Association between baseline IL‐6 and 1‐year recovery in lumbar radicular pain

Background In the present study, the influence of cytokines on 1-year recovery in lumbar radicular pain was examined. Methods In total, 110 patients with symptomatic lumbar disc herniation were followed for 1 year. Uni- and multivariate linear regression was used to assess the influence of interleukin (IL)-6, IL-8, disc degeneration and endplate changes (Modic changes) on the changes in the Oswestry Disability Index (ODI change; primary outcome) and visual analogue scale (VAS) for low back pain (LBP) and leg pain (secondary outcomes). Results Less favourable ODI outcome correlated with higher serum IL-6 levels (B = −3.41, 95% CI −5.52 to −1.30, p = 0.002), non-surgical treatment (B = −7.03, 95% CI 1.21 to 12.84, p = 0.018), higher baseline back pain intensity (B = −2.28, 95% CI −3.21 to −1.35, p < 0.001) and low educational level (B = −5.57, 95% CI 0.66 to 10.47, p = 0.027). High VAS for LBP and leg pain at 1 year was associated with high levels of serum IL-6, higher back pain intensity and longer duration of lumbar radicular pain at baseline. Conclusions High serum IL-6 levels, but not disc degeneration or Modic changes, were associated with less favourable recovery in patients with lumbar radicular pain. Intense initial back pain, non-surgical treatment, lower educational level and longer duration of radicular pain before treatment also correlated with a slower recovery the first year after disc herniation.