Blood flow evaluation of vascularized bone transfers in a canine model

Blood flow in vascularized bone transfers was evaluated in a canine model. Cortical bone blood flow was determined in undisturbed control bone, vascularized heterotopic bone transfers, and nonvascularized cortical bone grafts by means of the radionuclide‐labeled microsphere technique. Four animals were studied at 2 days, three at 1 week, eight at 2 weeks, four at 4 weeks, and three at 6 weeks postoperatively. In the 2‐day animals, the vascularized bone transfers exhibited intermediate levels of blood flow (1.4 ± 0.4 ml/100 g of bone/min) compared with undisturbed control bone (2.7 ± 0.5 ml/100 g of bone/min) and conventional cortical bone grafts (0.0 ± 0.0 ml/100 g of bone/min). At 1 week postoperatively, the differences in blood flow values of the vascularized transfers (1.7 ± 0.7 ml/100 g of bone/min) and control bone (1.4 ± 1.0 ml/100 g of bone/min) and of the nonvascularized grafts (0.2 ± 0.1 ml/100 g of bone/min) and control bone (1.6 ± 1.1 ml/100 g of bone/min) were no longer significant. At 2 weeks postoperatively, blood flow had increased in both graft groups. At 4 weeks postoperatively, the bone blood flow values in the vascularized transfers (4.8 ± 1.4 ml/100 g of bone/min) were significantly greater than the bone blood flow in control specimens (1.6 ± 0.5 ml/100 g of bone/min) and conventional cortical bone grafts (2.5 ± 2.0 ml/100 g of bone/min). At 6 weeks postoperatively, the bone blood flow values in the vascularized transfers (4.0 ± 2.1 ml/100 g of bone/min) remained greater than the bone blood flow in control specimens (1.7 ± 0.5 ml/100 g of bone/min) and conventional cortical bone grafts (2.5 ± 2.7 ml/100 g of bone/min), but the differences were no longer significant.