In a poster presented at the 63rd Annual Meeting of the American Academy of Dermatology, Keyvan Nouri, M.D., associate professor and director of Mohs, dermatologic, and laser surgery, and Maria P. Rivas, M.D., research fellow, reported clinical and histological findings from a study comparing the effects of both types of PDLs with no treatment in 14 patients with 19 new, linear surgical scars. Each scar was divided into three equal fields. The central field was always left as the untreated control and the two outer fields were randomized to treatment with the 585 nm or 595 nm PDL. A total of three treatments was administered beginning immediately after suture removal and repeated monthly.
Outcomes were assessed at one month after the last laser treatment by a blinded observer who rated features of scar appearance (pigmentation, height, vascularity) and quality (pliability) using the Vancouver Scar Scale (VSS) and judged overall cosmetic appearance using a visual analogue scale. In both endpoint analyses, PDL treatment was associated with significant benefits compared with control. There were no statistically significant differences between the two devices, although the results for both efficacy measures showed a trend for a better outcome using the shorter wavelength laser."Based on these results and our experience in a previous study of the 585 nm PDL, we encourage physicians to consider this treatment regimen with a PDL to optimize the appearance of surgical scars in cosmetically conscious patients. However, we emphasize that this technique is not advocated for individuals with darker skin due to the potential for causing adverse pigmentary changes," Dr. Nouri says.
The prior trial he referred to was published in 2003 (Dermatol Surg 2003;29:65-73) and showed that the quality and appearance of surgical scars could be improved when treated three times with the 585 nm PDL, also starting immediately after suture removal. Benefits were seen relative to no treatment in the overall cosmetic appearance, VSS total score, and the individual parameters of scar height, erythema and pliability.
"The 585 nm and 595 nm PDLs are the two most common lasers in medical practices, and so we were interested in seeing if similarly good results could be achieved with the 595 nm device," Dr. Nouri explains.
In the current study, the two lasers were used with identical operating parameters, including a spot size of 10 mm, a fluence of 3.5 J/cm2 and a pulse duration of 450 microseconds.
Relative to baseline, mean VSS scores improved 32 percent for the control sites, 55 percent for fields treated with the 595 nm PDL, and 67 percent at the sites treated with the 585 nm laser. Results of the cosmetic appearance ratings were consistent with those outcomes. Cosmesis was rated on a scale of 0 (worst) to 10 (best). Mean scores were 7.3, 8.3 and 8.6 for the control, 585 nm and 595 nm PDL treated sites, respectively.