The potential effect of intradermal Botulinum Toxin Type-A (BTA) injection to increase extended random skin flap survival

Background:Extended random skin flap failure often occurs due to insufficient vascularization. Several attempts have been tried to increase the viability of the flap, but none of these attempts have achieved maximal success. Previous research has shown that Botulinum toxin type A (BTA) increases the viability of cutaneous flaps by inhibiting muscle contraction along with increasing vasodilation and angiogenesis. This study examines the effect of intradermal BTA injection on extended random skin flaps viability. Methods: In thirty-six Wistar rats, a rectangular random cutaneous flap (6 cm × 1.5 cm) was made on each dorsal rat area and then elevated the flap. The treatment group was intradermally injected evenly with BTA 8 IU and saline solution for the control group. Each rat flap viability was observed after five days. Primary outcome measures are survival flap area using Visitrak, microscopic assessment of the number and diameter of capillaries and Vascular Endothelial Growth Factor (VEGF) expression was analyzed using immunohistochemistry semi-quantitative scoring system. Data were analyzed using SPSS version 21 for Windows. Results: The treatment group has better results in all observed parameters than the control group. However, Only the VEGF expression of proximal edge showed a statistically significant increase in the group treated with BTA injection (p=0.004). Conclusion:This study showed that the BTA treatment has a positive effect on random skin flap survival and the reduction of distal necrosis in rats, so it has been proven that BTA has the potential to increase flap survival rates in small animal models. Further studies are needed to determine whether BTA treatment can produce similar findings in humans.