Background: Synkinetic dysfunction of the Depressor Anguli Oris (DAO) and Mentalis muscle (MM) in conjunction with a weak Depressor Labii Inferiors (DLI) produces a characteristic deformity in the perioral region. Chemodenervation, myectomy and facial nerve neurectomy have been utilized to treat this imbalance with varying degrees of success. This study explores the value of highly selective Mentalis denervation combined with transfer of the hypertonic DAO to the hypotonic DLI for improving facial symmetry. Methods: A retrospective review of ten patients treated with a DAO-DLI transfer and mentalis denervation was undertaken. Still preoperative and postoperative photographs were evaluated utilizing a facial landmark detection system (Emotrics) and direct photographic measurement utilizing an iris calibrated technique. Results: An average improvement of 3.7 mm of lower lip depression was identified (p value 0.001). Additionally, a statistically significant improvement in smile angle and dental show (p value < 0.05) was also encountered along with a positive trend in commissure height deviation. Conclusion: This early experience suggests that DAO-DLI muscle transfer in conjunction with highly selective denervation of the mentalis muscle can have a positive effect in the treatment of labio-mental synkinesis.
Klebuc et al. (Fri,) studied this question.