Phenotype profiling of Modic changes of the lumbar spine and its association with other MRI phenotypes: a large-scale population-based study

Abstract

BACKGROUND CONTEXT: Modic changes (MC) are associated with low back pain. They represent vertebral endplate and adjacent vertebral marrow changes on magnetic resonance imaging (MRI), classified into three types. Because of small sample sizes, patient cohorts, and limited phenotype assessment, the morphology and involvement of MC and their association with other spinal phenotypes remain speculative. PURPOSE: We addressed and proposed a phenotypic profiling of MC and their relationship with lumbar MRI phenotypes in a large-scale population-based study. STUDY DESIGN/SETTING: A cross-sectional study of the Hong Kong Disc Degeneration Cohort. PATIENT SAMPLE: The study population consisted of 1,546 Southern Chinese volunteers. OUTCOME MEASURES: Topographical and morphological dimensions of MC, presence of disc degeneration (DD) and displacement, and Schmorl nodes were evaluated. METHODS: Axial T1-weighted and sagittal T2-weighted MRIs (3T) were assessed. RESULTS: Females were 62.4% (mean age, 49 years). The overall prevalence of MC was 21.9% (6.3% Type I and 15.5% Type II). Of all MC, 76% were located at the two lowest lumbar levels. Modic changes at the two lowest lumbar levels were more commonly located laterally (p<.001), less commonly anteriorly (p<.001), and were more extensive horizontally (p=.006) but not in vertical height compared with the upper levels. Type I MC were less common in the anterior part (p=.022), larger in size (height p=.004), and affected more likely the whole horizontal plane (p=.016) than Type II MC. Modic changes were associated with disc displacement, Schmorl nodes, and DD at the affected level (all p<.001), and the strength of association increased with the size of the lesion. Type I MC were associated more strongly with disc displacement (p=.008) and DD (p=.022) than Type II MC. CONCLUSIONS: Our large-scale MRI study is the first to definitely note that MC were size- and type-dependently significantly associated with disc pathology and endplate abnormalities. Our phenotype profiling of MC may have clinical utility.