Objective: This study aimed to investigate the clinical application and efficacy of local injection of botulinum toxin A (BTX-A) at the depressor anguli oris in patients with congenital drooping mouth corner.
Methods: From September 2013 to March 2015, 36 cosmetic patients received local injections of botulinum toxin A at the depressor anguli oris, with 1-3 injection sites in the moving region of the depressor anguli oris on each side. At each injection site, 2-4 U of BTX-A was injected, and the total dose for any unilateral treatment did not exceed 8 U. The change in the degree of drooping of the mouth corner before and after the injection was analyzed using statistical methods. The clinical efficacy, preservation time, and adverse reactions were observed.
Results: The degree of drooping of the mouth corners of the cosmetic patients before the treatment was compared with that at 1 month after using a paired t test, and the difference was statistically significant, with P < 0.01. The treatment results were satisfactory, and the effect was preserved for 6-9 months. None of the 36 cosmetic patients had any complications of bruising, infection, dysfunction in opening and closing the mouth, smile asymmetry, drooling, or dysarthria after the injection.
Conclusions: The local injection of BTX-A at the depressor anguli oris can effectively lift a drooping mouth corner, thereby improving the depressed, stern, and aged appearance of the face. The performance of this treatment is simple, safe, and easy to perform in clinical applications.
Level of evidence v: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
Keywords: Botulinum toxin A; Congenital drooping mouth corner; Depressor anguli oris.