Study design: A cross-sectional study in sciatic population.
Objectives: To evaluate the separate roles of nerve root entrapment-based on magnetic resonance imaging-and other discogenic pain mechanisms on disability and physical signs among symptomatic sciatic patients.
Summary of background data: Data symptoms of sciatica are generally understood to be generated by nerve root compression, but other pain mechanisms of sciatica have been suggested.
Methods: The authors obtained magnetic resonance scans from 160 patients with unilateral sciatic pain. The patients reported the intensity of their back and leg pain and their back-specific disability. Clinical examination and magnetic resonance imaging (1.5 T) was performed on every patient. The degree of disc displacement, neural enhancement, and nerve root compression was evaluated from magnetic resonance scans. The correlations of symptoms and signs with magnetic resonance imaging findings were calculated.
Results: The degree of disc displacement in magnetic resonance imaging did not correlate with any subjective symptoms, nor did nerve root enhancement or nerve compression. Magnetic resonance imaging classification was associated, however, with straight leg raising restriction. In regression analysis, straight leg raising restriction was best explained with a simple classification of nonherniations versus herniations.
Conclusions: The results suggest that a discogenic pain mechanism other than the nerve root entrapment generates the subjective symptoms among sciatic patients. The findings of this study thus indicate that magnetic resonance imaging is unable to distinguish sciatic patients in terms of the severity of their symptoms.