Abstract
Background：Dual fluoroscopic imaging system (DFIS) was employed to identify the Center of Rotation(COR) in the lower lumbar spine and determine its relationship with weight bearing.
Methods：Nine participants were recruited in this study. The lumbar spine of each participant was 3D modeled based on CT images, and their relative positions were obtained using DFIS. By combining CT and DFIS, the kinematic data of the participants' spines during motion were acquired. The lower lumbar spine's Center of Rotation (COR) was calculated using the method of perpendicular bisectors.
Results：While flexing and extending, the Center of Rotation (COR) initially moved downward with increasing load, followed by upward movement as the load further increased.
The anterior-posterior position of the COR shifted posteriorly with increasing weight-bearing. Throughout the lateral bending exercises, the upper and lower COR positions increased as the load increased, while the left and right COR positions remained unaffected by the load increment. The COR height differed between flexion and lateral bending. We observed variations in the COR position of the lumbar spine during lateral bending and flexion-extension movements. This enhanced our comprehension of coupled motion patterns within the lumbar spine.
Conclusions：Position of the lumbar spine COR changes with variations in the load. During different movements, the COR location of the lower lumbar spine varied. Furthermore, the manner in which the COR position changes with load differs during different motions. This finding suggests the presence of distinct motion patterns in the lower lumbar spine. It helps enhance our understanding of the kinematic traits of the lumbar spine and clarifies the mechanisms that contribute to different diseases.