About 40% of all chronic spine pain is related to a problem in one or more intervertebral discs. If you have chronic neck or low back pain, but you don't have a herniated disc, you may have discogenic pain.
Discogenic pain is thought to occur in relationship to disc degeneration (video), a condition in which the physical and chemical properties of the disc slowly deteriorate. But the problem is, degenerating discs don't always cause pain, and experts have yet to explain this relationship in full.
Causes of Discogenic Back Pain
The theory goes that discogenic pain occurs when nerve receptors located in the outer part of the annulus are irritated by degenerative changes in the spine. Inflammation or other conditions in the disc may also affect these nerve receptors. For example, if the inflammatory chemicals from an annular tear reach the nerves in the outer part of the annulus, the tear may be the cause of your discogenic pain. This type of injury is called internal disc disruption, or IDD.
Genetics likely play a role in the formation of discogenic pain. Genetics may alter the chemical composition of discs, and may bring about metabolic changes in the body. The result is that the discs dry out faster than normal, which renders them less capable of bearing the spinal load evenly. Then, normal every day wear and tear puts pressure on one or a few small areas in the disc, increasing the risk of an annular tear. Damage to the edge of the vertebra adjacent to the disc may also occur. This releases inflammatory chemicals and increases the speed at which discs degenerate.
Along with genetics, nutritional and mechanical factors may also contribute to discogenic pain.
Risk of Discogenic Pain
The degenerative changes in the spine thought to give rise to discogenic pain are age-related. Discogenic pain occurs most often in middle aged and elderly people. (Disc problems in younger people are generally limited to disc herniation because younger people have more water in their discs.)
Symptoms of Discogenic Pain
The main symptoms of discogenic pain are an achy pain that does not refer into your leg or arm and decreased function.
In the low back, pain usually worsens when your spine is compressed: Activities like sitting, bending, coughing and sneezing tend to bring it on, while lying down tends to relieve it. There may be pain or other sensations going into the back of your thigh or your buttock, but not into your lower leg.
In the neck, there may be pain when you turn or tilt your head. The pain may worsen if you hold your head in one position too long. Muscle spasms sometimes accompany discogenic pain in the neck. It's possible to get pain or other sensations down your arm, as well.
Diagnosis of Discogenic Pain
An MRI is often used to diagnose discogenic pain. A discogram may also be used, but this is a controversial test for a number of reasons. First, it intentionally causes pain and asks you to rate the intensity on a VAS scale. Not only does this type of test have ethical implications, but it's subjective, as well (you are reporting what you feel). Discograms are used to definitively confirm that the pain arises from a specific disc or discs. But a number of researchers have found that because of the subjective nature of the discogram, it may yield false-positive results, particularly if you are not in a lot of pain, you have mental impairment or you are afraid of pain.
As mentioned above you may have pain or other sensations down your arm or leg. These are called radicular symptoms. But radiculopathy and discogenic pain are not the same disorder. Like radiculopathy, discogenic pain results from irritation of nerves. The difference is that radiculopathy affects spinal nerve roots, while discogenic pain irritates the nerves located in the outer rings of the annulus. (The annulus is the tough fibrous covering of the intervertebral disc. It contains and protects the centrally located nucleus pulposus.) It can be difficult for the doctor to differentiate between these two conditions when working up a diagnosis. Yet the distinction will make a difference in the treatment you receive.Another method of diagnosis is called the McKenzie Method. This involves a manual exam to find movements that decrease pain and increase your range of motion.
Treatments for Discogenic Pain
Discogenic pain often subsides on its own, or it may come and go. Conservative care is usually the first type of treatment that's tried. It may include controlling pain with anti-inflammatories, using ice and/or heat and physical therapy. Physical therapy may consist of back exercises, traction and other treatments. An injection may help quell the pain and make you more comfortable.
As far a surgery goes, generally it's not necessary. But if you're in debilitating pain for 3 months or longer and/or have spinal instability, it may be an option. Ask your doctor about your options.
A minimally invasive spine surgery known as IDET (Intradiscal Electrothermal Therapy) looks promising for discogenic pain. This surgery cauterizes (heats) the fibers of the annulus so that the tear knits together and the nerve endings die. With the nerve endings dead, you won't be able to feel the discogenic pain anymore. Only a few small studies have been done on the IDET as of June 2010, but the results were good. Most people report significant pain relief and few, if any, side effects from IDET.
The most common surgery for discogenic pain is spinal fusion. However, its use is controversial and it does not always provide relief. In the US, the number of spine surgeries performed has been on the rise since the early 1990s, and data reviews strongly suggest that many are unnecessary. Disc degeneration is a part of aging, but this does not automatically mean you need a spinal fusion when the pain shows up. Be sure to research your options, including your health care providers, and work with your chosen doctor to determine the best course of action for you.
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