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 full-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 microns) layers of tissue and narrow (20-150 microns) zones of thermal injury following one, two, or three passes on intact skin. CONCLUSION: The pulsed and scanned technologies are capable of producing "char-free" tissue ablation with minimal residual thermal damage.