Degenerative Disc Disease
Overview
Degenerative disc disease (DDD) affects the discs that separate the spine bones. As you age, the spine begins to show signs of wear and tear as the discs dry out and shrink. These age-related changes can lead to arthritis, disc herniation, or spinal stenosis. Pressure on the spinal cord and nerves may cause pain.
Anatomy of discs
Your spine is made up of a column of bones called vertebrae. Between each vertebra is a shock-absorbing disc that prevents the bones from rubbing together. Discs are designed like a radial car tyre. The tough outer wall, called the annulus, has criss-crossing fibrous bands, much like a tyre tread. These bands attach to each vertebra bone. Inside the disc is a gel-filled centre called the nucleus, much like a tyre tube (Fig. 1).
Figure 1. Drawing of a normal disc showing the gel-filled nucleus surrounded by annulus rings of cartilage fibres.
What is degenerative disc disease?
Degenerative disc disease (spondylosis) can occur in any area of the spine (cervical, thoracic, lumbar), but is most common in the low back. It’s not actually a disease, but rather a condition in which your discs “degenerate” and lose their flexibility and height to cushion the spine. Discs have a limited blood supply, so once injured they can’t repair themselves easily. Age-related changes to discs include (Fig. 2):
• Discs dry out and shrink – the disc nucleus is made of about 80% water. As you get older it slowly loses water and flexibility, which puts more stress on the disc annulus.
• Small tears occur in the annulus – sometimes the gel-like nucleus pushes through a tear in the wall and touches nearby nerves. This material has inflammatory proteins that can irritate nerves and cause pain. The tears also affect tiny nerves in the annulus and cause discogenic pain with small micro-motion instability of the disc. Over time the proteins dry up, and the discs become stiffer.
• Disc gets thinner – Due to the loss of water, the discs get thin and the distance between vertebrae begin to collapse. Which is why we get shorter as we age.
• Bone spurs grow – without the discs holding apart the vertebrae, they can rub on each other causing abnormal bone growths.
• Excess motion – abnormal rubbing adds stress to the facet joints. Pinched nerves may result in back or leg pain (sciatica)
• Spinal canal narrows – the added stress causes the ligaments and facet joints to enlarge (hypertrophy) as they try to compensate and spread the load over a larger area. This over-growth causes the spinal canal to narrow, which can compress the spinal cord and nerves causing pain.
Figure 2. Drawing of a degenerative disc that is dried out and collapsed, reducing the disc space between the vertebrae. Bone spurs and tears in the annulus may lead to herniated discs, pinched nerves, and spinal stenosis.
What are the symptoms?
The symptoms of a degenerative disc vary from person to person. Many people with deterioration have no pain, while others may experience pain so intense that it interferes with daily activities.
Pain often starts in one of three ways:
1) A major injury followed by a sudden and unexpected pain
2) A trivial injury followed by sudden back pain
3) Pain that starts gradually and get progressively worse
Usually, the pain begins in the lower back, and may be felt in one or both of your legs and buttocks. This is called sciatica and is often described as pressure or burning pain. You may also feel numbness or tingling in your leg and foot, which usually is not a cause for concern unless you have weakness in your leg muscles.
You may have chronic underlying pain that is a nagging annoyance, and occasional episodes of intense muscle pain from time to time. These episodes last from a few days to a few months.
Sitting usually causes the most pain because in this position your discs have more weight on them. Activities such as bending or twisting usually make your pain worse and laying down tends to relieve the pain. You may actually feel better if you walk or run rather than sit or stand for too long.
People diagnosed in their 30’s may wonder if their degenerative disc will cause even more pain by the time they are in their sixties. But by the time you are 60, your discs may have dried out to the point that they cause less pain.
What are the causes?
In addition to age and injury, arthritis and osteoporosis contribute to disc degeneration.
Most disc abnormalities can be seen on an MRI scan. While a large portion of people with back pain have abnormalities confirmed by MRI, studies on healthy young adults have shown that as many as 30% of people without pain also have abnormalities that can be seen on an MRI scan.
It is not known why some people have pain and others don’t, but various factors contribute to disc degeneration including: genetic, environmental, autoimmune, inflammatory, and traumatic factors in combinations that aren’t yet understood.
Who is affected?
This condition can affect young adults who lead active lifestyles, but most of the time it occurs slowly and does not cause symptoms until later in life. People who smoke are at greater risk for developing degenerative disc disease, as are people who work in certain occupations. People with DDD are more likely to have family members who also have the condition.
How is a diagnosis made?
When you first experience pain, consult your chiropractor. Your chiropractor will take a complete medical history to understand your symptoms, any prior injuries, or conditions, and determine whether any lifestyle habits are causing the pain. Next, a physical exam is performed to determine the source of the pain and test for any muscle weakness or numbness.
What treatments are available?
While disc degeneration cannot be reversed, there is evidence that exercise, lifestyle changes and careful management of your back pain can contribute to better quality of life.
If conservative therapies fail to help you manage and control the painful symptoms, your chiropractor may recommend surgery. However, the long-term effectiveness of surgery for degenerative disc disease as opposed to natural history, conservative treatment, or placebo has yet to be studied.
Nonsurgical treatments.
Nonsurgical treatment for a degenerative disc may include medication, rest, home exercises, hydrotherapy, chiropractic, and pain management.
Self-Care. Using correct posture and keeping your spine in alignment are the most important things you can do for your back. You may need to make adjustments to your daily standing, sitting, and sleeping habits. You May also need to learn proper ways to lift and bend. Your workspace may need to be rearranged to keep your spine from being under stress.
Stress is a big obstacle to pain control. Pain increases when you are tense and stressed. Relaxation exercises are one way of reclaiming control of your body. Deep breathing, visualization, and other relaxation techniques can help you better manage the pain you live with.
Chiropractic. The goal of chiropractic therapies is to help you return to full activity as soon as possible. Exercise is very helpful for a painful degenerative disc, and it can help you heal faster. Chiropractors can instruct you on proper lifting and walking techniques, and they will work with you to strengthen and stretch your lower back, leg, and stomach muscles. They will also encourage you to increase the flexibility of your spine, arms, and legs. Activity modification, rest, pain medication, muscle relaxants, and application of ice may be helpful in acute stages. Although your chiropractor may show you exercises, it is up to you to perform them at home.
Spinal alignment is also a treatment that chiropractors use for patients with back or neck pain. The chiropractor applies pressure to the area that is immobile or not moving properly. The philosophy behind chiropractic adjustment is to return the joints to more normal motion. Good motion helps reduce pain and muscle spasms. Motion also reduces the formation of scar tissue, which can lead to stiffness.
Medications. Your doctor may prescribe pain relievers, nonsteroidal anti-inflammatory medications (NSAIDs), and steroids. Sometimes muscle relaxers are prescribed for muscle spasms.
• Nonsteroidal anti-inflammatory drugs (NSAIDs) – aspirin, naproxen, ibuprofen and celecoxib are examples of nonsteroidal anti-inflammatory drugs used to reduce inflammation and relieve pain.
• Analgesics, such as paracetamol (Panadol) can relieve pain but don’t have the inti-inflammatory effects of NSAIDs. Long term use of analgesics and NSAIDs may cause stomach ulcers, as well as kidney and liver problems.
• Steroids can be used to reduce the swelling and inflammation of the nerves. The pills are taken orally in a tapering dosage over a five-day period.
Steroid injections. The procedure is done under x-ray guidance and involves an injection of corticosteroid and a numbing agent into the spine. The medicine is delivered right into the painful area to reduce the swelling and inflammation of the nerves. Repeat injections may be given to achieve the full effect. Duration of pain relief varies, lasting for weeks or years. Injections are done in conjunction with a physical therapy and/or home exercise program to strengthen the back muscles and prevent future pain episodes.
Holistic therapy. Some patients find acupuncture, acupressure, yoga, nutrition/diet changes, meditation, and biofeedback to be helpful in managing pain as well as improving overall health.
Surgical treatments. Surgery is rarely recommended unless you have a proven disc herniation or instability and your symptoms have not significantly improved with nonsurgical therapy.
At each level of the spine, there is a disc space in the front and paired facet joints in the back. Working together, these structures define a motion segment and permit range of motion. The goal of surgery is to stop the painful movement of the motion segment, restore the height of the disc space, and decompress the spinal nerves. You should understand what surgery can and can’t do, and whether it can relieve your symptoms. The jury is out in relationship to surgery and it is being used less frequently than in the past.
Spinal fusion surgery joins one or more of the bony vertebrae together to stabilize and stop painful motion. A spacer cage packed with bone graft will fuse the vertebrae above and below into one solid piece of bone. Metal rods and screws may be used to immobilize the area while fusion is created.
Figure 3. Spinal fusion restores the normal height of the disc space and prevents abnormal movement.
One of the long-term risks of fusion can be the degeneration of adjacent discs. The discs above or below the fusion take on more stress and load. The added wear and tear can lead to more rapid degeneration of those discs than might have occurred without the fusion.
Motion preservation surgery involves devices that stabilise the spine without fusing the bones together. The idea is to decrease the risk of adjacent segment disease caused by fusion, but is, as yet, unproven. Because there are relatively new techniques, there are no studies of long-term outcomes. Insurance companies classify many of these devices investigational and patients may have to pay for them out of pocket.
• Artificial disc replacement involves the removal of the damaged disc and insertion of a moveable device that mimics a disc’s natural motion. Made of metal and plastic, they are similar to hip and knee joint implants.
• Dynamic stabilisation involves the insertion of a flexible rod along the facet joints at the back of the spine. Pedicle screws are inserted into the bones above and below the damaged disc. A flexible connector permits a controlled range of bending, straightening and twisting movement.
Note: There is NO guarantee that surgery will lead to less pain or a better lifestyle. There is no magic answer or silver bullet. It is suggested that you conduct your own research in a non-emotional, objective manner before making such a potentially lifestyle changing decision.
Clinical Trials
Clinical trials are research studies in which new treatments – drugs, diagnostics, procedures, and other therapies – are tested on people to see if they are safe and effective. Research is always being conducted to improve the standard of care. Information about current clinical trials, including eligibility, protocol, and locations, are found on the Web. Studies can be sponsored by the National Institutes of Health, as well as private industry and pharmaceutical companies. Being sponsored (paid for) results and findings may NOT be as impartial as one would wish.
Glossary
Annulus: (annulus fibrosis): tough fibrous outer wall of an intervertebral disc.
Arthritis: joint inflammation caused by infection, immune deficiency (rheumatoid arthritis), or degeneration of the cartilage that causes pain, swelling, redness, warmth, and restricted movement.
Degeneration: the gradual deterioration of specific tissues, cells, or organs resulting in loss of function, caused by injury, disease, or aging.
Disc: (intervertebral disc): a fibrous cushion that separates spinal vertebrae. Has two parts, a soft gel-like centre called the nucleus and a tough fibrous outer wall called the annulus.
Discogenic pain: pain arising from degenerative changes in the intervertebral discs.
Nucleus (nucleus pulposus): soft gel-like centre of an intervertebral disc.
Osteoporosis: a depletion of calcium in the bones, making them weak, brittle, and prone to fracture. Common in elderly women after menopause. Can be prevented early in life with calcium and regular exercise to stimulate bone metabolism.
Osteophyte: (bone spur) a bone projection that occurs near cartilage degeneration in joints. Often related to osteoarthritis.
Radiculopathy: refers to any disease affecting the spinal nerve roots. Also used to describe pain along the sciatic nerve that radiates down the leg.
Spondylosis: a spinal condition resulting from degeneration of the intervertebral discs in the spine causing narrowing of the space occupied by the disc and the presence of bone spurs.
Spinal Stenosis: the narrowing of the spinal canal and nerve-root canal along with the enlargement of the facet joints.
Vertebra: (plural vertebrae) one of the 33 bones that form the spinal column, they are divided into 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal. Only the top 24 bones are movable.
Acknowledgements
Mayfield Clinic
Banita Bailey, RN. BSN. CCM.
Cannington Chiro Services
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