下颈椎前路椎弓根螺钉人工椎体系统生物力学性能及对骨质疏松椎骨稳定性的影响

Biomechanical properties of lower anterior vertebral pedicle screw system and its effects on osteoporotic vertebral stability

背景:老年性骨质疏松椎骨骨折传统手术治疗虽然能改善患者症状,但是治疗后容易产生植骨融合失败、假关节形成等并发症,影响临床疗效。目的:探讨颈椎前路椎弓根螺钉人工椎体系统生物力学性能及对骨质疏松椎骨稳定性的影响。方法:取16具新鲜尸体颈椎标本,分解为C_(3-4),C_(4-5),C_(5-6),C_(6-7),共64个运动节段。将64个节段按植入方式不同随机分为普通前路椎体螺钉锁定固定系统组和下颈椎前路椎弓根螺钉人工椎体系统组,每组32个节段,在生物力学试验机上对各组生物力学性能进行测定。结果与结论:(1)生物力学检测:与普通前路椎体螺钉锁定固定系统组相比,下颈椎前路椎弓根螺钉人工椎体系统组最大拔出力、钉道长度、治疗后骨折椎体中柱高度、表面最大应变、应变最大值及最大值的范围均增加(P<0.05);(2)结果提示:与普通前路椎体螺钉钢板系统相比,下颈椎前路椎弓根螺钉所需要的拔出力较大,对于骨质疏松椎骨更加稳定。

BACKGROUND： Although the traditional surgical treatment can improve the symptoms of patients with senile osteoporotic vertebral fracture, the treatment easily produces bone graft fusion failure and pseudoarticulation formation and affects clinical effects. OBJECTIVE： To investigate biomechanical properties of anterior cervical pedicle screw and the effects on osteoporotic vertebral stability. METHODS： A total of 16 fresh cadaver cervical specimens contained 64 motion segments （C3-4, C4-5, C5-6 and C6-7）. The 64 segments by the way of implantation were randomly divided into ordinary anterior locking screw fixation group and lower anterior vertebral pedicle screw system group （32 segments per group）. The mechanical properties were determined on the biomechanical testing machine for each group. RESULTS AND CONCLUSION： （1） Biomechanics： Compared with the ordinary anterior locking screw fixation group, the maximum pull-out strength, screw path length, postoperative vertebral column height, the maximum surface strain, strain maximum and the range of maximum values were increased in the lower anterior vertebral pedicle screw system group （P 〈 0.05）. （2） Results suggest that compared with the ordinary anterior locking screw fixation group, lower cervical anterior pedicle screw required larger extraction force and was more stable for osteoporotic vertebrae.