β-tricalcium phosphate as a bone substitute for dorsal spinal fusion in adolescent idiopathic scoliosis: preliminary results of a prospective clinical study

Abstract.

The aim of this study is to evaluate the ability of β-tricalcium phosphate (TCP) in granular form to achieve dorsal spondylodesis in adolescent idiopathic scoliosis (AIS). Twenty-eight patients underwent surgical correction and were followed up for 13±8 (range 6–33) months. Posterolateral grafting was performed, using either autograft bone mixed with allograft bone (n=19; "bone group") or autograft bone mixed with 25 g TCP (n=9; "TCP group"). Patients were followed by clinical examination, X-rays and computed tomographic (CT) scans to measure bone mineral density. Fusion involved 12±1 (range 10–14) vertebrae. The segments were fused after 6±1 months in both groups according to the radiographs. No pseudarthrosis was observed. Bone mineral density was 430±111 (range 273–629) mg/cm³ in the TCP group versus 337±134 (range 130–669) mg/cm³ in the bone group. Resorption of TCP was complete on the radiographs after 8±2 (range 6–10) months. Based upon the results of this small preliminary study, the use of TCP appears to be a valuable alternative to allografts for application in the spine, even when large amounts of bone are needed.