Estimation of Vertebral Rotation and the Spinal and Rib Cage Deformity in Scoliosis by Computer Tomography

TLDR

CT can determine vertebral rotation and spinal/rib cage deformity along the longitudinal axis. The study aims to evaluate vertebral rotation in the frontal plane using CT. The authors define and discuss various rotation angles, distances, and indices for measuring vertebral rotation. CT shows negligible radiation risk compared to standard AP radiographs and measures vertebral rotation with 0.3º accuracy when tilt is ≤20º in a single plane, but accuracy degrades when tilt exceeds 20º in both planes.

Abstract

Computer tomography (CT) presents a method of determining longitudinal axis vertebral rotation and vertebral, spinal, and rib cage deformity. Different rotation angles, distances, and indexes are defined and discussed. Radiation risks were evaluated and considered exceedingly small when compared to the ordinary spinal anteroposterior radiograph. In a model study the mean difference between actual vertebral rotation and measured rotation was 0.3º if the vertebrae were tilted up to 20º in either the frontal or sagittal plane. This accuracy was lost if the vertebrae were tilted 20º in both the frontal and the sagittal plane. Computer tomography can be used for evaluation of the vertebral rotation in the frontal plane.