前凸弯棒预加压固定对胸腰段椎体骨折复位稳定的影响  

Effect of lordotic rod curvature and preloading on postoperative stability of thoracolumbar fractures

作　　者：阎崇楠[1] 王欢[1] 范波[1] 崔少千[1] 段景柱[1] 金国鑫[1] 张磊[1] 

机构地区：[1]中国医科大学附属盛京医院脊柱外科,沈阳110004

出　　处：《中华创伤杂志》2017年第1期19-25,共7页Chinese Journal of Trauma

摘　　要：目的通过有限元模拟分析，探讨不同弯棒角度对胸腰段椎体骨折复位后稳定性及应力的影响。方法（1）选择30岁健康男性志愿者的胸腰段三维CT数据建立有限元模型，对T11～L1皮质骨、松质骨、椎间盘、韧带和关节进行赋值，并建立T12骨折模型。加载T11～L1的双侧椎弓根螺钉固定，根据双侧连接棒角度分为直棒模型组和预弯棒模型组（前凸15°～25°）。在T11上终板施加400N的压力模拟上身重力，同时施加10N·m的力矩，使模型产生前屈、背伸、侧弯及旋转运动。比较两组胸腰段骨折复位后各工况下内固定物的应力分布情况。（2）采用回顾性队列研究分析2012年7月-2016年7月胸腰段骨折接受内固定治疗的患者56例，按照术中连接棒角度分为直棒组（31例）和预弯棒组（25例），观察两组术前、术后、末次随访时胸腰段伤椎邻近椎体终板间角度变化及内固定情况。结果（1）在各工况条件下，两模型组固定方式均能较好地限制胸腰段位移。直棒模型组在前屈、背伸、侧弯、旋转的工况条件下连接棒的应力峰值分别为151MPa、315MPa、369MPa、377MPa，预弯棒模型组分别为110MPa、239MPa、281MPa、189MPa。预弯棒模型组在各工况下内固定物的应力集中范围均小于直棒模型组。（2）患者均获得随访4—33个月，平均21．4个月。术前后凸角直棒组、预弯棒组分别为（21．7±7．4）°、（20．3±6．8）°（P〉0．05），术后前凸角直棒组、预弯棒组分别为（3．3±1．2）°、（8．3±2．8）°（P〈0．05），末次随访时直棒组前凸角较术后减少（8．7±2．3）°，预弯棒组较术后减少（3．9±1．7）°（P〈0．05）。直棒组内固定失效3例，预弯棒组无内固定失效。结论胸腰段骨折内固定术中对连接棒进行预弯形成15°～25°前凸固定并预加压，可减少连接棒的应力，减少内固定失效发生，�Objective To study the effect of different rod curvature on the postoperative stability and stress of thoracolumbar junction fracture using the finite element simulation. Methods （ 1 ） Thoracolumbar finite element model of T11 to L1 from three-dimensional CT data of a 30-year-old healthy male volunteer was established, including the assignment of cortical bone, cancellous bone, disc, ligaments and facet joints. On this basis, the T12 fracture model was also established. T11 to L1 bilateral pedicle screw fixation was loaded, and the rod connection was divided into straight rod group and pre-bended rod group （lordotic 15°-25°） according to angle of the rod. A 400 N stress was loaded on the top of the upper endplate of T11 to simulate the upper part body gravity, while applying a 10 N·m torque to generate flexion and extension, lateral flexion and rotation. Stress distribution of different methods of pre-bending for thoracolumbar fractures after reduction was compared. （2）A retrospective cohort analysis was made on 56 cases of thoracolumbar fractures surgically treated from July 2012 to July 2016, including 31 cases in straight rod group and 25 cases in pre-bended rod group. Two groups were compared in angle between adjacent level before operation, after operation and at final follow-up. Results （1） An flexion, extension, lateral bending and rotation, both rod bending methods effectively controlled the thoracolumbar junction displacement. The peak stress of connecting rod （151, 315, 369, 377 MPa respectively） in pre-bended rod group was lower than that in straight rod group （110, 239, 281, 189 MPa respectively） （P 〈 0.05 ）, and straight rod group appeared relatively obvious stress concentration. （2） Mean follow-up time was 21.4 months （range, 4-33 months）. Preoperative kyphosis angle was （21.7 ±7.4） °in straight rod group and （ 20. 3 ± 6. 8 ） ° in pre-bended rod group （ P 〉 0. 05 ）. Postoperative lordosis angle in straight rod group was （3.3 ± 1.2） o ve

关 键 词：胸椎 腰椎 内固定器 

分 类 号：R683.2[医药卫生—骨科学]