The joints in your body are either immobile, like the joints of the bones in your skull, or mobile, like the ankle, shoulder, and knee. The word mobile in this context simply means "movable." The spine is made up of a complex series of interdependent, highly mobile joints. Like the bones of any other mobile joint, the bones of the spine-the vertebrae-are vulnerable to a painful degenerative condition known as osteoarthritis, or just "arthritis" for short. Because arthritis affects the facet joints of the spine, the condition is sometimes called facet joint arthritis.
What is arthritis of the spine?
The cervical, thoracic, and lumbar segments of the spine are all vulnerable to osteoarthritis (osteo– means “bone,” arthr– means “cartilage,” and the suffix –itis refers to “inflammation”). Each of these segments is composed of bones called vertebrae. Vertebrae connect at joints called facets. The word facet (fuh-SETT), incidentally, comes from the French word facette, meaning “little face.” You can remember what a facet joint is, then, by thinking of it as the point at which two vertebrae face each other. A vertebral bone typically has four facet surfaces on the back, above and below the spiny part you can see beneath the skin. The two facets above this spiny knob are known as the superior facets, and the two below are known as the inferior facets. Each facet surface (or meniscus), is lined with cartilage, lubricated with synovial fluid, and housed within a protective capsule of connective tissue. Each facet joint also has a network of blood vessels that supply the tissues with oxygen and cart away waste products. Nerves within the joint space allow perception and communication of pain signals. Capsular ligaments surrounding each facet joint help to stabilize it by restricting motion to a safe range. These ligaments also work with the spinal musculature to keep the facets in alignment, so that their flat upper and lower surfaces meet up properly. The degenerative process of osteoarthritis doesn’t just wear away the cartilage on the facet joint surfaces—it affects every aspect of joint structure and function:
- New blood vessels form where they shouldn’t.
- Changes in the composition of the synovial fluid compromise its ability to lubricate the joint.
- Supporting ligaments become lax and muscles lose conditioning. As a result, the joint becomes unstable, making injury more likely, and facet surfaces no longer mesh smoothly.
- The meniscus wears away, causing painful friction, which in turn stimulates overgrowth of vertebral bone, inflammation of the joint space, and formation of osteophytes (bone spurs).
How common is arthritis of the spine?
In a recent study of the facet joint, researchers found degenerative changes in 100% of study participants. Of course, the extent of the changes is key, but it’s helpful to understand that the degenerative process is inevitable.
There appears to be a close relationship between knee, hip, and spine arthritis—that is, people with arthritis in one location often have it in another. In 2005 in the United States, 21.4 million people had osteoarthritis or other degenerative joint problems affecting the knee, hip, or spine. Researchers believe that figure is likely to double by 2030.
What causes arthritis of the spine?
Researchers used to believe that overuse was the key cause of arthritis. Those in physically demanding occupations, such as baggage handlers, deckhands, and roofers, were thought to be at much greater risk of developing arthritis than, say, tollbooth operators, taxi drivers, and teachers.
Joints that move do suffer wear and tear as we age—that much is certain. But researchers are learning that the degeneration (deterioration) process may be governed primarily by genetic factors that predispose some of us to an accelerated rate or increased severity of joint degeneration. Studies that may shed light on these genetic mechanisms are under way.
What are the symptoms an arthritic spine?
Most patients with osteoarthritis have pain, stiffness, or muscle spasms in the neck or back. If the spinal nerves or the spinal cord are being compressed, you might also have numbness or weakness in the arms or legs. Lying down might give you some relief, but unfortunately, it’s pretty tough to type and do dishes and drink coffee that way.
Sometimes lying down doesn’t help anyway, since the pain of facet joint osteoarthritis is typically worse in the morning and at night. You may wake up and feel stiff for an hour or so and have trouble sleeping or staying asleep at night. Be sure to tell your doctor about all of your symptoms, so that he or she can prescribe the appropriate physical therapy, medications, or other treatments.
If your discomfort makes it tough to walk or drive, you may start to feel isolated. Pain can make your usual hobbies and social activities less enjoyable, and some of them — gardening, bowling, golfing, and dancing, for example — might become impossible. Being unable to participate in these activities might leave you feeling lonely or depressed. You should mention these feelings to your doctor, since he or she might be able to help. In addition, your doctor will probably view withdrawal from your normal activities an important indicator of the severity of your pain and dysfunction.
How is arthritis of the spine diagnosed?
As with any other spinal condition, a diagnosis of osteoarthritis begins with a thorough physical examination and a look at your medical and family history. Your doctor will ask about your general health, including your prescription medications and any past surgeries.
Your doctor will also ask you to describe your pain—for instance, is it dull, burning, or aching? Does it feel prickly or tingly or numb? The physician will ask when the pain began and what makes it worse or better. A thorough physical examination will help him or her assess your strength, reflexes, range of motion, and level of dysfunction or disability.
Your doctor will look not only for signs of arthritis, but also for signs that your condition has an associated structural or pathological (disease) component. The degenerative changes of osteoarthritis represent the beginning of a cascade that can lead to one of the following:
- Degenerative disc disease, characterized by deterioration of the intervertebral discs in the spine. Usually the condition causes no problems, but in some people it limits range of motion and produces chronic pain.
- Disc herniation, which can cause either radiculopathy (nerve pain caused by spinal nerve compression) or myelopathy (nerve pain caused by spinal cord compression and narrowing of the spinal canal [spinal stenosis]).
- Facet joint syndrome, a condition in which one or more arthritic facet joints cause pain and stiffness, limit range of motion, or reduce mobility.
- Spondylolisthesis, a condition in which a vertebra (usually in the cervical or lumbar spine) slips forward. The displaced vertebra compresses surrounding structures or narrows the space within the spinal canal (stenosis).
X-ray images are used to confirm osteoarthritis of the spine. X-rays can exclude fractures and reveal extensive destruction of cartilage, as well as bone spurs and stenosis (narrowing of the spinal canal). They cannot, however, show early damage to facet joint cartilage.
If your pain persists after at least 6 weeks of conservative treatment, an MRI can be useful in checking for possible disc damage associated with arthritis. MRI images can also pinpoint narrowing of the vertebral foramen—small openings through which the spinal nerves pass as they enter and exit the spine.
How is arthritis of the spine treated?
Your physician will probably allow 6 to 12 weeks to elapse before pursuing any treatment or diagnostic testing, since most back pain resolves on its own (see “What are the symptoms of spinal arthritis?”). Treatment focuses on improving your daily functioning while relieving pain.
As with other conditions, most physicians opt for conservative measures before considering surgical options. Losing weight if necessary, exercising, or a beginning a program of physical therapy can improve flexibility, increase blood flow to the area, strengthen the heart, and lift your spirits. Engaging in low-impact physical activity, such as swimming, water aerobics, and walking, is unlikely to provoke significant pain, but offers the possibility of substantial pain relief.
Your doctor might also suggest some combination of massage, heat or cold application, use of a TENS unit, and over-the-counter or prescription pain medications. Surgery is usually not necessary for osteoarthritis of the spine, but each patient must be evaluated individually.