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Updated: Aug 7, 2026
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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.
Plastic and Reconstructive Surgery
|August 5, 2026
Summary
Lower depressor anguli oris (DAO) muscle injections of botulinum toxin type A (BTX-A) effectively lift mouth corners. Combining DAO with platysma (PLT) injections further enhances results and patient satisfaction for improved facial aesthetics.
Area of Science:
- Aesthetic medicine
- Facial rejuvenation techniques
- Neuromodulator treatments
Background:
- Drooping oral commissures negatively impact psychosocial well-being.
- Botulinum toxin type A (BTX-A) is effective for mouth corner lifting.
- Optimal BTX-A injection strategies for the depressor anguli oris (DAO) muscle remain debated.
Purpose of the Study:
- To compare BTX-A efficacy and safety at different DAO injection sites.
- To evaluate the added benefit of platysma (PLT) BTX-A injections.
- To optimize treatment for drooping oral commissures.
Main Methods:
- Two-stage prospective study: randomized trial and non-randomized trial.
- Three-dimensional photogrammetry assessed oral commissure position (OCDA, OCLA) and lip asymmetry (DSL).
- Evaluated patient satisfaction, pain, and side effects.
Main Results:
- Lower DAO injections demonstrated superior improvement in OCDA and OCLA compared to upper DAO injections.
- DAO+PLT injections significantly improved OCLA at 1 month and OCDA at 6 months.
- Higher patient satisfaction was reported with DAO+PLT injections; minimal lip asymmetry (<1 mm) and no severe adverse events were observed.
Conclusions:
- Targeting the lower DAO muscle is more effective for controlling DAO movement.
- DAO+PLT BTX-A injections provide superior mouth corner lifting with a favorable safety profile.
