The effect of capsaicin ointment on skin for the survival of a cutaneous flap

Abstract.

Recent studies have shown that capsaicin has three major effects: vasodilation, platelet disaggregation and pain reduction. In this study, vasodilation and platelet disaggregation effects were compared using an ointment (Surgilube) containing capsaicin. Forty rats were divided into four groups of 10. A distally-based dorsal skin flap was raised and sutured back into place. The circulatory territory of the flap was measured by a fluorescein technique. In group A, Surgilube was applied on and around the flap as a control for the surgical technique and ointment base. Surgilube containing capsaicin (0.2%) was applied on the surface of the flap in group B to observe platelet disaggregation effects, and around the perimeter (avoiding the incision) of the flap in group C to observe vasodilation effects. Group D received the capsaicin ointment both on and around the flap. Survival distance in millimeters was calculated as the difference from the distal end of the fluorescein stain to the distal margin of flap survival at 7 days after surgery. Analysis for difference among the groups was assessed by the method of Kruskall-Wallis followed by Mann Whitney tests for differences between the two group. The survival distances (mm) for the groups were, in order of better survival, group C (19.9), group D (14.6), group B (9.7) and group A (7.2). The improvement in survival related to the control group was statistically significant for group C (P=0.002), with group D also approaching significance (P=0.052). Furthermore, the survival distance of group C was significantly better than that of group B (P=0.004). Capsaicin was most effective in promoting skin flap survival when applied around the flap. This suggests that the vasodilation effect in flap survival is stronger than that of platelet disaggregation.