基于OpenSim的轻度青少年特发性脊柱侧凸个性化建模与分析

Personalized Modeling and Analysis of Mild Adolescent Idiopathic Scoliosis Based on OpenSim

目的建立青少年特发性脊柱侧凸患者的个性化脊柱运动学和动力学建模方法并验证其准确性,为脊柱侧凸的非手术矫形治疗提供治疗机制分析与效果评估的工具。方法基于患者影像学数据计算并调整Schmid开发的OpenSim青少年脊柱模型的骨骼与肌肉参数,使模型与特定患者相匹配;基于文献数据添加椎间刚度并在侧凸段进行修正,使模型符合脊柱侧凸患者椎关节力学特征,进而建立患者侧凸脊柱的个性化运动学和动力学仿真分析模型;基于运动捕捉数据计算逆运动学,并使用静态优化计算肌肉激活度,将计算结果与影像学及肌电(electromyogram,EMG)数据进行对比验证。结果站立状态逆运动学计算得到的各椎骨冠状面角度平均误差为0.164°,符合运动学误差要求;站立状态胸椎段与腰椎段竖脊肌凸侧与凹侧肌肉激活度比值分别为0.489与0.631,与EMG数据吻合;侧屈运动中对椎间刚度进行修正后的模型与未修正模型相比,肌肉激活更接近EMG数据。结论本文方法建立的模型满足运动学与肌肉力的准确性要求。

Objective To develop a method for modeling spinal kinematics and dynamics of patients with adolescent idiopathic scoliosis(AIS)and verify its accuracy,so as to provide a tool for analyzing the mechanism and evaluating the effect of non-surgical orthopaedic treatment on scoliosis.Methods The skeletal and muscular parameters of the OpenSim adolescent spinal model developed by Schmid were calculated and adjusted based on imaging data to match the model with specific patients.Based on the literature data,the intervertebral stiffness was added in each vertebral joint,and modified in the scoliosis segments to make the model conform to mechanical characteristics of the vertebral joints in patients with scoliosis,and then a personalized kinematics and dynamics simulation analysis spinal model for patients with scoliosis was established.Inverse kinematics was used based on motion capture data and muscle activation was calculated using static optimization method.The calculated results were compared with imaging and electromyogram(EMG)data.Results The average angle error for the coronal plane of each vertebra was 0.164°,which met the kinematic error requirements.The ratios of muscle activation rates for convex and concave paraspinal muscles of thoracic and lumbar segments in standing state were 0.489 and 0.631,respectively,which were consistent with the EMG data.Muscle activation was closer to EMG data in the modified model for intervertebral stiffness during lateral flexion than that in the unmodified model.Conclusions The model established by the method in this study meets the accuracy requirements of kinematics and muscle force.