CONTROL OF HYPERTROPHIC SCAR GROWTH USING SELECTIVE PHOTOTHERMOLYSIS

Background and Objective: Previous studies have shown a clinical impro vement of hypertrophic scars (HS) after treatment with a pulsed dye la ser. The objective of this study was to investigate the effects of var iations in pulse wavelength and energy density on HS tissue using huma n HS implanted in athymic mice. Study Design/Materials and Methods: Sm all pieces (similar to 1 mm(3)) of HS tissue were implanted into athym ic mice and allowed to grow for 5 days. The implant site was then expo sed to a single 450 ps pulse, and implant growth and histology were mo nitored for an additional 12 days. Laser wavelength and energy density ranges tested were 585-600 nm and 2-10 J/cm(2), respectively. Results : Using a wavelength of 585 nm, laser treatment inhibited implant grow th by 70% at 6 J/cm(2) and 92% at 10 J/cm(2), respectively. The inhibi tory effect decreased as the laser wavelength was increased from 585 t o 600 nm. A widespread destruction of the implant microvasculature wit h a minor effect on surrounding extracellular matrix at the highest li ght dose were observed. Conclusion: Pulsed laser treatment inhibits HS implant growth in nude mice. This effect is Likely mediated by select ive photothermolysis of the implant microvasculature. (C) 1997 Wiley-L iss, Inc.