Efficacy of topical nitroglycerin and transcutaneous electrical nerve stimulation on survival of random-pattern skin flaps in rats

We compared the efficacy of topical nitroglycerin and transcutaneous electrical nerve stimulation (TENS) on the survival of random-pattern skin flaps in rats. Thirty Wistar albino rats were used and a dorsal, cranially-based random-pattern flap was raised. The rats were divided into three groups of 10 rats each. The first group had only the flap raised while the second and third groups were given topical nitroglycerin 5 mg or TENS for one hour a day for seven days. The amount of flap necrosis was measured on the seventh postoperative day. The mean area of necrosis in the flaps were 726.2, 544.2, and 150.0 mm(2) in the control, nitroglycerin, and TENS groups, respectively. The mean percentage of flaps that necrosed were 51.9, 38.9, and 10.7 in the corresponding groups. The TENS group had significantly higher percentage area of flap surviving than the control (p < 0.0001) and nitroglycerin groups (p = 0.002). TENS, with its efficacy on survival and with negligible side-effects, could be a reliable treatment. Clinically, it can easily be used postoperatively when flaps become ischaemic, and will be tolerated well by patients.