Correlation between serum complement and severity of lumbar degenerative disease: A cross-sectional study

PURPOSE: To investigate the relationship between preoperative serum complement level and the severity of lumbar degenerative disease (LDD), as well as the severity of pain and the improvement rate of surgical symptoms. METHODS: The serum complements (C3, C4 and C1q) levels were determined by enzyme-linked immunosorbent assay. MRI was used to determine the degree of spinal degeneration. Mann-Whitney non-parametric test and Pearson correlation analysis were performed to predict the distance of relationships. RESULTS: Compared with the control group, the serum complements levels (C3, C4) of patients with LDD were significantly increased. We observed a significant correlation between the C3 level and the dural sac cross-sectional area (S1) (R = 0.6022, p = 0.0383) and S1/lumbar canal area (S0) (R = 0.6212, p = 0.0311). In addition, a correlation between preoperative serum C1q level and improvement rate of pain (R = -0.6607, p = 0.0140) was observed. CONCLUSION: The findings showed that serum levels of C3 and C4 were elevated in patients with LDD. Pearson correlation analysis showed that the C3 level could predict the dural sac cross-sectional area and be adopted as a promising predictive biomarker for spinal cord compression. Moreover, preoperative serum C1q concentration could predict the improvement rate of surgical symptoms.