Prediction of future first-time low back pain based on baseline MRI findings

Abstract

BACKGROUND CONTEXT: Previously, it has been noted that there is no predictive value of MRI findings of degenerative changes of the lumbar spine in asymptomatic individuals in the development of first-time episodes of low back pain (LBP). However, past studies presented small sample sizes, did not thoroughly assess various imaging and demographic phenotypes related to pain, and were heterogeneous. PURPOSE: In a population-based cohort, this study addressed if radiographic findings on MRI in asymptomatic individuals are predictive in the development of first-time episodes of LBP and pain severity. STUDY DESIGN/SETTING: Prospective study. PATIENT SAMPLE: 248 asymptomatic (93 males and 155 females, mean age: 42.9 years) Southern Chinese with no previous history of LBP at baseline were included in this study. OUTCOME MEASURES: The incidence of LBP and its baseline determinants were addressed. METHODS: A prospective, radiographic and clinical study was performed of 248 asymptomatic Southern Chinese (mean age: 42.9 years) with no previous history of LBP. All subjects underwent sagittal MRI assessment of the lumbar spine. Assessment of disc degeneration was based on the Schneiderman et al radiographic criteria to determine the presence, extent and severity of disc degeneration. A summated degenerative disc disease (DDD) score of the lumbar spine was obtained, representing the global severity of disc degeneration. The presence of disc bulge/extrusion, Schmorl’s nodes, and Modic changes were also noted. At 2 years minimum follow-up, clinical assessment was performed and subject demographics were noted to identify the development of LBP and functional outcome status (eg, Oswestry Disability Index). RESULTS: Overall presence of disc degeneration, disc space narrowing and disc bulge/extrusion was noted in 60.5%, 19.0%, and 34.3% of individuals, respectively. The mean DDD score was 2.2. Schmorl’s nodes and Modic changes were noted in 10.5% and 1.2%, respectively. Clinical follow-up was performed at a mean of 4.3 years. The incidence rate of first-time LBP episodes on clinical follow-up was 34.7%. The mean age of first-time LBP episode was 44.8 years. Regression modeling noted that the presence of disc bulge/extrusion (OR: 2.37; 95% CI: 1.30-4.32) and increasing DDD score (O7 score OR: 6.90; 95% CI: 1.86-25.52), in particular if segments involved the mid lumbar region, demonstrated significant predictive utility for developing first-time LBP episode. DDD score and disc bulge/extrusion were found predictive to the severity of LBP, greater functional disability and increased frequency of future LBP episodes (p!0.05). CONCLUSIONS: This is the largest prospective study, to the authors’ knowledge, to address the development of future, first-time LBP episodes based on baseline MRI. This study substantiates the belief that spinal changes are found in asymptomatic subjects on MRI; however, the 'global severity' of disc degeneration on initial MRI may be predictive in the development of first-time LBP episodes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.