significantly higher rate of cases with Terzis grade IV or V postoperatively. In the Emotrics-based evaluation, the dual group exhibited significantly enhanced improvements in smile excursion in the dynamic state compared with the single. The degree of improvement in the resting state did not differ between groups.Conclusion: The dual-innervation technique might provide promising results in achieving enhanced smile excursion.