Kai Tang, Shao-qing Guo, Geng-ting Dang
Department of Orthopaedics, Third Hospital of Peking University, Beijing, People's Republic of China.
Spine (Phila Pa 1976). 2003 Aug 1;28(15):1653-8. doi: 10.1097/01.BRS.0000083168.37329.B4.
Autogenous bone marrow stromal-derived osteoblasts-porous calcium phosphate ceramic composites were constructed in vitro under cell culture for 48 hours and implanted as a bone graft substitute for lumbar intervertebral spinal fusion in rabbits.
To evaluate the efficacy of autogenous bone marrow stromal-derived osteoblasts-porous calcium phosphate ceramic composites as an alternative to autogenous graft materials in a lumbar interbody spinal fusion model.
Bone marrow contains a population of rare progenitor cells capable of differentiating into bone, cartilage, muscle, tendon, and other connective tissues. These cells can be induced and differentiated into osteogenic osteoblasts with addition of osteogenic supplements. Combining bone marrow stromal-derived osteoblasts with porous ceramics gave rise to bone tissue in subcutaneous sites and repaired critical size segmental femoral defects. Little work has been done in the spine to assess fusion rates and associated biomechanical characteristics.
Five experimental groups were evaluated: sham operation (Group I); porous calcium phosphate ceramics alone (Group II); autogenous tricortical iliac crest (Group III); bone marrow stromal-derived osteoblasts-calcium phosphate ceramic composites (Group IV); bone marrow stromal-derived osteoblasts-calcium phosphate ceramic composites with rhBMP-2 (Group V). All rabbits were killed 12 weeks after surgery, and the spinal fusion segments underwent the evaluation of gross inspection, manual palpation, radiography, computed tomography, nondestructive biomechanical testing, and histologic analysis.
Successful spinal fusion was achieved by manual palpation in 100% (6/6) of animals in Group IV and Group V, 66.7% (4/6) in Group III, 50% (3/6) in Group II, and 0% (0/6) in Group I. Radiographic studies showed that minimal disc height loss was observed with ceramic blocks than with autograft. Biomechanical testingconfirmed that spines from Group IV and Group V were statistically significantly stiffer in flexion, extension, left and right bending, and left and right torsion than Group III and Group II. Histologic analysis demonstrated a qualitative increase of bone formation in fusion mass in Group IV and Group V versus all other groups. The size of fusion mass and the stiffness of fusion segments were greatest in Group V.
The results indicate that bone marrow stromal-derived osteoblasts-calcium phosphate ceramic composites may provide an alternative to autogenous graft materials for lumbar interbody spinal fusion. Adding recombinant human bone morphogenetic protein-2 into the composites may reinforce the biomechanical stiffness for spinal fusion segments. Porous calcium phosphate ceramics alone were not suitable as a bone graft substitute for lumbar interbody spinal fusion.
自体骨髓基质来源的成骨细胞 - 多孔磷酸钙陶瓷复合材料在体外细胞培养48小时后构建，并作为骨移植替代物植入兔腰椎椎间融合部位。
在腰椎椎间融合模型中评估自体骨髓基质来源的成骨细胞 - 多孔磷酸钙陶瓷复合材料作为自体移植材料替代品的疗效。
骨髓中含有一群罕见的祖细胞，能够分化为骨、软骨、肌肉、肌腱和其他结缔组织。添加成骨补充剂后，这些细胞可被诱导分化为成骨的成骨细胞。将骨髓基质来源的成骨细胞与多孔陶瓷结合可在皮下部位形成骨组织，并修复临界尺寸的股骨节段性缺损。在脊柱方面，评估融合率和相关生物力学特性的工作做得很少。
评估五个实验组：假手术组（I组）；单纯多孔磷酸钙陶瓷组（II组）；自体三面皮质髂嵴组（III组）；骨髓基质来源的成骨细胞 - 磷酸钙陶瓷复合材料组（IV组）；骨髓基质来源的成骨细胞 - 磷酸钙陶瓷复合材料加重组人骨形态发生蛋白 -2组（V组）。所有兔子在手术后12周处死，对脊柱融合节段进行大体检查、手动触诊、X线摄影、计算机断层扫描、无损生物力学测试和组织学分析。
IV组和V组100%（6/6）的动物通过手动触诊实现了成功的脊柱融合，III组为66.7%（4/6），II组为50%（3/6），I组为0%（0/6）。X线摄影研究表明，与自体移植相比，陶瓷块观察到的椎间盘高度损失最小。生物力学测试证实，IV组和V组的脊柱在屈伸、左右侧弯和左右扭转方面在统计学上比III组和II组更硬。组织学分析表明，IV组和V组融合块中的骨形成质量相对于所有其他组有所增加。V组融合块的大小和融合节段的刚度最大。
结果表明，骨髓基质来源的成骨细胞 - 磷酸钙陶瓷复合材料可能为腰椎椎间融合提供自体移植材料的替代品。在复合材料中添加重组人骨形态发生蛋白 -2可能会增强脊柱融合节段的生物力学刚度。单纯多孔磷酸钙陶瓷不适合作为腰椎椎间融合的骨移植替代物。
