Introduction

Modic changes (MC) are a representation of degenerative changes of vertebral bone marrow and endplate, which are frequently related to disc degeneration (DD), and clinical symptoms like low back pain (LBP) and/or sciatica. However, MC were also observed to coincide with abdominal aortic calcification (AAC). A possible hypothesis for this phenomenon is that MC are an indication of insufficient endplate vascularization. The objective of this literature review was to assess correlations between abdominal aortic calcification (or systemic lipid status of patients), lumbar MC and DD, and LBP or sciatica.

Methods

A literature search was performed (up to February 2021) in PubMed, Embase, Web of Science, Emcare, Cochrane Library, and Academic Search Premier using a sensitive search string combination. Studies were selected by predefined selection criteria, and the risk of bias was assessed using a validated Cochrane checklist adjusted for this purpose. Studies investigating the association of AAC or systemic lipid status and either MC/DD and/or LBP/Sciatica were selected.

Results

Following PRISMA guidelines, 22 papers were included. Six studies examined the association of aortic calcification, arterial stenosis, or cardiovascular risk factors with clinical LBP and sciatica. Five of these were assessed as low risk of bias and one as intermediate risk of bias. All studies showed a positive correlation, especially severe AAC and newly formed artery stenosis were more likely to coincide with LBP and sciatica. Ten studies investigated the correlation between atherosclerosis and its risk factors and MC/DD; 8 showed a positive correlation, of which 3 demonstrated a correlation after adjusting for age. Four of the five laboratory studies on the correlation between lipid levels and DD found a positive correlation. Three other studies showed a correlation between apolipoprotein levels and DD coinciding with chronic inflammation of the endplate.

Discussion

The hypothesis that disc degeneration and endplate degeneration are caused by an insufficient blood supply, which may induce inflammation and clinical symptoms, is not contradicted in the available literature. There is some evidence that there is a direct impact on the endplate due to insufficient blood supply due to poor quality vasculature. However, there are also indications that systemic properties of a patient's lipid profile affect degeneration of the lumbar spine. This is an incentive to develop further research in this direction.