摘要
目的评价不同骨质疏松条件下膨胀式椎弓根螺钉(expansive pedicle screw,EPS)的稳定性,为其应用于合并有骨质疏松症的患者脊柱手术提供力学理论基础。方法取新鲜尸体脊柱(T12～L5)标本,根据骨密度检测结果,按临床骨质疏松程度诊断标准分成骨质正常、骨量减少、骨质疏松和重度骨质疏松4个水平,每个水平各2具标本12个椎体。于每个椎体两侧椎弓根分别植入普通椎弓根螺钉(conventional pedicle screw,CPS;CPS组)和EPS(EPS组)。采用AG-IS万能材料试验机,以5 mm/min匀速加载进行螺钉轴向拔出试验,测定最大拔出力、刚度和能量吸收值。结果两组随骨密度水平下降,最大拔出力及刚度均逐渐下降(P<0.05);CPS组能量吸收值逐渐下降(P<0.05),EPS组能量吸收值除正常骨质与骨量减少间比较、骨质疏松与重度疏松间比较差异无统计学意义(P>0.05)外,其余各密度水平间比较差异均有统计学意义(P<0.05)。同一骨密度水平EPS组最大拔出力均显著高于CPS组(P<0.05);除正常骨质水平外,同一骨密度水平EPS组刚度均显著高于CPS组(P<0.05);除骨量减少水平外,同一骨密度水平两组能量吸收值比较差异均无统计学意义(P>0.05)。骨质疏松水平EPS组最大拔出力、刚度、能量吸收值与骨量减少水平CPS组比较,差异均无统计学意义(P>0.05);但重度骨质疏松水平EPS组以上指标均显著低于骨量减少水平CPS组(P<0.05)。结论与CPS相比,EPS能明显提高固定强度,尤其对于骨量减少或骨质疏松患者。
Objective To evaluate the fixation strength of expansive pedicle screw（EPS） at different bone mineral density（BMD） levels,further to provide theoretical evidence for the clinical application of the EPS in patients with osteoporosis. Methods Fresh human cadaver spines（T12-L5 spines） were divided into 4 levels： normal BMD,osteopenia,osteoporosis,and severe osteoporosis according to the value of BMD,12 vertebra in each level.Conventional pedicle screw（CPS） or EPS was implanted into the bilateral vertebra in CPS group and EPS group,respectively,12 screws in each group per BMD level.Screw pullout tests were conducted.The maximum pullout strength,stiffness,and energy absorption were determined by an AG-IS material testing machine with constant rate of loading in a speed of 5 mm/ min. Results With the decline of BMD from normal to severe osteoporosis level,the maximum pullout strength and the stiffness correspondingly declined（P 0.05）.In CPS group,the energy absorption gradually decreased（P 0.05）;in EPS group,significant difference was found between other different BMD levels（P 0.05） except between normal BMD and osteopenia and between osteoporosis and severe osteoporosis（P 0.05）.At the same BMD level,the maximum pullout strength of EPS group was significantly larger than that of CPS group（P 0.05）;the stiffness of EPS group was significantly higher than that of CPS group（P 0.05） except one at normal BMD level;and no significant difference was found in the energy absorption between 2 groups（P 0.05） except one at osteopenia level.No significant difference was found in maximum pullout strength,stiffness,and energy absorption between EPS group at osteoporosis level and CPS group at osteopenia level（P 0.05）;however,the maximum pullout strength,stiffness,and energy absorption of EPS group at severe osteoporosis level were significantly lower than those of CPS group at osteopenia level（P 0.05）. Conclusion Compared with CPS,the EPS can significantly improve the fixation strength,especially in patients with osteopenia or osteoporosis.
出处
《中国修复重建外科杂志》
CAS
CSCD
北大核心
2013年第8期969-973,共5页
Chinese Journal of Reparative and Reconstructive Surgery
基金
国家高技术研究发展计划(863)资助项目(2007AA02Z468)~~
