Enhancement of dorsal random-pattern skin flap survival in rats with topical lidocaine and prilocaine (EMLA): Enhancement of flap survival by EMLA

Various topical pharmacologic agents have been investigated for their efficacy in preventing or reversing skin flap ischemia. Most of these studies have focused on agents that act on the vascular smooth muscles to cause vasodilatation and improve circulation in the flap. Most of local anesthetics relax vascular smooth muscle and produce peripheral vasodilatation. Topical lidocaine administration was shown that it was an effective and prompt resolution of mechanically induced vasospasm. The topical analgesia cream, EMLA is a mixture of the substances lidocaine and prilocaine. EMLA causes a biphasic vascular response comprising initial blanching and vasoconstriction (maximal after 1.5 h of application) and late erythema and vasodilatation at application times longer than 3 h.To investigate the effect of EMLA on random flap survival, 40 rats were divided in 2 groups of 20 animals. Caudally based random pattern skin flaps were elevated on dorsa of the rats in 10 x 3 cm dimensions. In group 1 which was the treatment group, topical EMLA was applied and covered with Opsite for 1 week whereas in group 2 which was the control group, carrier for EMLA was applied to the flaps. At the end of treatment period, the areas of flap necrosis were measured and percentages of flap survivals were calculated.The mean percentages of flap survivals in group 1 and 2 were 81.2 +/- 1.2 percent and 58.7 +/- 2.3 percent, respectively.Topically administered EMLA might lead to a significant improvement in flap survival. In addition, it is safe, cost-effective, easily applied, and clinically available.