EXPERIMENTAL STUDIES ON THE EFFECT OF LIDOCAINE ON WOUND-HEALING

Local anesthetics have several effects on wound healing. In experiment al studies, procaine at high concentrations has been proved to retard healing in surgical wounds by diminishing the synthesis of mucopolysac charides and hence probably collagen. Other studies hare shown that li docaine and bupivacaine inhibit collagen synthesis in fibroblast tissu e cultures in rats, This study was designed to evaluate the effect of lidocaine on wound healing, An experimental, prospective, comparative, crossover and double-blind study was designed. Forty male guinea pigs , weighing 300 to 600 g. were randomly assigned to two groups. In cont rol group A (20 animals), skin and subcutaneous tissue in a clean woun d were incised and infiltrated with regular saline Solution; in group B 20 animals were infiltrated with 1% lidocaine. All animals were sacr ificed on day 8 and evaluated for breaking strength, number of collage n fibers by morphometry, and histologic examination of collagenization , edema, vascularity, and presence of acute and chronic inflammatory c ells. The histopathologic appearance of tissues infiltrated with lidoc aine did not vary consistently in relation to collagenization, edema, or acute and chronic inflammatory processes, The mean breaking strengt h between both groups was not statistically significant (p = 0.120). I mportant statistical differences were observed in vascularity (p < 0.0 03) and morphometric results (p < 0.001), where collagen was found in small amounts in the lidocaine group. The results of this study sugges t that local infiltration of lidocaine produces significant histopatho logic changes, but it does not substantially alter wound healing as th ere were no differences in the breaking strength of the wounds.