In Vivo Three-Dimensional Analysis of the Facet Joint Surface Center

Facet joints are considered to play important roles in controlling spinal segmental motion and load transmission. It has been reported that 15–45% of low back pain is caused by facet joint diseases (1). Numerous studies on facet joint orientation have been reported in the literature; however, data on facet joint position is limited. Since the so-called “three-joint complex” is comprised of an intervertebral disc and two facet joints, it is important to determine the spatial relationship among these components to understand motion segment kinematics. Three-dimensional (3D) location of the facet joint may also provide important information for the studies on lumbar canal stenosis and spondylolisthesis. There has been no study, to our knowledge, to evaluate 3D position of the facet joint within the spine. The aim of this study was to determine accurately the facet joint position by using a subject-based computed tomography (CT) model and 3D measurement techniques, and analyze level, gender, ages and effects.