Intraspinal cross-section areas measured on myelography--computed tomography. The relation to outcome in nonoperated lumbar disc herniation.
STUDY DESIGN: A prospective cohort study with computed tomographic-myelographic and clinical base registrations and follow-up by questionnaire 14 months after the onset of leg pain. OBJECTIVES: To detect predictive relations between intraspinal area measures and outcome in nonoperated lumbar disc herniation. SUMMARY OF BACKGROUND DATA: Myelography and computed tomography are qualitative methods ordinarily. The authors wanted to investigate the quantitative possibilities of computed tomographic technology in the pursuit of predictive measures. METHOD: Cross-section areas of the disc hernia, the dural sac, and the residual spinal canal were measured on computed tomography-myelography in 58 patients with lumbar disc herniation who did not undergo surgery. Pain, disability, and vocational status were asked for in a questionnaire after 8 months. RESULTS: After a median of 14 months from the onset of leg pain, 77% had returned to work, and only 7% were pain-free. The hernia size was not associated with the outcome measures. A high score for pain intensity and distal pain distribution was associated with a wide dural sac and a wide residual spinal canal. Disability and vocational status were not associated with any of the areas measured. Patients with the longest duration of leg pain had the narrowest spinal canals. CONCLUSIONS: Area measurements on computed tomography-myelography could not predict outcome in patients with lumbar disc herniation who were not operated on. There was an association between pain and a wide dural sac, which might underscore the sensory role of dura in protracted cases of sciatica.