全颈椎模型建立及不同牵引方位下的牵引力与牵引角度特征

Establishment of a total cervical spine model and characteristics of traction force and traction angles under different traction orientations

背景:作者设计了一种新型的颈椎牵引机器人,在该设备研发过程中存在有牵引力与牵引角度不确定的问题,这些问题是影响患者治疗效果的重要因素。目的:建立C1-C7颈椎骨的三维有限元模型并验证该模型的有效性,讨论不同牵引力和牵引角度变化对颈椎间盘的影响。方法:采用1名30岁健康无颈椎病史的成年志愿者的颈椎CT数据,通过Mimics 21.0、3-matic软件生成颈椎间盘及颈椎骨实体CAD模型,并对该模型划分网格。然后导入Abaqus 2016有限元分析软件中添加颈椎韧带并对其进行有效性验证。在生成的颈椎模型上施加相应约束及载荷,模拟人坐位时牵引力及角度发生变化的牵引,分析牵引力和牵引角度对牵引效果的影响。结果与结论:(1)对于新型牵引设备来说,在50-150 N的牵引力范围内,牵引力越大牵引效果越好,但牵引力过大会导致患者疼痛大幅增加,可以选择治疗效果较好的130 N作为牵引力;(2)随着牵引角度从0°增加到20°,前屈位下的椎间盘变形量逐步变小,<10°的牵引角度比较适合新型牵引设备的前屈位治疗;(3)后屈和左右屈曲位下的椎间盘变形量随角度增大而逐渐增大,并在16°-17°时到达相对稳定的变形量,故该设备的后屈和左右屈位应选择16°-20°的牵引角度;(4)成功建立C1-C7颈椎模型并对牵引力和牵引角度进行了有限元分析。

BACKGROUND:This paper designs a new type of cervical spine traction robot.During the development of the equipment,there are problems of uncertain traction and traction angle.These problems are important factors that affect the treatment effect of patients.OBJECTIVE:To establish a three-dimensional finite element model of the cervical vertebrae C1-C7,verify the validity of the model,and discuss the influence of different traction forces and traction angle changes on cervical intervertebral discs.METHODS:The cervical spine CT data of a 30-year-old healthy adult volunteer with no history of cervical spondylosis were collected.The intervertebral disc and cervical bone body CAD models were generated by Mimics 21.0 and 3-matic software,and the grids were divided.The data were imported into Abaqus 2016 finite element analysis software to add cervical ligaments and verify their effectiveness.Constraints and loads were applied on the generated cervical spine model to simulate the traction treatment with the change of traction force and angle when the person was sitting,and the influence of traction force and angle on traction effect was analyzed.RESULTS AND CONCLUSION:(1)For the new type of traction equipment,in the range of 50 N to 150 N traction,the greater the traction,the better the traction,but too much traction would cause the patient’s pain to increase significantly.130 N with better therapeutic effect could be chosen as the traction.(2)As the traction angle increased from 0°to 20°,the deformation of the intervertebral disc in the anterior flexion position gradually decreased.The traction angle less than 10°was more suitable for the anteflexion treatment of the new traction equipment.(3)The deformation of the intervertebral disc in the posterior flexion and left-right flexion position gradually increased with the increase of the traction angle,and reached a relatively stable amount of deformation at about 16°to 17°.Therefore,the traction angle of 16°to 20°should be selected for the posterior and left-right flexion of the new equipment.(4)The model of C1-C7 cervical spine was successfully established and the traction force and traction angle were analyzed by finite element method.