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DISC HERNIATION (Herniated Disc)
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A disc herniation is a rupture and/or bulge of an interverterbral disc. Commonly, a herniated disc is called a "ruptured" or "slipped" disc and occurs when part of the disc material pops out of place and bulges into the spinal canal, sometimes placing pressure on the nerves. The following text is a general overview of types, causes, symptoms and diagnosis of a disc herniation.
Types of Disc Herniations
Disc herniations most commonly occur in the neck (cervical disc herniation) and lower back (lumbar disc herniation). Detailed information on these disorders including treatments and case studies is provided on the following pages:
Anatomy and Function of the Spine
To better understand how a disc herniation (herniated disc) occurs, it is helpful to know some anatomy of the spine and more specifically, the parts of the spine involved. See Spinal Anatomy for more information.
The intervertebral discs are the cushions that act as shock absorbers between each of the vertebra in your spine. There is one disc between each vertebra. Each disc has a strong outer ring of fibers called the annulus, and a soft, jelly-like center called the nucleus.
The annulus is the disc's outer layer and the strongest area of the disc. The annulus is actually a strong ligament that connects each vertebra together. The mushy nucleus of the disc serves as the main shock absorber.
Causes of Disc Herniation
A herniated disc occurs when the intervertebral disc's outer fibers, the annulus, are damaged and the soft inner material of the nucleus ruptures out of its normal space. If the annulus tears near the spinal canal, the nucleus material can push into the spinal canal.
Herniated discs can occur in children, although this is rare. Usually a true herniated disc is most common in young and middle-aged adults.
Discs can rupture suddenly because of excessive pressure. For example, falling from a ladder and landing in a sitting position can cause a great amount of force across the spine. If the force is strong enough, either a vertebra can fracture or break, or a disc can rupture. Bending over places a great amount of force on the discs between each vertebra. If you bend and try to lift something that is too heavy, the force can cause a disc to rupture.
Discs can also rupture from a small amount of force - usually due to weakening of the annulus fibers of the disc from repeated injuries that add up over time. As the annulus weakens, at some point you may lift something or bend in such a way that you cause too much pressure across the disc. The weakened disc may rupture while you are doing something that five years earlier would not have caused a problem. Such is the aging process of the spine.
A herniated disc causes problems in two ways. First, the material that has ruptured into the spinal canal from the nucleus can cause pressure on the nerves in the spinal canal. There is also some evidence that the nucleus material causes a chemical irritation of the nerve roots. Both the pressure on the nerve root and the chemical irritation can lead to problems with how the nerve root works. The combination of the two can cause pain, weakness, and/or numbness in the area of the body that the nerve connects to.
A herniation may develop suddenly or gradually over weeks or months. The four stages to a herniated disc include:
- Disc Degeneration: chemical changes associated with aging cause discs to weaken, but without a herniation. These changes can be seen on MRI scans, and are usually asymptomatic.
- Prolapse: the form or position of the disc changes with some slight impingement into the spinal canal. Also called a bulge or protrusion.
- Extrusion: the gel-like nucleus pulposus breaks through the tire-like wall (annulus fibrosus) but remains within the disc.
- Sequestration or Sequestered Disc: the nucleus pulposus breaks through the annulus fibrosus and lies outside the disc in the spinal canal.
Symptoms
The symptoms of a true herniated disc may not include back pain at all! The symptoms of a herniated disc come from pressure on, and irritation of, the nerves. However, many people do have back pain because they have other problems in their back when the disc ruptures. The symptoms of a herniated disc usually include:
- Pain that travels into one or both legs
- Numbness or tingling in areas of one or both legs
- Muscle weakness in certain muscles of one or both legs
- Loss of reflexes in one or both legs
Where these symptoms occur depends on which nerve(s) has been affected in the lumbar spine. Therefore, the location of the symptoms helps determine your diagnosis. Communicating the exact source of your pain assists your doctor in determining which disc has probably ruptured.
Diagnosis
Making the diagnosis of a herniated disc begins with a complete history of the problem and a physical examination. The main questions your doctor will be interested in are:
- Did you have an injury?
- Where is the pain?
- Do you have any numbness? Where?
- Do you have any weakness? Where?
- Have you had this problem or something like it before?
- Have you had any weight loss, fevers, or illnesses recently?
Finally, your doctor will be interested in knowing if you have problems when you have to urinate or have a bowel movement. This is important to make sure there is no pressure from the herniated disc on the nerves that go to the bowels and bladder. If you do, this may be an emergency, and require immediate surgery.
Your doctor may suggest taking X-rays of your back. Regular X-rays will not show a herniated disc, but they will give your doctor an idea of how much wear and tear is present in the spine and may show other causes of your problem.
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Excerpts of this article (text/graphics) were provided by
"AllAboutBackandNeckPain.com" DePuy Spine ©2003.
All rights reserved.
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