Clinical significance of magnetic resonance imaging findings in chronic low backache

Magnetic resonance imaging (MRI) is frequently done for the evaluation of chronic low backache (CLBA), however, its significance in Indian patients has not been evaluated. We report here the MRI findings in patients with CLBA and their sensitivity and specificity with clinical evidence of radiculopathy and localized CLBA as well as correlate these with pain severity and disability.

Seventy two patients with CLBA aged 20-70 yr without trauma, infection, tumour, metastasis and vascular malformation were included in the study. Their demographic characteristics, lifestyle, education and employment were noted. Lumbosacral MRI was carried out and 19 MRI parameters at six levels (D12-L1-L5-S1) were noted. The severity of pain was assessed by Numeric Rating Scale (NRS, 0-10) and disability by Oswestry Disability Index (ODI).

MRI was abnormal in all patients, the most common being disc desiccation (90.3%) followed by facet joint arthropathy (FJA; 75%) and nerve root compression (NRC; 72.2%). Endplate changes and high-intensity zone were noted in 58 and 50 per cent of patients, respectively. One-third patients with FJA, however, were below 30 yr of age. NRC on MRI had 61.3 per cent sensitivity and 10 per cent specificity with clinical radiculopathy. FJA had 60.7 per cent sensitivity and 15.9 per cent specificity with localized CLBA. None of the MRI parameters and MRI sum score correlated with NRS and ODI. On multivariate analysis, NRS was independent predictor of ODI (odds ratio 0.58, 95% confidence interval 0.35-0.98, P=0.04).

In patients with CLBA, NRC on MRI showed poor specificity with corresponding clinical radiculopathy and FJA with localized backache. None of the MRI abnormality correlated with the severity of pain or disability.