Abstract

Objectives: This research aims to evaluate the effectiveness of using high-frequency ultrasound to enhance the accuracy of BoNT-A injections in the DAO muscle Introduction: The precision of Botulinum toxin type A (BoNT-A) injections in facial muscles, particularly in the depressor anguli oris (DAO) and depressor labii inferioris (DLI), is crucial due to their close anatomical proximity. Incorrect injection sites can lead to undesirable facial expressions. This study investigates the accuracy of injections in the DAO muscle under high-frequency ultrasound guidance compared to traditional methods. Materials / method: Four fresh frozen cadavers were subjected to BoNT-A injections at the P5 region (DAO) on the left side of the face and under high-frequency ultrasound on the right side. Subsequent dissection examined the precision of these injections in targeting the DAO muscle Results: Among the injections performed without ultrasound guidance on the left facial side, only one accurately targeted the interface between the DLI and DAO, while the others directly hit the DAO. In contrast, all injections on the right side under ultrasound guidance accurately reached the DAO muscle (4/4). This demonstrates a significantly higher precision rate with the use of ultrasound. Conclusion: High-frequency ultrasound guidance in administering BoNT-A injections significantly improves the accuracy of targeting the DAO muscle, minimizing the risk of inadvertently affecting the DLI. This technique promises to enhance the safety and efficacy of facial aesthetic and therapeutic procedures involving muscle-specific BoNT-A injections.