MRI findings poor reflection of back pain severity
medwireNews: Degenerative findings on magnetic resonance imaging (MRI) do not correlate with the degree of disability or pain in people with lower back pain, a cross-sectional study has found.
Accordingly, the study authors caution against using localized MRI findings to explain clinical measures in patients with longstanding, non-radicular lower back pain.
Ansgar Espeland (Haukeland University Hospital, Bergen, Norway) and team studied 170 patients (mean age 41 years; 88 women) who were due to undergo lumbar disc prosthesis surgery. All patients had localized disc degeneration on MRI.
“In these patients, the MRI findings used as indications for surgery are assumed to reflect relevant pain sources rather than irrelevant or age-related changes,” explain Espeland et al writing in Skeletal Radiology.
Pretreatment MRIs were evaluated for four measures of degeneration - modic type I/II changes, a posterior high intensity zone (HIZ), a dark/black nucleus pulposus signal, and a 40% or greater decrease in disc height – and the results used to calculate an MRI total score from 0 to 10.
MRI total score did not correlate with either Oswestry Disability Index (ODI), which is a back pain-specific measure of disability, or with lower back pain intensity rated on a visual analog scale, Espeland et al report.
Similarly, the individual MRI measures of degeneration did not correlate with the clinical measures, with the exception of a weak negative correlation between HIZ at L5/S1 and ODI scores.
The researchers then repeated the analyses but incorporated a fifth MRI measure, facet arthropathy, into the MRI total score, as well as adjusting for physical workload and physical leisure-time activity. Again, MRI total score was not related to either ODI or pain intensity.
The team concludes that localized degenerative findings on MRI are unlikely to explain variation in disability or pain intensity in candidates for lumbar surgery with disc prosthesis or fusion.
They write: “Further studies should explore other variables that may explain differences in pain and pain-related disability among patients with chronic non-radicular [lower back pain] and degenerative MRI findings.”
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By Joanna Lyford, Senior medwireNews Reporter