脳自重変形解析時間短縮のための有限要素モデルの開発

Abstract

In order to predict intraoperative brain tissue deformation after dura opening, our research group developed the threedimensional finite element brain model (whole model). Gravity induced brain shift in the case of left fronto-temporal craniotomy was simulated with the whole model. However, long computation time was required. The goal of this study is achieving drastic computation time reduction of brain shift simulation for future clinical application by developing a new finite element brain model. Since the deep zone, e. g. areas around third ventricle, exhibited smaller amount of brain shift than the superficial zone of left temporal lobe, authors proposed a new left hemispherical brain model without right cerebral hemisphere. Equivalent force boundary conditions were introduced and then applied to the cross section of the hemispherical brain model. In the numerical simulation, gravity induced brain shift of the left cerebral hemisphere was computed by ABAQUS/Explicit. The results obtained by the proposed hemispherical brain model were good agreement with that by the whole model except only part of cerebellum and brain stem. In this analysis case, deformation of adjacent area of the left temporal lobes is especially important. The displacement error between proposed and whole models around cerebellum and brain stem are acceptable since these areas are away from the surgical field. The brain shift analysis using the proposed model successfully achieved up to 61% reduction of computation time compared with that using the whole model. The computation time reduction capability of the proposed model was successfully demonstrated.