COMPARATIVE CLINICAL-TRIAL OF 2 CARBON-DIOXIDE RESURFACING LASERS WITH VARYING PULSE DURATIONS - 100 MICROSECONDS VS 1 MILLISECOND

Objectives: To compare the clinical and histological effects of 2 carb on dioxide lasers with different pulse durations and to evaluate the e ffect of carbon dioxide laser pulse duration on postprocedure erythema , wound healing, and efficacy of wrinkle treatment. Design: Prospectiv e, randomized, comparative clinical, trial. Setting: A university-affi liated hospital-based laser center. Patients: Thirty-five patients wit h facial wrinkles were enrolled in the study. Treatment sites included 15 perioral, 14 periorbital areas, and 6 full face.Intervention: A 2- sided comparison was performed. One side of the study site was treated with. the TruPulse laser (Tissue Technologies, Palomar Medical Produc ts Inc, Lexington, Mass). The other side of the study site was treated with the UltraPulse 5000 laser (Coherent Medical Inc, Pale Alto, Cali f). The 2 sides were treated to equivalent tissue effects rather than maintaining the number of passes. Main Outcome Measures: Photographs o f the treatment areas at baseline, week 1, week 2, month 2, and month 6 were evaluated by a 5-member panel for degree of erythema, amount of edema, and percentage of wrinkle improvement. Silicon skin casts for profilometry measurements before and after the treatment were compared . To evaluate skin shrinkage, surface area before and after treatment of square tattoos on both cheeks of the full-face patients were comput ed using a digital imaging system. Histological sections before and af ter the procedure were analyzed. Results: At week 1, 75% of the patien ts had more erythema on the UltraPulse than TruPulse sides. The differ ence in erythema (TruPulse less than UltraPulse) between the 2 treatme nt sides was clinically mild yet statistically significant for weeks I (P = .05) and 2 (P = .05). Although observed results favored the Ultr aPulse over the TruPulse, the difference in efficacy between the 2 las ers did not reach statistical significance. Conclusions: Compared with the longer pulse-duration carbon dioxide laser, the shorter pulse-dur ation carbon dioxide laser, used with higher energy and more passes, c aused slightly less erythema while maintaining efficacy. The longer pu lse-duration laser required lower energy and fewer number of passes to achieve an equivalent depth of ablation, level of residual thermal da mage, and degree of efficacy. The shorter TruPulse allows for more sup erficial tissue damage per pass and therefore is best suited for situa tions requiring superficial or more controlled ablation. The longer Ul traPulse achieves a desirable depth of tissue damage with fewer passes . The data did not support the long-term presence of tissue collagen s hrinkage in the treated areas.