One-pass CO2 versus multiple-pass Er:YAG laser resurfacing in the treatment of rhytides:: A comparison side-by-side study of pulsed CO2 and Er:YAG lasers

Background. The CO2 laser is normally described as an aggressive resurfacing tool, whereas the erbium:YAG laser has enjoyed a reputation as the ideal tool for superficial resurfacing. The implication from many studies is that the CO2 laser is incapable of "minimally invasive" resurfacing. Objective. To compare a short-pulsed CO2 laser with an Er: YAG laser over a range of parameters intended to produce equivalent microscopic and clinical injuries. Methods. A prospective, randomized, comparative interventional trial was conducted in a tertiary care teaching hospital. Thirteen patients with facial wrinkles were enrolled in the study. A side-by-side comparison was performed using periorbital and perioral regions as treatment sites. One side was treated with a pulsed CO2 laser and the other with an Er-YAG laser. Postauricular skin was treated in an identical fashion to the study sites and biopsied for microscopic analysis. The biopsies were obtained before treatment, immediately after treatment, and either 3 or 6 months after treatment to evaluate the acute level of injury and subsequent degree of fibroplasia. Photographs were taken at baseline, immediately after treatment, 1, 2, and 6 weeks, and 3 and 6 months after treatment. Nine physicians evaluated the photographs for erythemia, pigmentation, and wrinkle improvement. Results. Investigator assessment showed no statistically significant differences between the lasers with respect to hyperpigmentation and wrinkle reduction. There was less erythema at the CO2 laser-treated sites 2 weeks after treatment; the differences had resolved by 6 weeks after treatment. Histologic examination demonstrated equivalent dermal thermal injury on immediate postoperative biopsies and equivalent fibroplasia on subsequent biopsies. Both CO2 and Er:YAG laser-treated sites showed overall modest wrinkle improvement compared to the pretreatment photographs. Conclusion. When CO2 and Er:YAG lasers are used in a manner such that there are equivalent immediate postoperative histologic results, equivalent healing and cosmetic improvement occurs. One can Use CO2 laser with one pass to mimic a moderately aggressive Er:YAG laser treatment.