Lumbar endplate and modic changes, epidemiology, determinants and pain profiles in southern Chinese

Abstract

Intervertebral disc(IVD) degeneration is associated with low back pain (LBP).Despite the endplates are located adjacent to the IVD, the phenotypes of endplate and vertebral bone marrow changes remain unclear. The objective of this study is to assess the prevalence and the associated determinants of these phenotypes of the lumbar spine.

2449 Southern Chinese subjects (aged 10 –88 years) undergone sagittal T2-weighted magnetic resonance imaging (MRI)examination to assess the presence of endplate and vertebral bone marrow changes including Schmorl’s nodes (SN) and Modic changes (MC),respectively, and scored for additional radiographic features over the lumbar spine. Subjects’ demographics, clinical profile, and functional status were assessed by means of standardized questionnaires. Anovel6-domain SN morphological classification based on MRI was developed to further analyze the characteristics of SN and its association with disc degeneration (DD).

The prevalence of SN was 16.4%. Males, taller and heavier individuals had a significantly increased likelihood of SN. Overall presence of SN was age-independent, but was significantly associated with DD, and linearly correlated with increase in severity of DD. SN were particularly associated with severe DD at the upper two lumbar levels (L1/2 – L2/3).

Based on the SN classification system, specific SN characteristics and endplate linkage patterns were found. Of these, two SN types were identified:“Typical SN” and “Atypical SN”. “Typical SN” were those smaller size SN with various shapes that were frequently located at caudal endplates of L1/2–L3/4disc levels. One variant of “Atypical SN” were those rectangular shape SN, which predominantly located at the posterior region of the rostral endplates of L1/2–L2/3disc levels. The other variant of “Atypical SN” was larger size SN with irregular shape that frequently presented at the L4/5endplates, they were also likely to be associated with marrow changes. Despite “Atypical SN” only entailed 8.3% of all identified SN, they were associated with increased severity of DD than “Typical SN”.

Although the overall prevalence of MC among Southern Chinese was low (5.8%), after adjustments for other confounding factors, the presence of MC was associated with the presence and severity of LBP. Interestingly, the determinants of MC at upper (L1/2 – L3/4) and lower (L4/5 – L5/S1) lumbar showed distinct difference. The presence of MC at upper lumbar levels was only associated with the disc integrity only (i.e. the presence of disc displacement, and DD score), while the presence of MC at the lower levels, apart from the disc integrity, was also associated with increasing age, the presence of SN, smoking and obesity status.

This study is the largest MRI study assessing the phenotypes of endplate and vertebral bone marrow changes in-vivo. The prevalence and distribution of SN and MC vary throughout the lumbar spine, and there are level and region-specific variations regarding these phenotypes. Determinants of SN and MC may be similar but do vary, suggesting distinct etiological factors. Findings of this study broaden the understanding of the various phenotypes of the lumbar spine and its association with DD.