Spinal stenosis is a narrowing of one or more areas in your spine including the neck, and upper and lower back. This narrowing can put pressure on your spinal cord or on the nerves that branch out from the compressed areas.
Spinal stenosis can cause cramping, pain or numbness in your legs, back, neck, shoulders or arms; a loss of sensation in your extremities; and sometimes problems with bladder or bowel function. Spinal stenosis is most commonly caused by osteoarthritis-related bone damage, and/or herniated intervertebral discs.
Spinal narrowing doesn't always cause problems. But if the narrowed areas compress the spinal cord or spinal nerves, you're likely to develop signs and symptoms. These often start gradually and grow worse over time.
What Causes Spinal Stenosis?
Some patients are born with this narrowing, but most often spinal stenosis is seen in patients over the age of 50. In these patients, stenosis is the gradual result of aging and “wear and tear” on the spine during everyday activities. There most likely is a genetic predisposition to this since only a minority of individuals develops advanced symptomatic changes. As people age, the ligaments of the spine can thicken and harden (called calcification). Bones and joints may also enlarge, and bone spurs (called osteophytes) may form. Bulging or herniated discs are also common. Spondylolisthesis (the slipping of one vertebra onto another) also occurs and leads to compression. When these conditions occur in the spinal area, they can cause the spinal canal to narrow, creating pressure on the spinal nerve.
Symptoms of Stenosis
The narrowing of the spinal canal itself does not usually cause any symptoms. It is when inflammation of the nerves occurs at the level of increased pressure that patients begin to experience problems. Patients with lumbar spinal stenosis may feel pain, weakness, or numbness in the legs, calves or buttocks. In the lumbar spine, symptoms often increase when walking short distances and decrease when the patient sits, bends forward or lies down. Cervical spinal stenosis may cause similar symptoms in the shoulders, arms, and legs; hand clumsiness and gait and balance disturbances can also occur. In some patients the pain starts in the legs and moves upward to the buttocks; in other patients the pain begins higher in the body and moves downward. This is referred to as a “sensory march”. The pain may radiate like sciatica or may be a cramping pain. In severe cases, the pain can be constant. Severe cases of stenosis can also cause bladder and bowel problems, but this rarely occurs. Also paraplegia or significant loss of function also rarely, if ever, occurs.
How Stenosis is Diagnosed
Before making a diagnosis of stenosis, it is important for the doctor to rule out other conditions that may have similar symptoms. In order to do this, most doctors use a combination of tools, including:
- History: The doctor will begin by asking the patient to describe any symptoms he or she is having and how the symptoms have changed over time. The doctor will also need to know how the patient has been treating these symptoms including what medications the patient has tried.
- Physical Examination: The doctor will then examine the patient by checking for any limitations of movement in the spine, problems with balance and signs of pain. The doctor will also look for any loss of extremity reflexes, muscle weakness, sensory loss, or abnormal reflexes which may suggest spinal cord involvement.
- Tests: After examining the patient, the doctor can use a variety of tests to look at the inside of the body. Examples of these tests include:
- X-rays - these tests can show the structure of the vertebrae and the outlines of joints and can detect calcification.
- MRI (magnetic resonance imaging) - this test gives a three-dimensional view of parts of the back and can show the spinal cord, nerve roots, and surrounding spaces, as well as enlargement, degeneration, tumors or infection.
- Computerized axial tomography (CAT scan) - this test shows the shape and size of the spinal canal, its contents and structures surrounding it. It shows bone better than nerve tissue.
- Myelogram - a liquid dye is injected into the spinal column and appears white against bone on an x-ray film. A myelogram can show pressure on the spinal cord or nerves from herniated discs, bone spursor tumors.
- Bone scan - This test uses injected radioactive material that attaches itself to bone. A bone scan can detect fractures, tumors, infections, and arthritis, but may not tell one disorder from another. Therefore, a bone scan is usually performed along with other tests.
Non-surgical Treatment of Spinal Stenosis
There are a number of ways a doctor can treat stenosis without surgery. These include:
- Medications, including non-steroidal anti-inflammatory drugs (NSAIDs) to reduce swelling and pain, and analgesics to relieve pain.
- Corticosteroid injections (epidural steroids) can help reduce swelling and treat acute pain that radiates to the hips or down the leg. This pain relief may only be temporary and patients are usually not advised to get more than 3 injections per 6-month period.
- Rest or restricted activity (this may vary depending on extent of nerve involvement).
Physical therapy and/or prescribed exercises to help stabilize the spine, build endurance and increase flexibility.
What is Arachnoiditis?
Arachnoiditis describes a pain disorder caused by the inflammation of the arachnoid, one of the membranes that surround and protect the nerves of the spinal cord. The arachnoid can become inflamed because of an irritation from chemicals, infection from bacteria or viruses, as the result of direct injury to the spine, chronic compression of spinal nerves, or complications from spinal surgery or other invasive spinal procedures. Inflammation can sometimes lead to the formation of scar tissue and adhesions, which cause the spinal nerves to “stick” together. If arachnoiditis begins to interfere with the function of one or more of these nerves, it can cause a number of symptoms, including numbness, tingling, and a characteristic stinging and burning pain in the lower back or legs. Some people with arachnoiditis will have debilitating muscle cramps, twitches, or spasms. It may also affect bladder, bowel, and sexual function. In severe cases, arachnoiditis may cause paralysis of the lower limbs.
What is the prognosis?
Arachnoiditis appears to be a disorder that causes chronic pain and neurological deficits. Surgery may only provide temporary relief. Aging and pre-existing spinal disorders can make an accurate prognosis problematic. The outlook for someone with arachnoiditis is complicated by the fact that the disorder has no predictable pattern or severity of symptoms. One treatment that may be helpful is Spinal Cord Stimulator Implantation.