Sagittal balance of the spine in patients with osteoporotic vertebral fractures

This study aims to compare the sagittal global spinal balance of patients consulting for osteoporosis, aged above 50 years with and without osteoporotic vertebral fractures (VFs). Global spinal balance is abnormal even in subjects without VFs. VFs and age are determinants of sagittal global balance; however, pelvic parameters play a role in compensatory mechanisms. Introduction This study aims to compare the spine curvatures, pelvic parameters, and the sagittal global spinal balance of patients aged above 50 years with and without osteoporotic vertebral fractures. Methods Two hundred patients (95 % women) aged 68.3 +/- 9.5 years underwent full skeleton radiographs in the standing position, by EOSA (R), a low dose biplane X-ray imaging system. VFs were evaluated according to Genant's classification. Spinal (thoracic and lumbar Cobb's indices, thoracic and lumbar tilts) and pelvic (pelvic tilt, sacral slope, and pelvic incidence) parameters were measured. Sagittal spinal balance was measured using the C7 plumb line and the spinosacral angle (SSA). We compared these parameters in patients with and without vertebral fracture and assessed the determinants of abnormal sagittal spinal balance. Results Sixty-nine patients had at least one VF. The sagittal spinal balance was significantly altered in patients with at least one VF, and there was an effect of the number and severity of VFs on parameters. Discriminative value for identification of patients with at least one VF, assessed by Area Under the Curves (AUCs) was 0.652 and 0.706 for C7 plumbline and SSA, respectively. Using multivariate analysis, parameters significantly associated with abnormal spinal balance (SSA) were the presence of at least one VF (OR = 4.96, P < 0.0001), age (OR = 1.07, P = 0.0006), and high pelvic incidence as a protective factor (OR = 0.93, P < 0.0001). Conclusions Global spinal balance is abnormal in subjects consulting for osteoporosis, even in subjects without VFs. VFs and age are determinants of abnormal sagittal global balance; however, pelvic parameters play a role in compensatory mechanisms.