目的 分析万向椎弓根螺钉在不同矢状轴成角下对连接棒把持力的变化及与固定钉的抗拔出力比较.方法 取Bonovo 公司阿尔卑斯(ALPS)5.5系统万向钉、5.5连接棒共24件,平均分为3组,按矢状轴成角0°(A组)、20°(B组),-20°(C组)组装螺钉与连接棒,对照组(D组):市场上常用的威高5.5固定钉、5.5连接棒共8件,体外组装.采用拉力测试机器测试连接棒的横向拔出力.结果 B组及C组椎弓根螺钉拔出力最大,且基本相同,A组万向螺钉组拔出力其次,D组拔出力最小.B、C组与A组、A组与D组之间最大拔出力进行比较,提示各组之间差异均有统计学意义(P<0.05).结论 万向椎弓根螺钉对连接棒的把持力大于固定螺钉,矢状轴成角对连接棒把持力大于无成角,且与矢状轴成角方向无关.%Objective To analyze the change of horizontal pull-out strength of the connecting rods when the ployaxial pedicle screws were installed in different sagittal axis angles, then comparing them with the normal pedicle screws. Methods Take 24 sets of ployaxial pedicle screws and connecting rods produced by Bonovo company, divided them into 3 groups. The pediele screws and connecting rods were installed invitro by the angle of the pedicle screw and sagittal axis are 0° (group A)、20°(group B)or -20°(group C ).The control group(group D):8 sets of the commonly used no.al pedicle screws were installed like the same. To test the horizuntal inll-out strength of the connecting rods by pull-out strength testing machine. Results Group B and group C had the coequally maximum pull-out strength, the pull-out strength of group A was lesser than B and C;group D had the minimum pull-out strength. The difference between B,C and A,A and D is significant (P＜O.O5). Conclusion The holding strength of ployaxial pedicle screw is greatcr than normal pedicle screw and it is greater with sagittal axis angle. and it is unrelated to the direction of sagittal axis angle.
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