Laser skin resurfacing using a frequency doubled Nd:YAG laser after topical application of an exogenous chromophore

Abstract

Background and Objectives: Although laser skin resurfacing performed with CO 2 or Er:YAG lasers is efficient, side effects such as prolonged postoperative erythema, delayed healing, scarring, and pigmentation, have been reported. These side effects are due to skin characteristics but also to variations of the thermal effects associated with laser skin resurfacing. The study aimed to evaluate a new laser resurfacing method based on a previous topical application of an exogenous chromophore in order to have reproducible thermal effects. Materials and Methods: Exogenous chromophore consisted in carbon dispersed and mixed with film-forming polymers and water. The resultant solution was applied to the skin surface using an airbrush. Experimental evaluation was performed in vivo on hairless rat skin using the following parameters (532 nm, 2.7 W, 1 mm, 50-200 ms, 17.2-68.8 J/cm 2 , single pass). Skin biopsies were taken to evaluate histological changes and to quantify epidermis ablation and dermal coagulation depth. Wound healing was followed up during 10 days. Results: Total epidermis ablation was achieved with all pulse durations used. Dermal coagulation depth increased as a function of exposure time. Scar formation was correlated with dermal coagulation depth. Conclusion: The concept of applying a carbon-based solution onto skin in order to obtain laser light conversion into heat followed by heat transfer to the tissue is valid for laser skin resurfacing. By selecting exposure time, the thermal effects are predictable and dermal coagulation depth can be either that observed with a Er:YAG laser or that obtained with a CO 2 laser. Moreover, frequency doubled Nd:YAG laser, already used in dermatology for angiodysplasias treatment, could be easily used for resurfacing of periorbital or perioral zones. Lasers Surg. Med. 25:43-50, 1999.

The spectrum of laser skin resurfacing: Nonablative, fractional, and ablative laser resurfacing

“…1,2 Initially, the Q-switched Nd:YAG laser at 1064 nm, either alone or in combination with a carbon particle solution, was shown to induce some dermal remodeling. 3,4 Subsequently, vascular lasers, such as the PDL or pulsed 532-nm lasers were used, with minimal efficacy as discussed later. The use of these aforementioned lasers has been largely replaced by the longer wavelength infrared lasers, which more effectively target the mid dermis, resulting in more consistent mild improvement in rhytides.…”

In vivo experimental evaluation of skin remodeling by using an Er:Glass laser with contact cooling

“…These animals are covered by thin hair, which falls out through the fourth week, grows in by the seventh to ninth week, and falls out again thereafter (male rats). This skin model has been used already for evaluation of laser irradiation in vivo [13][14][15]. Thanks to the absence of hair during the period, quantification of superficial skin damage can be easily performed.…”

Optimization of laser osteotomy at 1064 nm using a graphite topical absorber and a nitrogen assist gas jet

“…The use of topical chromophores have been studied in laser skin resurfacing applications to increase thermal ablative damage for improved resurfacing results. Sumain et al proposed the viability of carbon-based topical chromophores on skin with 532nm laser irradiance for increased laser light absorption and subsequent heat transfer to dermal tissue [8]. The results showed that the coagulation depth was dependant on laser dose, and it was claimed that the use of the carbon-based chromophores were effective.…”