不同充填材料应用于山羊经皮椎体成形术的组织学研究

目的:研究聚甲基丙烯酸甲酯(PMMA)、磷酸钙人工骨(CPC)和复合重组人骨形态发生蛋白-2的磷酸钙人工骨(rhBMP-2/CPC)在山羊骨质疏松症模型上行经皮椎体成形术(PVP)后的组织学表现。方法:6～8岁雌性山羊8只,均行双侧卵巢切除术,术后4个月建立骨质疏松症模型。在C形臂X线机监视下,随机选取8只山羊的L2-L6的两节椎体行PVP,分别充填PMMA、CPC和rhBMP-2/CPC,保证每只山羊的两节穿刺椎体的充填材料各不相同,术后4个月处死所有动物,取出椎体,组织学观察。结果:8只山羊16个椎体的PVP均成功,共出现4个椎体的渗漏。肉眼观察:PMMA与松质骨界限清晰,一个椎体取材时交界面出现破碎和脱落现象;而CPC和rhBMP-2/CPC与椎体内松质骨界限不清,互相融合生长。HE染色光镜观察:PMMA与骨小梁松散结合,界限明显,未见PMMA吸收和新生骨形成;CPC均匀分布于骨小梁和骨髓组织内,有CPC吸收现象,同时可见有新生软骨样团块形成,并有新生骨组织形成向其中心长入;rhBMP-2/CPC除了CPC的表现外,可见成骨活动活跃。结论:在组织学上,rhBMP-2/CPC和CPC均具有降解活性和骨传导活性,优于PMMA。rhBMP-2/CPC还具有诱导成骨活性,可能成为PVP中强化骨质疏松性椎体的首选充填材料。

Histological study of vertebral body after percutaneous vertebroplasty with different filling materials:an experimental study in osteoporotic goats

Objective:To investigate histological manifestation of vertebral body after percutaneous vertebroplasty(PVP)in osteoporotic goats with three different filling materials:polymethylmethacrylate(PMMA),calcium phosphate cement(CPC)and rhBMP-2/CPC.Methods:Eight healthy ewes(from 6 to 8 years old)underwent ovariectomy of both sides(OVX).So the osteoporotic models were established 4 months after the OVX.Two vertebral bodies(L2-L6)of each ewe were randomly selected,which were filled with PMMA,CPC and rhBMP-2/CPC respectively under fluoroscopic guidance.The filling materials were different in the two vertebrae of the same ewe.Sixteen vertebral bodies from eight ewes were histologically analyzed four months after filling.Results:PVP was successfully performed in all the sixteen vertebral bodies,and cement leakage was found in four vertebrae.The evaluation with naked eyes showed that PMMA was not in tight contact with the bone,and the phenomenon that PMMA fell to piece and broke off at the interface was found in one specimen.However,CPC and rhBMP-2/CPC were in tight contact with the bone.Light microscopic evaluation(HE staining)showed that PMMA was in loose contact with the bone trabecula,PMMA could not be resorbed,and new bone could not be found.On the contrary,CPC was distributed evenly in the trabecula,and CPC resorbtion and new bone formation can be discovered.Besides the same change as that of CPC mentioned above,the osteoinduction of rhBMP-2/CPC was active.Conclusion:The results indicate that CPC and rhBMP-2/CPC have better activity of degradation and osteoacusis than PMMA.Besides rhBMP-2/CPC can induce ossification,which make it the first candidate material(as a bone substitute in the PVP)for the treatment of compression fracture of vertebral body caused by osteoporosis.