Does minor trauma cause serious low back illness?

Study Design. Prospective, 5-year, cohort study of working subjects. Objectives. To assess whether the occurrence of common minor trauma events affects the risk of developing serious low back pain ( LBP) and LBP disability in subjects with and without degenerative changes to the lumbar spine. Summary of Background Data. Although some theories suggest that minor traumatic events in combination with preexisting degenerative changes commonly cause significant structural injury to spinal segments and serious LBP illness, no prospective data exist on the relationship of minor trauma, detailed structural changes, and outcome measures of serious LBP episodes and occupational disability. Methods. Two hundred subjects without clinical LBP problems were recruited, and underwent baseline clinical and imaging studies. Every 6 months, subjects completed a scripted, algorithm-based interview assessing interval back pain episodes, severity, medical treatment, occupational disability, and the subject's perceived relation of this LBP episode to any preceding event. If a serious LBP episode clinically required a new magnetic resonance examination, the follow-up imaging was obtained and compared to baseline for interval changes. Results. There was no association of minor trauma to adverse LBP events. For each 6-month study interval, the risk of developing a serious LBP episode was 2.1% unassociated with minor trauma and 2.4% following minor trauma ( P = 0.59). Neither the frequency of minor trauma events nor the reported severity of the event correlated with adverse outcomes. Subjects with advanced structural findings were not more likely to become symptomatic with minor trauma events than with spontaneously evolving LBP episodes. Follow-up magnetic resonance imaging evaluating new serious LBP illness rarely revealed new clinically significant findings. Age and sex-adjusted prediction models, including abnormal psychometric testing, smoking, and compensation issues, accurately identified 80% of serious LBP events and 93% of LBP disability events. Conclusions. In this study cohort, minor trauma does not appear to increase the risk of serious LBP episodes or disability. The vast majority of incident-adverse LBP events may be predicted not by structural findings or minor trauma but by a small set of demographic and behavioral variables.