Radiating leg pain from a lumbar disc herniation is often attributed to either mechanical compression of the nerve root by the herniated disc, and/or local inflammation. This study of 53 subjects searched for associations between pain intensity and 5 contributing factors: 1) inflammatory markers, 2) herniated disc size, 3) infection, 4) psychological factors and 5) conditioned pain modulation in patients with MRI confirmed painful lumbar radiculopathy scheduled for spine surgery.
From authors: “Two main findings emerge from the study. First, pain intensity was not associated with pro-inflammatory serum and disc cytokine levels nor with MRI disc-size measures. Second, rather than these objective parameters, pain intensity correlated with the patients’ reported measures of pain catastrophizing and with their conditioned pain modulation magnitude.”
What this study shows is that the brain is more involved in disc herniation leg pain than many believe or think. It wasn´t the disc or local inflammation that was most associated with pain. Instead two psychological brain factors had the most significant impact on pain. Not surprising as I see this in many patients and also data from other studies supports both catastrophizing and conditioning as risk factors for pain intensity.