Abstract

Objectives: The targeted diffusion and migration of the botulinum toxin A (BTX-A) formulations used have been repeatedly discussed as one of the factors that may influence the overall therapeutic outcome. Therefore, the diffusion characteristics of Letibotulinumtoxin A, the market leader in South Korea, were compared with other BTX formulations in a randomized, double-blind, intra-individual split-face comparison. Introduction: Injection points for BotulinumtoxinA are close to muscles that should not be affected by side effects. Therefore, it is important to know the spread of BotulinumtoxinA formulations in order to precisely select the treatment. So far, data on the diffusion properties of letibotulinumtoxinA are lacking, but are essential for the adaptation of clinical protocols and injection points. Materials / method: 30 subjects aged between 24-64 years with symmetric dynamic forehead lines and having not received any BotulinumtoxinA treatment in the last 6 months were enrolled. Patients were randomized to receive two of the three BTX-A formulations, with Letibotulinumtoxin A guaranteed. The frontal muscle was injected (intramuscular) with 4 U per injection point, 2 points per forehead side (4 U Leti/Ona or 10 U Abo). Diffusion characteristics were evaluated before and within 6 weeks (3 visits) using the iodine starch test. Standardized photos with VisioFace® 1000 D assessed the anhidrotic area. Results: Of the total subjects, 27 successfully completed the observation period and showed a positive response to treatment with BotulinumtoxinA. Within 6 weeks, there was a significant difference in both patient satisfaction and anhidrotic areas with letibotulinumtoxinA compared to Ona and AbobotulinumtoxinA. LetibotulinumtoxinA showed a significantly smaller anhidrotic halo than the other serotypes. Conclusion: The significant differences in the diffusion characteristics of various BotulinumtoxinA formulations should be considered, particularly when switching products. Selecting the appropriate formulation for each indication is important, as diffusion properties may influence therapeutic efficacy. Further studies are needed to explore the correlation between anhidrotic area and muscle relaxation for each area, as well as the impact of diffusion on the therapeutic index of different BotulinumtoxinA formulations.