An ultrastructural study of recurrent disc herniation: a preliminary report.

One early and two late recurrent herniations located at the same interspace as the original prolapse were studied by light and electron microscopy. In the early recurrent herniation, most chondrocytes appeared to be actively engaged in protein synthesis, and the intercellular matrix contained densely packed collagen fibers, numerous matrix vesicles, and abundant electron-dense amorphous material. In late recurrent herniations, chondrocytes had scant endoplasmic reticulum and extensive cytoplasmic filaments, and the intercellular matrix showed intermediate features between fibrocartilage and fibrous connective tissue. On the basis of these morphologic characteristics, it seems reasonable to assume that the newly formed disc tissue arose mainly from remnants of the original herniation in the early recurrent prolapse and from the annulus fibrous and the granulation tissue invading the disc space after discectomy in the late recurrent herniations.