HERNIATED DISC
Protrusion of the intervertebral disc into the space occupied by the spinal cord and nerves is a common condition. One to three percent of people around the world are affected by herniated lumbar discs
(discs of the lower back); this means that hundreds of thousands of Americans and millions of people worldwide have pain from this common condition. Protrusion of the disc can be caused by damage to the disc or spinal bones from trauma. It can also be caused by degeneration from disease or the aging process.
The disc itself is designed like a tire where a strong outer layer protects the tube inside. If the outer layer gets a hole in it, the tube can protrude through the surface. The only way to get the tube back in is to reduce the air pressure or fix the surface of the tire.
The intervertebral disc is made of a strong outer covering called the annulus fibrosus and an inner gelatinous core called the nucleus pulposus. Herniation occurs when the nucleus pulposus bulges or extrudes through the annulus fibrosus. Herniation usually begins with damage to the annulus fibrosis.
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 Contained Herniated Disc
A contained herniated disc
results when damage to the
annulus fibrosus allows a
bulging into the spinal canal
that presses on the nerves.
Although weakened, the
annulus fibrosus is intact. |  Uncontained Herniated Disc
An uncontained herniated disc
occurs when there is a tear
completely through the annulus
fibrosus, allowing the nucleus
pulposus to leak out. In an
extruded disc, the portion of the
nucleus pulposus pressing on
the spinal nerves is still attached
to the larger portion of the disc. |  Sequestered Disc
In a sequestered disc, the portion
of the nucleus pulposus pressing
on the nerves has completely
detached from the main body
of the disc. In these cases, the
extruded disc material can move
within the spinal canal. |
| |
Treatment for a herniated disc depends on the degree of herniation. When the herniation is uncontained, surgery may be recommended. For a contained herniated disc, initial treatment is typically the same as discussed for low back pain. If nonoperative treatments are not effective, injection of steroids and long-acting analgesics into the area adjacent to the disc or injection of enzymes into the disc break down the herniated nucleus pulposus may be attempted. If these treatments are not effective, minimally invasive surgeries aimed at removing a portion of the disc may be performed. In severe cases, removal of the diseased disc and fusion of the vertebrae may be necessary.
1. Frymoyer JW, editor. The Adult Spine: Principles and Practice. New York: Raven Press; 1997: 93-141.
2. Weiner BK, Patel R. The accuracy of MRI in the detection of lumbar disc containment. J Orthop Surg Res. 2008;3:46.
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