Association of Selected Inflammatory Markers and Risk Factors with Pain in Patients Undergoing Cervical or Lumbar Disc Herniation

Introduction: Radicular pain following disc herniation may be due to local or systemic inflammatory responses than nerve compression. This study assessed the association of serum interleukin-6 (IL-6) levels, high-sensitivity C-reactive protein (hs-CRP) and related risk factors (occupational and behavioural) in patients undergoing discectomy following cervical disc herniation (CDH) or lumbar disc herniation (LDH).
Methods: The study recruited 77 patients from the main tertiary care hospital in Sri Lanka with cervical or lumbar pain and undergoing discectomy for LDH or CDH. Patients with any type of tissue/muscle injury not related to disc herniation, and those having acute and chronic infections were excluded. Sociodemographic information was gathered using a questionnaire. IL-6 and hs-CRP levels were measured using ELISA and an auto-analyzer respectively. Independent sample t-test and Pearson correlation coefficient were used for statistical analysis considering 0.05 significance level.
Results: There was no significant correlation between serum IL-6 and hs-CRP levels (p=0.86) among patients with acute and chronic CDH and LDH. Patients with chronic neck/back pain showed significantly higher IL-6 levels (p=0.043) than those with acute neck/back pain. Serum hs-CRP levels were significantly higher (p=0.048) in patients with acute neck/back pain than patients with chronic pain. There was no significant association between; the nature (p=0.542) and duration (p=0.446) of occupation, type of exercise (p=0.371), and type of sports (p=0.339) in either CDH or LDH patients.
Conclusion: The absence of a substantial link between IL-6, hs-CRP, CDH, or LDH indicates that these inflammatory biomarkers may not directly influence the development of CDH or LDH. However, increased IL-6 levels in patients with chronic pain indicates a significant association between IL-6 and chronic pain. Elevated hs-CRP levels in acute pain patients suggest a distinct inflammatory response specific to acute pain. Occupation, type of exercise and type of sports demonstrated no significant association with CDH or LDH.