This retrospective observational study was conducted to identify factors associated with low back-related leg pain (LBLP) using axially loaded magnetic resonance imaging (AL-MRI). Ninety patients with low back pain (LBP) underwent AL-MRI of the lumbar spine. A visual analog scale and patient pain drawings were used to evaluate pain intensity and location and determine LBLP cases. The values of AL-MRI findings were analyzed using a logistic regression model with a binary dependent variable equal to one for low back-related leg pain and zero otherwise. Logistic regression results suggested that intervertebral joint effusion (odds ratio (OR) = 4.58; p = 0.035), atypical ligamenta flava (OR = 5.77; p = 0.003), and edema of the lumbar intervertebral joint (OR = 6.41; p = 0.003) were more likely to be present in LBLP patients. Advanced disc degeneration (p = 0.009) and synovial cysts (p = 0.004) were less frequently observed in LBLP cases. According to the AL-MRI examinations, the odds of having LBLP are more likely if facet effusion, abnormal ligamenta flava, and lumbar facet joint edema are present on imaging than if not. The assessment of lumbar spine morphology in axial loaded MRI adds value to the potential understanding of LBLP, but further longitudinal and loaded-unloaded comparative studies are required to determine the role of acute dynamic changes and instability in LBLP development.
Keywords: axial loading; logistic regression; low back pain; low back-related leg pain; lumbar spine; magnetic resonance imaging.