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 skin following CO2 laser cutaneous resurfacing with either the Sharplan SilkTouch handpiece or the Coherent UltraPulse laser.
Study Design/materials and Methods: Three-hundred five human tissue samples and matched controls were used. Up to five laser passes were performed per specimen. Parameters evaluated included: lateral skin shrinkage, transient temperature change, isometric tension development, elasticity change, and histologic change.
Results: Skin shrinkage increased in direct proportion to laser pass number. Isometric tension exponentially increased and elasticity exponentially decreased with successive laser passes. The zone of thermal denaturation for the SilkTouch handpiece was 115 +/- 15 microns, and was independent of laser pass number. The zone of thermal denaturation was patchy for the UltraPulse laser treatments, regardless of pass number. A greater temperature increase was also measured for SilkTouch irradiation than with the UltraPulse laser.
Conclusion: The observed alterations in tissue length, tension development, and elasticity obtained with SilkTouch or UltraPulse treatment may contribute to the changes in clinical appearance associated with laser cutaneous resurfacing. Our findings support a role for extracellular matrix contraction in the mechanism of action for CO2 lasers in cutaneous resurfacing.