Biomechanical changes of lumbar segment after fusion analyzed with three-dimensional nonlinear finite element / 中国组织工程研究

ABSTRACT

BACKGROUND:MATLAB has capabilities of large numerical calculation, mathematical drawing and simple finite element analysis. It can establish models rapidly and can be able to identify the grayscale with BMP and JPG format, and it can directly transform the identified data into ANSYS finite element software-readable format, thus avoiding personal error produced by the repositioning and secondary treatment in the Autocad software. OBJECTIVE:To find a simple, convenient and accurate method to construct the model of lumber fusion and to analyze the biomechanics of lumbar motion segment after lumbar fusion. METHODS:Lamel ar CT and Matlab (Matrix Laboratory) scientific computing software combining Ansys finite element software was used to construct the models of lumber fusion. Then the models were loaded to analyze the biomechanical change of the fusion model. RESULTS AND CONCLUSION:The established models were loaded with axial, bending and stretching loads, and the biomechanical analysis showed that interbody fusion had the best stability among al the fusion models. Combined with joint fusion, the axial displacements of interbody, rear side and rear fusion models were decreased by 5%, 1%and 4%than that of simple interbody fusion, posterolateral fusion and posterior fusion models. Under the stretch-buckling load conditions, the rotation angles were reduced by 23%, 11%and 45%. Stress concentration to the fusion parts showed fusion block could increase the load displacement. The technology of lamel ar CT, Matlab software and Ansys finite element software can accelerate the construction of lumber fusion model and make the model more accurate. Facet joint fusion combined with interbody fusion, posterolateral fusion and posterior fusion can get better lumbar stability, and this increased stability is more significant in the rear fusion. Stress distribution of posterior fusion is more reasonable.