A histopathological comparison of ''char-free'' carbon dioxide lasers

BACKGROUND. New ''char-free'' carbon dioxide lasers are capable of precise tissue vaporization with minimal residual thermal damage. These lasers Operate either by producing high energy, rapid pulses or by scanning a highly focused continuous mode beam. OBJECTIVE. TO determine the depth of ablation and the depth of residual thermal injury produced with one to three passes of the pulsed and scanned systems. METHODS. The distal ends of preauricular donor skin from 12 patients requiring fall-thickness skin grafts following Mohs micrographic surgery were treated with zero to three passes of each of the lasers, and fixed for histopathological analysis. RESULTS. The three lasers tested produced vaporization of thin (20-50 mu m) layers of tissue and narrow (20-150 mu m) zones of thermal injury following one, two, or three passes on intact skin. CONCLUSION. The pulsed and scanned technologies ave capable of producing ''char-free'' tissue ablation with minimal residual thermal damage.