经骶1-2侧块螺钉与骶1前外骶骨翼螺钉的比较研究

目的：通过测量经骶1-2侧块螺钉与骶1前外骶骨翼螺钉的钉道长度和最大拔出力，比较两者的固定效果。方法对27例（男14例，女13例）骶尾椎CT检查的影像学资料进行三维重建，利用Advantage worksta-tion 4．2后处理工作站软件测量经骶1-2侧块螺钉与骶1前外骶骨翼螺钉的钉道长度。取8具甲醛溶液固定的湿润成人骶骨标本，采用双能X线吸收测定仪测定骶1椎体骨密度，记录其平均值。在同一骶骨标本左右侧分别随机植入经骶1-2侧块螺钉和骶1前外骶骨翼螺钉。将标本固定于858型MTS材料试验机上，对螺钉施加轴向拔出力，计算最大拔出力。结果经骶1-2侧块螺钉平均钉道长度为（53．78±3．02） mm，骶1前外骶骨翼螺钉为（44．73±2．59）mm，差异有统计学意义（P＜0．05）。经骶1-2侧块螺钉即刻平均最大拔出力为（379．62±73．10） N，骶1前外骶骨翼螺钉为（230．62±98．52）N，差异有统计学意义（P＜0．05）。结论经骶1-2侧块螺钉固定的钉道长度及最大拔出力均优于骶1前外骶骨翼螺钉，可作为临床上一种有效的选择。

A comparative study of S1-2 lateral mass screws and anterolateral S1 sacrum alae screws

Objective To compare the effects of S 1-2 lateral mass screws and anterolateral S 1 sacrum alae screws by measuring the maximal length and pull -out force.Methods CT images of the sacrum were collected from 27 pa-tients （14 men and 13 women） to perform three-dimensional reconstruction .Using the Advantage Workstation （ AW） 4.2 software, the maximal lengths were measured for S1-2 lateral mass screws and anterolateral S1 sacrum alae screws. Eight adult cadaver specimens fixed in formalin were adopted to examine the bone mineral density of S 1 vertebral using dual-energy x-ray absorptiometry （DEXA）.After randomly implanted with S1-2 lateral mass screws and anterolater-al S1 sacrum alae screws on both sides , the specimens were placed on a MTS 858 bio-nix testing machine to record the maximal pull-out force .Results Statistical differences were found in the average maximal length between S 1-2 lateral mass screws [（53.78 ±3.02） mm, P〈0.05] and anterolateral S1 sacrum alae screws [（44.73 ±2.59） mm, P〈0.05）].The average maximal pull -out force was 379.62 ±73.10 N for S1-2 lateral mass screws, which was signifi-cantly different from that of anterolateral S1 sacrum alae screws [（230.62 ±98.52） N, P〈0.05].Conclusion S1-2 lateral mass screws are superior to anterolateral S 1 sacrum alae screws in terms of the maximal length and pull -out force, indicating its promising use in clinical setting .