头颈椎位置对不同类型寰椎横韧带损伤影响的有限元分析

Effect of head posture on different types of transverse atlantal ligament injuries under vertical impact: an analysis of finite dement

目的采用有限元方法分析受到垂直向下暴力时不同头颈椎位置对不同类型寰椎横韧带损伤的影响。方法在前期建立已经过验证有效的上颈椎有限元模型上,预设不同的头颈椎位置(中立位、屈曲位、伸展位、侧屈位及旋转位),设定加速度为80 m/s^2来模拟垂直向下暴力。计算出DickmanⅠ、Ⅱ型寰椎横韧带损伤区域的Von Mises应力值,同时将不同的应力值以不同的颜色显示,并且连接起来构成可显示各个工况下寰椎横韧带和寰椎侧块的应力云图。结果旋转位DickmanⅠ型寰椎横韧带损伤区域的Von Mises应力值最大(5.55 MPa),中立位DickmanⅠ型寰椎横韧带损伤区域的Von Mises应力值最小(1.07 MPa)。在所有工况中,横韧带实质部的左右端点和中部的应力值差别不大。侧屈位DickmanⅡ型寰椎横韧带损伤区域的Von Mises应力值最大(11.21 MPa),左侧寰椎横韧带附着点和寰椎侧块体部的Von Miss应力值均明显高于右侧。结论受到垂直向下的暴力时,头颈椎处于旋转位时容易出现DickmanⅠ型寰椎横韧带损伤,当头颈椎处于侧屈时容易出现DickmanⅡ型寰椎横韧带损伤。

Objective To evaluate the effect of head posture on different types of the transverse atlantal ligament injuries under vertical impact. Methods Neutral position, flexion, extension, axial rotation and lateral bending of neck were preset on the finite element model of the upper cervical spine. A size of 80 m/s^2 downward impact was applied on the model which was on different head positions. The yon Mises stresses, and stress cloud of transverse atlantal ligament and atlas were measured and analyzed by Abaqus 6.12. Results In Dickman type Ⅰ injury region, the greatest von Miss stress was 5.55 MPa when the head was on rotational position, and the minimum yon Mises stress was 1.07 MPa when the head was on neutral position. In Dickman type Ⅱ injury region, the greatest von Mises stress was 11.21 MPa when the head was on lateral bending position, and the yon Mises stress of left lateral mass of the atlas was higher than those of right. Conclusion Under vertical impact, the transverse atlantal ligament （type Ⅰ ） is easily injured when the head is on rotational position, and lateral mass of the atlas （type Ⅱ ） is easily injured when the head is on lateral bending position.