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Updated: Aug 7, 2026
Ultrasound-guided Botulinum Toxin-A Injections: A Method of Treating Sialorrhea
Published on: November 9, 2016
"Optimizing Injection Sites of Botulinum Toxin Type A for Improving Oral Commissure Position: A Two-Stage,
Mengyuan Zhang1,2, Yuyan Yang1,2, Nan Zhao3
1Department of Plastic and Aesthetic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China.
Background:
Drooping oral commissures can impart a displeased appearance, negatively affecting psychosocial interactions and well-being. Botulinum toxin type A (BTX-A) is an efficacious treatment for mouth corner lift. However, the optimal injection strategy is controversial. Therefore, this study aims to compare the efficacy and safety of BTX-A injection at different sites of depressor anguli oris (DAO) muscle and to assess the added benefit of BTX-A injection into the platysma (PLT).
Methods:
This two-stage, single-center prospective study included a randomized, double-blind randomized trial (stage 1) and a non-randomized prospective study (stage 2). Primary outcomes were oral commissure position (OCDA, OCLA) and lip asymmetry (DSL) using three-dimensional photogrammetry. Secondary outcomes included patient satisfaction, pain, and side effects.
Results:
Both methods improved OCDA and OCLA across all time points, with lower DAO injection showing greater effects than the upper site. DAO+PLT further improved OCLA at 1 month and OCDA at 6 months. Satisfaction was higher with DAO+PLT (P < 0.05). DSL differences were <1 mm. No severe adverse events occurred.
Conclusion:
Lower DAO injection is more effective in inhibiting DAO movement. DAO+PLT yields superior commissure lifting with minimal side effects.
