Expression of cytokines at baseline correlate/predict in the disc the outcome of surgery after disc degeneration: A 12-month follow-up study

BACKGROUND: Low back pain (LBP) is a highly prevalent condition that comprise a large portion of outpatient practice, challenging the diagnosis and treatment. However, the diagnostic tools are limited to clinical history, physical examination and imaging. Degenerative disc disease (DDD) is a significant cause of LBP, and emerging literature confirms the elevated levels of biomarkers in the discs. These biomarkers may serve as a tool for diagnosis, but may also be useful in predicting the treatment outcome. Here, we examine the expression of various cytokines on 1-year recovery from patients with LBP.

METHODS: Patient-reported outcome (PRO) in terms of pain intensity (VAS), disability (ODI), and quality of life (Eq-5D) is collected from 44 patients at baseline and 12 months after surgery to study the influence of baseline TNF-α, IL-1β, and IL-6 mRNA expression in both annulus fibrosus (AF) and nucleus pulposus (NP).

RESULTS: Between baseline and follow-up, our cohort showed improvement in VAS back pain (p < 0.001), VAS leg pain (p < 0.001), ODI (p = 0.02), and Eq-5D (p = 0.01). Baseline levels of IL-1 β was positively correlated with VAS back pain scores in AF (p = 0.05) and NP (p = 0.01) at 1-year follow-up. TNF-α expression at baseline was also positively correlated to ODI scores (p = 0.01) at follow-up and inversely correlated to improvements in ODI score between baseline and follow-up, suggesting that high TNF-α expression at baseline is associated with poor outcomes from surgery.

CONCLUSION: The results from our study support that TNF-α expression at baseline can serve as a very important predictor of treatment response from lumbar fusion surgery.