Blood Flow Measurements in an Experimental Tibial Bone Transport Modelusing Tc-99m Mdp and Radiolabeled Red Blood Cell Bone Scans

Introduction: The Ilizarov method of distraction osteogenesis is a valuable tool for the treatment of segmental long bone defects. Successful treatment depends on stability of fixation; viability of the vascular supply and marrow cavity; rate, frequency and latency of distraction; and adequacy of consolidation. Several reports have described the induction of a prolonged hypervascular state during and following distraction, however previous reports have focused on angiogenesis or radiotracer emission rather than blood flow itself. Few studies have focused on blood flow and those that have utilized Tc-99m MDP bone scans to measure flow. This technique is thought to be inaccurate in states of elevated flow or with increased osteoblastic activity, both of which conditions are present in distraction osteogenesis. Because an intact vascular supply is necessary for successful union, accurate measurement of blood flow to and around the transported segment may be predictive of clinical outcome and applicable in both management and prognosis. We hypothesize that blood flow may be more accurately measured using radiolabeled red blood cells as compared to Tc-99m MDP bone scans in the hypervascular and osteogenic state induced by the Ilizarov method of distraction osteogenesis. We further hypothesize that segmental bone transport may not exhibit the same increases in blood flow previously reported for distraction osteogenesis.