Free Muscle Flap Transfer for Facial Reanimation: A Systematic Review and Meta-Analysis.

[OBJECTIVE] To summarize different types of free muscle flap transfer for facial reanimation and to provide a comprehensive evaluation of the outcomes.

[DATA SOURCES] PubMed, Web of Science, and EMBASE.

[REVIEW METHODS] Retrospective studies evaluating the surgical outcomes with proper objective or subjective methods beyond clinical observation were included. Data on surgical information, facial nerve function on the paralyzed side, facial symmetry, overall facial movement and coordination, and quality of life were collected or calculated.

[RESULTS] A total of 48 studies were included in the systematic review, and 24 studies were included in the meta-analysis. There were 1747 patients who underwent 1930 free muscle flap transfers in total. Seven types of muscle flaps and six types of innervations were recorded. Postoperative and preoperative comparisons showed statistically significant improvement in all four aspects: facial nerve function on the paralyzed side, facial symmetry, overall facial movement and coordination, and quality of life. However, postoperative evaluation showed that although favorable overall facial movement and coordination were achieved in 80.30% of the flaps, the difference between the normal side and the paralyzed side was still statistically significant. Masseteric nerve innervation was the most commonly adopted innervation and showed the best outcomes, although the differences were not statistically significant.

[CONCLUSION] Despite the postoperative bilateral difference in facial nerve function, free muscle flap transfer is a reliable and effective treatment for facial paralysis. The study supported masseteric nerve innervation and highlighted the importance of flap selection based on the anatomical advantages of muscles and the specific needs of patients.