Biomechanics of Lumbar Spondylotic Degeneration

Abstract

Abstract Human lumbar spinal columns exhibit different degrees of spondylotic degeneration. However, the biomechanical effects of these changes have not been fully studied. Understanding the potential patterns of such responses relative to the severity of degenerative changes assist in clarifying the influence on clinical and laboratory investigations. This study was conducted to obtain the three-dimensional biomechanical stability parameters of degenerated and non-degenerated spines. The degree of degeneration in disc and facet joints was graded individually for severity allowing evaluation of overall effects as well as individual component influences. Pure moment and complex loading were applied under flexion, extension, and left and right lateral bending modalities. The degenerated columns responded with greater variations in the moment-rotation (pure-moment loading) and force-deflection and moment-rotation (combined loading) than normal spinal columns. Furthermore, the response of the degenerated column depended not only on the overall quality of the spine, but also on the difference in severity and type of components affected. Complex loading showed increased sensitivity to variations in the biomechanical responses compared to pure moment loading. Disc degeneration showed increased changes in rotational stability, whereas facet alterations demonstrated greater effects on axial stiffness.