Despite widespread clinical use of cryogen spray cooling (CSC) in conjunction with laser dermatologic surgery, in vivo cutaneous effects have not been systematically evaluated.
The authors characterize the in vivo cutaneous effects for Fitzpatrick skin types I through VI after CSC exposures of varying spurt durations and spurt delivery patterns (single vs. multiple spurts).
Twenty-seven normal human subjects were exposed to single cryogen spurts from 10 to 80 milliseconds, and multiple spurt patterns consisting of two 20-millisecond spurts, four 10-millisecond spurts, and eight 5-millisecond spurts. Subjects were evaluated by clinical observation and photography at 1 hour, 1 day, and 1, 4, 8, and 12 weeks after CSC exposure.
Acute erythema and urticaria (1–24 hours) were noted in 14 of 27 and 3 of 27 subjects, respectively. Transient hyperpigmentation occurred in 4 of 27 subjects (skin types III–VI) but resolved spontaneously without medical intervention in all subjects by 8 weeks. No permanent skin changes were noted in any subjects. Skin reactions were more common with longer single-spurt durations (50 milliseconds or greater) and multiple spurt patterns.
Acute erythema, urticaria, and, less commonly, transient hyperpigmentation were observed after CSC exposure. Permanent skin injury was not observed and is unlikely.
*Beckman Laser Institute, Irvine, California
†Departamento de Optica, Instituto Nacional de Astrofísica, Optica y Electrónica, Puebla, México
‡Department of Dermatology, University of California, Irvine, California
§Department of Mechanical Engineering, University of California, Riverside, California
∥Department of Biomedical Engineering, University of California, Irvine, California
The cryogen spray cooling method described in this article is contained within U.S. Patent 5,814,040-Apparatus and Method for Dynamic Cooling of Biological Tissue for Thermal Mediated Surgery, awarded to J. Stuart Nelson, MD, PhD, Thomas E. Milner, PhD, and Lars O. Svaasand, PhD, and assigned to the Regents of the University of California.
Address correspondence and reprint requests to: Kristen M. Kelly, MD, Beckman Laser Institute and Medical Clinic, 1002 Health Sciences Road East, Irvine, CA 92612, or e-mail: KMKelly@uci.edu.
KMK was supported by the National Institutes of Health (AR51443), the Dermatology Foundation, and the Sturge-Weber Foundation. JRSJ acknowledges the Fondo de Repatriaciones CONACyT-México. JSN was supported by the National Institutes of Health (AR47551 and GM62177).