Use of three-phase bone scans and SPET in the follow-up of patients with allogenic vascularized femur transplants

The vascularized allotransplantation of femoral diaphyses under immunosuppr ession is a novel approach in orthopaedic surgery. To evaluate which method provides the best information about microvascularity and viability of the transplant, we compared different diagnostic approaches used in transplant surgery. Three patients were investigated four times over a period of 1 mon th (on days 2, 7, 15 and 30 post-transplantation) and 6 and 12 months later with planar Tc-99(m)-MDP three-phase bone scintigraphy and SPET. The resul ts were compared with duplex sonography, angiography and intraoperative bio psies. Rejection and thrombosis of the transplant were associated with decr eased or missing perfusion detected by duplex sonography, angiography and b lood pool scintigraphy. In these eases, late bone scans showed reduced or a bsent bone metabolism while biopsy revealed necrotic bone tissue. In cases without complications, blood pool scans revealed hyperaemia of the graft in dicating excellent perfusion and patency of vascular anastomoses and transp lant vessels. Late bone scans demonstrated increased bone metabolism. The c orresponding biopsies showed viable bone cells. We conclude that bone scint igraphy is a valuable diagnostic tool in vascularized femur allotransplanta tion, since it provides reliable information on both viability and perfusio n of the transplant within a single non-invasive investigation. ((C) 1999 L ippincott Williams & Wilkins).