The Large Individual Differences in the Range of Hip Joint Motion Rather Than Lumbar Spine Motion Affect Dynamic Spinopelvic Rhythm

Abstract

Introduction Global spinal balance and its relationship to the pelvis have received much attention, and various formulae have been used to predict postoperative spinopelvic alignment for spinal surgery. However, previous studies had limitations because no consideration was given to the dynamic factor. Methods Fifteen healthy adults without any lumbar disorder (group A) and 9 L4-spondylolisthesis patients (Group B) volunteered to participate in the study. Sequential images were captured with the subjects in the standing position with maximal forward bending followed by backward bending using a dynamic flat panel detector system. Spinopelvic parameters (LL: lumbar lordosis, SA: sacrofemoral angle, SS: sacral slope, PI: pelvic incidence, DP: distance of the horizontal movement of the pelvis) were evaluated. We also investigated the relationship between LL and SA (lumbar/hip [L/H] ratio) as the spinopelvic rhythm. Results In group A, the mean change in LL was 83.2 ± 9.5°; change in SA, 45.4 ± 16.6°; SS, 42.6 ± 8.9°; PI, 43.2 ± 7.7°; DP, 15.7 ± 3.4 cm, and L/H ratio, 3.6 ± 2.7. However, spinopelvic rhythm changed over time, because the change in LL was larger than the change in SA from the middle of the rising motion to the upright position. In group B, the mean change in LL was 50.3 ± 8.0°; SA, 56.9 ± 16.0°; SS, 27.5 ± 13.5°; PI, 47.4 ± 10.4°; DP, 12.7 ± 6.8 cm; and L/H ratio, 1.0 ± 0.5. Conclusions When compared with the change in LL, individual differences were largely noted in the change in SA. These results demonstrated that the range of hip joint motion under physiological conditions, unlike anatomical motion, differed substantially between individuals. Therefore, spinopelvic rhythm is dependent on the change in SA.

Is there a correlation between pelvic incidence and orientation of the acetabulum? An analysis based on a three‐dimensional statistical model of the pelvic ring

“…lumbal lordosis, scoliosis), pelvic anatomy and orientation (pelvic incidence [PI], pelvic tilt, sacral slope, pelvic inclination), the acetabular configuration (anteversion, inclination, dysplasia) and the surrounding tendons, muscles and ligaments. Spinopelvic balance is a frequently discussed issue especially in trying to describe and understand the interaction between the spine, pelvis and lower extremities (Hayden et al, 2018 ; Yoshioka et al, 2019 ). Several studies focus on the relation between spine configuration and pelvic anatomy, and the effect of impaired mobility of the lumbar spine on hip joint function.…”