空心侧孔椎弓根螺钉侧孔分布范围对应用安全性及生物力学影响的实验研究  

Experimental study of the effect of fenestration distribution on the safety and biomechanics of fenestrated pedicle screw

作　　者：吴剑维[1] 李阳[1] 臧渊[1] 修金涛[1] 雷伟[1] 吴子祥[1] 

机构地区：[1]陕西省西安市第四军医大学西京医院全军骨科研究所,西安710032

出　　处：《中国骨质疏松杂志》2013年第3期226-229,共4页Chinese Journal of Osteoporosis

基　　金：国家自然科学基金(31170913)

摘　　要：目的探讨骨水泥螺钉强化骨质疏松条件下椎体后,骨水泥不同分布形态对新型空心侧孔骨水泥椎弓根螺钉(Fenestrated pedicle screw,FPS)的安全性以及螺钉生物力学影响。方法使用平均年龄76岁的完整新鲜脊柱标本(T11～L5)3具,选取18个椎体,平均骨密度为0.542±0.13g/cm2。随机分为三组。侧孔间隔一个螺纹为A组(FPS-1)和侧孔间隔两个螺纹为B组(FPS-2),这两组均通过加压灌注筒装置进行骨水泥钉道灌注1.5ml,C组为常规椎弓根螺钉(conventional pedicle screwgroup)CPS组,不灌注骨水泥。24小时后行三维CT扫描,观察骨水泥椎体内的分布;随后进行生物力学实验。结果三维重建显示:FPS-1组骨水泥均分布于椎体内,FPS-2组有部分骨水泥分布于椎弓根内。最大轴向拔出力:A组(573.2±136.30)N,B组(769.2±92.30)N,C组(361.8±58.84)N。FPS-1组和FPS-2组的螺钉稳定性均显著强于CPS组(P<0.05),且FPS-2组优于FPS-1组,差异有统计学意义(P<0.05)。结论空心侧孔椎弓根螺钉远端三分之一为侧孔设计的安全区域;骨水泥在椎体内的分布形态能够影响螺钉的生物力学。Objective To investigate the effect of different distribution of bone cement, which was used to strengthen vertebral body with osteoporosis, on the safety and biomechanics of new type fenestrated pedicle screw （FPS）. Methods Eighteen vertebrae （T11-L5） obtained from 3 fresh cadavers （1 male and 2 females; mean age was 76 years old） were used. The average bone mineral density was 0. 542±0. 13 g/ cm2. They were randomly divided into three groups： one-thread fenestration interval group （ FPS-1 ）, two- thread fenestration interval group （FPS-2）, and the conventional pedicle screw group （CPS）. Polymethylmethacrylate（PMMA） cement of 1.5 ml was perfused through the screws into each vertebra in FPS-1 group and FPS-2 group. Group C had no perfusion. Twenty four hours later, three - dimensional CT reconstruction examination was performed on all samples in order to observe the distribution of bone cement. Biomechanical test was also performed. Results Three-dimensional reconstruction examination showed that cement was totally distributed in the vertebral bodies in FPS-1 group, while in FPS-2 group part of bone cement was distributed in vertebral pedicle. The maximum axial pull-out in FPS-1 group, FPS-2 group, and CPS group was 573.2 ± 136.30N, 769.2± 92.30N, and 361.8 ± 58.84 N, respectively. The screw stability in FPS-1 group and FPS-2 group were significantly superior to that in CPS group （ P 〈 0. 05 ） , and the screw stability in FPS-2 group was superior to that in FPS-1 group （P 〈 0. 05）. Conclusion The zone at the distal third of the screw thread following cement augmentation is safe. The distribution of bone cement in vertebral body can affect the biomechanics of pedicle screw.

关 键 词：骨质疏松 椎弓根螺钉 骨水泥 生物力学 

分 类 号：R68[医药卫生—骨科学]