Intradural disc herniations in the cervical, thoracic, and lumbar spine: report of three cases and review of the literature.

The clinical, neuroradiological, and surgical management of three cases of intradural disc herniations--one each in the cervical, thoracic, and lumbar regions--are presented. Intradural disc herniations comprise only 0.27% of all herniated discs. Three percent occur in the cervical, 5% in the thoracic, and 92% in the lumbar spinal canal. Those with cervical or thoracic lesions frequently exhibit profound myelopathy, whereas those with lumbar lesions demonstrate radicular or cauda equina syndromes. Although varying combinations of the MRI, non-contrast CT, myelogram, and myelo-CT scans may at times fail to accurately establish the diagnosis of an intradural disc herniation prior to surgery, the index of suspicion raised by the lack of clinical correlation with surgical findings justifies an intradural exploration.