Evaluation of a novel high-intensity focused ultrasound device: Preclinical studies in a porcine model

Abstract

Background: High-intensity focused ultrasound (HIFU) has been applied clinically for the noninvasive treatment of pathological conditions in various organs for over 50 years; however, there are little data describing the use of thermal HIFU to ablate fat for body contouring and treatment of collagen-rich layers. A novel device under clinical investigation (LipoSonix; Medicis Technologies Corporation, Bothell, Washington) uses HIFU to eliminate unwanted adipose tissue. Objectives: The authors describe the results of HIFU treatment in a series of preclinical studies performed in a validated porcine model. Methods: Preclinical research included in vivo treatment of the abdominal subcutaneous adipose tissue of swine with transcutaneous HIFU therapy. Endpoint analyses included thermocouple temperature data, full-body necropsy, local pathology and histology studies, clinical hematology, urinalysis, and blood chemistry parameters, including lipid panels. Results: The application of HIFU energy levels of 166 to 372 J/cm 2 generated tissue temperature approaching 70°C, which was restricted to the focal area (n = seven). Application of 68 and 86 J/cm 2 did not produce clinically-significant changes in serum liver function tests, free fatty acids, or cholesterol (n = eight). Gross examination of tissue from various organs showed no evidence of fat emboli or accumulation (n = two). Histology demonstrated well-preserved vasculature and intact nerve fibers within the HIFU focal area (n = three). Following treatment with 85.3 to 270 J/cm 2, normal healing response included the migration of macrophages into the damaged tissue and removal of disrupted cellular debris and lipids (n = 8). Conclusions: In a preclinical swine model, the controlled thermal effect of HIFU appears to provide a safe and effective means for ablating subcutaneous adipose tissue. © 2011 The American Society for Aesthetic Plastic Surgery, Inc.