Green H A, Domankevitz Y, Nishioka N S
Department of Dermatology, Massachusetts General Hospital, Boston 02114.
Lasers Surg Med. 1990;10(5):476-84. doi: 10.1002/lsm.1900100513.
Pulsed lasers produce efficient and precise tissue ablation with limited residual thermal damage. In this study, the efficiency of pulsed CO2 laser ablation of burned and normal swine skin was studied in vitro with a mass loss technique. The heats of ablation for normal and burned skin were 2,706 and 2,416 J/cm3 of tissue ablated, respectively. The mean threshold radiant exposures for ablating normal skin and eschar were 2.6 J/cm2 and 3.0 J/cm2, respectively. Radiant exposures greater than 19 J/cm2 produced a plasma, which decreased the efficiency of laser ablation. Thus the radiant exposures for efficient ablation range from 4 to 19 J/cm2, and within this radiant exposure range 20-40 microns of tissue are ablated per pulse. We also examined, on a gross and histopathologic basis, in vivo burn eschar excision with a pulsed CO2 laser. The laser allowed bloodless excisions of full thickness burns on the backs of male hairless rats. The zone of thermal damage was approximately 85 microns over the subjacent fascia. The pulsed CO2 laser can ablate burn eschar efficiently, precisely, and bloodlessly and may prove valuable for the excision of burned and necrotic tissue.
脉冲激光能够产生高效且精确的组织消融，同时残留的热损伤有限。在本研究中，采用质量损失技术在体外研究了脉冲二氧化碳激光对烧伤和正常猪皮肤的消融效率。正常皮肤和烧伤皮肤的消融热分别为每消融1立方厘米组织2706焦耳和2416焦耳。消融正常皮肤和焦痂的平均阈值辐射曝光量分别为2.6焦耳/平方厘米和3.0焦耳/平方厘米。大于19焦耳/平方厘米的辐射曝光会产生等离子体，从而降低激光消融的效率。因此，高效消融的辐射曝光范围为4至19焦耳/平方厘米，在此辐射曝光范围内，每个脉冲可消融20 - 40微米的组织。我们还在大体和组织病理学基础上，对用脉冲二氧化碳激光进行体内烧伤焦痂切除进行了研究。该激光能够对雄性无毛大鼠背部的全层烧伤进行无血切除。在下方筋膜上，热损伤区域约为85微米。脉冲二氧化碳激光能够高效、精确且无血地消融烧伤焦痂，可能对切除烧伤和坏死组织具有重要价值。
