Purpose: Modic changes (MCs) have been suggested to be a diagnostic subgroup of low back pain (LBP). However, the clinical implications of MCs remain unclear. For this reason, the aims of this study were to investigate how MCs developed over a 14-month period and if changes in the size and/or the pathological type of MCs were associated with changes in clinical symptoms in a cohort of patients with persistent LBP and MCs.
Methods: Information on LBP intensity and detailed information from MRI on the presence, type and size of MCs was collected at baseline and follow-up. Changes in type (type I, II, III and mixed types) and size of MCs were quantified at both time points according to a standardised evaluation protocol. The associations between change in type, change in size and change in LBP intensity were calculated using odds ratios (ORs).
Results: Approximately 40% of the MCs followed the expected developmental path from type I (here type I or I/II) to type II (here type II or II/III) or type I to type I/II. In general, the bigger the size of the MC at baseline, the more likely it was that it remained unchanged in size after 14 months. Patients who had MC type I at both baseline and 14-month follow-up were less likely to experience an improvement in their LBP intensity as compared to patients who did not have type I changes at both time points (OR 7.2, CI 1.3-37). There was no association between change in size of MCs type I and change in LBP intensity.
Conclusions: The presence of MCs type I at both baseline and follow-up is associated with a poor outcome in patients with persistent LBP and MCs.