Clinical effects of dynamic cooling during pulsed laser treatment of port-wine stains

Abstract

Pulsed dye lasers permit effective treatment of port-wine stains without a significant risk of complications. However, epidermal damage manifested by weeping or crusting of the treated area have been reported in 48-83% of patients, and transient hyperpigmentation after treatment is observed in 10-57%. Theoretically, the epidermis can be protected from thermal damage with the use of the concept of selective epidermal cooling.This study examined the clinical effects of rapid cooling of the epidermis with a liquid refrigerant R-134a (boiling point - 26.5 double daggerC) during pulsed dye laser therapy. In 23 patients with port-wine stains, a 50-ms-long cooling pulse delivered immediately prior to laser irradiation with a fluence of 6.0 J cm(-2) significantly reduced the pain, and shortened the period with purpura without compromising the clinical blanching. Cooling periods longer than 60 ms, as well as additional cooling pulses immediately after laser exposure, reduced the blanching in areas irradiated with 6.0 J cm(-2).Post-treatment hyperpigmentation was not prevented with dynamic cooling.

Update on the Clinical Management of Port Wine Stains

“…Children may be afraid of the 'hiss' associated with the cryogen release; thus, the procedure should be demonstrated to them before beginning treatment. The duration of post-laser treatment purpura is also decreased with CSC, but the incidence of hyperpigmentation is una#ected [20,22,24].…”

“…CSC decreases treatment pain [20,23,24] especially in patients with darker skin types. This benefit is less marked in children possibly because some of their discomfort is a result of anticipatory fear.…”

Dynamic skin cooling with an environmentally compatible alternative cryogen during laser surgery

“…Dynamic skin cooling with cryogen spray has proved to be an effective means in minimizing adverse effects, reducing patient pain and allowing higher light dosage during laser dermatologic surgery [1][2][3][4][5][6]. The current U. S. Food and Drug Administration (FDA) approved cryogen is 1,1,1, 2-Tetrafluoroethane (R-134a), a non-toxic, non-flammable hydrofluorocarbon [7].…”

Improvement of port wine stain laser therapy by skin preheating prior to cryogen spray cooling: A numerical simulation

“…Unfortunately, for many lesions, the threshold laser dosage for epidermal damage may be lower than that required for permanent PWS blanching. An important approach to the aforementioned problem is to selectively cool the most superficial layers of the skin with cryogen spray cooling (CSC), which has led to improved therapeutic outcome of PWS and other vascular lesions [1][2][3][4][5][6][7]. However, the current approach to PWS laser surgery does not produce complete lesion blanching in the vast majority of patients [8][9][10].…”