Effectiveness of the Normal-Mode Ruby Laser and the Combined (Normal-Mode Plus Q-Switched) Ruby Laser in the Treatment of Congenital Melanocytic Nevi: A Comparative Study

Abstract

The effect of the normal-mode ruby laser (NMRL) and the combined (normal mode plus Q-switched) ruby laser on congenital melanocytic nevi (CMN) was evaluated, and the degree to which both laser treatment regimens remove melanocytes was compared in 15 patients. Each nevus was marked to designate half of the lesion for the NMRL treatment and half of the lesion for combined ruby laser treatment. The efficacy of each laser treatment was correlated with the degree of clinical improvement determined by photographic assessment, histological examination, and melanin reflectance spectrometry before and 3 months after laser treatment. A single treatment using the NMRL with energy fluences of both 20 J per square centimeter and 30 J per square centimeter resulted in a slight, but not significant, improvement in lightening of pigmentation (42.61% and 30.38%, respectively). A better clinical response (excellent to good) and higher percentage of lightening (64.45%-72.43%) was noted in the combined ruby laser-treated areas than the NMRL-treated areas. Histological results showed that the combined ruby laser provided a marked decrease in the number of the nevomelanocytic nests in both the junctional area and the papillary and reticular dermis, whereas the NMRL (with energy fluences of either 20 J per square centimeter or 30 J per square centimeter) caused a decrease in the junctional area and the papillary dermis. None of the nevi had complete clearance of the pigmentation after a single treatment. Therefore, multiple (four to five) treatment sessions are needed to cause complete removal of nevomelanocytic nests in CMN. In conclusion, the combined ruby laser is more effective than the NMRL alone in the treatment of CMN without scarring or textural change of the skin.

Q‐switched ruby versus long‐pulsed dye laser delivered with compression for treatment of facial lentigines in Asians

“…The degree of lightening of the lesions was assessed by a red-green skin reflectance spectrometer (Dermaspectrometer, Cortex Technology, Hagland, Denmark) [8]. The mean of melanin index (MI) measurements taken from the lentigines before (MI Pre ), 4 weeks after laser irradiation (MI Post ) and the adjacent normal skin (MI Normal ) was calculated.…”

A Treatment of Medium-to-Giant Congenital Melanocytic Nevi with Combined Er:YAG Laser and Long-Pulsed Alexandrite Laser

“…7 Funayama et al reported significant pigment removal of giant CMN in six patients using combined pulsed dye laser and QS ruby laser treatment with minimal scarring, but the average number of treatments necessary was 7.7 sessions. 11 Our patient with giant CMN achieved good (51-75%) reduction of pigment after only one session of combined Er:YAG/LP-Alex laser treatment, and no signs of malignant transformation in the treated area were seen in follow-up. Near complete clearance of pigment was achieved in areas relatively lighter in color, but pigmented nevomelanocytic nests might persist in the deeper dermal layers in darker areas, which would require further treatment sessions.…”

“…In order to solve this problem, many studies have utilized ruby lasers in various combinations of different modes, including normal mode, QS mode, and long-pulsed mode. 5,[11][12][13][14][15] Some of these studies reported good results, although multiple treatment sessions were required.…”

Congenital melanocytic nevi: Where are we now?

“…Treatment failures with QSRL are thought to result from their short pulse durations and limited depth of penetration (1 mm). 53,68,69 Ueda et al 70 suggested that long-pulsed lasers might allow more heat dispersion to surrounding cells, allowing for more effective targeting of nevus nests, including nonpigmented melanocytes rather than individual nevus cells. 70 Studies using NMRLs have shown efficacy at nevus clearance of small to giant sized CMN in Japanese patients.…”