髂骨钉与腰骶椎弓根钉连接技术在腰骶骨盆固定中的生物力学评价

背景:腰骶骨盆间的固定技术临床应用较多,但作者尚未查到一种既安全又牢固且较成熟的理想的内固定方法.目的:探讨骼骨钉与腰骶椎弓根钉连接技术在腰骶骨盆固定中的稳定性.设计、时间、地点:对照实验,于2006-0112007-12在中山大学生物力学研究室完成.材料:因创伤致死男性成人尸体6具,采用新鲜冷藏的腰骶椎、骨盆标本;髂骨钉为8.5mm×100mm、L5椎弓根钉为6.5mm×45mm、S1椎弓根钉为6.5mm×35mm,均由美国枢法模公司提供;测试用美国MTS855型微型生物力学测试机.方法:实验分为4组:无固定组和3种固定组,即髂骨翼拉力螺钉、L5～S1椎弓根钉棒系统、髂骨钉与L5椎弓根钉连接系统.对固定组试件分别与无固定组进行生物力学稳定性比较.主要观察指标:各组旋转、侧弯、前屈、后伸的三维运动数据.结果:在3个固定组中,采用髂骨钉与L5椎弓根钉链接系统固定在腰骶骨盆固定中的稳定性最好,各种运动状态下的活动度均明显减少,在6.4Nm力矩下的三维运动度为:旋转(1.07±0.86)°、侧弯(0.95±0.47)°、前屈(1.22±0.67)°、后伸(1.80±0.73)°;髂骨钉与L5椎弓根钉链接系统组腰骶骨盆间稳定性明显强于无固定组,差异有显著性(P<0.01).结论:髂骨钉与腰骶椎弓根钉连接技术具有维持腰骶骨盆间稳定的生物力学优势.

Biomechanical evaluation of connectible skills using iliac screw and lumbar-sacral spine pedicle screw in the fixation between lumbar-sacral spine and pelvis

BACKGROUND: There have been many methods of fixation between lumbar-sacral spine and pelvis. However, a safe, firm, and ideal method of internal fixation has not been found.OBJECTIVE: This study was designed to investigate the stability of the fixation between lumbar-sacral spine and pelvis with the connectible skills using iliac screw and lumbar-sacral spine pedicle screw.DESIGN, TIME AND SETTING: This study, a control experiment, was performed at the Institute of Biomechanics, Sun Yat-sen University, Guangzhou, Guangdong Province, China between January 2006 and December 2007.MATERIALS: The lumbar-sacral spine and pelvis specimens were collected from six freshly cryo-preserved male adult corpses caused by trauma. Iliac screw (8.5mm×100mm), L5 pedicle screw (6.5mm×45mm), and S1 pedicle screw (6.5mm×35mm) were provided by Sofamor Company, USA. MTS 858 Bionix Material Testing System (USA) was also used.METHODS: The lumbar and iliac vertebrae, pelvis from six fresh frozen cadaveric specimens were operated in three different ways of fixation respectively: iliac ala lag screw, L5-S1 pedicle screw rod system, iliac screw and L5 pedicle screw connecting system. Three ways of fixation as mentioned above were compared with the intact group in biomechanical stability.MAIN OUTCOME MEASURES: The mobility of whirl, lateral bending, proneness, and backward stretching among groups.RESULTS: Using iliac screw for the fixation between lumbar-sacral spine and pelvis turned out to be the best in stability. The range of motion (ROM) decreased obviously in each situation. The three-dimensional mobility in the 6.4Nm moment of force was (1.07±0.86)° for whirl, (0.95±0.47)° for lateral bending, (1.22±0.67)° for proneness, and (1.80±0.73)° for backward stretching. There was significant difference between the intact group and the group carried out by iliac screw and L5 pedicle screw for the fixation between lumbar-sacral spine and pelvis (P<0.01).CONCLUSION: The connectible skills using iliac screw and the lumbar-sacral spine pedicle screw possesses the biomechanical advantages of maintaining the stability between lumbar-sacral spine and pelvis.