Spinal Coupling in Frontal and Transversal Plane During Gait - A Segmental and Time-Dependent Analysis of the Thoracic and Lumbar Spine

2026-08-13

AI Summary

Current research lacks a dynamic, segment-level understanding of the coupled behavior of thoracolumbar spinal segments in the coronal and transverse planes during gait and its relationship with sagittal plane posture. This study leverages non-invasive rasterstereography combined with an instrumented treadmill to perform time-varying coupling analyses of axial rotation and lateral deviation across vertebral levels T3–L4 in 642 participants during walking, while also evaluating the influence of static sagittal alignment. For the first time, it provides a vertebra-resolved dynamic characterization of spinal coupling during gait, revealing a craniocaudal pattern of coupling variation significantly modulated by sagittal posture. Using metrics including absolute phase lag, normalized signed area, and tilt angle, the study demonstrates substantial differences in coupling behavior between adjacent segments and identifies multiple critical transition points along the thoracolumbar spine.

Abstract

Introduction: Coupling between lateral deviation and axial rotation is a known feature of spinal mechanics, yet its behavior at the individual vertebral level during gait, as well as the association with sagittal posture remains poorly understood. Methods: This study analyzed spinal kinematics in a diverse cohort (n=642) using a non-invasive rasterstereography system with an instrumented treadmill, quantifying time-dependent coupling of rotation and lateral deviation for each vertebra from T3 to L4 during walking as well as the influence of sagittal posture on this coupling. Coupling behavior was analyzed with absolute phase lag, normalized signed area and tilt angle derived from the Fourier series. Results: Results revealed cranio-caudal patterns for all three metrics with differences between almost all adjacent vertebrae and different turning points, i.e., where the coupling behavior changed (from increase to decrease and vice versa). Generalized, as well as pooled static sagittal posture significantly modulated these patterns, while individual deviations from static sagittal posture influenced the metrics. Conclusion: These findings provide the first dynamic, vertebra-level characterization of spinal coupling during gait. Furthermore, they offer a foundation for an understanding of spinal biomechanics and the influence of static sagittal posture, potentially relevant to the diagnosis and treatment of spinal disorders.

Problem

• spinal coupling
• gait
• vertebral kinematics
• sagittal posture
• lateral deviation

Innovation

• spinal coupling
• rasterstereography
• gait analysis
• vertebral-level kinematics
• sagittal posture