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Long-Term Outcomes of Free-Muscle Transfer for Smile Restoration in Adults

Background: The cross-facial nerve grafting/free-muscle transfer strategy for smile restoration is superior to static reconstruction or regional muscle transposition. The purpose of this study was to evaluate the long-term outcomes of this technique in adult patients. Methods: Eighty-one adult patients received a free-muscle transfer for midface reanimation in the authors’ center. Of this group, the authors identified 24 cases with follow-up of 5 years or longer. Smile symmetry and function were evaluated at three points: preoperatively, early postoperatively, and at long-term follow-up. To better evaluate the effect of time, patients were divided into groups according to the length of follow-up: group A, 5 to 6 years; group B, 7 to 10 years; group C, 11 to 15 years; and group D, more than 15 years. Four independent observers rated each patient’s smile using a five-category scale ranging from poor to excellent. Panelists were asked to comment on whether the patient’s smile weakened over time. Results: All patients obtained higher scores at 2 years from free-muscle transfer in comparison with their preoperative rates (p < 0.0001). Late outcomes demonstrated that muscle regeneration continues beyond the initial 2 years, with a further increase of the scores and motor units on electromyography at the late follow-up (p < 0.0001, p = 0.0313). No significance was found when comparing both variables among the four groups, indicating that time does not have a differential effect on muscle function. In 80 percent of the evaluations, the four observers agreed on maintained smile symmetry over time. Conclusions: Cross-facial nerve grafting/free-muscle transfer is an effective technique for smile restoration in late facial paralysis. These data indicate maintenance of effective muscle function and progressive improvement with time.