Comparison of tensile strength and thrombus formation between mechanical microvascular anastomoses using a biodegradable ring device and sutured anastomoses.

The purpose of this study was to evaluate whether early motion following mechanical anastomosis using a biodegradable ring device was possible or not, by measuring tensile strength and the rates of thrombus formation at anastomotic sites. Bilateral femoral arteries and veins of 24 rabbits were repaired by sutured anastomoses and biodegradable ring anastomoses. The tensile strength of the anastomotic site was measured by constant loading with a material-testing machine, using specimens excised at 24 hr, 72 hr, 1 week, and 2 weeks after anastomosis. The tensile strength of biodegradable ring arterial anastomoses was significantly stronger than sutured anastomoses at 24 hr, 72 hr, 1 week, and 2 weeks. No statistically significant differences were observed in venous anastomoses at any interval. In separate experiments, biodegradable ring anastomoses and sutured anastomoses of the bilateral femoral arteries of 18 rabbits were constructed, and early passive knee motion was carried out at 100 times once a day with maximum spreading of the hip joint for 24 hr, 72 hr, and 1 week. Thrombus formation at the anastomotic sites was evaluated by scanning electron microscope (SEM). SEM showed no thrombus formation in the biodegradable ring anastomoses at any interval; however, thrombi were observed in the sutured anastomoses (33 to approximately 50 percent).