A Longitudinal Study of Lumbar Sagittal Change in Middle-Aged Healthy Volunteers

INTRODUCTION: Recent research has shown that spinal sagittal alignment plays a critical role in health-related quality of life. However, most of these studies were cross-sectional in nature, and longitudinal studies of lumbar lordosis (LL) in healthy subjects were few. This study aims to evaluate the change in lumbar sagittal parameters during a 10-year period. METHODS: The study population included 45 individuals (mean age, 65.7 years; male, n=20; female, n=25) who underwent sagittal lumbar radiography and a basic health checkup during a 10-year period. The radiologic parameters were LL, disc angle, sacral slope angle (SS), and pelvic incidence (PI). The change of LL during the 10-year period was defined as ΔLL. The subjects were divided into the LL maintenance group (n=33) and the LL non-maintenance group (n=12) based on their LL values. RESULTS: The radiologic baseline/final parameters were as follows: LL, 45/34 degrees (P<0.001); L1/L2 disc angle, 4.5/2.5 degrees; L2/L3 disc angle, 5.5/2.7 degrees; L3/L4 disc angle, 6.2/4.2 degrees; L4/L5 disc angle, 8.1/5.1 degrees; L5/S disc angle, 14.2/12.2 degrees; and SS, 32.0/32.1 degrees. The mean PI (50.5 degrees) was tended to be associated with the final LL (R=0.31, P=0.044) and was correlated with the ΔLL (R=0.43, P<0.01). The data of the LL maintenance/non-maintenance groups were as follows: age, 65.0/67.0; primary LL, 43.2/50.2 degrees (P<0.05); final LL, 36.2/27.8 degrees (P<0.05); and PI, 52.8/43.8 degrees (P<0.01). CONCLUSIONS: During the 10-year study period, the LL in middle-aged and elderly volunteers decreased by 11 degrees. The factor of maintenance of LL was PI.