Objective: The purpose of this study is to review the differences between continuous wave (CW) and UltraPulse (UP) on thermal damage of the laser with different power.
Methods: Four adult beagle dogs underwent transoral laser microsurgery (TLM) using CO2 laser. The laser emission mode and power was CW (3 W, 5 W, and 8 W) and UP (3 W and 5 W), respectively. The tissue from 4 animals was evaluated histologically on postoperative days 1 and 3. The thermal damage of the laser was measured using slide scan system via SlideViewer version 1.5.5.2 software.
Results: All dogs underwent TLM uneventfully. Under microscope examined, the laser damage area was composed of 2 parts: the vaporized zone (VPZ) and thermal damage area. The thermal damage area can be divided into thermal coagulative necrosis area (TCN) and hydropic degeneration area. The width of VPZ and TCN in UP mode was less than that in CW mode (P < .01). The data indicate that lower laser power created less thermal damage (P < .01). In addition, the width of VPZ on postoperative day 3 was less than that on postoperative day 1 (P < .01).
Conclusion: CO2 laser with UP and lower power could decrease the laser thermal damage and may offer more prompt wound healing.
Keywords: canine; carbon dioxide laser; laryngology; thermal damage; vocal fold.