Beneficial effect of botulinum toxin A on secondary ischaemic injury of skin flaps in rats.

Botulinum toxin A (BTX-A) protects against primary ischaemia of skin flaps, but its effect on secondary ischaemia is unknown. We induced secondary arterial or venous ischaemia in skin flaps of 32 Wistar rats, and tested the effectiveness of BTX injected subcutaneously 12hours before the flap was raised. The animals were divided into two groups of 16 (arterial or venous). Eight animals in each group were then treated with saline 1ml (control), and eight with BTX-A 5 IU (treatment). Ischaemia and necrosis were assessed after five days. There was no significant difference in necrosis between the two treatments in either group, but the amount of ischaemia did differ significantly (p=0.031 in the artetial ishcemia and p=0.015 in the venous ischemia group). BTX helped to salvage poor reperfusion in secondary ischaemia of skin flaps.