Effects of high-frequency ultrasound treatment on human skin tissues

Introduction - Transcutaneous ultrasounds are viewed as the most effective non-surgical treatments for facial skin rejuvenation, although their mechanisms of action are poorly understood. This study aims at evaluating the morphological changes induced by ultrasound treatment on skin tissues: epidermis, papillary and reticular dermis, and subcutaneous fat. To evaluate the clinical efficacy of ultrasound treatment for facial skin tightening. Materials & Methods - Ex vivo human skin samples were sham-treated or treated with high-frequency ultrasounds using MedVisageTM (General Project Ltd.). Different parameters of power output (1.5 and 3 W) and frequency modulation (100, 500, 3000, 3500 Hz) were compared. Clinical efficacy was evaluated upon a single 5-min. ultrasound treatment (3 W, 3000 Hz) on 4 volunteers. Results – Ultrasound treatment caused significant compaction of collagen and elastic fibers in the reticular dermis, whereas less prominent changes occurred in the papillary dermis. The overall effects varied depending on energy output and modulation frequency. No changes of subcutaneous adipocytes, blood capillaries, epidermal keratinocytes, dermal fibroblasts and mast cells were observed. Clinically, ultrasound treatment consistently caused a well-tolerated, objective reduction of facial skin wrinkles. Conclusions - High frequency ultrasounds are an effective and safe noninvasive technique for skin-tightening purposes.