Degeneration of the intervertebral disc

Abstract

The intervertebral disc is a cartilaginous structure that resembles articular cartilage in its biochemistry, but morphologically it is clearly different. It shows degenerative and ageing changes earlier than does any other connective tissue in the body. It is believed to be important clinically because there is an association of disc degeneration with back pain. Current treatments are predominantly conservative or, less commonly, surgical; in many cases there is no clear diagnosis and therapy is considered inadequate. New developments, such as genetic and biological approaches, may allow better diagnosis and treatments in the future.

Figure 1

A schematic view of a spinal segment and the intervertebral disc. The figure shows the organization of the disc with the nucleus pulposus (NP) surrounded by the lamellae of the annulus fibrosus (AF) and separated from the vertebral bodies (VB) by the cartilaginous end-plate (CEP). The figure also shows the relationship between the intervertebral disc and the spinal cord (SC), the nerve root (NR), and the apophyseal joints (AJ).

Figure 2

The normal and degenerate lumbar intervertebral disc. The figure shows a normal intervertebral disc on the left. The annulus lamellae surrounding the softer nucleus pulposus are clearly visible. In the highly degenerate disc on the right, the nucleus is desiccated and the annulus is disorganized.

Figure 3

Magnetic resonance images of the lumbar discs of 44-year-old identical twins. Note similarities in the contours of the end-plates, particularly at L1-L2 (white arrow head). The spines also show similar degenerative changes in the disc, particularly at L4-L5 (white arrow). From [102], with kind permission from the authors and publishers.