Associations between NCLBP, spinal sagittal alignment and age groups: a cross-sectional cohort study.

Purpose: Nonspecific chronic low back pain (NCLBP) is one of the most common manifestations of degenerative spondylitis. It affects many patients of all ages and seriously interferes with quality of life. However, the associations between NCLBP, sagittal alignment and age remain unclear. We aimed to investigate the typical features of sagittal alignment in individuals with NCLBP and to discuss the relationships between age and these NCLBP-related changes in sagittal alignment.

Methods: We measured the sagittal parameters of patients with NCLBP and investigated their sagittal alignment and compensatory mechanisms by comparing them with those of asymptomatic individuals.

Results: A total of 905 elderly patients (≥ 50 years old) and 1296 young patients (< 50 years old) were included. An analysis of sagittal parameters revealed that elderly patients with NCLBP had a smaller lumbar lordosis (LL, p = 0.001) and a greater T1 pelvic angle (TPA, p < 0.001). Age was significantly correlated with the TPA (r_s = 0.549, p < 0.001) and pelvic tilt (PT, r_s = 0.471, p < 0.001). The AUC value of the TPA was 0.782 (95% CI 0.764 to 0.799).

Conclusions: Although decreased lumbar lordosis is the most typical sagittal feature in patients with NCLBP, there are still differences in sagittal alignment between different ages. Compared with young patients, elderly patients with NCLBP more commonly present with a decompensated pattern of the anterior inclination of the trunk as the main sagittal alignment abnormality. TPA is more predictive than LL for the diagnosis of geriatric NCLBP.