Lumbar Spinal Stenosis
A common cause of low back and leg pain is lumbar spinal stenosis. As we age, our spines change. These normal wear -and -tear effects of aging can lead to narrowing of the spinal canal. This condition is called spinal stenosis.
Degenerative changes of the spine are seen in up to 95% of people by the age of 50. Spinal stenosis most often occurs in adults over 60 years old. Pressure on the nerve roots is equally common in men and women. A small number of people are born with back problems that develop into lumbar spinal stenosis. This is known as congenital spinal stenosis. It occurs most often in men. People usually first notice symptoms between the ages of 30 and 50.
Your spine is made up of small bones, called vertebrae, which are stacked on top of one another. Muscles, ligaments, nerves, and inter vertebral disks are additional parts of your spine. Understanding your spine and how it works can help you better understand spinal stenosis.
Spinal stenosis occurs when the space around the spinal cord narrows. This puts pressure on the spinal cord and the spinal nerve roots, and may cause pain, numbness, or weakness in the legs.
Arthritis is the most common cause of spinal stenosis. Arthritis refers to degeneration of any joint in the body. When we are young, disks have a high water content (left). As disks age and dry out, they may lose height or collapse (right). This puts pressure on the facet joints and may result in arthritis. In the spine, arthritis can result as the disk degenerates and loses water con- tent. In children and young adults, disks have high water content. As we get older, our disks begin to dry out and weaken. This problem causes settling, or collapse, of the disk spaces and loss of disk space height. As the spine settles, two things occur. First, weight is transferred to the facet joints. Second, the tunnels that the nerves exit through become smaller. As the facet joints experience increased pressure, they also begin to degenerate.
- In children and young adults, disks have high water content. As people age, the water content in the disks decreases and the disks become less flexible. The disks begin to shrink and the spaces between the vertebrae get narrower. Conditions that can weaken the disk include:
- Improper lifting
- Excessive body weight that places added stress on the disks (in the lower back)
- Sudden pressure (which may be slight)
- Repetitive strenuous activities
People with spinal stenosis may or may not have back pain, depending on the degree of arthritis that has developed. Burning pain in buttocks or legs (sciatica). Pressure on spinal nerves can result in pain in the areas that the nerves supply. The pain may be described as an ache or a burning feeling. It typically starts in the area of the buttocks and radiates down the leg. As it progresses, it can result in pain in the foot.
Numbness or tingling in buttocks or legs
As pressure on the nerve increases, numbness and tingling often accompany the burning pain. Although not all patients will have both burning pain and numbness and tingling.
Weakness in the legs or "foot drop"
Once the pressure reaches a critical level, weakness can occur in one or both legs. Some patients will have a foot -drop, or the feeling that their foot slaps on the ground while walking. Less pain with leaning forward or sitting.
Studies of the lumbar spine show that leaning forward can actually increase the space available for the nerves. Many patients may note relief when leaning forward and especially with sit- ting. Pain is usually made worse by standing up straight and walking. Some patients note that they can ride a stationary bike or walk leaning on a shop- ping cart. Walking more than 1 or 2 blocks, however, may bring on severe sciatica or weakness.
Medical History and Physical Examination
After discussing your symptoms and medical history, your doctor will examine your back. This will include looking at your back and pushing on different areas to see if it hurts. Your doctor may have you bend forward, backward, and side to side to look for limitations or pain.
Tests which may help your doctor confirm your diagnosis include:
- X-rays: Although they only visualize bones, X-rays can help determine if you have spinal stenosis. X-rays will show aging changes, like loss of disk height or bone spurs. X-rays taken while you lean forward and backward can show "instability" in your joints. X-rays can also show too much mobility. This is called spondylolisthesis.
- Magnetic resonance imaging (MRI): This study can create better images of soft tissues, such as muscles, disks, nerves, and the spinal cord. Conditions such as a herniated disk or an infection are more visible in an MRI scan.
- Computerized axial tomography (CAT) scans: If your doctor suspects a bone problem, he or she may suggest a CAT scan. This study is like a three dimensional X-ray and focuses on the bones. CAT scans can create cross section images of your spine.
- Myelogram: Your doctor may also order a myelogram. In this procedure, dye is injected into the spine to make the nerves show up more clearly. It can help your doctor determine whether the nerves are being com- pressed. bones, aging changes, curves, or deformities. X-rays do not show disks, muscles, or nerves.
- Bone scan: A bone scan may be suggested if your doctor needs more information to evaluate your pain and to make sure that the pain is not from a rare problem like cancer or infection.
- Bone density test: If osteoporosis is a concern, your doctor may order a bone density test. Osteoporosis weakens bone and makes it more likely to break. Osteoporosis by itself should not cause back pain, but spinal fractures due to osteoporosis can.
Nonsurgical treatment: Nonsurgical treatment options focus on restoring function and relieving pain. Although nonsurgical methods do not improve the narrowing of the spinal canal, many people report that these treatments do help relieve symptoms.
Physical therapy: Stretching exercises, massage, and lumbar and abdominal strengthening often help manage symptoms.
Lumbar traction: Although it may be helpful in some patients, traction has very limited results. There is no scientific evidence of its effectiveness.
Anti-inflammatory medications: Because stenosis pain is caused by pressure on a spinal nerve, reducing inflammation (swelling) around the nerve may relieve pain.
Non -steroidal anti-inflammatory drugs (NSAIDs) initially provide pain relief. When used over the course of 5-10 days, they can also have an anti-inflammatory effect. Most people are familiar with nonprescription NSAIDs, such as aspirin and ibuprofen. Whether over-the-counter or prescription strength, these medicines must be used carefully. They can lead to gastritis or stomach ulcers. If you develop acid re-flux or stomach pains while taking an anti-inflammatory, be sure to talk with your doctor.
Steroid injections: Cortisone is a powerful anti-inflammatory drug. Cortisone injections around the nerves or in the "epidural space" can decrease swelling, as well as pain. They also reduce numbness, but not weakness, in the legs. Patients should receive no more than three injections a year.
Acupuncture: Acupuncture can be helpful in treating some of the pain for less severe cases of lumbar stenosis. Although it can be very safe, long-term success with this treatment has not been proven scientifically.
Chiropractic manipulation: Chiropractic manipulation is generally safe and can help with some of the pain from lumbar stenosis. Care should be taken if a patient has osteoporosis or disk herniation. Manipulation of the spine in these cases can worsen symptoms or cause other injuries.
Surgical treatment: Surgery for lumbar spinal stenosis is generally reserved for patients who have poor quality of life due to pain and weakness. Patients may complain of difficulty walking for extended periods of time. This is often the reason that patients consider surgery. There are two main surgical options to treat lumbar spinal stenosis: laminectomy and spinal fusion. Both options can result in excellent pain relief. Be sure to discuss the advantages and disadvantages of both with your doctor.
- Laminectomy: This procedure involves removing the bone, bone spurs, and ligaments that are compressing the nerves. This procedure may also be called a "decompression." Laminectomy can be performed as open surgery, in which your doctor uses a single, larger incision to access your spine. The procedure can also be done using a minimally invasive method, where several smaller incisions are made. Your doctor will discuss the right option for you.
- Spinal fusion: Spinal fusion is essentially a"welding" process. The basic idea is to fuse together the painful vertebrae so that they heal into a single, solid bone spinal fusion eliminates motion between vertebral segments. It is an option when motion is the source of pain. For example, your doctor may recommend spinal fusion if you have spinal instability, a curvature(scoliosis), or severe degeneration of one or more of your disks. The theory is that if the painful spine segments do not move, they should not hurt.