Pulsed carbon dioxide laser ablation of burned skin: In vitro and in vivo analysis

Abstract

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.

Multimodal evaluation of ultra-short laser pulses treatment for skin burn injuries

“…The use of lasers for removing skin burn debris and necrotic tissue has few studies in the literature [23]. Our results concerning burned skin wound depth and healing phases are comparable to prior works [24][25][26].…”

Effects of heterogeneous absorption of laser radiation in biotissue ablation: Characterization of ablation of fat with a pulsed CO2 laser

“…Using this model and our mass loss observations, the heat of ablation for fat was 2.4 kJ/cm 3 , and the ablation threshold radiant exposure was 1.05 J/cm 2 . These values for the ablation threshold (F th ) and heat of ablation (H a ) do not agree with the following values derived from energy balance, where the ablation threshold for fresh fat is given by:…”

“…and the heat of ablation by H a ‫ס‬ a F th (3) where w and f represent water and anhydrous fat, v represents ''vaporization,'' and, a is the absorption coefficient for fresh fat; 0.3 and 0.7 are the weight fractions of water and anydrous fat in fresh adipose tissue. The temperature before heating is assumed to be 25°C.…”

“…The best-fit slope was then divided by the irradiated area (0.00785 cm 2 ), to yield an equivalent slope of 380 g/J. If the density of fat is assumed to be 0.9 g/cm 3 , the slope can be converted to a heat of ablation of 2.4 kJ/cm 3 . The threshold radiant exposure for ablation was taken to be the radiant exposure at which the linear regression line crosses the x axis.…”

“…It can remove tissue with better hemostasis than mechanical devices and can debride burn wounds [1][2][3]. Pulsed CO 2 laser ablation of dermis has been studied extensively and provides hemostatic ablation with residual thermal damage limited to ∼ 80-200 m [1][2][3].…”