Prevalence of vertebral endplate modic changes in degenerative lumbar scoliosis and its associated factors analysis.

Study Design. A retrospective study of Modic changes (MCs) in degenerative lumbar scoliosis (DLS). Objective. To investigate the prevalence of vertebral endplate MCs in DLS and explore their associated factors. Summary of Background Data. MCs are common in spinal degenerative diseases. Presently, most of the researches have been focused on investigating the relationship between MCs and chronic low back pain. Little has been known on the distribution of MCs in DLS and the relationship between MCs and scoliosis. Methods. The image data of 120 patients who had been diagnosed with DLS in our hospital from March 2005 to March, 2011 were retrospectively reviewed as the study group. The image data of 89 patients who had been diagnosed with degenerative lumbar diseases without scoliosis were selected as the control group. The prevalence, type, and distribution of MCs in 2 groups were observed and compared. Disc degeneration, Cobb angle, body weight, and smoking were recorded in the study group, and the relationship of MCs with these influential factors was analyzed. Results. Of 1440 endplates from 120 patients in the study group, 247 (17.2%) from 71 (59.2%) patients were found to have MCs. Compared with the control group, of 1068 endplates from 89 patients, 49 (4.5%) endplates from 21 (23.6%) patients were found to have MCs. The prevalence of MCs was significantly higher in the study group than that in the control group (P < 0.01). The MCs in DLS usually had asymmetric distribution with more frequent occurrence on the concave side than on the convex side of major or compensatory curve and mainly occurred at L2-L3, L4-L5, and L5-S1, which were in accordance with the common levels of apex vertebrae. Intervertebral disc degeneration, lumbar scoliosis, overweight and heavy smoking are considered as risk factors to MCs. By multinomial logistic regression analysis on these factors, the regression function was obtained: logit Y = -0.82 + 1.27D + 0.55S + 1.77 D x S (Y for MCs, D for intervertebral disc degeneration, S for scoliosis Cobb's angle and D x S for interaction of D and S). Conclusion. The prevalence of MCs in patients with DLS was significantly higher than that of patients without DLS. Most of them were type 2 and usually located on the concave side of apex vertebrae. MCs were significantly associated with intervertebral disc degeneration and lumbar scoliosis.