A large‐scale study of Modic changes in the lumbar spine: morphology and association with MRI phenotypes

Abstract

INTRODUCTION: Modic changes (MC) are associated with low back pain. They repre‐ sent vertebral endplate (EP) and adjacent vertebral marrow changes on MRI, tradi‐ tionally classified into three types (M1, M2, M3). Due to methodological biases in previ‐ ous studies, the morphology, involvement of MC and their association with other spi‐ nal phenotypes remains speculative. As such, the aim of this study was to evaluate the relationship of MC with spinal MRI phe‐ notypes in a large‐scale population‐based study. METHODS: Based on the Hong Kong Disc Degeneration (DD) Cohort of Southern Chi‐ nese, we assessed the T1‐ and T2‐weighted MRIs of 1,604 subjects (62.4% females; mean age 49 years) from L1 to S1. The MC assessment included: the presence, type, vertical height and axial area. Additional imaging findings were assessed (herni‐ ations/bulges, Schmorl’s nodes). A global degenerative disc disease (DDD) score was tabulated. RESULTS: The prevalence of MC was 24.7% (M1: 6.3%, M2: 15.5%). Of all MC, 77% were at L4‐S1. Subjects with MC were older (mean age: 53 vs. 48 years, p<0.001) and had higher DDD scores (p<0.001). M1 were more common at lower levels (p=0.021), were less likely located in the anterior re‐ gion only (p=0.017), and were associated with disc herniations (p<0.001) in compari‐ son to M2. MC of the lower levels (L4‐S1) were not commonly noted in the anterior region only, involved the left or right EP, had a higher prevalence of disc herniation and DD in comparison to upper levels (L1‐ L4) (p<0.001). Large MC (=2/3 of the axial area) were more likely located at lower lev‐ els (83% vs. 73%, p=0.001), higher preva‐ lence of disc herniation (83% vs. 72%, p=0.001) and Schmorl’s node at the affected level (52% vs. 39%, p<0.001) compared to smaller MC. DISCUSSION: Based on one of the largest population‐based studies, MC were clearly associated with disc and endplate changes. However, MC type‐ and level‐related find‐ ings in relation to MRI phenotypes were identified.