Experimental free tissue transfer over perivascular-injured vessels: effect of in vivo freezing

Vascular spasm of recipient vessels can increase failure rates in free tissue transfer, especially in post-traumatic perivascular-injured vessels. To investigate the effect of freezing-induced spasmolysis of recipient vessels, an experimental model of perivascular injury was developed in the rat through previous dissection of the femoral artery and epigastric vein (6 weeks before). The contralateral epigastric flap was free-transferred to healthy recipient vessels in group I, to the previously dissected vessels in group II, and to frozen-dilated perivascular-injured vessels in group III. The injured artery showed the same degree of spasm as normal arteries, while the vein showed greater spasm. Ethyl chloride reverted spasm in the injured artery and vein to the same degree as in normal vessels. Flap viability rates were 73.3% in group I, 60% in group II, and 66.7% in group III. The differences were not statistically significant. In conclusion, although further research is needed to improve the experimental model, in vivo freezing with ethyl chloride does not seem to impair free flap viability when used to treat spasm in recipient vessels.