Comprehensive histologic analysis of interstitial lipolysis with the 1444 nm wavelength during a 3-month follow-up

A number of near-infrared wavelengths have been proposed and studied for laser lipolysis, but the histologic evaluation of tissue response to laser lipolysis during long-term follow-up has been lacking. A 1444 nm Nd:YAG laser with better absorption in both fat and water has recently attracted attention. The present study was designed to investigate the comprehensive histopathology of 1444 nm Nd:YAG laser-assisted lipolysis at different energy levels during a 3-month follow-up. Laser lipolysis was performed on porcine fat tissue in vivo using a 1444 nm Nd:YAG laser (AccuSculpt®, Lutronic Corporation, Ilsan, Republic of Korea) and the total energies delivered interstitially to 10x10 cm² areas were 750 J, 1500 J, 2250 J, 3000 J, 3750 J, 4500 J, and 5250 J. Biopsy samples were taken and histologically analyzed immediately after biopsy and at 1, 2, 4, and 12 weeks postoperatively. With a fluence setting above 3000J/100 cm², inflammation was severe and remained by the 3-month follow-up, resulting in severe scarring of the fat tissue. Below this energy level, mild lobular inflammation in the early phase biopsy had resolved with no scarring by the 3-month follow-up. No histologic changes in the epidermis or dermal connective tissue were present. This study suggested that controlling the energy level is important for clinical applications of laser lipolysis with no significant complications.