INTRODUCTION
Wound healing is a complex and dynamic process that can on occasion alterations that lead to the formation of hypertrophic and keloid scars. Their cosmetic appearance is a major problem for patients when these scars are on the face or visible areas. They can also cause functional alterations when they are located in areas of mobility. During healing a process of angiogenesis takes place that presents clinically as skin erythema, telangiectasia, and edema during the first days after trauma.1 The healing process tends to be exaggerated and techniques have been studied to reduce vascularity because this reduces the essential nutrients needed to produce collagen and other extracellular matrix substances that cause scars.2 Pulsed dye laser (PDL) has a wavelength of 585-595 nm, which targets the chromophore hemoglobin, making it ideal for the treatment of vascular or highly vascularized lesions as in the case of post-surgical scars1-2 a principle also known as selective photothermolysis, which was described by Anderson and Parrish in 1983.3 Also it has been described a decrease in cell activity due to localized tissue anoxia has been described with this technique.4
PDL can be used as soon as skin sutures are removed. It has been shown to be an effective and safe procedure for early treatment of scars.5 The best results are seen when the laser is applied at least 3 times after skin suture removal.6
There is no report for this treatment in Fitzpatrick skin types III and IV, it is know that this skin types are more prone to hyperpigmentation; and there is very few studies that exam biopsies of the treated skin to determine the degree of changes before and after the PDL laser in scars.
The objectives of this study were to determine the level of improvement of post-dermatological surgery scars clinical and histopathological and to validate the use of PDL for the treatment of scars in a Latin American population with the parameters described con caucasians.
MATERIALS AND METHODS
Thirty patients attending the dermatology department in a public hospital or to a private clinical practice for excision of either a benign or malignant lesion were recruited. The study protocol was previously approved by the ethics committee of the institution. Patients provided written informed consent for the procedure. The surgical procedure was performed in the same manner, using the same types of instruments and under the same conditions. After surgery, the patient was referred for suture removal (time according to anatomical site). At this time they were randomized to one of two groups of 15 patients each, single blind study, the number of the patients and if it was placebo or treatment group were previously asigned. In Group 1,
