The Control Study Of Two Methods To Rebuild The Pelvic Ring After Removing The Whole Sacrum By Three-dimensional Finite Element Analysis

ObjectivesTo investigate the effect about biomechanics on two methods, the MGF(Modified Galveston Reconstructon) and fibula transplantation by Three-Dimensional Finite Element Analysis, the MGF to rebuild the pelvic ring, contrasting them and find which method is better on rebuilding the pelvic ring, To provide more reasonable method and theory to rebuilding the pelvic ring after removing the sacrum.Methods1. To choose one female healthy volunteer,Sean Plane was situated between the bottom of Fourth lumbar vertebra and inferior margin of fibula。Taking information of lumbar vertebra , pelvic and fibulars,conservation them in CD with DICOM.2. To import the information of lumbar vertebra , pelvic and fibulars into mimics10.0 and Patran 2008 r2, construct Three-Dimensional Finite Element Model consistent with the request of two methods. and import them into the nastran to analyze.3. Using 960N to compress Fourth lumbar vertebra in axial direction, 7Nm in lateral bending and intortion in axial direction. on the performed Three-Dimensional Finite Element Model. to observate mechanotransduction and disposition.4. To analyze the results, contrast the stress and strain nephograms of the two methods, obtaine the results which method is better on stability after rebuilding pelvic ring.Results1.A serial Precise of data of DICOM format were obtained with CT seanning. Finally the solid modeling was achieved by being reconstructed by the software of Mimics, The 3D solid modeling of two methods were imported into the Patran. The Precise 3D finite-elemental modeling was obtained with the function of Pre-processing modular in Patran,such as meshing tool. The first modeling Possesses 149,536 nodes and 33,198 elements. The second modeling Possesses 13,2681 nodes and 29,479 elements.2.The two model of the operative methods were simulated and analyzed. From the stress and strain nephograms,we can conclude that:①After loading it on axial direction perpendicular, the max stress of The first model's was 2.243E+02MPa, locating the Ti-stick between nail in the neck of fifth lumbar vertebra and the first flank bone nail, and the combining site between nail in the neck of fifth lumbar vertebra and the Ti-stick. The displacement of the lumbar opposite pelvic was 0.89345mm, EF was 1074.48654;But the max stress of The second model's was 2.736E+03MPa, locating the Ti-stick between nail in the neck of fifth lumbar vertebra and the first flank bone nail, The displacement of the lumbar opposite pelvic was 15.333mm, EF was 62.6100567.②After loading them on lateral bending direction, the max stress of The first model's was 1.576E+02Mpa, locating the Ti-stick of the combining site between nail in the neck of fifth lumbar vertebra and the Ti-stick, The triaxiality translation and the triaxiality cycloposition translation were x=-0.021294mm, y=-0.54271mm, z=-0.18913mm, rotx=0.0078817rad,roty=-0.00058998 rad,rotz=0.00051123 rad;But the max stress of The second model's was 3.119E+02Mpa, locating the Ti-stick between nail in the neck of fifth lumbar vertebra and the first flank bone nail, The triaxiality translation and the triaxiality cycloposition translation were x=-0.15845mm,y=-2.9283mm,z=-1.6024mm,rotx=0.039399 rad,roty=-0.0023664 rad,rotz=0.00089123rad.③After loading them on intortion in axial direction, the max stress of The first model's was 1.553E+02Mpa, locating the Ti-stick between nail in the neck of Fourth lumbar vertebra and the first flank bone nail, and the crank arm, The triaxiality translation and the triaxiality cycloposition translation were x=0.12552mm, y=-0.017706mm,z=-0.014572mm,rotx=0.00046303rad,roty=0.00070301rad,rotz=0.0093962rad;But the max stress of The second model's was 2.143E+02Mpa, locating the Ti-stick between nail in the neck of fifth lumbar vertebra and the first flank bone nail, and the crank arm, The triaxiality translation and the triaxiality cycloposition translation were x=0.77342mm, y=0.05311mm,z=-0.04295mm,rotx=0.00087675rad, roty=0.0016011rad,rotz=0.023621rad.To contrast them we knew the first method was not utmost centered on 3D-movement,the pelvic ring was more stable sfter fixation.ConclusionsThe stability of the the MGF and fibula transplantation was better than the MGF, thereby it can degrade the problem about the internal fixation cinching or breaking.