REGRESSION OF CERVICAL DISC HERNIATION OBSERVED ON MAGNETIC-RESONANCEIMAGES

Study Design. A retrospective study of cervical disc herniation using results of repeated magnetic resonance imaging examinations. Objective s. To clarify the cervical disc herniation morphological changes over time in order to establish a strategy for treatment. Summary of Backgr ound Data. In the authors' previous magnetic resonance imaging follow- up study of patients with lumbar disc herniation, spontaneous regressi on was observed in the sequestration-type lesions, and it was found th at the tendency toward regression differed based on the anatomic posit ion of extruded disc material. Methods. Thirty-eight patients with cer vical disc herniation who underwent repeated magnetic resonance imagin g examinations were studied. The changes over time in herniated disc s ize were evaluated using this imaging technique. Evaluation showed the characteristics of those in whom spontaneous regression was found, su ch as extrusion pattern, and the clinical outcome was evaluated by sym ptoms. Results. In 15 patients (40%), the volume of herniated material was decreased. The interval from onset of symptoms to the initial exa mination was significantly shorter In the regression group than in the group that showed no change in disc herniation. By extrusion pat tern , cervical disc herniation, which was divided into migration type on s agittal view and lateral type on axial view most frequently exhibited spontaneous regression. All of the patients with radicular pain and up per limb amyotrophy were treated successfully with conservative therap y. Conclusion. Although the possibility of the combination of hemorrha ge and disc material could not be denied, active resorption of herniat ed material probably occurred during the acute phase. Extruded materia l ex posed to the epidural space may be resorbed more quickly than tha t beneath the ligament. Vascular supply probably plays a role in the m echanism of resorption. The phase and position of extrusion were the s ignificant factors affecting cervical disc herniation resorption. It w as demonstrated that examination performed during the acute phase usin g magnetic resonance imaging is necessary for elucidation of the patho genesis of cervical disc herniation, and that migrating, lateral-type herniations regress so frequently that conservative treatment should b e chosen not only for patients with radicular pain, but also for those with upper limb amyotrophy.