Khoury Jane G, Saluja Raminder, Keel Douglas, Detwiler Susan, Goldman Mitchel P
Dermatology/Cosmetic Laser Associates of La Jolla, Inc., La Jolla, California, USA.
Lasers Surg Med. 2008 Aug;40(6):402-6. doi: 10.1002/lsm.20649.
Laser lipolysis using a pulsed Nd:YAG laser has been shown to be a safe and effective modality for the treatment of small areas of fat in conjunction with microcannula liposuction. The purpose of this study is to compare the histologic effects on ex vivo human fatty tissue using three separate wavelengths of laser light (1064, 1320 and 2100 nm) at three predetermined energy levels.
STUDY DESIGN/MATERIALS AND METHODS: Nine samples of freshly harvested abdominal subcutaneous tissue were tumesced and then cannulated in a single tunnel in the superficial subcutaneous tissue. They were irradiated with a 320 microm polyimide fiber using a pulsed 1064 nm Nd:YAG, 1320 nm Nd:YAG and 2100 nm thulium holmium chromium:YAG (THC:YAG) laser at 4, 6 and 8 W (CoolTouch Corp., Roseville, CA). The fiber was withdrawn at a rate of 1 mm/second in a single pass. A tenth sample was cannulated without irradiation and served as a control. Irradiation with the 1320 nm Nd:YAG was performed in vivo on a lipoma in a similar fashion with repetitive tunneling. Fat was removed the following day by incisional punch biopsy for histologic evaluation. The tissue was studied in a blinded fashion with hematoxylin eosin staining.
Light microscopy after irradiation showed thermal damage in the subcutaneous tissue that preferentially affected the fibrous septae with some fat cell damage. The diameter of thermal damage around the fiber ranged from 1 to 4-5 mm depending on the laser wavelength and average power of the settings. No clear fat liquefaction was seen histologically in the ex vivo samples but was seen with the 1320 nm Nd:YAG irradiation of the in-vivo lipoma tissue.
Laser lipolysis works through a combination of photoacoustic ablation and selective photothermolysis of fibrous septae. Acoustic damage occurs with thermal damage and is difficult to capture histologically. The greatest amount of thermal damage was seen in the specimens with the highest energy per pulse, however, the patchiness and variability of thermal damage within the cross-sections evaluated make it difficult to draw any strong conclusions. Further studies are warranted to more fully evaluate the histologic effects and mechanisms behind laser lipolysis.
已证明使用脉冲Nd:YAG激光进行激光溶脂与微套管吸脂术联合应用时，是治疗小面积脂肪的一种安全有效的方式。本研究的目的是比较在三个预定能量水平下，使用三种不同波长的激光（1064、1320和2100纳米）对离体人体脂肪组织的组织学影响。
研究设计/材料与方法：采集9份新鲜的腹部皮下组织样本，进行肿胀麻醉，然后在浅表皮下组织的单一通道中插入套管。使用脉冲1064纳米Nd:YAG、1320纳米Nd:YAG和2100纳米铥钬铬：YAG（THC:YAG）激光，通过320微米的聚酰亚胺光纤，以4、6和8瓦的功率（CoolTouch公司，加利福尼亚州罗斯维尔）对样本进行照射。光纤以1毫米/秒的速度单次抽出。第10个样本插入套管但未照射，作为对照。以类似方式对1例脂肪瘤进行体内1320纳米Nd:YAG激光照射，通过重复穿刺通道进行。次日通过切口穿刺活检取出脂肪进行组织学评估。对组织进行苏木精-伊红染色，以盲法进行研究。
照射后的光学显微镜检查显示皮下组织有热损伤，主要影响纤维间隔，伴有一些脂肪细胞损伤。根据激光波长和设置的平均功率，光纤周围热损伤的直径范围为1至4 - 5毫米。在离体样本的组织学检查中未发现明显的脂肪液化，但在1320纳米Nd:YAG激光照射的体内脂肪瘤组织中可见脂肪液化。
激光溶脂通过光声消融和纤维间隔的选择性光热解作用相结合发挥作用。声损伤伴随热损伤发生，在组织学上难以捕捉。在每个脉冲能量最高的标本中观察到最大程度的热损伤，然而，在评估的横截面内热损伤的不均匀性和变异性使得难以得出任何有力的结论。有必要进行进一步研究，以更全面地评估激光溶脂的组织学影响及其背后的机制。
