Freezing Therapy for Relief of Vasospasm on Microvascular Anastomosis with Damaged Endothelium: An Experimental and Clinical Application

ABSTRACT

The histologically confirmed endothelial damage, which appears as a normal vessel under the operative microscope, may lead to thrombus formation or vasospasm, and ultimately result in the anastomotic failure. Vascular freezing has been reported to be an effective method of relieving spasm. This study examined if the freezing therapy could safely relieve the vasospasm accompanying microvascular anastomosis of vessels, which had histologically confirmed endothelial damage, but with no other harmful effects. In the experimental model, Microvascular anastomoses of the femoral arteries(n = 80) of 40 Sprague-Dawley rats were performed after producing crush injuries on both femoral arteries with energy to cause vasospasm and histologically confirmed endothelial damage. Freezing was achieved with ethyl chloride for 4 seconds before the anastomosis and the vascular spasm was disappeared immediately after freezing and maintained its expansion for 2,10 and 30 days after the operation. No significant difference was observed in the patency rates of the crush-freezing group and the crush group (p > 0.05). In the clinical model, a case was presented in which ethyl chloride in vivo freezing was used to relieve a refractory spasm in the recpient vessels of free latissimus dorsi muscle transfer in a soft tissue defect of dorsum of foot. The spasm was relieved and the flap survived. This study found that the vascular freezing relieved the spasm in the microvascular repair, which was accompanied by histologically confirmed endothelial damaged vessels, and that no harmful effects of vascular freezing were observed when the technique was used to prevent or elieve vascular spasm in case of microvascular repair.