THE NATURAL-HISTORY OF HERNIATED NUCLEUS PULPOSUS WITH RADICULOPATHY

Study Design. The present study retrospectively investigated the morph ologic changes that occurred during conservative treatment of patients with unilateral leg pain resulting from herniated nucleus pulposus wi thout significant lumbar canal stenosis. Objectives. The results were correlated with clinical outcomes and extruding forms to determine whi ch type of herniated nucleus pulposus had the greatest capacity for sp ontaneous regression and how rapidly such regression might occur.Summa ry of Background Data. The study population consisted of 77 patients w ith radiculopathy, All patients complained primarily of unilateral leg pain, and 94% had positive tension signs. Additionally, 32% exhibited muscle weakness corresponding to the symptomatic nerve root. Methods. All patients were studied more than twice using magnetic resonance im aging during conservative therapy at a mean interval of 150 days. Morp hologic changes on magnetic resonance imaging fell into four categorie s, with herniated nucleus pulposus classified into three types using T 1-weighted sagittal views. Each patient was reexamined on the same sca nner: 53 patients were examined twice, and 24 patients were examined m ore than three times. Results. Morphologic changes, with the exception of 13 false-negative cases, basically corresponded to clinical outcom e, In half of the cases that showed some improvement at follow-up eval uation, improvement of clinical findings were seen before those observ ed on magnetic resonance imaging. Migrating herniated nucleus pulposus frequently presented an obvious decrease in size, and even disappeara nce in seven cases. The further the herniated nucleus pulposus migrate d, the more decrease in size could be observed. The cases apparently c orresponding to ''protrusion'' showed little or no change on follow-up magnetic resonance imaging. Regarding the mechanism of herniated nucl eus pulposus disappearance, exposure to the vascular supply undoubtedl y took a part, although many factors were suspected to have some influ ence. Conclusion. Morphologic changes on magnetic resonance imaging ma inly corresponded to clinical outcomes but tended to lag behind improv ement of leg pain. Disappearance of herniate nucleus pulposus was seen frequently in the cases of migrating disc herniation, and it was pres umed that exposure to the vascular supply had a lot to do with this ph enomenon.