The aim of this study was to compare the effects of the pulsed-dye laser (PDL) at a wavelength of 585 nm with those at 595 nm in the treatment of post-surgical scars, starting on the day of suture removal. The study was a prospective, non-randomized, double-blind, controlled, clinical trial, set in an outpatient clinic. Fifteen outpatients with 21 post-operative scars at least 3 cm long were recruited, and 14 patients with 19 scars completed the study. Scars were divided into three equal portions. Each outer portion was randomly allocated to PDL at 585 nm or at 595 nm (3.5 J/cm(2), 450 micros, 10 mm spot size), and the center was an untreated control; treatment was composed of three laser sessions at 4-week intervals. A blinded examiner evaluated the three scar sections using the Vancouver scar scale for pigmentation, vascularity, pliability, and height. Cosmetic appearance was evaluated with a visual analog scale. Punch biopsies of three randomly selected scars were evaluated. Pigmentation: more scars after laser treatments were of normal color than in the control, but the difference was not statistically significant. Vascularity: after treatment, more scars had normal vascularity in all three groups than at baseline (P < 0.05); the largest increase was with a wavelength of 585 nm (10.5-94.7%), then 595 nm (15.8-78.9%), then control (5.2-36.6%). Pliability: there was more normal pliability in all three groups than at baseline (P < 0.05), with greater improvements in the laser-treated groups. Height: significantly more flat scars after 585 nm PDL (63.2%) than at baseline (21.1%) (P < 0.05). We observed a slight but non-significant decrease in the scar heights with 595 nm PDL in comparison with the control.
Histology: after laser irradiation, the treated sections were more similar to a non-scarring process than the control. Cosmetic outcome: visual analog scales increased in all groups (P < 0.05), but the greatest increases were observed in the 585 nm and 595 nm laser-treated groups (50% and 60%, respectively) compared with controls (30%). There were significantly higher scores with the lasers than for the control (P < 0.001) at each visit after baseline. Both the 585 nm and 595 nm PDL treatments were effective in improving the appearance and normalizing the vascularity and pliability of post-operative scars. Both wavelengths improved the scars' visual appearance more than controls. We found that 585 nm appears to be the preferred wavelength, as it substantially normalized the height in addition to the vascularity and pliability in a significant number of scars.