Research on lumbar MRI findings has mainly focused on single MRI findings and their association with low back pain (LBP). Some studies suggest that summing or combining MRI findings may show stronger associations with LBP than single findings. This systematic review investigates how sum scores and combinations of lumbar MRI findings are associated with LBP-related outcomes. We searched Embase, PubMed, CINAHL, Scopus and SPORTDiscus for studies reporting cross-sectional associations between sum scores/combinations of MRI findings and LBP. Two reviewers independently performed screening, data extraction and risk-of-bias (RoB) assessment. Study characteristics, definitions of sum scores/combinations of MRI findings and associations between sum scores of MRI findings and LBP outcomes were extracted and synthesised. We identified 11,537 studies and included 49 with 37 different study populations. Twelve studies had low RoB. Thirty-one studies investigated sum scores of one specific MRI finding. Ten out of 16 studies investigating disc degeneration, two out of three investigating herniation and seven out of 10 investigating endplate-related changes reported stronger associations between increasing sum scores and LBP. Additionally, seven of nine studies reported the same for disc degeneration and LBP-related disability. Sixteen studies investigated a sum score of different MRI findings. Eight of 11 studies reported stronger associations between increasing findings and LBP, and five of eight found the same for LBP-related disability. Most studies reported stronger associations between increasing sum scores of MRI findings and LBP. We recommend focusing on cumulative MRI findings when investigating the relationship with LBP outcomes. This review emphasises the relevance of assessing MRI findings as a sum rather than as individual findings in understanding the mechanisms of low back pain. The findings offer a foundation for future research, promoting a more standardised approach to the assessment of MRI findings and their clinical relevance.
Dragsbæk et al. (Fri,) studied this question.