Quantitative histomorphometric evaluation of spinal arthrodesis after biphasic calcium phosphate ceramic implantation in sheep
Résumé
The effectiveness of a macroporous biphasic calcium phosphate ceramic was studied after laterovertebral arthrodesis in sheep. A ceramic with a TCP/HAP ratio of 35/65 was compared with autogenous bone graft 1, 3, 6, 9 and 12 months after implantation. Surface, lengths, and relative pore parameters have been quantified by using light microscopy and image analysis. Quantitative analysis of the results indicated that the biphasic ceramic allows an arthrodesis after 12 months, although control graft is effective after six months. The implanted material is still present after 12 months. Degradation of the ceramic is initially fast, then slows down. The intra-implant new bone formation reaches 15% after three months and 19% after 12 months. In contrast, bone ingrowth increases from 9% after three months to 23% after 12 months in intertransverse zone. Bone formation was seen with a higher frequency in pores of 240–480 µm in average diameters. New bone fills only one part of the area of a pore. A spinal fusion can be obtained with this biphasic ceramic, but the use of this material cannot be currently recommended without further investigations.