A personalized treatment approach of frontalis muscle with botulinum toxin A (Bont-A) related to functional anatomy:...

Background: The forehead is one of the most frequent sites of botulinum toxin (Bont-A) application. To date, few data are available about the anatomy of the frontalis muscle. Its anatomy is highly heterogeneous in Caucasian people. Consequently, personalized treatments with botulinum toxin-A (Bont-A) are needed to obtain good esthetic results and to reduce side effects. Recently, a study on cadavers found four anatomical shapes of the frontalis muscle, corresponding to four horizontal wrinkle patterns in live patients.Objective: To perform a personalized, reproducible, and safer treatment with Bont-A of the forehead, by classifying patients according to four specific anatomical shapes of the frontalis muscle related to skin wrinkle patterns during contraction.Methods: We treated four patients classified according to the four anatomic types (I, II, III, and IV). The patients' forehead was divided into 21 areas and matched with 4 horizontal wrinkle patterns. Detecting different activities of the muscle in the different areas of the forehead, treatment injections were performed with a different dose, dilution, and at different anatomical layers (intramuscular or intradermal) per point.Conclusions: We confirmed four different wrinkle patterns after forehead contraction according to the anatomical shape of the frontalis muscle. This allows us to perform a tailored treatment with Bont-A. Nevertheless, some patients with atypical patterns still need "ad hoc" treatment.