Application Of Pulsed Dye Laser Combined With Long-pulsed 1064nm Nd:YAG Laser In Treating Fresh Scars

Objective:To evaluate and compare the effectiveness of pulsed dye laser(PDL)and the combination of PDL and long-pulsed Nd:YAG laser in the treatment of fresh scars starting 3 to 4 weeks after wound healing.Methods:Each scar was divided at the midline into two fields,with half receiving treatment using pulsed dye laser(Vbeam,Candela Corp.)with a 7 mm spot size at0.45ms with 6-9 J/cm~2 and a 20 ms spray duration with a 20 ms delay.The other half was treated using a combination of PDL with the same parameter and Nd:YAG(GentleYAG,Candela Corp.)with 3mm spot size at 10 ms with 150-180J/cm~2 and a20ms spray duration with a 20ms delay.Patients received 3 laser treatment sessions at1-month interval.The follow-up time is 3 months after final treatment.The scars were evaluated for height with Doppler ultrasound system(M7,MindRay),vascularity with Laser speckle detector(Perimed PSI)and pliability with Cutometer~○RR MPA580.Immunological histology was used to detect the destruction of capillaries.The infrared thermography(Fotric 228s)was used to monitor the temperature of the epidermis in the treatment process.Results:Twenty-eight patients with average 3.4-week scars were involved.All objective indicators analysis of the combined laser site was significantly better than the PDL site and was significantly improved compared to pre-treatment(p<0.05).The average height of scars was 0.28±0.72cm for PDL and 0.19±0.56cm for combined site,the speckle flow index was 112.72±16.79PU for the combined cite versus144.59±22.97PU for PDL alone.The gross elasticity index was 0.70±0.05 in PDL compared to 0.87±0.09 in combined site.The histological penetration depth of Nd:YAG was about 1mm,which was obviously deeper than that in group PDL.The combined treatment group immediately after the average temperature of 30.1℃,no patients developed persistent erythema,edema,permanent pigmentation change or scar formation.Conclusion:The combination of pulsed dye laser and long-pulsed Nd:YAG provides a more effective option compared to use pulsed dye laser alone to improve the cosmetic appearance of fresh scars.