Thoracic kyphosis and pelvic anteversion in patients with adult spinal deformity increase while walking: analyses of dynamic alignment change using a three-dimensional gait motion analysis system

Purpose To determine dynamic changes of spinopelvic alignment while walking using a three-dimensional (3D) gait motion analysis in adult spinal deformity (ASD) patients. Methods This study included 20 ASD patients. The 3D gait motion analysis (Vicon) was performed during continuous walking to their limit. Dynamic parameters were obtained using reflective markers on the spinous processes, which were segmented into thoracic (T-), lumbar (L-), and whole spine (S-), sagittal spinal distance (SVA) and coronal one (CVA), sagittal spinal angle to the vertical axis (SA) and coronal one (CA), sagittal pelvic angle to the horizontal axis (P-SA) and coronal (P-CA), and thoracic limited spinal angle to the pelvic angle (T-P SA) and lumbar one (L-P SA). The dynamic variables at the final lap were compared with those at the first lap of an oval walkway. Results Spinal kyphotic deformity deteriorated significantly. As for pelvic angle, the mean P-SA parameters (first lap/final lap) were 3.2°/5.2°. Anteversion of pelvic sagittal angle increased significantly after continuous walking to their limit. In particular, regarding limited spinal angle to the pelvic angle, the mean T-P SA parameters were 30.5°/36.2° and L-P SA parameters were 6.4°/6.8°. Thoracic kyphotic angle increased significantly, but lumbar kyphotic angle did not change. Conclusion Decrease of thoracic kyphosis and pelvic retroversion has been recognized as a compensation for ASD on standing radiograph. Our 3D gait motion analysis to determine spinal balance found thoracic kyphosis and pelvic anteversion increased significantly in patients with ASD after continuous walking to the limit of their endurance until they were fatigued, indicating a failure of compensation for ASD. Graphic abstract These slides can be retrieved under Electronic Supplementary Material.