改良钉棒系统治疗垂直不稳定骨盆骨折的生物力学研究

Biomechanical research on the improved pedicle screw system to treat vertically unstable pelvic fracture

目的 探讨改良钉棒系统治疗垂直不稳定型骨盆骨折,并分析其生物力学性质.方法 在8例尸体骨盆标本上造模成垂直不稳定型骨盆骨折,分别行TOS术式固定、骶髂螺钉固定、改良钉棒系统固定,检测1000 N载荷下骨盆刚度、骨折分离移位距离及局部应变改变.结果 骨盆标本骨折模型采用各种不同固定方式,经生物力学测试,改良钉棒系统在载荷1000 N下刚度（224.3±18.3）N/mm及骨折分离移位距离（1.98±0.24）mm,明显优于骶髂螺钉固定（169.10±17.60）、（8.08±0.71）mm,差异有统计学意义（P＜0.01）,与TOS（233.20±12.90）、（1.62±0.31）mm比较,差异无统计学意义（P＞0.05）.结论 改良钉棒系统是一种生物力学性能较好的治疗垂直不稳定型骨盆骨折的新方法.

Objective To evaluate the biomechanical properties of posterior pelvic fixation by pedicle screw system. Methods In 8 human cadaver pelvises, biomechanical testing in a double-leg-stance model of vertically unstable pelvic fracture was done by material testing machine. Cadavers were loaded with 1000 N stress. In cadavers, three fixation methods-pedicle screw system, triangular osteosynthesis （TOS） and iliosacral screw-were assessed for stiffness and separation displacement. Results Stiffness for TOS, pedicle screw and screw was （233. 2 ± 12. 9）, （224. 3 ± 18. 3） and （ 169. 1 ± 17.6） N/mm, respectively. ANOVA showed significant difference between pedicle screw system and iliosacral screw, but not between pedicle screw and TOS （ P 〉 0. 05 ）. Separation displacement was （ 1.62 ± 0. 31 ） mm（TOS）, （ 1.98 ± 0. 24） mm （ pedicle screw system）, （ 8.08 ± 0. 71 ） mm （ iliosacral screw） respectively.Pedicle screw system differed significantly from iliosacral screw （ P 〈 0. 01 ）, but not from TOS （ P 〉0. 05）. Conclusion Pedicle screw system successfully treats vertically unstable pelvic fractures biomechanically.