Evaluation of a free vascularized medial tibial bone graft in dogs

Objective-To develop a free vascularized tibial bone graft based on the per iosteal saphenous blood supply. Study Design-Preliminary anatomic study of medial tibial blood supply. in v ivo comparison of a vascularized and avascular tibial bone graft. Animals-Nine canine cadavers; 14 healthy adult dogs that weighed 25 to 32 k g. Methods-An anatomic study of the vascular supply of the medial aspect of th e tibia was performed using the Spalteholz technique. A bone graft consisti ng of the medial aspect of the tibia was transferred to a mandibular defect as a vascularized graft in 7 dogs and as an avascular graft in 7 dogs, Bon e scans were performed to evaluate graft perfusion. Radiographic evaluation of the mandibles and tibias was performed. The dogs were killed after 60 d ays, five mandibles from each group were examined histologically, and two F rom each group were evaluated using the Spalteholz technique. Results-The saphenous vascular pedicle provides vascular perfusion to the m edial tibial cortex. Bone scans and radiographic evaluations were consisten t with viable bone in the vascularized grafts, and nonviable bone in the av ascular grafts. Histological examination revealed live, healing bane in vas cular grafts and necrotic bone in avascular grafts. Spalteholz evaluation r evealed many small arborizing vessels in the vascular grafts and no organiz ed vasculature in the avascular grafts. Conclusions-The vascularized medial tibial cortical bone graft survived and proceeded to bony union in the mandibular body defect more readily than th e avascular graft in this experimental model. Clinical Relevance-A vascularized medial tibial bone graft is a suitable fr ee graft for use in reconstructing bone defects in dogs. (C) Copyright 2000 by The American College of Veterinary Surgeons.