CARLSBAD, CALIF. Treating pigmented lesions by combining different lasers "is tempting, since the single-modality approach remains imperfect," Dr. Jerome M. Garden said at a symposium on laser and cosmetic surgery sponsored by SkinCare Physicians.
The number of available options is "wide open. You can use different wavelengths and different pulse durations. But there is a serious potential for greater side effects," and it's worthwhile to ask, "Is it worth it, and is there something as good and maybe safer?" he said.
As a case in point, he discussed a recent study in which researchers used the CO2 laser and the Q-switched alexandrite laser to treat congenital nevomelanocytic nevi in 11 patients (Dermatol. Surg. 2005;31:51821). The nevi were first treated with one or two CO2 laser passes to peel off the dermis. This was followed by treatment with the Q-switched alexandrite laser.
The average improvement was 51%70%, but nearly 30% of patients had hypertrophic scarring. The researchers were "able to get rid of the nevus, but [they] also scarred the whole area, which is something you're not trying to do," said Dr. Garden of the department of dermatology at Northwestern University, Chicago.
In a more recent study, researchers used the 532-nm Nd:YAG laser followed by the 1064-nm Q-switched Nd:YAG laser to treat patients with acquired bilateral Hori's nevus (Dermatol. Surg. 2006; 32:3440). Patients' right cheeks were treated with the 532-nm laser plus the 1064-nm laser, while the left cheeks were treated with the 1064-nm laser alone. The combination treatment yielded more effective results, but the combined approach also caused more postinflammatory hyperpigmentation.
"I think the reason was that there was just more heat to the area," Dr. Garden said.
He shared his own experience with one patient whose pigmented lesions he treated with a Q-switched ruby laser and a long-pulsed diode laser. The patient got some reduction in color, but also experienced hypertrophic scarring. "It's interesting that [this combination approach] is helpful. Unfortunately, because we are tossing in more energy, it's also very scary in terms of the outcome," he said.
Dr. Garden disclosed that he has received equipment from Candela, Hoya ConBio, Palomar, and Sinon. He has also received research funding from Candela.