Analysis of electronically pulsed versus quasi-continuous wave carbon dioxide lasers in an animal model.

In this study we sought to compare laser tissue interaction in both the quasi-continuous waveform and electronically pulsed waveform of the carbon dioxide laser. An intramode analysis of the electronically pulsed form (at 350 and 650 pulses per second) was also undertaken. Intraperitoneal laser incisions were made on New Zealand white female virginal rabbits and tested at days 0, 5, 15, and 20. Testing involved proximal and midsection analysis of the laser sites to evaluate total area of vaporization, total area of tissue thermal damage, maximum diameter of injury at epithelial surface, maximum depth of laser penetration, angle of vaporization crater edges, and angle of tissue thermal injury of the three modes. Analysis of proximal versus midsection preparation revealed different zones of vaporization and injury within the same laser site. The zone of injury with respect to time was nonuniform, suggesting that the laser output in the electronically pulsed mode was not constant. An in vivo tissue lens phenomenon was also detected, resulting in a compound thermal vaporization and injury pattern.