The inflammatory properties of contained and noncontained lumbar disc herniation

The inflammatory properties of nucleus pulposus were assessed in biopsy samples from patients who underwent surgery for lumbar disc herniation.

To investigate the inflammatory properties of the different types of disc herniation.

High levels of phospholipase A2 previously have been demonstrated in a small number of patients undergoing lumbar disc surgery. Phospholipase A2 is the enzyme responsible for the liberation of arachidonic acid from cell membranes at the site of inflammation and is considered to be the limiting agent in the production of prostaglandins and leukotrienes, which are powerful mediators of inflammation. Cytokines are among the many agonists inducing phospholipase A2 activation. Several reports previously have demonstrated the difference in clinical appearance of different types of lumbar disc herniation.

Thirty-seven patients undergoing surgery for lumbar disc herniation were investigated. During surgery the disc pathology of each patient was classified into one of three groups: bulging disc, contained herniation, and noncontained disc herniation. Also during surgery, biopsy samples were taken from the nucleus, immediately frozen in liquid nitrogen, and subsequently stored at -70 C until analyzed.

No traces of interleukin-6 or tumor necrosis factor alpha were found in the biopsy samples. There was a significant difference in the levels of leukotriene B4 and thromboxane B2 in contained versus noncontained disc herniation, and the highest concentration was found in the noncontained disc herniation group.

The results support the theory that inflammatory mechanisms are involved in sciatica because of lumbar disc herniation and indicate that the different types of disc herniation have different inflammatory properties.