A Study And An Application Of A New Method Of Reconstructing A Finite Element Model Of Human Vertebral Column

ObjectivesTo find a method of reconstructing a finite element model of human vertebral column based on MRI fault images and use this method to establish finite element models of L4-L5 segment of spine respectively in rectangle and trapezoid fenestration operation and provide theory supportive for clinic application of trapezoid fenestration operation.Materials and MethodsMaking use of 1mm isotropous resolution thin layer scan technique of SIMENS MIR and based on 1mm-thick 65 layer of human body spine and axis of MRI continuous 3-dimensional pictures, we read in original Dicom format picture in the ScanIP model of Simpleware directly, and then, image segmentation, data fairing, three-dimensional reconstruction ordinally, in the end, we get an accurate 3D nan-linear FE model of lumbar motion segment(L4-L5) including intercalated disc. then, the model is subjected to ScanFE model, which can not only dividatur the model body mesh, but also can assign Young's modulus and Poisson's ratio for cortical bone, cancellous bone, nucleus pulposus and anulus fibrosus respectively, then generate a formatted document which can be subjected to ANSYS 10.0. ANSYS 10.0 can subject the model above directly, and it also can superimpose anterior longitudinal, posterior longitudinal, ligamentum flamvum, intertransverse longitudinal, capsular longitudinal, interspinous longitudinal, and superspinous longitudinal, at last, we get an accurate 3D nan-linear FE model of lumbar motion segment(L4-L5). By this method, we establish tow more FE model which imitate trapezoid fenestration operation and rectangle fenestration operation in therapy of lumbar spinal stenosis respectively, and analyze both long-term topo- stability of the tow model, we will get two sets of reverse turn data under 500N axial direction load and 15Nm moment.ResultsThe Simpleware can make the establishment of the finite element model more accurate and complete in human L4-L5 segment of vertebral column, form the network more quickly and can valuate the different parts respectively, and in the last place, the Simpleware can import ANSYS10.0 to seek advanced discriminate. Compared the new and the old kinds of operation in the finite element models, there are significant difference in data.ConclusionThe applications of thin layer MRI scanning technique and the Dicom standard can make the establishment of the finite element model more accurate and complete. The Simpleware improve the efficiency and quality greatly in the reconstructing model for it can establishes the digital model directly and can form network to make assignment and valuation for different materials. The analysis of finite elements shows the better long-term topo-stability obtained from trapezoid fenestration operation in therapy of lumbar spinal stenosis than the therapy traditional operation.