Inciting events associated with lumbar disc herniation.

BACKGROUND CONTEXT: No prior study has investigated the frequency of patient-identified inciting events in lumbar disc herniation (LDH) or their clinical significance.

PURPOSE: To examine the clinical frequency of patient-identified inciting events in LDH, and to identify associations between the presence of inciting events and the severity of the clinical presentation.

STUDY DESIGN/

SETTING

Cross-sectional analysis of data from a cohort study with prospective recruitment, with retrospective data collection on inciting events. The setting was a hospital-based specialty spine clinic.

PATIENT SAMPLE: One hundred fifty-four adults with lumbosacral radicular pain and LDH confirmed by magnetic resonance imaging.

OUTCOME MEASURES: Self-report measures of disability measured by the Oswestry Disability Index (ODI), the visual analog scale (VAS) for leg pain, and the VAS for back pain.

METHODS

Dependent variables included the presence of a patient-identified inciting event, which were categorized as spontaneous onset, nonlifting physical activity, heavy lifting (>35 lbs), light lifting (<35 lbs), nonexertional occurrence, or physical trauma. We examined the association of an inciting event, or a lifting-related event, with each outcome, first using univariate analyses, and second using multivariate modeling, accounting for important adjustment variables.

RESULTS

Sixty-two percent of LDH did not have a specific patient-identified event associated with onset of symptoms. Nonlifting activities were the most common inciting event, comprising 26% of all LDH. Heavy lifting (6.5%), light lifting (2%), nonexertional occurrences (2%), and physical trauma (1.3%) accounted for relatively small proportions of all LDH. Patient-identified inciting events were not significantly associated with a more severe clinical presentation in crude analyses. Spontaneous LDH was significantly associated with higher baseline ODI scores in multivariate analysis, although the magnitude of this effect was small. There were no significant associations (p< or =.05) between the presence of a lifting-associated event and the outcomes of ODI, VAS leg pain, or VAS back pain.

CONCLUSIONS

The majority of LDH occurred without specific inciting events. A history of an inciting event was not significantly associated with a more severe clinical presentation. There was no significant association between the occurrence of a lifting-related event and the severity of the clinical presentation. This information may be useful in the counseling of patients recovering from acute LDH.