Abstract
The present paper presents the numerical results of a finite-element analysis of the role of a linear buckling phenomena in the etiology of idiopathic scoliosis. In a previous study, we assumed that idiopathic scoliosis is a buckling phenomenon induced by the growth of vertebral bodies, and we used the finite-element method with a spine model to demonstrate the results of linear buckling. However, a program based on the theory of nonlinear buckling did not produce clear buckling modes that were similar to the observed clinical modes. In this study, we return to the starting point and use rather simple models to confirm the existence of a buckling phenomenon that has various geometrical properties. We assumed that the growth of the vertebral bodies can be modeled by the generation of a non-elastic bulk strain. We use the finite-element method to analyze linear buckling modes caused by the growth deformation, and we confirm the existence of the buckling phenomena and clarify the range of the geometrical parameters in which this buckling occurs. By a comparison of different models, we investigate the influence of the region of the buckling phenomena on the physiological curvature of the spine and the intervertebral articulation. Our results support Dickson's hypothesis that a flattening or reversal of normal thoracic kyphosis at the apex of the curvature of the spine causes the buckling phenomenon.
