Study on Lumbar Rotated and Localized Manipulation on Stress Based on Finite Element Method

The thesis established the three-dimensional, comprehensive and realistic finite element model(FEM) of lumbar spine (L4-L5) using datum of Dicom with reverse engineering software, which incorporated the geometric, material and contact non-linearities was used for studying the biomechanics of a lumbar motion segment under flexion ad extension, whose structure is comprehensive, its meshing of elements is accurate. The results were following as: The maximum stress concentrated on the pedicle and the vertebral arch, as well as the bottom of the upper vertebrae facet joint, and the stress on the below joint the left is higher than the right side of the joints. The displacement gradually increased in all structures of vertebral body, the maximum displacement appears on the left side of edge on the L4 and the left side of upper joints and spinous process of L4. The stress is mainly concentrated in the disc annulus, stress on the left anterior lateral is biggest, stress on right posterior lateral is small, the stress gradually increased. The displacement and stress on the intervertebral disc changes in the same direction, which concentrated in the annulus, the displacement on the left side is higher than that of the right side. The three-dimensional FEM could be used for studying the biomechanics of a lumbar spine to diagnose and treat the trauma and disease of lumbar spine.