Spinal stenosis is caused by a narrowing of either the Spinal Canal or the Foramen (the opening through which the nerve roots exit the spinal canal). The narrowing of these structures produces pressure on the spinal cord or the nerve roots. When the spinal cord or the nerve roots are compressed, a wide range of symptoms can occur.
Anatomy: The spine is made up of 33 vertebrae. These bones are stacked, one on top of the other, to form the spine or spinal column. The individual vertebrae are donut shaped with an opening in the middle (the spinal canal).
The vertebrae surround and protect the spinal cord, which lies in the spinal canal.
The intervertebral foramen (neural foramen) are the openings between two adjacent vertebra (there are two of these openings, one on each side of the vertebrae). These openings allow the nerve fibers (nerve roots) in the spinal cord to exit the spinal canal and travel to their specific body parts.
Narrowing of the spinal canal or intervertebral foramen does not always cause problems. But if the narrowed spaces compress the spinal cord or nerve roots, you are likely to experience the symptoms of spinal stenosis. As the space narrows more, it produces greater compression on the nerve, which increases the severity of the symptoms. The most common symptoms of spinal stenosis include:
- Sciatic nerve pain. When nerves are compressed in the lumbar spine, the usual cause is a herniated disc (the disc between two vertebra is no longer thick enough to protect the nerves leaving the spinal canal through the foramen. This results in pressure on the nerve, or nerve compression). This compression frequently leads to pain and numbness along the path of the sciatic nerve. The sciatic nerve runs down the buttocks and the back of each leg. Symptoms may include pain and/or tingling which most often begins in the buttocks or hip, and radiates down the leg. These symptoms are usually worse when sitting. Generally, only one side of the body is affected. Other symptoms may include weakness and numbness in the leg or feet.
- Pain in the neck and shoulders. When a nerve in the neck (cervical spine) is compressed, you may experience pain and/or tingling that usually begins in the neck or shoulder, and radiates down the arm into the hand. Other symptoms may include numbness and weakness in the arm and/or hand. Only one side of the body is usually affected.
- Loss of balance. This may occur when a cervical spinal nerve is compressed. The results of this compression may hinder our balancing mechanism, and cause one to be clumsy...even to the point of falling.
- Loss of bowel or bladder function (also known as cauda equina syndrome). When the spinal nerves to the bowel or bladder are compressed, one may experience partial or complete loss of bowel or urinary control. These are serious symptoms, and one should seek medical care immediately.
Some common causes of spinal stenosis are:
- The most common cause of spinal stenosis is osteoarthritis. Osteoarthritis is the most common form of arthritis in the world. It is usually due to the normal aging process. When osteoarthritis occurs in the spine, it affects the cartilage that cushions the ends of the vertebrae, and it is called Facet Arthropathy. Normal cartilage prevents the adjacent vertebrae from rubbing against each other. As we age, the cartilage throughout our entire body begins to deteriorate and becomes thinner. If it wears down completely, bone may rub painfully on bone. In an attempt to repair and replace the cartilage, the body may produce bony growths called bone spurs. When these form on the vertebrae in the spine, they narrow the spinal canal, and the intervertebral foramen, causing nerve compressions.
- Osteoarthritis can also affect the Intervertebral Discs that lie between each vertebra. These discs cushion and protect the ends of the vertebrae (they are filled with a jelly-like substance). By the time we hit 30, these discs may start to show sings of deterioration. They develop small leaks, and begin to lose their jelly-like material, becoming flatter and more brittle. When this occurs, these discs rupture or herniate , and they may slip out of place and press on the adjacent nerves. This may produce intense back pain. One may also experience tingling and numbness, along with weakness in the leg and foot on the affected side.
- The ligaments in our back may also undergo degenerative changes with aging. The result is a loss of elasticity of the ligaments, which may cause the entire spine to shorten. When the spine shortens the spinal canal becomes narrower, as do the intervertebral foramen. This may compress the nerves, causing pain, tingling, and numbness in the buttock, thigh, leg, and foot on the affected side.
- Injuries to the spine, such as those sustained in an auto accident may dislocate the vertebrae, which may compress the spinal cord. This may produce intense back pain that radiates to the buttocks, legs, and feet. Other symptoms may include tingling, numbness, and weakness in the legs.
In order to make an accurate diagnosis, your physician will want to take a careful history and perform a physical examination to rule our other causes. The examination may include observation of: your gait, muscle strength, limitations of motion, as well as checking your balance. Tests that might be ordered include:
- EMG- this is an electrical test that helps determine if a nerve is irritated or compressed.
- X rays- may show abnormal structures, such as bone spurs being present; and, they can show deterioration of the intervertebral discs; but x-rays cannot show the actual impingement of nerves.
- CT- (Computerized axial tomography) This is a three dimensional X-ray that can show the bony tissues as well as the nerves.
- MRI- (Magnetic resonance imaging). This is a three dimensional test that shows bony tissue and soft tissue as well as the nerve roots. This compliments or replaces CT in many situations.
The old adage, "An ounce of prevention is worth a pound of cure," is true when it comes to our spines. We cannot totally prevent the onset of spinal stenosis any more than we can stop the aging process. However, we can limit the damage caused by the aging process if we do just a few things, such as exercising, maintaining good posture, and watching our weight. For more information about these preventive measures, please see the next section (Self-Help and Exercises).
Treatment for the symptoms of spinal stenosis can be divided into non-surgical treatments and surgical treatments. The "Gold Standard" of medical care for spinal stenosis is to exhaust all possible non-surgical treatments before any surgical procedures are performed.
The following non-surgical treatments for spinal stenosis have been found to be the most successful in keeping people comfortable:
- Physical Therapy may include exercise, the use of modalities to limit muscle spasm, and working with gait training.
- Maintain good posture at all times...walking, sitting, and sleeping. Good posture reduces abnormal pressure on the spinal cord and the nerve roots; this should help to reduce pain. To see some products that we have found to be exceptionally effective, click here.
- Nonsteroidal Anti-Inflammatory Drugs (NSAID) include the following over-the-counter medications: Advil, Motrin, and Ibuprofen. Indomethacin is an example of a prescription NSAID. All of these medications can cause various side effects, some very severe. While they may help reduce the symptoms of spinal stenosis, we highly recommend that you discuss these medications (including the over-the-counter ones) with your doctor before taking them.
- Rest and restricted activities are a must until symptoms subside. Once the symptoms of spinal stenosis have subsided, you should gradually return to those activities that you can comfortably tolerate.
- Epidural steroid injections, while invasive, are still considered to be conservative treatments. During these injections your doctor will inject corticosteroid medications into the spinal fluid around your spinal cord and nerve roots. These injections help to suppress inflammation of the nerves. When the nerves are no longer inflammed, patients usually experience a decrease in the symptoms of spinal stenosis. Due to the possibilities of side effects that corticosteroids may produce, you must ask your doctor if this treatment is right for you.
For those who do not improve with conservative non-surgical treatments, surgery remains an option. The most common surgery performed to relieve the symptoms of spinal stenosis is a laminectomy. During this surgical procedure, tissue is removed from the spinal column to take pressure off the spinal cord. When only the intervertebral or neural foramen is narrowed, a foramanotomy may be performed. During this procedure, bone and tissue are removed within the foramen. If the spine is felt to be unstable, a fusion between two or more vertebrae may be performed as well.
Which surgical treatment is best for you will depend upon the cause of your symptoms, your age, and your health. The goals of surgery for spinal stenosis are: to relieve pressure on the spinal cord or nerve roots, and to improve the integrity and strength of the spine.
Good common sense is the best medicine that one can use in the self- treatment and prevention of spinal stenosis. Here are several "to do things" which may make you more comfortable, and keep you more active:
- Regular exercise helps to maintain the strength and flexibility of all your muscles, ligaments, and joints...including those in our spines. Regular exercising may reduce your chances of developing the symptoms of spinal stenosis. Before beginning any exercise program, you must consult with your family doctor. The most common exercises suggested for spinal stenosis include: walking, riding a bicycle, and swimming. If you begin to experience pain with these activities, stop immediately and of course, call your doctor.
- Use good posture at all times. You should try to do this even when sitting or lying down in bed. Good posture reduces the stress placed on the spinal cord by the vertebrae. This in turn will help to alleviate the pain of spinal stenosis, along with its other symptoms.
- Proper positioning of the neck is very important. A cervical pillow that provides a comfortable night's sleep, while positioning the neck in a neutral position should be used. For more information regarding the cervical pillows that we recommend, click here. For those of small stature, or those who have a short neck, a Junior Size Pillow is available.
- Maintain a healthy weight. Extra weight will place excessive stress on our back and abdominal muscles and on the joints between the vertebrae. The results are an unstable and weakened spinal column, which in turn sets the stage for the onset of spinal stenosis. A healthy weight helps to keep the spinal column straight and strong. This will help to prevent compression of the spinal cord and nerve roots thus reducing the chances of spinal stenosis occurring.