High-sensitivity C-reactive protein in chronic low back pain with vertebral end-plate Modic signal changes.

OBJECTIVE

To assess high-sensitivity C-reactive protein (hsCRP) level as a measure of low-grade inflammation in relation to Modic vertebral end-plate marrow signal change on magnetic resonance imaging (MRI) in patients with chronic low back pain.

METHODS

All patients hospitalized for chronic low back pain in our institution were prospectively enrolled in this pilot study. Serum hsCRP concentration was measured by immunoturbidimetric assay. MR images were evaluated independently by a panel of 2 spine specialists and a radiologist. Recording of clinical parameters, MRI evaluation, and hsCRP level of each patient was blinded.

RESULTS

Three groups of 12 consecutive patients (Modic 0, Modic I, and Modic II signal changes on MRI) were prospectively selected. Serum hsCRP level was significantly different in the 3 groups (P = 0.002) and especially high in the Modic I group (P = 0.002 compared with Modic 0 and II groups): mean +/- SD 1.33 +/- 0.77 mg/liter in the Modic 0 group, 4.64 +/- 3.09 mg/liter in the Modic I group, and 1.75 +/- 1.30 mg/liter in the Modic II group. The only difference in clinical parameters among the 3 groups (P = 0.001) was that the worst painful moment during the previous 24 hours occurred during the late night and morning for all Modic I patients (P = 0.001 compared with Modic 0 and P = 0.002 compared with Modic II).

CONCLUSION

Low-grade inflammation indicated by high serum hsCRP level in patients with chronic low back pain could point to Modic I signal changes. This result could help physicians predict the patients with Modic I signals to more precisely prescribe the correct imaging procedure and local antiinflammatory treatment in such patients.