Background: In MRI studies lumbar disk degeneration and endplate changes have been found in children and adolescents. Such MRI findings appear to be more strongly associated with LBP than in adults. However, this knowledge is mainly based on cross-sectional studies from which no inferences regarded causality can be drawn. The purpose of this presentation is to show how certain MRI findings at the age of 13 indicate seeking care for LBP at the age of 16. Methods: In a population based longitudinal cohort study two investigations were carried out at a three-year interval (at age 13 and 16). Individuals were sampled to be representative of Danish schoolchildren. Data about seeking care for LBP and lumbar spine MRI were collected independently of each other. The outcome was seeking care for LBP at the age of 16. The potential predictors were positive MRI findings at the age of 13 (disk signal intensity, nucleus form, annular tears, high intensity zones, bulging, herniation, nerve root compression, endplate changes, Modic changes, and spondylolisthesis). Associations were sought through logistic regression at each lumbar level for boys and girls separately. Statistically significant results were presented as odds ratios with 95% confidence intervals. Results: In the first study 439 13 year olds participated and 321 of these participated again when 16 years old. In the second study, 75 (23%) individuals reported seeking care for LBP. The prevalence of MRI changes increased with age. In boys, strong predictors (OR>5) of the seeking of care three years later included reduced signal intensity at disk levels L1 and L3. Moderate predictors (OR between 2 and 5) were endplate changes at L4. In girls, strong predictors included reduced disk signal intensity and changes in nucleus form at disk levels L2 and L3, and annular tears and bulging at L4. Moderate predictors included reduced signal L1 and L4, disk herniation and nerve root compression L4. Other levels and findings showed no statistically significant associations. Interestingly, the areas with the fewest findings showed the strongest associations to seeking care for LBP. Discussion: A clustering of strong positive associations between disk-related findings and seeking care were noticed in the three upper lumber levels in both boys and girls. Another clustering of moderate to strong associations were noted for disk bulging, annular tears, disk herniation and nerve root compression in the lower lumbar levels in girls. In general, these areas had few findings and are likely be abnormal and clinically relevant. Furthermore, it is possible that they reflect an underlying pathology like Scheuermann disease in the upper area and disc herniation in the lower area in girls. However, multiple testing increases the probability of chance findings. Conclusion: Some positive MRI findings seem to predict future seeking care for LBP. However, when interpreting lumbar spine MRI from young teenagers in a clinical setting, gender variations and the lumbar level of the specific finding should be taken into consideration and attention should be drawn to areas where positive findings are least likely.
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Melbourne International Forum XI: Primary Care Research on Low Back Pain., 2011