腰骶椎弓根螺钉翻修及强化固定后稳定性比较
椎弓根螺钉,,腰椎；骶椎；椎弓根螺钉；翻修；生物力学,1材料与方法,2结果,3讨论,参考文献：
摘要：[目的]从生物力学角度评价腰骶椎弓根螺钉翻修及强化固定的稳定性。[方法]采用7具新鲜成人尸体L5S1椎体标本，于L5椎体首先置入5.5mm/45mm椎弓根螺钉，然后再置入7.0mm/55mm螺钉翻修，最后应用骨水泥强化固定；S1椎弓根置入初始螺钉为6.25mm/35mm、翻修螺钉为8.0mm/45mm、最后同样行骨水泥强化固定。在858MiniMTS生物力学实验机上分别测试各状态轴向最大拔出力及最大扭力矩。[结果](1)在L5，初始、翻修及骨水泥强化固定状态的最大把持力分别为(1680.7±242.8)N、(2410.3±366.1)N、(3273.0±688.5)N(P<0.05)，最大扭力矩分别为(1006.1±205.3)N·mm、(1432.6±213.7)N·mm、(590.7±83.5)N·m(P<0.05)；(2)在S1，初始、翻修及骨水泥强化的把持力分别为(926.3±274.2)N、(957.5±336.3)N、(1825.3±199.9)N，最大扭力矩分别为(667.6±88.3)N·mm、(681.4±79.4)N·mm、(558.8±97.2)N·mm；其中初始及翻修状态把持力及扭力矩均无明显差别(P>0.05)，骨水泥强化固定后把持力明显增加、扭力矩明显减小(P<0.05)。[结论](1)L5椎弓根螺钉翻修时，螺钉直径增加1.5mm、长度增加10mm或骨水泥强化均可达到翻修固定的生物力学要求，增加脊椎稳定性，以骨水泥强化固定更为明显；(2)S1椎弓根螺钉翻修时，单纯增加螺钉直径和长度不能获得理想的稳定性，而骨水泥强化螺钉固定效果明显。关键词：腰椎；骶椎；椎弓根螺钉；翻修；生物力学
Biomechanical stabilization in the revision and augmentation for lumbar and sacral pedicle screws
DING Yu,RUAN Dike,LI Chao,et al.
Department of Orthopaedics, Navy General Hospital, Beijing 100037
Abstract：[Objective] To evaluate the biomechanical stabilization of augmentation and revision of L5 and S1 pedicle screws.[Method]Seven lumbosacral spines from fresh adult cadavers were harvested,and dismembered into single vertebrae before testing. 5.5mm/45mm screws were implanted in L5 pedicles as control initially, then 7.0mm/55mm screws were used for the revision, and finally, the failed pedicles were augmented by cement.The original screws implanting in S1 pedicles were 6.25mm/35mm, the revision screws were 8.0mm/45mm, and also cement was used to salvage failed pedicles finally.The maximum pullout strength and insertional torque in all groups was tested on 858MiniMTS.[Result](1)For L5 vertebrae, the screw pullout strength in control, revision and augmented groups were (1 680.7±242.8)N, (2410.3±366.1)N and (3273.0±688.5)N,respectively with significant difference(P<0.05).The insertional torque of the lumbar groups was (1006.1±205.3)N·mm, (1432.6±213.7)N·mm and (590.7±83.5)N·mm respectively with significant difference(P<0.05)；(2)For S1 vertebrae, the pullout strength in control, revision screws was (926.3±274.2)N, (957.5 ±336.3)N respectively without obvious difference (P>0.05).The strength of augmented screws was (1 825.3±199.9)N,and much higher than other two groups (P<0.05).The insertional torque was (667.6±88.3)N·mm, (681.4±79.4)N·mm and (558.84±97.2)N·mm respectively without any difference of the torque between control and revision group (P>0.05),but the torque of augmented group was smaller than other two groups (P<0.05).[Conclusion](1)Increasing the screw diameter with 1.5mm and the length with 10mm of screws,or using cement to salvage failed L5 pedicles can all increase biomechanical stability;(2)Increasing the screw length and diameter in S1 may not improve the pullout strength,but a good result is achieved by using cement augmentation. ......
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