Study The Spinal Growth Modulation According To The Finite Element Method Of Children Spinal Tuberculosis

Objective:The growth period of spinal tuberculosis occur both in active tuberculosis and in the healing period. There will be a change of spinal deformity angle. Patients with spinal tuberculosis in the growth process because of the vertebral growth may be accelerated or inhibited result in the increase of kyphosis, relieve, unchanged. There is the relationship between the growth of the vertebral endplate and pressure. The finite element method has become an effective method of study on spinal biomechanics, analysis of endplate, intervertebral disc, facet joint stress value and dynamic data, very detailed. Modeling using finite element software, can be obtained by solving the biomechanical properties of virtual objects and similar experimental specimens. The growth potential of internal fixation of mechanical load is not completely block the spine, but delayed the growth rate, when the mechanical load overkill, lift the corresponding mechanical load, patients may keep the growth potential. By application of CT 3D reconstruction in growing children we get the thoracic and lumbar pedicle width, height, angle and length. Then in the early morphological study results, using posterior pedicle screw fixation combined with minimally invasive video-assisted anterior decompression and interbody fusion surgery in the treatment of spinal tuberculosis and growth period, in different period to remove the internal fixation devices, clear the surgical effects on the growth of spinal column tuberculosis kyphosis and growth rate at the same time. It also discussed the value of the value of minimally invasive techniques in growing children in the treatment of spinal disorders. The growth period of spinal tuberculosis vertebral growth plate finite element model of local stress and biological fixation on spinal growth regulation based on.Methods:This project is composed of two parts.1. Based on growing spinal tuberculosis finite element model vertebral growth is associated with stress change law(1). Case study sample collectionChildren grouped according to age which spinal tuberculosis have been acquired between 0 to 16 years. Segmental lesions mainly located in the thoracic and lumbar segments, may be a single segment may also be a multi-segment. Selected cases of active tuberculosis requires a growth and healing 1 year,2 years and the final follow-up information and a complete collapse deformity angle of vertebral height (vertebral, posterior height) changes.(2) Establishment of three-dimensional CT image libraryIt selected growth of spinal tuberculosis cases has spiral CT machine adjacent vertebral lesions and scanning. After rebuilding thickness of 0.625 mm, the portion of the fault thickness<1 mm, three-dimensional image because the thinner the layer thickness by the establishment of more sophisticated, the less data loss, back to provide more accurate finite element analysis of the raw data. Scanning conditions: The median standard supine position, scanning voltage 120kV, current 320mA,0.75 pitch, each section DICOM image data size is 515 kb.(3) Image processing.Save the import of DICOM format CT reconstruction Materialise Mimics software, the image is obtained by screening. Adjust the contrast, remove the soft tissue shadow, defined threshold targets. Mimics will automatically extract the contour boundaries of different organizations depending on the threshold value, then using the inverse function of filling the vertebral body repair, to avoid the post-generating entity which has a hole, the impact on the future of meshing. The reconstruction of geometric 3 D model into Magic 9.9 MeshTool Mimics carrying, three-dimensional image reconstruction meshing, after a preliminary smooth, automatic detection and improve the quality of the grid mesh quality, to give satisfactory pre-meshing the three-dimensional image data to the output file format LIS, ready further processing.(4). The establishment of three-dimensional finite element modelMimics generated in the spine cervicothoracic junction surface geometry LIS format files into pre-processing software ANYSY10.0, through the network QA, smooth processing step is processed again grids, according to the reference model assign material properties. After you complete geometric modeling and material properties of the cell, the choice of free meshing method, the entity running ANYSY generation program (Volume Meshing generating entity based surface mesh) is automatically generated based on the finite element mesh dividing solid model, and automatic meshing to generate nodes and elements, growing spinal tuberculosis establish finite element model.(5) Stress analysis.By application of Pro/Ansys 6.0 finite element software model calculation and data processing, it obtained under different loading conditions Model Von mises stress cloud distribution.(6). Study on the vertebral growth with the associated rules of stress changeAccording to the active phase of spinal tuberculosis growth and changes in the healing of kyphosis and collapse of vertebral height (vertebral, posterior height), and finite element stress analysis of the relationship between the vertebral growth plate, elaborated vertebral growth with stress Relationship.2. The finite element model of the growth period of spinal tuberculosis case based on endoscopic assisted minimally invasive treatment and biological fixation of surgical treatment and biological fixation after the change of stress and the influence of the growth period of spinal deformity(1). Growing pedicle parameter measurement and age variationFor children of all ages pedicle CT, were measured for all ages pedicle angle in transverse, sagittal and coronal planes through three-dimensional reconstruction, width, pedicle axis and the axis of the spinous processes change the angle and the length of the horizontal line and the vertebral body. The resulting parameters of the data record into the computer, and statistical analysis, to establish changes in the scope of different ages thoracic and lumbar pedicle various parameters. We analysize the trend parameters with age.(2) Establishment of three-dimensional CT image libraryAccording to the system via the posterior pedicle screw fixation combined laparoscopic-assisted minimally invasive already acquired lesions anterior decompression, spinal fusion surgery growing TB cases, the patients were divided into three treatment groups, of different groups cases respectively in 1 year,1.5 years and 2 years to dismantle posterior fixation device (for the growth of spinal tuberculosis cases involving a single segment). All cases were recorded before and after surgery, after 0.5 years,1 year,2-year follow-up and final collapse deformity angle and vertebral height changes. Selected growth of spinal tuberculosis cases, spiral CT machine adjacent vertebral lesions and scan. By rebuilding thickness of 0.625 mm and the portion of the thickness<1 mm, it establishes three-dimensional CT graphics library.(3) Based on the finite element stress analysis of vertebral growth plateApplication of Pro/Ansys 6.0 finite element software model calculation and data processing. Analysis Von mises stress at different times of the growing season dismantle fixation of spinal tuberculosis cloud distribution model.(4) Statistical AnalysisComparative analysis of the results of changes in different groups, to determine the application of pedicle screw system fixation and laparoscopic-assisted minimally invasive anterior focus decompression, and fusion surgery growing influence of spinal tuberculosis spinal deformity and growth rate law, and explore the surgical treatment and internal fixation of vertebral growth plate pressure and influence of vertebral growth.Results:(1) According to the growth of spinal tuberculosis cases has been acquired, the establishment of three-dimensional CT image database (including the active phase and the healing phase)(2) To save the graphics into 3D CT reconstruction software Materialise Mimics, the image processing(3) Establish a growing spinal tuberculosis finite element model, derived Von mises stress cloud distribution model under loading conditionsConclusion:The biomechanical factors play an important role in the growth and development of the vertebral body, especially combined with tensile stress and compressive stress, affect the growth of vertebral growth plates, thereby causing distortion of the vertebral body, this aspect of clinical research work with a guide significance. the growth of spinal tuberculosis change process due to its special deformity in clinical treatment has been difficult, but also to many families bring economic and psychological burden. establish the normal range of each parameter pedicle growing children. application of pedicle screw fixation combined laparoscopic-assisted minimally invasive approach focus before decompression,spinal fusion surgery growing tuberculosis is an effective method. growing spinal tuberculosis by building the finite element model of the spine fixed gain influence within the vertebral body growth regulation of local stress and biological growth plate to follow the law of stress cartilage growth curve instead Hueter-Volkmann law,teat the tensile stress growth will accelerate,and stress within a certain range to promolie growth, over a certain range of the growth inhibition.