Finite Element Analysis Of Different Laminectomy In The Treatment Of Single-level Thoracolumbar Tuberculosis

Objective : By building the finite element model A(Normal T10-L2 thoracolumbar model),B(The removal internal fixation after total laminectomy,T11/T12 tuberculosis lesion clearance,bone graft fusion and internal fixation)and C(The removal internal fixation after hemilaminectomy,T11/T12 tuberculosis lesion clearance,bone graft fusion and internal fixation),the validation and biomechanical analysis of the model were carried out.Methods:Volunteer was recruited and underwent a computed tomography(CT)scanner from T10 to L2 vertebral levels.The image data were exported in Digital Imaging and Communications in Medicine(DICOM)format.The DICOM images were imported into the interactive medical imaging control system Mimics 19.0 to create 3-dimensional(3D)vertebral models of the T10 to L2 region.After Geomagic WRAP repair and processing model,the models of the intervertebral discs were built using SolidWorks2017.Model A was established that a 3D finite element model of a normal T10 to L2 thoracolumbar spine.Model B was constructed for the removal internal fixation after total laminectomy,T11/T12 tuberculosis lesion clearance,bone graft fusion and internal fixation.Model C was constructed for the removal internal fixation afterhemilaminectomy,T11/T12 tuberculosis lesion clearance,bone graft fusion and internal fixation.Models A,B and C were divided into plane-mesh models and endowed with material properties,including elastic modulus and Poisson ratio,into Ansys workbench 17.0 finite element analysis software.Ligaments were simulated by Spring element,loads and boundary conditions were set,500 N axial load and 7.5 Nm rotation moment were applied to simulate physiological activities(forward flexion and backward extension,left lateral bending and right lateral bending,left axial rotation and right axial rotation),validate the model.The overall range of motion(ROM)and von Mises stress of the spine were measured.Results:Under the same load and moment,there were significant difference in ROM between models A,C and model B(p < 0.05).There were no significant difference in rom between model A and model C,p > 0.05.There were no significant difference in von Mises stress between models A,B and C(p > 0.05).Conclusions:1.Hemilaminectomy,debridement of tuberculosis focus,bone graft fusion and internal fixation are better than total laminectomy,debridement of tuberculosis focus,bone graft fusion and internal fixation for spinal stability.2.After hemilaminectomy,if the vertebral body fusion is good,the internal fixation device can be removed.