CONTRAST-ENHANCED MAGNETIC-RESONANCE-IMAGING IN CONSERVATIVE MANAGEMENT OF LUMBAR DISC HERNIATION

Study Design. This study was designed to investigate the morphologic c hanges in contrast-enhanced magnetic resonance imaging that occur duri ng conservative treatment of patients with unilateral leg pain resulti ng from herniated nucleus pulposus without significant lumbar canal st enosis. Objectives. To compare the morphologic results with clinical o utcomes to ascertain whether enhanced magnetic resonance imaging contr ibutes to the management of lumbar disc herniation. Summary of Backgro und Data. Contrast-enhanced magnetic resonance imaging has already bee n reported to be useful in the postoperative examination of the lumbar spine and in visualization of symptomatic nerve roots. However, there have been few reports about its usefulness in the conservative manage ment of herniated nucleus pulposus or about the correlation between he rniated nucleus pulposus regression and enhanced effect. The study pop ulation consisted of 48 patients with radiculopathy. All patients prim arily reported unilateral leg pain, and 94% had positive tension signs . Additionally, 38% exhibited muscle weakness corresponding to the sym ptomatic nerve root. Methods. All patients were studied twice or more using gadolinium-magnetic resonance imaging during conservative therap y, at a mean interval of 191 days. Changes in the size of the herniate d nucleus pulposus on precontrast images fell into four categories, wi th changes in enhancement on postcontrast images classified into two c ategories: ''enlargement'' and ''no change.'' Results. In all cases of migrating type herniated nucleus pulposus, circular enhancement was s een on postcontrast images. In 17 of 22 cases, the enhanced area gradu ally thickened and intruded into the migrated disc materials as the si ze of the herniated nucleus pulposus decreased; the herniated nucleus pulposus disappeared in nine cases and showed a marked decrease in sev en cases. These cases showed good clinical courses of sciatica. In the other five patients, in whom there were no changes in the enhanced ar ea, there was less of a tendency for the herniated nucleus pulposus to decrease in size, and there were poorer clinical results. In six case s of extruding-type herniated nucleus pulposus, no enhanced effects we re observed throughout the follow-up period. The other 20 cases showed enhancement that was relatively weaker than that of migrating disc he rniation. Extension or expansion of the enhanced area was observed in the follow-up images of 15 cases, though only four showed obvious chan ges in the size of the herniated nucleus pulposus. These 15 cases had better clinical results than the other cases, in which enhanced effect s did not change or were not observed. Conclusion. Contrast-enhanced m agnetic resonance imaging is a useful prognostic parameter, and multip le use contributes to the proper management of lumbar disc herniation.