Abstract
Facial expressions and their emotional attributes are essential as an adjunct to verbal communication and for nonverbal communication. Botulinum toxin (BoNTA) used to limit wrinkles induced by aging changes on expressive faces. However, suboptimal injection techniques can lead to undesirable outcomes, such as brow ptosis, unnatural eyebrow elevation, flattening of the cheeks, and unnatural smiles. It is the intention here to investigate whether "on-label" standard injection techniques may be a contributing factor to poor results. A consensus group convened in 2023 looked at the relevant anatomy, expressions induced, complications of on-label BoNTA treatment, solutions, and alternative treatments. Interrogation of databases was supplemented by expert opinion of the consensus group. The authors of this review found that anatomical variations, generic on-label injection patterns, and inadvertent muscle recruitment contribute to suboptimal outcomes. Undesirable outcomes included brow ptosis, unnatural eyebrow shape, smile pattern alteration, and cheek flattening. These were linked to on-label standard protocols that fail to address individual anatomy and functional variations. Adjustments in dose, depth, and injection placement, along with simultaneous treatment of linked or antagonistic muscles, were identified as critical solutions. To optimize outcomes, it is critical to tailor injection strategies respecting individual anatomical and functional differences. Many unnatural appearances seen after BoNTA seem to have their origin in on-label techniques suggested by manufacturers. Although on-label protocols have been useful as a guide, the authors feel it is time to move past these to account for patient-specific needs and anatomical nuances. In this review, the authors provide practical recommendations for improved injection techniques. Level of Evidence: 5 (Therapeutic).