Rupture of fat cells using laser-generated ultra short stress waves

Background and Objectives: Ultrasound-assisted liposuction has been investigated as an aid to breakup fat for its less traumatic removal, and minimizing the post-operative recovery period. This research focused on understanding the mechanism of fat interaction with laser-generated ultra short stress waves with high amplitudes. Study Design/Materials and Methods: Freshly extracted human fat was secured in an Aluminum (Al) cavity. Sixteen nanoseconds duration stress waves were generated by exfoliating the bottom surface of the Al cavity by focusing 3 nanoseconds-long YAG laser pulses over a 2 mm. diameter area at 10 Hz with a maximum pulse energy of 0.95 J. The lipids released due to cell rupture were extracted and measured Results: Four minutes of pulsing released about 0.005 g, which was over 1% of the initial weight of the tissue. In situ temperature rise of only 5degreesC was measured at the maximum stress wave loading duration of 5 minutes. This was evidenced by histological sections, which showed no burn artifacts. Conclusions: This research shows that ultra short stress waves can mechanically cavitate fat in vitro without significant damage to adjacent structures, and forms the basis for future clinical work. (C) 2003 Wiley-Liss, Inc.