Ex vivo histological characterization of a novel ablative fractional resurfacing device

Abstract

Background and Objectives: 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. Study Design/Materials and Methods: A prototype 30 W, 10.6 mm CO 2 laser was focused to a 1/e 2 spot size of 120 mm 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 dehyrdogenase (LDH) stain. Pulse energies were varied to determine their effect on lesion dimensions. Results: 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 mm and depth 1 mm. In this configuration, the cavities were spaced approximately 500 mm apart and interlesional epidermis and dermis demonstrated viable tissue by LDH staining. Conclusion: 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. Lasers Surg. Med. 39:87-95, 2007. ß

Fractional CO2 laser‐assisted drug delivery

“…The CO 2 laser penetrates approximately 20 mm, and the Er:YAG laser penetrates approximately 2 mm into tissue. Deep tissue holes are created by a dynamic laser tissue interaction in which water absorption coefficients and pulse widths are responsible for the formation of MTZ with different dimensions of ablation and thermal coagulation zones (TCZ) [5,6,37]. In our study, the TCZ surrounding each laser hole was about 70 mm thick.…”

“…Fractional ablative lasers are commercially available as CO 2 lasers (10,600 nm) and erbium lasers (Er:YAG, 2,940 nm) [3][4][5]. Tissue absorption at these wavelengths is dominated by water.…”

“…AFR damages a fraction of the skin while leaving microscopic intervening areas of unexposed skin that are capable of remodeling the skin without scarring [1,2]. Fractional ablative procedures are available with carbon dioxide laser (CO 2 laser, 10,600 nm) and erbium YAG laser (Er:YAG laser, 2,940 nm) [3][4][5]. The concept of AFR has so far been used for dermal remodeling in the treatment of photodamaged facial skin, rhytides, acneiform scarring, and burn scar remodeling [3,[6][7][8][9][10].…”

The Advent of Laser Therapies in Dermatology and Urology: Underlying Mechanisms, Recent Trends and Future Directions

“…The Fraxel handpiece also comes with a feedback sensory system the Intelligent Optical Tracking System -(IOTS) that controls real-time dosage delivery as a function of physicians handspeed a unique tech -' nology in the laser dermatology industry. The ablative modality, termed Ablative Fractional Resurfacing (AFR) is developed with a high power CO2 laser [52], while the nonablative modality Nonablative Fractional -Resurfacing (NFR) is enabled with a 1550 nm (Fraxel re:store) or 1410 nm (Fraxel re:fine) laser [51]. Other fractional solutions that can be found in the market include the Lutronic MOSAIC & eCO2, Lasering Mixto, Alma Pixel, Palomar Lux1540 & LuxIR, etc.…”

Fractional ablative CO2 laser treatment versus scar subcision and autologous fat transfer in the treatment of atrophic acne scars: New technique

“…In contrast, traditional ablative laser resurfacing (with an ultra-pulsed CO 2 or Er:YAG laser) ablates 100% of the epidermal surface, which is associated with prolonged healing and an increased risk of scarring and infection. In addition, the fractional approach allows much deeper treatment (up to 1,500 µm) because of the extremely small beam diameter (100-300 µm) [9,10] . This is dramatically different from traditional ablative procedures that ablate the entire surface to approximately 300-350 µm.…”