The Effect of Human Intervertebral Disc Height on Its Mechanical Behavior — A Finite Element Study

Abstract Intervertebral disc height varies with individuals. Degeneration associated with pathologic changes and/or clinical treatments may also result in a change in disc height. Disc height variations affect the magnitude of axial displacement and radial bulge (Zhang et al. 1995). Clinical symptoms from compression may arise when: 1) disc bulge is large enough to encroach on the neural foramen and irritate a nerve root; and 2) the outer anulus is sufficiently stressed to irritate nerve fibers attached to its peripheral layer (Ashton et al. 1994). Therefore, the purpose of this study was to determine the effect of disc height on the mechanical behavior of the human lumbar intervertebral disc under compression in terms of axial displacement, intradiscal pressure, radial disc bulge, stress in the anular fibers and stress distribution at the inferior endplate-vertebra interface.