Clinical features, contrast-enhanced lumbar tomographic findings, and biochemical plasma fibrinolytic parameters were critically assessed in 70 patients suffering severe, chronic postsurgical low-back and radicular pain to determine the cause of their persisting symptoms. Patients exhibited gross functional disability and significant impairment of plasma fibrinolytic activity, compared with 84 normal control subjects. This fibrinolytic defect appeared attributable to disproportionate increases in circulating plasminogen activator inhibitor-1 levels. Clinical features were slightly worse in patients with radiologic epidural fibrosis, whereas the frequency of radiologic abnormalities, including epidural fibrosis, was higher in patients with fibrinolytic abnormalities. The results, however, demonstrated no significant associations between patients' symptoms and signs and their biochemical and radiologic abnormalities.