基于ANSYS/LS-DYNA的神经电极植入脑组织过程数值仿真  

Numerical simulation of neural probe inserting into brain tissues based on ANSYS/LS-DYNA

作　　者：马亚坤[1] 张文光[1] 杨鹏[1] 

机构地区：[1]上海交通大学机械系统与振动国家重点实验室,上海200240

出　　处：《医用生物力学》2015年第6期510-514,557,共6页Journal of Medical Biomechanics

基　　金：国家自然科学基金项目(51175334);上海交通大学医工(理)交叉基金项目(YG2013MS06)

摘　　要：目的 建立神经电极-脑组织数值仿真模型，研究神经电极在植入过程中对脑组织产生的植入损伤。方法 采用超黏弹性模型描述脑组织材料，基于单元删除法和最大主应变失效准则模拟组织破坏与分离，并通过平均等效应变量化组织植入损伤，考察神经电极楔形角、植入速度以及电极刚度对脑组织急性损伤的影响规律。结果 150°楔角所产生应变值较90°增加37.1%；100 μm/s慢速植入时电极植入路径上组织应变值较大（〉57%），500 μm/s较高速植入时植入路径上组织应变明显变小（〈25%）；而电极刚度对组织损伤影响不明显，电极刚度从165 GPa下降至5 kPa时，组织应变仅增加1%-2%。结论 数值仿真模型可为神经电极与植入参数设计提供参考，从而减少组织植入损伤，提高电极工作寿命，满足长期临床应用。Objective To establish a neural probe-brain tissue numerical model and investigate tissue injuries induced by probe during its insertion into brain tissues. Methods The material of brain tissue was described by a hyper-viscoelastic constitutive equation. Tissue failure and separation were simulated by the element deletion method based on a maximum principle strain failure criteria, and tissue injuries were quantified by the mean effective strain. Then effects of probe wedge angle, inserting speed and probe stiffness on the acute injury were investigated. Results Tissue strain generated by probe with wedge angle of 150° was increased by 37.1% compared with the strain induced with wedge angle of 90°. Along the insertion path, probe with a slow speed of 100 μm/s induced much higher strain value （〉57%） compared to that with relatively faster speed of 500 μm/s, which generated the strain value below 25%. The probe stiffness, however, had a negligible effect on tissue injury. The strain within the tissue was only increased by 1%-2% while the stiffness decreased from 165 GPa to 5 kPa. Conclusions The established numerical model can provide references for the design of neural probe and probe inserting parameters, which will be helpful to reduce tissue injuries induced by probe insertion and thus improve the working life of neural probe to meet the long-term clinical application.

关 键 词：神经电极 植入参数 组织损伤 单元删除 有限元分析 

分 类 号：R318.01[医药卫生—生物医学工程]