Inverse Model of Human Lumbar Spine Based on CT Image and Finite Element Analysis

Abstract

In order to accurately analyze the most vulnerable fracture points of normal human lumbar vertebrae under upright position, walking and left-right rotation, the spiral computer tomography (CT) was used to scan the segment from the upper edge of lumbar vertebra L1 to the lower edge of lumbar vertebra L5. After reading CT images with Mimics software, the threshold analysis, area segmentation and the whole filling were carried out. The generated 3D geometric model was reconstructed using the Finite Element Analysis (FEA) module of Mimics, and the 3D lumbar model with intervertebral disc established by UG software was used. The model was imported into ANSYS Workbench for finite element analysis. The results showed that when the human body was upright, the displacement of the vertebral body was larger than that of the articular process. The displacement of the leading edge of the upper surface of the disc was the largest and equal to 0.161 mm. The equivalent stress is concentrated on the articular process and spinous process, and the stress on the lower articular process of the L4 is the largest (15.073 MPa) indicating that the relative error between the finite element analysis result and the theoretical calculation result is small. Hence, it proves that the method is correct and feasible.