CAN MODIC CHANGES ON MRI PREDICT CLINICAL RESPONSE TO STEROIDS IN DISCOGENIC BACK PAIN

Study Design: A retrospective study of the clinical outcome of patients with lumbar discogenic pain with Modic changes on MRI prior to intradiscal steroid injection. Objectives: To determine whether the clinical outcome of patients with discogenic back pain who underwent intradiscal steroid injection could be predicted from MRI Modic changes. Methods: The pre-operative scans were studied by two senior spinal surgeons. The lumbar vertebral end-plate changes were then classified according to the method described by Modic. The intra- and inter-observer ratings were satisfactory. Subjects: 40 patients with discogenic back pain were recruited in this study. The mean age was 43.6 years (23 to 72 years). The male to female ratio was 1 to 1. Outcome Measures: The clinical outcomes at six months post-intradiscal steroid injection were correlated with the Modic changes. The clinical outcomes were assessed using visual analogue scores for back pain as well as Oswestry disability index (ODI). At least a 2-point improvement in visual analogue score and a 20-point improvement in ODI were required to indicate significant symptomatic relief. Results: We found that in those patients without Modic changes there was improvement of the low back pain in 9% (1/11). In those with Modic I changes there were significant relief in 64% (9/14), moderate relief in 29% (4/14) and no relief in 7% (1/14). In those with Modic II changes there were significant relief in 27% (4/15), moderate relief in 27% (4/15) and no relief in 47% (7/15). There were no cases with Modic III changes. Conclusions: Previous studies on intradiscal steroid injections have shown variable results. Two prospective double-blind clinical trials, using intradiscal steroids, identified no significant benefit or improvement in the clinical outcome. Our results however suggest that patients with Modic I changes on MRI are most likely to benefit from intradiscal steroid injection in the short term.