Evaluation of bone graft viability.

Radionuclide bone single photon emission computed tomography (SPECT) scintigraphy is an excellent method for the assessment of the vascular patency and bone viability. The scintigraphic findings are important in the management of microvascularized bone grafts used in the reconstruction of bone defects. These living bone grafts are necessary when the blood supply at the host site has been compromised as a result of radiation therapy or when the bone defect is greater than 6 cm. Bone scintigraphy is unique because the uptake of radiopharmaceutical is dependent both on an adequate delivery system and a living network of osteocytes. SPECT scintigraphy provides improved imaging characteristics and structural detail of the grafted bone. Eleven patients with microvascularized bone grafts to the mandible demonstrated marked bone reaction of the entire bone graft in the postoperative period. The accumulation of radiolabelled 99mTc methylene diphosphonate (MDP) correlated extremely well with postoperative findings and clinical response. SPECT bone scintigraphy was a safe, simple and effective method for the assessment of both patency of anastomosed blood vessels and the metabolic viability of the microvascularized bone graft.