椎弓根螺钉置入椎体深度与其稳定性的生物力学分析  

Depth of pedicle screw into the vertebral body and its stability: a biomechanical analysis

作　　者：杜炜[1] 钱明权[1] 

机构地区：[1]南京医科大学附属无锡市第二人民医院骨科,江苏省无锡市214002

出　　处：《中国组织工程研究》2016年第9期1289-1294,共6页Chinese Journal of Tissue Engineering Research

摘　　要：背景:椎弓根螺钉系统置入对于骨折复位或对力学稳定性的影响由多方面因素决定。椎弓根螺钉固定失败的原因主要是折断及疲劳松动,研究证明影响椎弓根螺钉生物力学稳定性的主要影响因素为其长度及直径,有关其置入深度的研究报道较少。目的:基于生物力学分析椎弓根螺钉置入椎体深度与其固定稳定性的关系。方法:在15个5月龄猪L2椎体标本上制作单椎体压缩骨折模型。根据椎体前后径长度,依次经骨折椎体上下椎弓根置入不同深度的螺钉,置钉深度分别为椎体前后径的80%,90%,100%。固定标本后,在WDT-10KN型万能材料试验机上,以频率为0.5 Hz(340±125)N的的载荷对标本进行10 000次疲劳实验。测量疲劳实验后各组标本前屈、后伸、左弯、右弯4个方向的活动度以及螺钉最大轴向拔出力大小,并比较各组间的差异。结果与结论:(1)疲劳实验后各组标本前屈、后伸、左弯、右弯4个方向的活动度,置入100%组和置入90%组均显著小于置入80%组(P<0.05),置入100%组显著小于置入90%组(P<0.05)。(2)疲劳试验后各组螺钉最大拔出力,置入100%组和置入90%组显著大于置入80%组(P<0.05),置入100%组显著大于置入90%组(P<0.05)。(3)结果提示,椎弓根螺钉置入椎体的深度与其固定稳定性显著相关。椎弓根螺钉置入越深入,椎体稳定性越强,置入100%组>90%组>80%组。BACKGROUND： Effects of pedicle screw placement on fracture reduction or stability of mechanics are influenced by various factors. Pedicle screw fixation failure is mainly due to fracture, loosening and fatigue. The main influential factors for biomechanical stability of pedicle screw are length and diameter. The research on the depth is less. OBJECTIVE： To analyze the relationship between pedicle screw placement depth of vertebral body and the fixed stability based on the biomechanics. METHODS： A model of single vertebral compression fractures was made in 15 pigs aged 5 months on L2 vertebral specimen. According to the length of anteroposterior diameter, vertebral pedicle screws were inserted in different depths（80%, 90% and 100% of anteroposterior diameter）. After fixation, specimens were loaded 10 000 times at the frequency of 0.5 Hz（340±125） N on a WDT-10 KN type universal material testing machine. Ranges of motion at anteflexion, backward extension, left bending and right bending and the maximum axial pullout force were measured in each group, and the difference of intergroup data was compared. RESULTS AND CONCLUSION：（1） Ranges of motion at anteflexion, backward extension, left bending and right bending in each group were significantly smaller in the 100% and 90% groups than in the 80% group（P〈0.05）, and above parameters were smaller in the 100% group than in the 90% group（P〈0.05）.（2） After fatigue test, the maximum axial pullout force was significantly larger in the 100% and 90% groups than in the 80% group（P〈0.05）, and above data were significantly larger in the 100% group than in the 90% group（P〈0.05）.（3） Results indicate that the depth into the vertebral body was significantly associated with its fixed stability. The deeper the depth into the vertebral body, the stronger the vertebral stability was： 100% group 90% group 80% group.

关 键 词：骨钉 内固定器 生物力学 组织工程 骨科植入物 脊柱植入物 椎弓根螺钉 置入椎体深度 内固定 稳定性 活动度 轴向拔出力 

分 类 号：R318[医药卫生—生物医学工程]