Investigation of Facet Joint Capsule Biomechanics of the Lumbar Spine: A Finite Element Study

Abstract

Low back pain is one of the most costly ailments in the world today. A key biological structure studied in the research of low back pain is the facet joint. The facet joint is thought to both play a role in the causation of low back pain through its response to noxious loading and in its relief through beneficial loading caused by spine manipulation. The purpose of these studies is to use a computational model to predict the biomechanical response of the facet joints to various loading parameters. This was accomplished using a linear 3D Finite Element model of the T12-S1 vertebrae of the spine with detailed facet geometry. The model was validated against a cadaver model under simulated chiropractic spine manipulation. The model was then modified and utilized to observe the effects of microgravity of the facet joints and predicted that the facets do not play a role in the cause of back pain among astronauts due to exposure to microgravity environments. Finally, the model was modified to have degenerated discs at the L5S1, L4L5, and L3L4 vertebral gaps and was used to show that degenerated discs affect the stresses and strains on the facets in adjacent intervertebral gaps.