The diagnosis of disc sequestration.

Sequestration of a disc herniation is an important cause of failure of chemonucleolysis. It therefore is important to recognize this particular variety of disc herniation before considering enzymatic discectomy. In order to determine the clinical and myelographic signs of sequestration, we reviewed the charts, myelograms, and surgical findings of 98 patients operated on for a disc herniation. A correlation was made between the three anatomic types of disc herniation found during surgery and the clinical and myelographic signs observed preoperatively. No characteristic clinical sign was found. No pathognomonic myelographic features were discovered. However, when the myelographic defect appears irregular and at a distance from the disc space, sequestration should be highly suspected.