Italian Consensus and Review in Lower Face Mimetic Muscle Treatment with Botulinum Toxin-A

Treatment of the lower face with botulinum toxin type A (BoNT-A) is particularly challenging because of the important functional roles of the involved muscles, which increases the risk of adverse events and complications.

To address this issue, a panel of 14 experts conducted a three-round consensus study, including digital surveys and a formal meeting, on the aesthetic treatment of the mentalis (MT), depressor anguli oris (DAO), and platysma (PL) muscles using BoNT-A. The study was complemented by a literature review of 16 international consensus papers published between 2004 and 2024.

The primary indications for MT treatment that achieved strong consensus were "peau d'orange" ("golf ball") chin appearance and hyperactivity. The Italian panel recommended a mean total dose of 8 U (distributed bilaterally), which was higher than the international mean dose of 6.5 U. The preferred injection technique consisted of a combination of intramuscular and intradermal injections. For the DAO, the strongest indication was correction of downturned oral commissures. Both the Italian panel and the international consensus reported a mean total dose of 5.6 U. Most experts (92.8%) preferred intramuscular injections, typically administered at a single injection point lateral to the marionette line in order to remain within a safe treatment zone and avoid diffusion to the depressor labii inferioris muscle. Indications for PL treatment included platysmal bands, jawline recontouring, and improvement of skin texture. The techniques discussed included treatment of both platysmal bands and the jawline. The consensus panel recommended a significantly higher mean total dose (48.4 U) than the international average (38.2 U). The paper also highlights the growing importance of ultrasound imaging as a tool for identifying individual anatomical variations in the lower facial musculature.

As the demand for lower face rejuvenation continues to increase, standardized injection techniques and the integration of ultrasound imaging are essential for minimizing functional complications and optimizing aesthetic outcomes.