In vivo histological evaluation of a novel ablative fractional resurfacing device


  • K.F.C. has disclosed a potential financial conflict of interest with this study.


Background and Objectives

A novel carbon dioxide (CO2) laser device employing ablative fractional resurfacing was tested on human skin in vivo for the first time.

Study Design/Materials and Methods

An investigational 30 W, 10.6 µm CO2 laser system was focused to a 1/e2 spot size of 120 µm to generate an array of microscopic treatment zones (MTZ) in human forearm skin. A range of pulse energies between 5 and 40 mJ was tested and lesion dimensions were assessed histologically using hematoxylin & eosin. Wound healing of the MTZ's was assessed immediately-, 2-day, 7-day, 1-month, and 3-month post treatment. The role of heat shock proteins was examined by immunohistochemistry.


The investigational CO2 laser system created a microscopic pattern of ablative and thermal injury in human skin. The epidermis and part of the dermis demonstrated columns of thermal coagulation that surrounded tapering ablative zones lined by a thin eschar layer. Changing the pulse energy from 5 to 30 mJ resulted in a greater than threefold increase in lesion depth and twofold increase in width. Expression of heat shock protein (hsp)72 was detected as early as 2 days post-treatment and diminished significantly by 3 months. In contrast, increased expression of hsp47 was first detected at 7 days and persisted at 3 months post-treatment.


The thermal effects of a novel investigational ablative CO2 laser system utilizing fractional resurfacing were characterized in human forearm skin. We confirmed our previous ex vivo findings and show for the first time in-vivo, that a controlled array of microscopic treatment zones of ablation and coagulation could be deposited in human skin by varying treatment pulse energy. Immunohistochemical studies of heat shock proteins revealed a persistent collagen remodeling response lasting at least 3 months. We successfully demonstrated the first in-vivo use of ablative fractional resurfacing (AFR™) treatment on human skin. Lasers Surg. Med. 39:96–107, 2007. © 2007 Wiley-Liss, Inc.