Disc disease is a frequent source of low back pain as well as neck pain. Sciatica is defined as neuralgia along the course of the sciatic nerve.
The intervertebral discs act as shock absorbers and are found between the bodies of the vertebrae. They have a central area composed of a colloidal gel, called the nucleus pulposus, which is surrounded by a fibrous capsule, the annulus fibrosis. This structure is held together by the anterior longitudinal ligament, which is anterior to the vertebral bodies, and the posterior longitudinal ligament, which is posterior to the vertebral bodies and anterior to the spinal cord. The muscles of the trunk provide additional support.
The most common site of disc herniation is at the L5-S1 interspace in the lumbosacral region. This is believed to be due to the thinning of the posterior longitudinal ligament as it extends caudally.
Nomenclature specific to lumbar disc disease is as follows:
- Disc bulge – Annular fibers intact
- Disc protrusion – Localized bulging with damage of some annular fibers
- Disc extrusion – Extended bulge with loss of annular fibers, but disc remains intact
- Disc sequestration – Fragment of disc broken off from the nucleus pulposus
Sciatica has been reported by various authors to occur in 1-10% of the population.
The male-to-female ratio is approximately 1:1.
The group most commonly affected is adults aged 25-45 years.
Service utilized for Disc Disorders