Ex vivo histological characterization of a novel ablative fractional resurfacing device

Abstract

We introduce a novel CO(2) laser device that utilizes ablative fractional resurfacing for deep dermal tissue removal and characterize the resultant thermal effects in skin. A prototype 30 W, 10.6 microm CO(2) laser was focused to a 1/e(2) spot size of 120 microm and pulse duration up to 0.7 milliseconds to achieve a microarray pattern in ex vivo human skin. Lesion depth and width were assessed histologically using either hematoxylin & eosin (H&E) or lactate dehydrogenase (LDH) stain. Pulse energies were varied to determine their effect on lesion dimensions. Microarrays of ablative and thermal injury were created in fresh ex vivo human skin irradiated with the prototype CO(2) laser device. Zones of tissue ablation were surrounded by areas of tissue coagulation spanning the epidermis and part of the dermis. A thin condensed lining on the interior wall of the lesion cavity was observed consistent with eschar formation. At 23.3 mJ, the lesion width was approximately 350 microm and depth 1 mm. In this configuration, the cavities were spaced approximately 500 microm apart and interlesional epidermis and dermis demonstrated viable tissue by LDH staining. A novel prototype ablative CO(2) laser device operating in a fractional mode was developed and its resultant thermal effects in human abdominal tissue were characterized. We discovered that controlled microarray patterns could be deposited in skin with variable depths of dermal tissue ablation depending on the treatment pulse energy. This is the first report to characterize the successful use of ablative fractional resurfacing as a potential approach to dermatological treatment.