Analysis of intervertebral disc CCR6 and IL‐6 gene levels with short‐term postoperative low back pain after spinal fusion in lumbar degenerative disease

BACKGROUND: Previous studies have reported that specific pro‐inflammatory cytokines or chemokines are more highly expressed in painful than in nonpainful intervertebral discs (IVDs). However, few studies have investigated their correlation with postsurgical outcomes or the relationship between postoperative pain and inflammatory cytokines in IVDs. Thus, the present study examined the correlation among the gene expression levels of pro‐inflammatory cytokines and chemokines in IVD tissues removed during surgery and low back pain (LBP), leg pain (LP), and leg numbness (LN) at one year after spinal fusion surgery in patients with a lumbar degenerative disease (LDD). METHODS: Chemokine and cytokine gene expression levels were measured in IVD samples from 48 patients with LDD. The associations between chemokine and cytokine gene expression levels and pain intensity (numeric rating scale [NRS]) were also analyzed. A correlation analysis was performed between gene expression in each IVD and preoperative and postoperative pain intensity. RESULTS: In the preoperative analysis, CCR6 was associated with NRS(LBP) (r = −0.291, P = 0.045). Postoperative pain analysis revealed correlations between postoperative NRS(LBP) and CCR6 (r = −0.328, P = 0.023) and between postoperative NRS(LBP) and IL‐6 (r = −0.382, P = 0.007). Furthermore, patients with high postoperative LBP intensity (NRS(LBP) ≥ 7) also had high LBP intensity (NRS(LBP) ≥ 6) before surgery, and a correlation was observed (r = 0.418, P = 0.003). None of the gene mRNAs correlated with NRS(LP) or NRS(LN), respectively. CONCLUSIONS: CCR6 and IL‐6 gene expression in the IVD was associated with postoperative LBP intensity and may indicate a need for postoperative pain management.