Chen B K, Clark G M, Jones R
Department of Mechanical Engineering, 900 Dandenong Road, Caufield East, Monash University, Melbourne, VIC 3145, Australia.
Med Eng Phys. 2003 Mar;25(2):141-7. doi: 10.1016/s1350-4533(02)00150-9.
A two-dimensional (2D) finite element analysis has been used in this study to model the insertion of the Nucleus electrode array with different stiffness properties in order to evaluate the propensity of damage by visualizing the predicted trajectories and by comparing the buckling stresses and the contact pressures at the tip (and its distribution along the length) of the electrode array. Previous temporal bone studies have shown that damage during insertion of an electrode array around the basal turn of the cochlear spiral could be related to the design and the stiffness properties of the electrode array. However, it is difficult to evaluate different designs of electrode arrays purely by experimental methods as the experimental conditions and their results are difficult to reproduce. Three electrode arrays with different mechanical properties, i.e. uniform stiffness, graded stiffness, and a soft tip have been modelled. Buckling stress and contact pressure at the tip of the electrode array were found to be highest for the arrays with uniform stiffness. The contact pressures at the tip of the electrode array appeared strongly influenced by the stiffness profile and were optimal for graded stiffness. The results indicate the importance of the electrode array design and stiffness properties in minimizing trauma. However, there are a number of limitations in the present 2D evaluation which will require further analysis using a three-dimensional model to obtain definitive results.
本研究采用二维（2D）有限元分析来模拟具有不同刚度特性的Nucleus电极阵列的插入过程，以便通过可视化预测轨迹以及比较电极阵列尖端（及其沿长度方向的分布）的屈曲应力和接触压力，来评估损伤倾向。先前的颞骨研究表明，在耳蜗螺旋基部转弯处插入电极阵列时的损伤可能与电极阵列的设计和刚度特性有关。然而，仅通过实验方法很难评估电极阵列的不同设计，因为实验条件及其结果难以重现。对三种具有不同力学性能的电极阵列进行了建模，即均匀刚度、渐变刚度和软尖端电极阵列。发现对于具有均匀刚度的电极阵列，电极阵列尖端的屈曲应力和接触压力最高。电极阵列尖端的接触压力似乎受刚度分布的强烈影响，渐变刚度的接触压力最为理想。结果表明电极阵列设计和刚度特性对于最小化创伤的重要性。然而，目前的二维评估存在一些局限性，这需要使用三维模型进行进一步分析以获得确切结果。
