Effects of thermal conducting media on the skin surface during laser irradiation

Objectives: To investigate the effects of thermally conductive, optically t ransparent media placed on skin during treatment with the flashlamp excited dye laser (FEDL). The use of higher energy densities to treat persistent c utaneous vascular lesions may result in a decrease in the number of treatme nt sessions, However, increased fluences can cause complications of scarrin g, hyperpigmentation, infection, skin texture changes, or hypopigmentation, The thermally conductive media should assist in dissipating surface therma l energy and thereby protect the skin from the complications. Study Design: This was a prospective laboratory study using an animal model. The results were verified in a prospective, pilot, human-use trial, Methods: The thres hold for acute skin damage and measurements of the thermal transients were made using: a rabbit model, The threshold for purpura was noted with and wi thout the use of a sapphire as a thermal conductor. The thermal transients were measured with small thermocouples placed subcutaneously. On a human su bject, purpura intensities were photographed and measured using computer mo rphometrics after treatment with the FEDL and skin surface protection with air, glass, sapphire, and diamond as conductive media. Results: With the in terposition of the sapphire thermal conductor during the FEDL treatment, ex cessive temperature increases of the epidermis were prevented during the la ser pulse compared with glass and controls. Both sapphire and diamond resul ted in decreased purpuric intensities with the applications of equivalent f luences. Wound recovery time for the purpura was decreased by approximately half a day when any of the surface conductors were used. Conclusions: The decreased transient temperature and decrease in purpura seen with the use o f sapphire and diamond protecting the epidermis during treatment; with the FEDL should result in fewer untoward effects during treatment of vascular l esions and facilitate their management.