HELIUM-NEON LASER IRRADIATION AT FLUENCES OF 1, 2, AND 4 J CM(2) FAILED TO ACCELERATE WOUND-HEALING AS ASSESSED BY BOTH WOUND CONTRACTURE RATE AND TENSILE-STRENGTH/

Background and Objective: Reports in the literature indicate that low energy laser irradiation has a biostimulatory effect on wound healing; however, no mechanism of this effect has been elucidated. Study Desig n/Materials and Methods: We attempted to establish a model from which to study the mechanism of biostimulation. The effects of low energy he lium-neon irradiation on wound healing were observed in two rat models . In the first model, 1.5 cm diameter full thickness excisional skin d efects were created in the dorsal midline of rats (n = 32). All animal s were anesthetized and all eschars were debrided daily. Wound area wa s determined by caliper measurements for 2 weeks postoperatively. Rats that received a treatment of 1 J/cm(2) had two defects in the dorsal skin. One wound was treated and the second was used as its own control . These measurements were not blinded, Rats that received 2 J/cm(2), 4 J/cm(2), or anesthesia alone had one defect on the dorsal skin. Calip er measurements of these wounds were blinded. We were unable to demons trate any difference in the rate of wound contracture in rats that rec eived a daily dose of 1 J/cm(2), 2 J/cm(2), 4 J/cm(2), or anesthesia a lone (P > 0.8 by student's t-test). In the second model, a single 2 cm longitudinal full thickness skin incision was created in the dorsal m idline of each rat (n = 24). No difference was found between rats that received anesthesia alone and those treated daily with 2 J/cm(2) as a ssessed by tensile strength measurements on postoperative days 7 and 1 4 (P > 0.8 by student's t-test between groups at both time points). Th ese determinations were blinded. Results: Despite our intentions of st udying the mechanism of low energy HeNe biostimulation, we were unable to demonstrate a beneficial effect. Conclusion: In this study, helium -neon laser irradiation produced no measurable benefit on wound healin g. (C) 1997 Wiley-Liss, Inc.