The Role of Ultrasound Guidance in Preventing Complications of Botulinum Toxin Injections in the Lower Face Muscles

Abstract

Botulinum toxin (BoNT) injections have become an increasingly popular treatment in aesthetic medicine. Although generally safe and effective, injections into intricate facial muscles such as the masseter, mentalis, and depressor anguli oris (DAO) carry inherent risks of complications due to their complex anatomy, proximity to vital structures, and potential for unintended toxin diffusion. This article reviews the benefits and evidence supporting the use of real-time ultrasound guidance as an important tool to enhance the precision, efficacy, and safety in BoNT injections into these specific facial muscles. By this direct visualization of muscle anatomy, needle placement, and surrounding neurovascular structures, ultrasound guidance can significantly reduce the incidence of complications such as paradoxical bulging, asymmetrical facial expressions, salivary dysfunction, and bruising. Copyright © 2025 by Mutaz B. Habal, MD