The Correlation Comparison of Vertebral Axial Rotation Relative to Curvature and Torsion in Scoliosis by Simplified 3D Spine Model

This paper reports a study on correlation comparison of the vertebral axial rotation relative to curvature and torsion of scoliotic spine. The goal of this study is to understand whether the vertebral axial rotation is more correlated to the curvature or to the torsion of the scoliosis spinal deformity. For this purpose, the simplified 3D spine models are constructed on the randomly chosen images of scoliosis patients. The 3D spine model is based on two orthogonal spinal radiographic images taken from coronal and sagittal planes. Superimposed on these two images, the 3D Bezier curves are fitted interactively onto the center of the spine on both coronal and sagittal images. Upon the 3D Bezier Curve fitting, a series of simplified 3D vertebrae are implemented onto the 3D Bezier Curve proportional in size to its axis. The curvature and torsion then are obtained by difference quotients algorithm. In determining the vertebral axial rotation, the measurements are conducted directly on the coronal spine images. The lateral margins and centers of pedicles are used as landmarks for the rotation calculation. The correlation coefficients are calculated from both vertebral axial rotation relative to the curvature and to the torsion found on each vertebra. The strength of correlations from both cases is compared in the table.