An in-vitro experiment on lysing adipose tissue by shock waves

Extracorporeal shock wave (ESW) technology has been widely used for non-invasive therapy such as disintegrating ureteral stones within the human body, and also used in the treatment of orthopedic disorders. Following the use of focused ultrasound by UltraShape™ for body contouring, this study considers the application of ESW to lyse fat tissues in order to avoid the possible burning problem associated with ultrasound focusing. This study was aimed at the development of lipoplasty by using shockwave-assisted technology. In in-vitro experiments, a pressure sensor was used to measure the pressure inside pig fat specimens at different operation voltages. Shock waves with an energy flux density of approximately 0.249±0.0361 mJ/mm² were found to have the least energy flux density necessary to disrupt fat cells, which corresponded to an operational voltage of 10 kV on our ESW machine. After the ESW treatment, the treated fat tissues underwent the processes of forinalin fixing, paraffin-embedding, and hematoxylin-eosin staining were pathologically examined. Damage in the treated specimens was observed and photographed through a microscope. It was found that, for the treated fat tissue, the mechanical and cavitation effects caused by focused shock waves occurred only in the subcutaneous layer, resulting in broken membranes of the fat cells. However, this treatment did not damage the skin layer, near-by blood vessels, or peripheral nerve fibers. Moreover, the number of shock waves would be at least 650 with energy flux density of 0.249 mJ/mm² to damage the treated fat tissue.