Effect of Previous Irradiation on Vascular Thrombosis of Microsurgical Anastomosis: A Preclinical Study in Rats

BACKGROUND The objective of the present investigation was to compare the effect of neoadjuvant irradiation on the microvascular anastomosis in cervical bundle using an experimental model in rats. METHODS One hundred forty male Sprague-Dawley rats were allocated into 4 groups: group I, control, arterial microanastomosis; group II, control, venous microanastomosis; group III, arterial microanastomosis with previous irradiation (20 Gy); and group IV, venous microanastomosis with previous irradiation (20 Gy). Clinical parameters, technical values of anastomosis, patency, and histopathological parameters were evaluated. RESULTS Irradiated groups (III and IV) and vein anastomosis groups (II and IV) showed significantly increased technical difficulties. Group IV showed significantly reduced patency rates (7/35) when compared with the control group (0/35). Radiotherapy significantly decreased the patency rates of the vein (7/35) when compared with the artery (1/35). Groups III and IV showed significantly reduced number of endothelial cells and also showed the presence of intimal thickening and adventitial fibrosis as compared with the control group. CONCLUSION Neoadjuvant radiotherapy reduces the viability of the venous anastomosis in a preclinical rat model with a significant increase in the incidence of vein thrombosis.