Histologic Evaluation of Laser Lipolysis Comparing Continuous Wave vs Pulsed Lasers in an In Vivo Pig Model

Abstract

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 reticular dermis.

Histological evaluation of dermal tissue remodeling with the 1444‐nm neodymium:yttrium–aluminum–garnet laser in in vivo model

“…In this study, collagen fibers were more tightly arranged and more parallel than the treatment group. In an animal study by Levi et al ., some tissues irradiated subdermally with the 1440‐nm Nd:YAG laser developed collagen deposition in subdermal tissue and in the reticular dermis at 1 week and 1 month after treatment. Skin fibroblasts are the principle cells synthesizing collagens in the dermis.…”

“…This affords safer contouring with less risk of adjacent tissue damage . Histological evaluation of laser lipolysis in an in vivo pig model with various wavelengths and powers led researchers to suggest that a high‐absorption wavelength with a low power is a better choice for skin safety . The 1064‐nm and 1320‐nm Nd:YAG lasers, mainly used for laser lipolysis, have appeared to have a weaker affinity to fat and water than the 1444‐nm Nd:YAG laser, which is a recently developed and introduced laser .…”

Combination Laser-Assisted Liposuction and Minimally Invasive Skin Tightening with Temperature Feedback for Treatment of the Submentum and Neck

“…Several wavelengths have been used for LAL, but the current study is the first to attempt a randomized clinical comparison of wavelengths. One study compared the histologic effects of three continuous wave lasers at 980, 1,370, and 1,470 nm and three pulsed lasers at 1,064, 1,320, and 1,440 nm in a pig model . It failed to reveal statistically significant differences in neocollagenesis but showed that continuous‐wave lasers were associated with greater hemorrhage .…”

“…One study compared the histologic effects of three continuous wave lasers at 980, 1,370, and 1,470 nm and three pulsed lasers at 1,064, 1,320, and 1,440 nm in a pig model . It failed to reveal statistically significant differences in neocollagenesis but showed that continuous‐wave lasers were associated with greater hemorrhage . A retrospective study of a 980‐nm laser for LAL reported skin contraction clinically, and ultrasound‐detected changes in collagen .…”

Model development and experimental validation for analyzing initial transients of irradiation of tissues during thermal therapy using short pulse lasers

“…Histological studies allow for analysis of the heat affected zone during laser irradiation which may not be evident from temperature measurements alone and have demonstrated the advantages of pulsed lasers. For example, Levi et al showed greater hemorrhage post irradiation with CW lasers than with microsecond pulsed lasers with similar wavelength using in vivo pig models. Clinical histopathology on human buccal specimens by Suter et al identified that a significant difference between the thermal damage zones produced by pulsed and CW laser modes exists.…”