Effect of botulinum toxin a and nitroglycerin on random skin flap survival in rats

Background A suitable pharmacological substitute for the well-established surgical delay technique for random skin flaps to increase viability has been elusive. Objective To evaluate the effects of nitroglycerin and botulinum toxin type A on random flap survival in a rat model. Methods The present controlled experimental study was performed in the four groups of rats. One week after intervention in each group, the flap was raised and kept in situ, and flap necrosis was evaluated through follow-up. Group 1 received intradermal botulinum toxin type A (BTX-A) and topical nitroglycerin 2%; group 2 received BTX-A and topical Vaseline (Unilever, USA); group 3 received topical nitroglycerin and intradermal normal saline; and group 4 received topical Vaseline and intradermal normal saline. Results BTX-A reduced the area of necrosis compared with control (24% versus 56% respectively; P<0.001). Nitroglycerin application was associated with a trend toward improved flap viability (42% versus 56%; P=0.059). The combination of topical nitroglycerin and BTX-A, compared with Vaseline and BTX-A, was associated with decreased flap necrosis (16.1% versus 24%, respectively), although it was not statistically significant (P=0.45). Conclusions BTX-A was effective in reducing distal flap necrosis. The effect of BTX-A was significantly more pronounced than nitroglycerin ointment.