An Accurately Represented Finite Element Model of Lumbar Motion Segment / 航天医学与医学工程

ABSTRACT

Objective To construct a detailed, 3-dimensional, anatomically accurate finite element (FE) model of lumbar L4-L5 segment from CT data with a new kind of computer aided design (CAD) method. Methods A modified "no-seed region segmentation" was done to extract the interest region in the CT scan images and produce a binary image. "Best cross-section planes" accounting for the preferential direction dictated by lumbar spine were placed on the initial iso-surface model, forming a "non-regular piecewise subspace". This subspace and the embedded iso-surface mode were transformed by local affine transforms to a "regular subspace", in which a surface mesh of high quality was generated quickly. Finally a reverse transform procedure was employed to recover the shape feature of the lumbar surface mesh of lumbar L4-L5 in the original 3-dimensional space, which was then imported into ANSYS for the 3-dimensional FE mesh construction. Results All complicated anatomical features of the L4-L5 segment were explicitly represented in the unprecedented finite element model. The predicted results for compression, flexion and extension correlated well with experimental data under similar loading configurations. Conclusion The presented CAD method containing advanced algorithm implements fast and accurate simulation of such complicated geometry with fine mesh representation for lumbar FE analysis.