by Dr. David Borenstein M.D. updated 11/2018
Spinal stenosis refers to narrowing in the spinal canal or neural foramina that puts pressure on the nerves within. With aging, the volume in the central canal and foramina decrease. The discs lose height, the ligaments that hold the bones together fold over themselves taking up space. Extra bone, or osteophytes form near the facet joints because of increasing pressure placed upon them. The osteophytes grow into the canal or foramina also taking up room.
When the spinal cord or spinal nerves is compressed, the blood flow to the nerve is compromised. Without oxygen, the nerve loses its ability to function. A loss of function can result in weakness, pain, or numbness in the areas of the body supplied by the nerve. Reestablishing blood flow to the compressed nerve can quickly restore function and is the goal of spinal stenosis therapy.
Symptoms of cervical stenosis in the neck may be different than those of the low back. Compression of the entire spinal cord occurs with narrowing of the canal in the cervical spine. Any structure below the area of compression can be affected. The variety of symptoms associated with spinal cord compression (myelopathy) includes weakness or numbness in the arms or legs, difficulty with balance or walking, increasing incontinence.
Lumbar spinal stenosis can cause pain in many locations from the low back to the feet, including the buttocks, thighs, and lower legs. Pain may be combined with numbness, tingling, or muscle weakness. Not all patients with lumbar stenosis have back pain. Certain positions that decrease room in the canal increase symptoms. Bending backwards, standing in one position, or walking can cause pain in the legs. Classically, these symptoms are improved by sitting down only to recur when assuming a standing posture. Narrowing at the sides of the canal near the foramina tends to affect a single nerve and thereby one leg. Narrowing in the center of the canal has the potential to affect multiple nerves eventually affects one, or both legs.
The specifics for the diagnosis of spinal stenosis remain to be determined. In the interim, the diagnosis is based upon the summation of the patient complaints, physical findings, in combination with radiographic findings that confirm the presence of narrowing. The diagnosis cannot be made just based on MRI findings alone. Other conditions can cause similar complaints of those of a spinal stenosis patient. For example, vascular claudication is a condition in which blood vessels in the legs narrow, cutting off blood flow. Leg pain is brought on by physical activity. However, the pain usually starts in the foot and travels up the leg as opposed to stenosis pain that runs down the leg. If individuals with vascular claudication just stand without moving, their pain will decrease. A spinal stenosis patient will have to sit down to relieve pain. Hip arthritis patients also have pain that will radiate from the buttock to the knee made worse with walking. Movement of the hip, not the spine causes leg pain. Hip xrays are useful to identify the extent of joint disease.
Treatment of spinal stenosis must take into account the benefits and risks of any intervention. In addition, other disorders may also have an impact on treatment choices. For example, heart problems may limit the choices of drugs because of potential side effects that could affect heart function. In these circumstances, you are only as young as your oldest part. Limitations of function may not be related to leg pain of spinal stenosis but the shortness of breath related to heart failure. This problem needs to take priority. If leg pain related to stenosis is the limiting factor, this symptoms needs to be treated aggressively.
The basic goal of therapy is to maximize the space in the spinal canal for the blood vessels that supply oxygen to the nerves. Being at a good weight for you is helpful at putting less strain on the back. Even a small amount of weight loss can be helpful. Even pound counts!
Remaining active is essential. Find the activity you can do that does not increase your pain but exercises your body. A stationary bicycle is an excellent way to burn calories and maintain cardiovascular health while limiting strain on the spine. Water exercise can be a good form of exercise for people who have difficulty walking short distances.
Physical therapy can be a way to be educated about ways to increase strength and stamina without causing more damage to structures that are painful. Exercises for the neck, chest, and low back can improve function even in those individuals who are skeptical.
Drug therapy can be effective by decreasing pain and improving function. Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil, Motrin) or naproxen (Aleve) have a dual benefit reducing swelling of tissues in the spinal canal and relieving pain. Shrinking tissues allows more room for blood vessels supplying nerves with oxygen. The side effects of NSAIDs include gastrointestinal bleeding and ulcers, high blood pressure, and water retention in the legs. The basic principal in regard to NSAIDs is that they are used at the lowest effective dose for the shortest periods of time.
Opioids have pain relieving properties but have many limiting toxicities. In older individuals, opioids can cause mental confusion, increased risk of falls, and excessive sleepiness. They also cause constipation. They also have abuse potential. The opioids are drugs of last resort.
Epidural injections in the cervical or lumbar spine are offered for those patients who have failed exercise and NSAIDs. Epidural injections are the same procedure offered to pregnant women during labor. The difference is the medicine injected. Pregnant women receive anesthetics while spine patients receive corticosteroids. The role of the corticosteroids delivered inside the vertebral column is to shrink inflamed tissues. People receiving corticosteroid injections need to consider the side effects of the steroids. These include high blood pressure, worsening of diabetes, and thinning of bones. Because of the cumulative effects of steroids, only 3 injections of corticosteroids are given in a 6 month period. If leg pain returns, people can receive an injection every 2 months. These can be repeated over years while side effects are minimized.
Spinal surgery is considered for individuals who have failed medical therapy and demonstrate persistent neurologic problems. Patients with cervical spine stenosis may have progressive difficulty with balance and increasing number of falls. Bladder and bowel function may be compromised. Patients with lumbar spine stenosis have leg pain that starts as soon as they stand. They are unable to walk. Age is not a deciding factor in the decision to undergo surgery. Individuals in good general health are good candidates.
The goal of surgical treatment is to remove an adequate amount of bone or disc to reestablish blood flow to compressed nerves without destabilizing the spine. The key factor is identifying the level of stenosis that corresponds to the patient’s complaints. Once the level is identified, the surgeon should explain the procedure necessary to decompress the area. If instability will be a result of the procedure, a spinal fusion may be required.