Comparison of wound healing between chopped mode-superpulse mode CO2 laser and steel knife incision

The healing of surgical incisions made with the steel knife and CO2 laser chopped wave mode (ChW) or rapid superpulse (RSP) mode were compared using histologic parameters and breaking strength of the scars on postoperative day 14. Using a miniature pig model the Sharplan 1100 laser incisions were made with an average power of 15 W and power density of 7.68 kW/cm2. Histological sections on postoperative day 14 revealed the knife scar measured .49 mm, was hypocellular, and contained visible bundles of collagen fibers. Both CO2 laser scars were less mature, the ChW scar measured 1.04 mm, the RSP scar measured 1.37 mm, and both contained cellular granulation tissue without visible collagen fibers. The breaking strength of the scars was measured with a tensiometer. Laser wounds were weaker than the knife wound. Scheffe test for variables was significant at P = .01 between the two laser modes and the knife. No significant difference was noted in the breaking strengths of incisions made with the chopped mode and superpulse mode.