Ultrapulse-mode versus superpulse-mode fractional carbon dioxide laser on normal back skin

Ultrapulse-mode (UPCO2) and superpulse-mode (SPCO2) fractional carbon dioxide lasers have been widely used to treat photo-aged skin, acne scars, and other skin conditions. This study was designed to compare the efficacy of new SPCO2 and UPCO2 lasers.

Seven healthy Chinese women received one pass of UPCO2 treatment on the left back and SPCO2 treatment on the right back. Pulse energies were 15 mJ at a density of 5%. Clinical outcomes and side effects were evaluated. Dermatoscope, in vivo reflectance confocal microscopy (RCM), and high-frequency ultrasonic equipment were used to observe skin responses noninvasively. Biopsies were taken for histologic evaluation.

There was no significant difference between the two sides with regard to pain, edema, crust formation, erythema, or pigmentation. Histopathology showed that SPCO2 treatment could penetrate as deep as UPCO2. The two modes have similar efficacy in stimulating the synthesis and remodeling of collagen and elastin according to hematoxylin and eosin and Verhoeff-iron-hematoxylin stains, and the ultrasonography images showed a remarkable increase in skin thickness and density on both sides.

There is no significant difference between UPCO2 and SPCO2 treatment on back skin in clinical side effects, histologic findings, RCM, or ultrasonographic observation.