R Kaufmann1, R Hibst. 1. Department of Dermatology, University of Frankfurt Medical School, Germany.
Abstract
BACKGROUND AND OBJECTIVE: Among the various pulsed midinfrared-lasers studied in skin surgery the 2.94 microns Erbium:YAG laser has been shown to combine most efficacious ablation with least thermal damage due to its unique absorption characteristics in tissue water. A newly developed high-power Erbium:YAG laboratory laser providing output energies (up to 1.5 J/pulse) and repetition rates (up to 15 Hz) appropriate for clinical use enabled us to investigate its potential indications in dermatological surgery. STUDY DESIGN/ MATERIALS AND METHODS: Erbium:YAG laser ablation was performed in vitro on pig skin and in vivo on a total of 30 patients presenting with different skin disorders. RESULTS: In vitro ablation efficiency linearly increased with radiant exposure and was inversely correlated with pulse frequency. Ablation rate at 10 Jcm-2 (used clinically) measured from approximately 10 microns (at 10 Hz) to 40 microns (at 1 Hz). Also for high repetition rates thermal necrosis did not exceed 50 microns, corresponding clinically to capillary bleeding after exposure of the dermis. Superficial lesions, such as epidermal nevi, were easily ablated and re-epithelization was unimpaired owing to the absence of tissue necrosis. In tattoos, exposed pigment particles were precisely removed. However, in deeper lesions the casual onset of bleeding impeded the procedure and scar formation was observed after reepithelization. CONCLUSION: Pulsed 2.94 microns Erbium:YAG laser surgery allows an extremely precise etching of delicate superficial skin lesions and also should have a potential for skin resurfacing.
BACKGROUND AND OBJECTIVE: Among the various pulsed midinfrared-lasers studied in skin surgery the 2.94 microns Erbium:YAG laser has been shown to combine most efficacious ablation with least thermal damage due to its unique absorption characteristics in tissue water. A newly developed high-power Erbium:YAG laboratory laser providing output energies (up to 1.5 J/pulse) and repetition rates (up to 15 Hz) appropriate for clinical use enabled us to investigate its potential indications in dermatological surgery. STUDY DESIGN/ MATERIALS AND METHODS: Erbium:YAG laser ablation was performed in vitro on pig skin and in vivo on a total of 30 patients presenting with different skin disorders. RESULTS: In vitro ablation efficiency linearly increased with radiant exposure and was inversely correlated with pulse frequency. Ablation rate at 10 Jcm-2 (used clinically) measured from approximately 10 microns (at 10 Hz) to 40 microns (at 1 Hz). Also for high repetition rates thermal necrosis did not exceed 50 microns, corresponding clinically to capillary bleeding after exposure of the dermis. Superficial lesions, such as epidermal nevi, were easily ablated and re-epithelization was unimpaired owing to the absence of tissue necrosis. In tattoos, exposed pigment particles were precisely removed. However, in deeper lesions the casual onset of bleeding impeded the procedure and scar formation was observed after reepithelization. CONCLUSION: Pulsed 2.94 microns Erbium:YAG laser surgery allows an extremely precise etching of delicate superficial skin lesions and also should have a potential for skin resurfacing.