X-ray Prediction of Magnetic Resonance Imaging in Low Back Pain.

Magnetic resonance imaging use in low back pain management can be associated with added costs and increased surgical interventions. Lumbar x-ray findings predicting magnetic resonance imaging results were assessed in patients with low back pain, excluding postsurgical, red flag, or spinal stenosis history. At an outpatient pain clinic, 100 patients were selected (sequentially) from 12/1/2021 to 3/15/2022 that had lumbar x-rays within 1 yr prior to lumbar magnetic resonance imaging. X-ray and magnetic resonance imaging reports were analyzed by two readers. Forty-six patients had moderate facet hypertrophy on x-ray, 35 (76.1%) also had moderate facet hypertrophy on magnetic resonance imaging (Spearman's rank correlation Rs = 0.386, P < 0.0001). Thirty-eight patients had moderate multilevel degenerative changes on x-ray, 34 (89.5%) also had moderate disc bulge on magnetic resonance imaging (Spearman's Rs = 0.360, P < 0.001). Eighteen patients who had moderate disc height loss on x-ray, 14 (77.8%) also had moderate disc desiccation, height loss, or space narrowing on magnetic resonance imaging (Spearman's Rs = 0.554, P < 0.00000001). Forty-three patients had a listhesis on x-ray, and 20 (46.5%) also had a listhesis on magnetic resonance imaging (Spearman's Rs = 0.458, P < 0.0001). Lumbar x-ray is a reasonable study in the setting of axial and subacute radicular low back pain, where red flags are absent, predicting moderate pathology on magnetic resonance imaging > 75% of the time, and being more sensitive for listhesis.