IN-VITRO CHANGES IN NON-FACIAL HUMAN SKIN FOLLOWING CO2-LASER RESURFACING - A COMPARISON STUDY

Background and Objective: We evaluated the physical changes in human s kin following CO2 laser cutaneous resurfacing with either the Sharplan SilkTouch(R) handpiece or the Coherent UltraPulse(R) laser. Study Des ign/Materials and Methods: Three-hundred five human tissue samples and matched controls were used. Up to five laser passes were performed pe r specimen. Parameters evaluated included: lateral skin shrinkage, tra nsient temperature change, isometric tension development, elasticity c hange, and histologic change. Results: Skin shrinkage increased in dir ect proportion to laser pass number. Isometric tension exponentially i ncreased and elasticity exponentially decreased with successive laser passes. The zone of thermal denaturation for the SilkTouch(R) handpiec e was 115 +/- 15 mu m, and was independent of laser pass number, The z one of thermal denaturation was patchy for the UltraPulse(R) laser tre atments, regardless of pass number. A greater temperature increase was also measured for SilkTouch(R) irradiation than with the UltraPulse(R ) laser. Conclusion: The observed alterations in tissue length, tensio n development, and elasticity obtained with SilkTouch(R) or UltraPulse (R) treatment may contribute to the changes in clinical appearance ass ociated with laser cutaneous resurfacing. Our findings support a role for extracellular matrix contraction in the mechanism of action for CO 2 lasers in cutaneous resurfacing. (C) 1996 Wiley-Liss, Inc.