Evaluation of a Novel High-Intensity Focused Ultrasound Device for Ablating Subcutaneous Adipose Tissue for Noninvasive Body Contouring: Safety Studies in Human Volunteers

Background: High-intensity focused ultrasound (HIFU) is an energy-based medical technology with many clinical applications. A device under clinical investigation in the United States (LipoSonix; Medicis Technologies Corporation, Bothell, Washington) uses HIFU to reduce localized deposits of abdominal adipose tissue. Objectives: The authors describe the results from their clinical trial investigating the safety of this HIFU device in human patients. Methods: Over the course of three studies evaluating the safety of the HIFU device for ablating human subcutaneous adipose tissue (SAT), 152 healthy patients were treated with total HIFU energy doses of 47 to 331 J/cm(2)), including patients who presented for elective abdominoplasty and underwent treatment to areas identified for subsequent excision. The safety of each treatment regimen was confirmed before the energy levels were raised. Abdominoplasty was performed up to 14 weeks following the HIFU procedure, and a pathologist performed histopathological analyses of excised tissues. Safety evaluations included an assessment of clinical chemistry and hematology profiles, physical examinations, and adverse events. Results: Posttreatment ultrasound confirmed that the HIFU effects were limited to targeted SAT layers. Histopathology revealed well-demarcated disruption of adipocytes within the targeted SAT. Phagocytosis of released lipids and cellular debris occurred after 14 to 28 days. Phagocytized lipids underwent normal hepatic metabolism. Healing progressed normally and was 95% complete after eight to 14 weeks. Adverse events consisted primarily of temporary treatment discomfort, edema, erythema, dysesthesia, and ecchymosis. There were no changes in clinical laboratory parameters, and no serious device-related adverse events occurred. Optimal clinical outcomes were achieved with lower energy levels, which provided beneficial effects with the least amount of discomfort. Conclusions: HIFU appears to provide a safe means for removing and remodeling unwanted deposits of abdominal SAT.