Histologic evaluation of laser lipolysis comparing continuous wave vs pulsed lasers in an in vivo XXXX model.

@entity1707 @entity548 @entity1711 @entity1504 @entity1710 @entity272 @entity2363
OBJECTIVES: To evaluate acute and delayed laser effects of subdermal lipolysis and collagen deposition using an in vivo @entity1707 model and to compare histologic findings in fatty tissue after continuous wave diode (CW) vs pulsed laser treatment. METHODS: Three CW lasers (980, 1370, and 1470 nm) and 3 pulsed lasers (1064, 1320, and 1440 nm) were used to treat 4 G  ttingen minipigs. Following administration of Klein tumescent solution, a laser cannula was inserted at the top of a 10 * 2.5-cm rectangle and was passed subdermally to create separate laser "tunnels." Temperatures at the surface and at intervals of 4-mm to 20-mm depths were recorded immediately after exposure and were correlated with @entity272 . Full-thickness cutaneous biopsy specimens were obtained at 1 day, 1 week, and 1 month after exposure and were stained with @entity1710 - @entity1711 and trichrome stain. Qualitative and semiquantitative histopathologic evaluations were performed with attention to @entity1504 , lipolysis, and collagen deposition. RESULTS: Skin surface damage occurred at temperatures exceeding 46  C. Histologic examination at 1 day after exposure showed @entity548 , fibrous collagen fiber coagulation, and adipocyte damage. Adipocytes surrounded by histiocytes, a marker of lipolysis, were present at 1 week and 1 month after exposure. Collagen deposition in subdermal fatty tissue and in @entity2363 of some specimens was noted at 1 week and had increased at 1 month. Tissue treated with CW laser at 1470 nm demonstrated greater @entity548 and more histiocytes at damage sites than tissue treated with pulsed laser at 1440 nm. There was a trend toward more collagen deposition with pulsed lasers than with CW lasers, but this was not statistically significant. Histopathologic comparison between results of CW laser at 980 nm vs pulsed laser at 1064 nm showed the same trend. @entity548 differences may result from pulse duration variations. A theoretical calculation estimating temperature rise in vessels supported this hypothesis. CONCLUSIONS: Pulsed lasers with higher peak powers provided better hemostatic effects than CW lasers. The degree of lipolysis depended on wavelength, laser power, and energy density. Subdermal laser irradiation can stimulate collagen deposition in subdermal tissue and @entity2363 .
