FE modeling and analysis of L4-L5 lumbar segment under physiological loadings

Because of the complexity and construction, the failure rate of lumbar surgery is still high. It is necessary to find a solution to help improve the accuracy and safety of surgery.

Construction and stress analysis of lumbar spine.

The generated FE model based on CT scan images was validated and used to investigate the motion, and stress/strain of the vertebrae under different physiological loadings. A degenerated model was also simulated by changing the materials properties (E and Poisson's Ratio) of the intervertebral disc nucleus and annulus fibers from 1.0 N/mm^2 to 3.0 N/mm^2, and 0.42 to 0.45, respectively.

When annulus fibrosis is degenerating or under ictal external loadings, the annulus fibrosis will be in a state of protrusion and there will potential for other pathological changes, such as herniation of the nucleus pulpous.

The effects of these changes in the corresponding motion and stress/strain of the spinal motion segments were investigated with some conclusions drawn in relation to the normal model for future application of medical diagnosis and surgical treatment.