The Effect of Botulinum Toxin-A on the Survival of Random-Pattern Cutaneous Flap in Rat

ABSTRACT

PURPOSE: Botulinum toxin type A(BoTA) can block the release of vasoconstriction cotransmitters as well as acetylcholine in nerve terminal. The authors observed that BoTA increases flap survival by preventing sympathetic collapse of peripheral vessels. METHODS: 10 Sprague Dawley rats were divided into control(n=5), and BoTA group(n=5). 3x10cm sized random pattern cutaneous flaps were elevated on the dorsal side in both groups. In BoTA group, BoTA was injected into the flap via intradermal to subdermal route, 7 days before the flap elevation. Flap survival rates (survival area/total area) were measured 7 days after the elevation. Cutaneous blood flow was measured in proximal, middle and distal compartments of the flap using laser Doppler flowmetry initially, preoperatively, at immediate postoperation, and 7 days after flap elevation, respectively. Histological examination was performed 7 days after the flap elevation. The number and shape of the vessels were evaluated under microscope. RESULTS: Mean flap survival was 53.18+/-6.58% in control group and 93.79+/-6.06% in BoTA group, displaying statistically significant difference(p=0.0008, p< 0.05). In the control group, blood flow to the middle and distal compartments of the flap decreased significantly immediately after flap elevation. In the BoTA group, blood flow to the middle compartment did not decrease(p=0.002) and slightly decreased in the distal compartment(p=0.001). Cutaneous blood flow was significantly higher in all compartments of the flap in BoTA group than in control group, 7 days after the flap elevation. In histopathologic examination, greater number of vessels were noted in the BoTA group than in the control group. CONCLUSION: Botulinum toxin A can increase the survival of the random pattern cutaneous flap in rats by preventing the sympathetic collapse of peripheral vessels.