Spontaneous regression of extruded lumbar disc herniation: three cases report.

Herniated nucleus pulposus (HNP) is a common disease that induces back pain and radicular pain. Some cases require surgical treatment due to persistent severe pain. However, in some cases, pain can be relieved with conservative treatment or at times relived spontaneously. Therefore, the most effective treatment method for HNP is undefinable. Spontaneous regression of HNP has been recognized with the advancement of radiological diagnostic tools and can explain the reason of spontaneous relief of symptoms without treatment.