持续性过载条件下飞行员峡部裂腰椎的动力学响应及损伤预测

Dynamic Response and Injury Prediction for Lumbar Vertebrae of Pilots with Spondylolysis under Persistent Overload

目的 在腰椎有限元模型构建及验证的基础上,对飞行员腰椎正常、L5单侧及双侧峡部裂模型动力学响应进行仿真计算和损伤预测,探究持续性飞行过载对飞行员腰椎正常及峡部裂状态下的影响。方法 基于腰椎CT图像,采用逆向工程软件和计算机辅助工程(computer-aided engineering,CAE)技术建立人体腰椎精细的三维有限元模型;利用腰椎静态与动态体外实验验证模型的有效性;开展持续性过载条件下飞行员正常腰椎及峡部裂腰椎生物力学仿真分析,并结合动态响应指数(dynamic response index,DRI)损伤评价预测方法对脊柱损伤情况进行预测分析。结果 单侧及双侧峡部裂模型的L5椎体峡部最大应力分别为105.29、126.32 MPa,明显高于正常模型;峡部裂模型的L4~5和L5~S1节段椎间盘相比正常模型更易出现过早退行性改变;结合DRI脊柱损伤预测方法,正常腰椎、L5单侧及双侧峡部裂的脊柱损伤概率分别为0.001 4%、2.26%和3.21%,峡部裂发生后脊柱损伤概率明显升高。结论 峡部裂加重了飞行过载下腰椎峡部的负荷。研究结果为制定训练方案和防具开发提供更精确的数据支撑,保证飞行安全。

Objective Based on construction and verification of the lumbar finite element model,the simulation calculation and injury prediction on dynamic response of normal lumbar model and L5 unilateral and bilateral spondylolysis models of the pilot were carried out,so as to explore the influence of persistent flight overload on normal and spondylolysis lumbar vertebrae of the pilot.Methods The precise finite element model of lumbar vertebrae was established using reverse engineering software and computer-aided engineering(CAE) technology based on CT images.The validity of the lumbar vertebrae model was verified by static and dynamic in vitro experiments.The biomechanical simulation analysis on normal and spondylolysis lumbar vertebrae of the pilot under persistent overload was carried out,and the spinal injury was predicted and analyzed by dynamic response index(DRI) injury evaluation and prediction method.Results The maximum isthmus stress of L5 vertebra in unilateral and bilateral spondylolysis models were 105.29 MPa and 126.32 MPa,respectively,which were significantly higher than those in normal model.The L4-5 and L5-S1 intervertebral discs of the spondylolysis model were more prone to premature degenerative changes than those of normal model.Combined with DRI spinal injury prediction method,the probability of spinal injury in normal lumbar vertebrae,lumbar vertebrae with L5 unilateral and bilateral spondylolysis were 0.001 4%,2.26% and 3.21%,respectively,and the probability of spinal injury was significantly increased after the occurrence of spondylolysis.Conclusions The spondylolysis increases the load of lumbar isthmus under flight overload.The results provide more accurate data support for the formulation of training programs and the development of protective devices to ensure flight safety.