复合椎体重建兔颈椎的生物学实验研究

Biological study of allogenic composite implants on reconstruction of rabbit cervical vertebrae

目的探讨同种异体皮质骨环(humeral cortical ring allograft,HCA)及异体松质骨(cancellous allogenic bone,CAB)复合椎体材料重建颈椎能力,为临床应用提供理论依据。方法取39只新西兰大耳白兔切除C4制成椎体缺损模型并分为3组:A组植入HCA-CAB复合物、B组植入自体髂骨、C组植入HCA-丙烯酸树脂骨水泥(acrylic bone ce-ment,ABC)。在术后不同时间分别进行大体标本、组织学、X线片和扫描电镜观察以及生物力学测试,检测血清中碱性磷酸酶(alkaline phophatase,ALP)活性、钙浓度、磷浓度,比较三者修复骨缺损的能力。结果术后各组血清ALP均开始升高,在2、4周时各组内差异有统计学意义(P<0.01)。A组和B组血清中ALP及磷浓度均高于C组(P<0.01),A组和B组血清中ALP及钙、磷浓度差异无统计学意义(P>0.05)。术后2个月X线片及大体标本观察示A组与B组植骨材料与上下颈椎融合,有大量骨痂;C组示未完全融合,只有少量骨痂生长。组织学观察术后1个月A组与B组可见有散在骨岛及骨小梁形成;2个月A组与B组形成大量成熟骨基质、骨小梁及骨髓腔。扫描电镜观察示A组有大量新骨形成。2个月生物力学测试结果表明A组与B组力学指标差异无统计学意义(P>0.05)。结论HCA-CAB复合物具有较强的成骨能力,可作为有效的椎体重建材料。

Objective To explore the ability of reconstructing cervical vertebrae with the compound of humeral cortical ring allograft （HCA） packed with cancellous allogenie bone （ CAB）, and to find some evidence to support the clinical practice of allogenie composite implants on reconstruction of vertebral body. Methods The animal models of C4 defect were created by surgery in the 39 New Zealand white rabbits. Group A were treated with HCA-CAB compound, and Group B with autngenous iliae crest, Group C with HCA and acrylic bone cement. Observations were made by gross specimen, X-rays, histology and scanning electron microscope （SEM） examination, and the effects were determined by biomechanieal tests as well as measurements of calcium, phosphorus and alkaline phophatase （ALP） in serum at different periods postoperatively. Results The amount of serum ALP elevated after operation in all the groups, .and the activity of ALP was significantly higher at the 4th weeks than that at the 2nd week （P 〈0.01 ）. The contents of serum ALP and phosphate in Group A and B were significant higher than those in Group C （P 〈0. 01 ） , but there was no difference on contents of serum ALP, calcium and phosphate between Group A and B （P 〉 0.05 ）. The gross specimen and X-rays examination showed the spine fusion with lots of bone callus in Group A and B, and a little bone callus without full fusion in Group C at the 2nd month. Histological analysis exhibited scat- tered bone island and bone trabecula formation at the 1 st month, and many mature bone matrix and bone marrow cavity formation at the 2nd month in Group A and B. The SEM also showed that there were many new bone formed in Group A. There was no difference on mechanics index between Group A and B according to the biomeehanical tests at the 2nd month （P 〉 0.05 ）. Conclusion The HCA-CAB compound possesses higher osteogenie potential and the ability of rebuilding vertebral body and can serve as an autograft substitute material.