Animal study of skin resurfacing using the ultrapulse carbon dioxide laser.

Ultrapulse carbon dioxide laser ablation of rabbit skin was investigated. Macroscopic and microscopic appearance of the ablation site was evaluated for 1 month. The Ultrapulse carbon dioxide laser was set in the ultrapulse mode and the parameters selected were 250 mJ of energy per pulse and 2 W average power with the 3-mm spot size collimated handpiece. Macroscopic investigation showed that ultrapulse carbon dioxide laser ablation removed rabbit skin precisely and bloodlessly without char formation. Skin re-epithelialization without scarring and perfect hair growth restoration within 3 weeks were impressive. Microscopic investigation demonstrated a layer of tissue thermal necrosis measured as 70 +/- 10 microns. During the first 2 weeks, laser ablation wound re-epithelialization begins with multiplying epidermal layers (from 2-3 cell layers to about 13 to 15 cell layers). There were marked fibroblastic reactions and capillary congestion within papillary dermis. By the end of 4 weeks, the thickened epidermal layer appeared normal. The repaired papillary dermal collagen showed a relative compact configuration and greater cellularity in Masson stain was found 2 to 3 weeks later and also was near normal 4 weeks after laser treatment. These findings suggest that Ultrapulse's delivery of short-duration, high-energy pulses may provide a new approach (laser dermal ablation) to damage selectively the epidermis and papillary dermis of rabbit skin in one single-pulse impaction with uneventful wound healing within 1 month.