Deconditioning in chronic low back pain: might there be a relationship between fitness and magnetic resonance imaging findings?

The presence of persistent low back pain leads to avoidance of daily activities, contributes to further exercise intolerance and subsequent further loss of functional capacity. We sought to search for the relationship between lumbar magnetic resonance imaging findings and deconditioning in a homogeneous subset of patients with low back pain. We studied 20 sedentary, nonsmoking patients with chronic low back pain using symptom-limited cardiopulmonary exercise testing using treadmill breath-by-breath analysis using modified Bruce protocol. Lumbar facet and disc degeneration involving L1-S1 levels were assessed using 1.5 Tesla MRI. The total number of levels involved was positively correlated with age (r = 0.478, P = 0.033). The Pfirrmann grading of lumbar disc degeneration was positively correlated with Weishaupt grading of facet degeneration (r = 0.502, P = 0.024); however, VO₂ peak was only negatively correlated with facet degeneration (r = −0.5, P = 0.025). Facet joint-mediated pain is a significant problem in all patients suffering from chronic low back pain. Since in this study, aerobic fitness level was negatively correlated with facet degeneration, we suggest that degeneration of facet joints might better reflect the chronicity of low back pain when compared to intervertebral disc degeneration.