The effect of venous occlusion on the integration of vascularized cortical bone graft

The biologic phenomena involved in the healing process of vascularized, cortical bone grafts, vascularized grafts with venous occlusion, and conventional cortical bone grafts, were studied in rabbits. The middle third of the radial diaphysis was the donor site, with a 1.6-cm-long bone cylinder delimited by double transverse osteotomies. The vascularized grafts were raised by extraperiosteal dissection, with preservation of their vascular pedicle, while the conventional grafts were obtained by subperiosteal dissection. The vascularized graft with venous occlusion had its draining vein ligated. Radiologic, scintigraphic, and histologic studies were undertaken at days 7, 15, 30, and 60 postoperatively. Results demonstrated that the vascularized graft healed earlier than the corresponding vascularized graft with venous occlusion and than the conventional graft, respectively. The vascularized graft with venous occlusion suffered some degree of impairment of its irrigation, probably due to retrograde block of the arterial blood flow. It underwent a degree of bone necrosis, followed by resorption and creeping substitution, which delayed its integration. This seemed to be a temporary effect, for it healed earlier than the conventional graft.