Do lumbar magnetic resonance imaging changes predict neuropathic pain in patients with chronic non-specific low back pain?

Abstract

The aim of this observational, cross-sectional study was to analyse lumbar magnetic resonance imaging (MRI) findings in patients with non-specific chronic low back pain (CLBP), and to evaluate any correlation with pain intensity and their capacity to predict neuropathic pain (NP) in these patients. Fifty-two patients with non-specific CLBP, between 21 and 62 years of age, 50% men, were investigated. Lumbar MRI was employed to assess disc degeneration, endplate changes, Modic changes, disc displacement, facet degeneration, foraminal stenosis and central lumbar spinal stenosis. The characteristics of pain were evaluated and patients were divided into 2 subgroups: with NP (24 patients) and without NP (28 patients), based on the results of a DN4-interview. Correlations between particular MRI changes and their relations to the intensity of pain were evaluated. Logistic regression was used to disclose predictors of NP. Lumbar spine degenerative features were frequent in patients with non-specific CLBP, with L4/5 the most affected level. A significant correlation emerged between the severity of degenerative changes in particular lumbar spine structures (correlation coefficient ranging between 0.325 and 0.573), while no correlation was found between severity of degenerative changes and pain. Multivariate logistic regression revealed only 2 independent predictors of NP – female sex (odds ratio [OR] = 11.9) and a mean pain intensity of ≥4.5 in the previous 4 weeks (OR = 13.1). Degenerative changes in the lumbar spine are frequent MRI findings, but do not correlate with the intensity of pain and do not predict NP. However, female sex and pain intensity do predict NP. Abbreviations: BMI = body mass index, CLBP = chronic low back pain, CT = computed tomography, DD score = disc degeneration score, DD sum score = disc degeneration summary score, DN4 = Douleur Neuropathique en 4 Questions, EP score = endplate score, EP sum score = endplate summary score, FD score = facet degeneration score, FD sum score = facet degeneration summary score, FS score = foraminal stenosis score, FS sum score = foraminal stenosis summary score, LBP = low back pain, MC = Modic changes, MRI = magnetic resonance imaging, NCS/EMG = nerve conduction studies/needle electromyography, NP = neuropathic pain, NPSICZ = Neuropathic Pain Symptom Inventory–Czech version, NPT = neuropathic pain treatment, NRS = numerical rating scale, NSAIDs = non-steroidal anti-inflammatory drugs, OR = odds ratio, SD = standard deviation, TEP score = total endplate score, TFD score = total facet degeneration score, TFS score = total foraminal stenosis score.