骨填充网袋修复椎体压缩骨折的生物力学变化

Bone filling mesh container repairs vertebral compression fractures: biomechanical changes

背景:经皮椎体成形、经皮椎体后凸成形是治疗椎体压缩性骨折的主要手段,存在骨水泥外溢,引起椎管狭窄、神经受压、肺栓塞、引起伤椎再骨折等问题。目的:验证以聚对苯二甲酸乙二酯材料制备的骨填充网袋应用于椎体压缩骨折的可行性。方法:按GB/T16886相关部分的试验方法规定检测骨填充网袋的生物学性能;检测骨填充网袋老化前后承受拉力的能力;向骨填充网袋内灌注骨水泥并测压,观察骨填充网袋膨胀抬升及骨水泥渗出情况。向新鲜猪椎体直接注入骨水泥或置入骨填充网袋后再灌注骨水泥,测试椎体的刚度及强度。向4月龄猪腰椎内置入骨填充网袋后再灌注骨水泥,定期观察椎体内骨组织生长情况。结果与结论:生物学性能检测表明骨填充网袋具有良好的生物相容性。骨填充网袋老化前后具有相近的力学强度,说明其可长期保持强度性能稳定。大气环境下,骨填充网袋在灌注骨水泥压力为5-10 atm时呈球形膨胀,能起到抬升作用;压力至7-10 atm时,骨水泥呈条状溢出,伸入到周围组织间隙,能起到黏附固定作用。置入骨填充网袋后再灌注骨水泥和直接灌注骨水泥的椎体具有相近的强度和刚度,强于正常椎体。猪腰椎内置入骨填充网袋后再灌注骨水泥6个月后周围骨组织与正常骨组织结构形态及色泽完全相同。表明在椎体压缩骨折手术中应用骨填充网袋可有效恢复椎体高度、强度,防止骨水泥外溢。

BACKGROUND：Percutaneous vertebroplasty and percutaneous kyphoplasty have become the mainstream clinical methods for the treatment of vertebral compression fractures. However, both of them have several shortcomings such as bone cement leakage, spinal stenosis, nerve compression, pulmonary embolism and other issues. OBJECTIVE：To verify the possibility of bone filing mesh container prepared by polyethylene terephthalate for the treatment of vertebral compression fractures. METHODS：The biological properties of bone filing mesh container were examined according to GB/T16886. After sample aging test, the tensile properties of the aged samples and the fresh prepared samples were compared. The expansion and bone cement leakage were evaluated by injecting bone cement into the bone filing mesh container and measuring the pressure. The initial strength and stiffness of the fresh pig vertebrae with calcium phosphate cement injection or with bone filing mesh container filed with calcium phosphate cement were compared. The in vivo bone tissue growth was periodicaly observed after the lumbar vertebra of 4-month-old pigs was implanted with the bone filing mesh container that was then ful of bone cement. RESULTS AND CONCLUSION： The bone filing mesh container had good biocompatibility. Bone filing mesh containers after 2-year storage had the same tensile strength to the fresh bone filing mesh containers. At ambient＆amp;nbsp;conditions, after bone cement injection, bone filing mesh containers could be expanded at 5-10 atm and therefore could play the role of uplift; at 7-10 atm, bone cement could leak out from the bone filing mesh container and enter into the interspace between surrounding bone tissues, thus playing the role of adhesion and fixation. The vertebrae after bone cement injection with or without bone filing mesh containers had the same initial strength and stiffness and exhibited bigger initial strength and stiffness than untreated vertebrae. Thein vivo animal experiments proved that bone filing mesh container had no obvious effect on the vertebrae. These findings indicate that the bone filing mesh container can be used to restore the height and strength of the fractured vertebrae. Moreover, it may eliminate bone cement leakage and therefore increase the surgery safety.