国产新型骨材料填充器行经皮椎体成形术的实验观察

Experimental study of percutaneous vertebroplasty with a novel bone void filling container system

目的 探讨应用不同层数设计的新型网袋状骨材料填充器行椎体成形术对椎体生物力学性能及骨水泥在椎体内分布的影响.方法 自4具新鲜冰冻尸体脊柱标本上28个胸腰段椎体,随机分成4组,测量各标本的骨密度、前缘和中线左右侧高度以及原始刚度和强度后,建立压缩骨折模型并测量骨折后标本的高度和刚度.分别应用单层和双侧设计的网袋状骨材料填充器经单侧或双侧椎弓根注射PMMA后再次测量椎体的高度、强度和刚度.观察填充器在椎体内的膨胀情况及PMMA在椎体内的分布情况.结果 各组椎体成形术后刚度和高度较骨折后水平均有恢复,双侧穿刺组刚度明显优于单侧穿刺组.术后强度均较原始值大,但各组术后强度、高度比较差异无统计学意义.轴位透视下见双层骨材料填充器组PMMA在椎体内呈椭圆形或长椭圆形分布,单层组分布不规则.横断标本后,见双层填充器能在椎体内良好膨胀,包裹绝大部分PMMA,仅少量PMMA渗漏到网层周围.单层填充器在椎体内膨胀欠佳,大量骨水泥渗漏到网层外.结论 虽然两种骨材料填充器均能较好恢复骨折椎体的力学性能和高度.但双层设计的骨材料填充器在椎体标本内能更好的包裹绝大部分PMMA,防止骨水泥渗漏,具有更好的临床应用前景.

Objective To investigate vertebral augmentation with a novel reticulate bone filling container system by polymethyl methacrylate （PMMA） injection in cadaveric simulated vertebral compressive fracture and explore the effect of reticulate bone filling container on cement distribution controlling within vertebral body and the restoration of biomechanical properties after augmentation. Methods A total of 28 freshly frozen human vertebrae specimens were randomly divided into 4 groups. After the measurements of bone mineral density （BMD） and vertebral height, each vertebra received an axle load by a MTS （material testing system） machine to test the initial strength and stiffness. Subsequently a simultaneous compressive fracture model was created to measure the stiffness and height of fractured vertebrae. Then the augmentation procedure was performed. Afterward the biomechanical properties and the vertebral height were similarly measured as pre-operatively. The expansion of bone filling container and the distribution of cement within vertebral body were morphologically observed by crossing the specimens in sagittal midline and also intergraded with the radiographic results. Results Stiffness was significantly restored comparing with that of fractured level （P ＜ 0. 05）. And the bipedicular groups had better restoration results than the unipedicular groups. The strength and height of specimens significantly increased after the augmentation procedure but without difference among groups. In axial radiographic view, the distribution of cement in vertebral body was oval or long oval-shaped in double-layer bone filling container groups while it was irregular in single-layer groups. After crossing, the double-layer version expanded well in vertebral body and could enwrap most of injected cement. There was only a little leakage near the vessel layer. But the single-layer version had a poor expansion and a large amount of cement leakage. Conclusion This novel reticulate bone void fillingcontainer system with different layers may restore both the biomechanical properties and the height of fractured vertebrae. But, with the benefit of reducing cement leakage, a double-layer design can enwrap most of injected PMMA and has a brighter prospect of clinical application.