| BackgroundThe position and structure of the spine is special to maintain the basic structural function of the trunk.At the same time,the adjacent stage connects by the intervertebral disc,small joint and other tissues,so that the human body can complete the bending rotation and other activities.In clinical,the finite element technique of the spine can accurately calculate the stress and movement of the lumbar spine,improve the accuracy of the surgical plan,and it effectively shorten the operation time.And,the finite element technique can not only analyze the mechanical properties of the specimen,but also obtain the specific value of the interaction between various tissues in the specimen,which is lower in cost and more efficient than in vitro specimen experiments.However,the finite element model of lumbar spine is established by the image data collected by CT.During the CT scan,the body is lying flat.Studies have shown that there are significant differences between the anterior convex Angle and the sacral inclination Angle when the lumbar spine in horizontal and vertical position.It is uncertain whether the calculated results can accurately reflect the mechanical environment of the lumbar spine in standing condition.Because of the lumbar finite element model constructed through a series of operations such as three-dimensional reconstruction,mesh substantialization,creation of material and section properties,and setting of constraints.After the calculation,there will still be hidden results such as setting errors and non-convergence,which will waste a lot of time in repeated operation,and greatly limit the application of finite element technology in lumbar treatment planning.PurposeThe purpose of this study was to verify the influence of imaging differences in horizontal and vertical position on the calculation of lumbar mobility.At the same time,an intelligent lumbar model reconstruction system was constructed to replace the manual batch reconstruction of samples,so as to achieve the purpose of constructing the finite element model activity calculation result database.MethodsThe method of the finite element modeling of spine was used to verify the differences in the mobility of the lower lumbar vertebrae under different body positions.In this paper,CT and lateral X-ray image data of 32 volunteers were collected to measure the anterior convex Angle(cobb Angle)of the lumbar vertebrae in the sagittal plane of standing and lying CT respectively.1.Analysis of the difference in activity of horizontal and vertical positionCT data were imported into mimics 19.0 to rebuild the lumbar spine,STL format files were exported to Geomagic for materialization,and the practical mold extraction function was imported into Solidwork to build the intervertebral disc and nucleus pulposus.The CT data were imported into Hypermesh to construct mesh and ligaments to segment cortical bone.Finally,the module parameters and correlation are set in Abaqus.2.Calculation of similar range of activityIn this paper,an intelligent lumbar vertebra reduction system was established to solve the repetitive modeling and lumbar vertebra reduction work in the process of various finite element calculations,and was intelligently imported into Abaqus for calculation.This paper use Python statements for programming,it is a non-associated lock screen script,divided into keyboard and mouse two parts,clear logic,low memory occupancy,with no compatibility problems.ResultThe results showed that the finite element model of the lumbar spine in the horizontal and vertical position with the same elastic modulus of each part of the material has no statistical difference in the activity of the lumbar spine.When solving repetitive computing tasks,intelligent scripts are almost completely free of manual operation,with smooth operation,no clutches and errors,which is the same as manual operation.ConclusionThis study provided theoretical support for the establishment of a lumbar finite element model based on CT data and the calculation of the activity of each body position.At the same time,it also proved that using the same elastic modulus calculation,there are differences also exist between different individual activity in the same or similar situation,to explore the main factors that cause differences between different individuals,and calculate the similar interval,can effectively improve the efficiency of lumbar spinal finite element model and the modeling,experiment to reduce costs,improve the utilization rate of clinical to help doctors to treat lumbar related diseases. |
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