Research On The Biomechanical Properties Of Spine Based On The 3D Finite Element Model

The research of spinal relevant diseases is a newly emerging interdisciplinary subject,the disease which caused by the spinal power imbalance or the inflammation changes of soft tissue surrounding spinal canal is common in clinic,it can arose other corresponding systems emerging disease symptoms.Because of its high morbidity,the research of the spinal diseases and cervical diseases becomes a hotspot.The purpose of this research is to understand the spinal biomechanical properties,especially the intervertebral disc's biomechanical properties,thus helping doctors analyze and make more specific,more accurate and higher-performance decisions to all kinds of spinal relevant diseases,solving troublesome problems caused by spinal relevant diseases in the end.According to the whole step of analyzing and experimenting of the biomechanical properties, the main contents of this paper can be divided into four stages:image preprocessing,geometry modeling,geometric model's data file format transforming and finite element model analyzing.Image preprocessing stage:Firstly,according to the medical imaging features of spinal images,this paper selects the threshold segmentation approach to segment the CT spinal images, and gets more efficient,better quality segmental results of vertebral bone and intervertebral disc; Secondly,considering the capacity of retaining data information of vertebral bone and intervertebral disc that resampled and the quality of geometric model,a appropriate rate is selected to resample the spinal images,and gets better resampled results.Geometry modeling stage:Firstly,two methods of volume rendering:vtkContourFilter and vtkMarchingCubes,are used to build model under different sizes of the images,and do some detailed compares among different instances,thus ensuring the 8:1 resampling rate and the vtkContourFilter volume rendering method.Secondly,the mesh simplifying and optimizing are done to the model,and well spinal modeling results are obtained.Geometric model's data file format transforming stage:Using vtkSTLWriter and Geomagic Studio 8,the spinal model's VTK data file format is successfully transformed into IGES data file format. Finite element model analyzing stage:In order to build solid model and do some finite elemental analysis,furthermore,considering the quality of meshing,we need to repair and subtract model,that is:remove small cells and fill big cells,make every cell has the same size as far as possible.Because the model has too many cells,the repairing work is heavy,and the calculating ability of computer is limited,this paper selects L4-L5 segmental model to do some detailed analysis,that is the model's displacement,intervertebral disc's displacement,model's stress and strain distribution and intervertebral disc's stress and strain distribution under different directions and loads.Finally,this paper summarizes the works and research fruits,presents the further research plan and objective.