Title: Comparison of the Q-switched alexandrite (755 nm) and Q-switched Nd:YAG (1064 nm) lasers in the treatment of benign melanocytic nevi.
Author: Rosenbach A, Williams CM, Alster TS
Publication: Dermatol Surg 1997 Apr;23(4):239-44; discussion 244-5
PMID: 9149789, UI: 97293895
Affiliated institution: Washington Institute of Dermatologic Laser Surgery, Washington, DC 20037, USA.
BACKGROUND: A variety of pigmented lesions have been shown to be effectively treated with several pigment-specific laser systems currently available. There has been recent evidence to indicate that they may also be useful in the treatment of melanocytic nevi.
OBJECTIVE: To compare the clinical and histologic effects of the Q-switched (QS) alexandrite (755 nm) and Nd:YAG (1064 nm) lasers in the treatment of melanocytic nevi.
METHODS: Eighteen patients received three QS alexandrite and Nd:YAG laser treatments to either half of a large nevus or to two small adjacent nevi. Tissue biopsies were obtained for histologic examination. Degree of clinical improvement was determined by comparative photographic global assessment scores. The amount of melanin present within the nevi before and after laser irradiation was measured by reflectance spectrometry.
RESULTS: Clinical global assessment scores were significantly reduced in all QS alexandrite and QS Nd:YAG laser-treated nevi after three treatments. Melanin reflectance spectrometry scores improved after the first laser treatment only. Histologically, a significant reduction in epidermal pigmentation and melanocytes were observed following laser irradiation with either QS system.
CONCLUSION: Both the QS alexandrite and Nd:YAG laser systems resulted in significant improvement (lightening) of treated nevi. The QS alexandrite laser produced slightly better results using the parameters outlined.