Aims. The aim of this study is to test the hypothesis that three grades of sagittal compensation for standing posture (normal, compensated, and decompensated) correlate with health-related quality of life measurements (HRQOL). Methods. A total of 50 healthy volunteers (normal), 100 patients with single-level lumbar degenerative spondylolisthesis (LDS), and 70 patients with adult to elderly spinal deformity (deformity) were enrolled. Following collection of demographic data and HRQOL measured by the Scoliosis Research Society-22r (SRS-22r), radiological measurement by the biplanar slot-scanning full body stereoradiography (EOS) system was performed simultaneously with force-plate measurements to obtain whole body sagittal alignment parameters. These parameters included the offset between the centre of the acoustic meatus and the gravity line (CAM-GL), saggital vertical axis (SVA), T1 pelvic angle (TPA), McGregor slope, C2-7 lordosis, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), PI-LL, sacral slope (SS), pelvic tilt (PT), and knee flexion. Whole spine MRI examination was also performed. Cluster analysis of the SRS-22r scores in the pooled data was performed to classify the subjects into three groups according to the HRQOL, and alignment parameters were then compared among the three cluster groups. Results. On the basis of cluster analysis of the SRS-22r subscores, the pooled subjects were divided into three HRQOL groups as follows: almost normal (mean 4.24 (SD 0.32)), mildly disabled (mean 3.32 (SD 0.24)), and severely disabled (mean 2.31 (SD 0.35)). Except for CAM-GL, all the alignment parameters differed significantly among the cluster groups. The threshold values of key alignment parameters for severe disability were TPA > 30°, C2-7 lordosis > 13°, PI-LL > 30°, PT > 28°, and knee flexion > 8°. Lumbar spinal stenosis was found to be associated with the symptom severity. Conclusion. This study provides evidence that the three grades of sagittal compensation in whole body alignment correlate with HRQOL scores. The compensation grades depend on the clinical diagnosis, whole body sagittal alignment, and lumbar spinal stenosis. The threshold values of key alignment parameters may be an indication for treatment. Cite this article: Bone Joint J 2020;102-B(10):1359–1367

Background and Aim. Spinal stability is associated with low back pain and affects the spines ability to support loads. Stability can be achieved if the applied force follows the curvature of the spine, passing close to the vertebral centroids. Previously we showed that calculated muscle forces required for stability in an idealised model increased with increasing and more evenly distributed lumbar curvatures. The purpose of this study was to calculate the muscle forces required for stability in standing in a group of healthy adults. Methods. Positional MRI was used to acquire sagittal images of the lumbar spine in a standing posture in 30 healthy adults. Sacral inclination was measured and active shape modelling used to characterise lumbar spine shape. A two-dimensional model of the lumbar spine was constructed using vertebral centroid positions and a simplified representation of the lumbar extensor muscles. The muscle forces required at each level to produce a follower load were calculated using a force polygon. Results. Sacral angle was positively correlated with the amount of overall curvature in the lumbar spine (P<0.001) but not the distribution of curvature. Muscle forces increased with increasing curvature at all lumbar levels (P<0.02). The distribution of curvature affected the muscle forces only at L3 (P<0.03). Conclusion. In a sample of healthy adults, muscle forces required to maintain stability are determined by the overall curviness of the lumbar spine and, to a lesser extent, the distribution of curvature. Variations in spinal shape should be considered when modelling lumbar spine loading. This abstract has not been previously published in whole or substantial part nor has it been presented previously at a national meeting. Conflicts of interest: No conflicts of interest. Sources of funding: This work was supported by a studentship granted to the University and awarded to AVP. An NHS Endowment grant provided further funding

Background and Aim. Low back pain is highly prevalent, particularly in manual occupations. We previously showed that the lumbar spine has an intrinsic shape, identifiable in lying, sitting and standing postures, that affects the spine's response to load. Its effects on motion are unknown. Here we investigate whether intrinsic spinal shape is detectable throughout a greater range of postures and its effect on how healthy adults lift a weighted box. Methods. The lumbar spine was imaged using a positional MRI with participants (n=30) in 6 postures ranging from extension to full flexion. Active shape modelling was used to identify and quantify ‘modes’ of variation in lumbar spine shape. 3D motion capture analysed participants' motion while lifting a box (6–15 kg, self-selected). Results. Two modes accounted for 89.5% of variation in spinal shape, describing the overall curvature (mode 1) and distribution of curvature (mode 2). Within the first 9 modes, scores were significantly correlated between all six postures (r = 0.4−0.97, P<0.05), showing that intrinsic shape was partially maintained throughout. Individuals with straighter spines lifted with greater knee flexion (r = 0.4, P = 0.03) typical of squatting. Knee flexion negatively correlated with lumbar (r = −0.5 to −0.86, P<0.01) and pelvic flexion (r = −0.81, P<0.001). Those with curvier spines flexed significantly more at the back (r = −0.79, P=0.02) typical of stooping. Conclusion. In summary, individuals with straight spines squatted to lift while those with curvy spines stooped, indicating that the way we move to pick up a load is associated with the shape of our spine

Background and Purpose of Study:. Differences in regional lumbar angles in sitting have been observed between subgroups of NSCLBP patients exhibiting motor control impairments (MCI) (O'Sullivan, 2005; Dankaerts et al, 2006). However, differences in standing posture and other spinal regions are unknown. This study aimed to compare regional spinal angles in healthy and MCI subgroups in sitting and standing. Methods:. An observational, cross-sectional study investigated spinal kinematics of 28 Flexion Pattern (FP), 23 Active Extension Pattern (AEP) (O'Sullivan, 2005) and 28 healthy controls using 3D motion analysis (Vicon) during usual sitting and standing. Mean sagittal angle for Total Lumbar (TotLx), Total Thoracic (TotTx), Upper Thoracic (UTx), Lower Thoracic (LTx), Upper Lumbar (ULx) and Lower Lumbar (LLx) regions between groups were compared using one-way ANOVA. Results:. No differences in total thoracic and lumbar regions were observed, except TotLx in sitting between FP and AEP (Mean Difference (MD)=15.81°, p=0.003). Significant differences were observed in ULx and LTx for standing and sitting between FP and AEP (ULx Standing MD=9.89°, p=0.003; ULx Sitting MD=12.32°, p=0.000; LTx Standing MD=7.57°, p=0.05; LTx Sitting MD=11.72°, p=0.001) with AEP demonstrating greater extension in these regions. FP exhibited greater flexion compared to controls in ULx and LTx, except LTx in standing (ULx Standing MD=7.69°, p=0.018; ULx Sitting MD=6.96°, p=0.014; LTx Sitting MD=11.28°, p=0.001). No differences between AEP and controls were observed in sitting or standing. Conclusion:. Observing subdivided regional spinal angles is key to identifying MCI sub-group differences, with ULx and LTx able to discriminate between FP and AEP, and FP and healthy controls. This abstract has not been previously published in whole or substantial part nor has it been presented previously at a national meeting. Conflicts of interest: No conflicts of interest. Sources of funding: Arthritis Research UK / Presidents Research Scholarship, Cardiff University