A Effect of Pretreatment Period on CO2 Laser Resurfacing in Guinea Pig Skin: A Comparative, Histologic Study

For the pre-treatment prior to laser resurfacing, materials such as glycolic acid, tretinoin, and/or hydroquinone have been widely used. However, the optimal duration of pretreatment is still controversial. The authors chose guinea pig skin which is similar to human skin, pre-treated it with tretinoin and hydroquinone with different duration, and examined gross and histologic changes after performing laser resurfacing in an attempt to study the effect of pre-treatment period on CO2 laser resurfacing. Sixteen guinea pigs were divided into four groups, and the dorsal skin was pre-treated with 0.05% tretinoin cream and 4% hydroquinone for 4, 8, and 12 weeks respectively while groupI underwent no pre-treatment as control. During the pre-treatment period, the authors observed gross skin reactions, and also examined the number of epithelial layers, thickness changes, the extent of epithelial regeneration, and collagen tissue change within dermis layer with skin tissue samples before and after laser resurfacing. Compared to group I(control) which received no pre- treatment, pre-treatment groups showed rapid epithelial hyperplasia and increase in the number and thickness of squamous epithelial cells and granular cell layer. However, there was no statistically significant difference in epithelial regeneration and number and thickness of epithelial cell layer between the 4-weeks, 8-weeks, 12- weeks pretreated groups. Pre-treatment with tretinoin and hydroquinone prior to laser resurfacing helped epithelial regeneration after resurfacing, but as to the benefit of long-term pre-treatment more than 4 weeks was not necessary.

Wound Dressing after CO2 Laser Resurfacing using a New Dressing Material: Medifoam(R)

CO2 laser resurfacing procedure on the face is an increasingly popular and highly effective for patients with facial rhytids and scarring. And there is a variety of dressing materials available for wound care after CO2 laser resurfacing. Among the dressing method, the authors have been used the Medifoam(R) (Il Dong Pharmaceutical Ltd. and Biopol Ltd.,Seoul, Korea; a hydrocelluar semi-permeable dressing material) after CO2 laser resurfacing. A total of 20 patients were treated for scar face and wrinkles (mainly scar face including small pox scar face) with ultra-pulsed CO2 lasers (Coherent, Palo Alto, USA). No pretreatment was done. The basic protocol of laser resurfacing was that, first pass was 300mJ on the shoulder of scar, second pass with 250-200mJ, and feathering with 150mJ. Immediately after the procedure, the wound must be cleansed and dried well so that the Medifoam(R) sticks better and early contamination is avoided. Medifoam(R) was fixed to wound surface using surgical tape or surgi-net. First dressing change was done after 24-48hours according to the amount of exudates. Because of the high absorption ability of the Medifoam(R), dressing change was not necessarily needed on postoperative day 1. Another dressing changes were done on days 3, 6, 9 postoperatively for evaluating wound healing and observation. The epithelialization was usually completed within 9 days in all cases. During the dressing change, there were no exudates outside, less crust, and less thin layer of gel formation on the wound surface than any other dressing materials. Also there was no detachment of reepithelialized layer on removing the dressing materials. The use of the Medifoam(R) after CO2 laser resurfacing accelerates the healing time, reduces the pain and anxiety of the patients due to exudation, reduces the inconvenience of the patients and surgeons by less dressing changes, and reduces the cost.