经皮椎体成形术与后凸成形术在老年女性骨质疏松性骨折中的生物力学研究

Biomechanical study on the percutaneous vertebroplasty and kyphoplasty in osteoporotic fracture in elderly female cadavers

目的:探讨经皮椎体成形术(PVP)和椎体后凸成形术(PKP)治疗单节段胸腰椎骨质疏松性骨折的生物力学性质。方法:从6例骨质疏松中老年女性的尸体中选取12个胸腰椎体,进行压缩性骨折造模,并随机分配为PVP组和PKP组。其中PVP组直接将骨水泥(PMMA)注入受试标本;PKP组使用球囊扩张专用器械对标本进行扩张,后注入骨水泥,对扩张后空腔进行充填。对两组标本进行几何测量与生物力学测试,并获取相关参数。结果:两组椎体的生物力学测试都显示出术后的椎体强度显著高于术前(P<0.01);但PKP组的术后椎体刚度能恢复至术前骨折前水平,而PVP组的术后椎体刚度无法恢复,PKP与PVP手术在恢复椎体高度方面有明显差异。结论:在体外条件下,PKP较PVP在恢复椎体高度与刚度方面有着明显的优势,但在恢复椎体强度方面PVP占优。

Objective： To probe the biomechanical characteristics of vertebroplasty （PVP） and kyphopIasty （PKP） to treat the osteoporotic fracture of the single segment thoracic and iumbar vertebral bodies in the elderly female cadavers. Methods： Tweive osteoporotic verte-bral bodies （T12L1） selected from 6 aged female cadavers were experimentaIly crunched as models and randomly divided into PVP and PKP two groups. Of whom, cement was directly injected into the vertebrai body in PVP group, while in PKP group, special devices were used to enIarge the specimen,then cement was injected into the vertebral body for padding the space. The geometri-cal and biomechanical measurements were performed to obtain the relevant data. Results： The biomechanical tests of the vertebral bodies in both groups ali showed that the post-operative stiffness of the body was obviously stronger than pre-operative stiffness（P〈0.01）. The post- operative stiffness of the vertebrai body of PKP group could basicaIly restore the pre-operative stiffness, whereas the stiffness of PVPgroup couIdn＇t restore. There was significant statls-tically difference in restoring the height of the vertebrai body between PVP and PKP operations. Conclusion： PKP in the restoration of the body height and stiffness in vitro is superior to PVP, but PVP in the restoration of the strength of the vertebral body has advantage.