The spinal cord is the main conduit for nerve impulses traveling from the brain to the lower part of the body. It runs through the spinal canal -- the channel between the 24 bones (vertebrae) that make up the spine. Spinal stenosis is a condition in which the spinal canal becomes narrower. This narrowing (stenosis) places pressure on the spinal cord and on the nerves branching out from it. Spinal stenosis can cause pain, numbness, or tingling in the back or legs.
Spinal stenosis typically results from aging-related degenerative changes in the spine. With age, the spongy disks between the vertebrae lose moisture and elasticity. The harder, drier disks lose height, bringing the vertebrae closer together. Sometimes they herniate (bulge out), pressing on nerves such as the sciatic nerve. The joints at the back of each vertebra (facet joints) also may deteriorate through the wear and tear of osteoarthritis. As the cartilage in these joints is destroyed, the joints and supporting ligaments thicken, and bone spurs may develop. Each of these changes can put pressure on the spinal cord.
- Pain in the neck or back
- Pain, weakness, numbness, or cramping in the legs, back, or buttocks
- Shooting pain down the back of one leg (sciatica), which often begins as pain in the hip or buttocks
- Feeling of heaviness or weakness in the legs
- Clumsiness, tripping, falls
- Pain from spinal stenosis typically worsens when you stand or walk. Sitting or leaning forward may relieve the pain by taking pressure off the involved nerves.
Diagnosis and treatment of spinal stenosis
A simple x-ray of your spine can show degenerative changes, including deterioration of disks or changes in the facet joints. In some instances, computed tomography (CT), myelography (which relies on injected dye to view the nerves), or a bone scan may be performed to detect spinal stenosis. Magnetic resonance imaging (MRI), however, is commonly performed to confirm a suspected diagnosis of spinal stenosis. Often a doctor will suggest a trial of conservative treatments to relieve symptoms before performing the more sophisticated and expensive tests.
If you have mild to moderate symptoms, your doctor may recommend a brief period of rest, along with an over-the-counter pain reliever like Tylenol, Motrin, or Advil. Significant, unrelieved pain may require a stronger pain medication or injection of the steroid medication cortisone into the spinal fluid (called an epidural injection).
Your doctor will prescribe general exercise, such as walking or stationary cycling, and specific exercises to strengthen your back and abdominal muscles. You may be referred to a physical therapist for help with posture, body mechanics, and flexibility or for instruction in your prescribed exercises. Some physicians may recommend use of a back brace for a brief period.
Back surgery for spinal stenosis typically is reserved for people with persistent pain, leg weakness, or bowel or bladder problems related to the spinal stenosis. The two major types of surgery are decompression surgery (also called laminectomy) and spinal fusion. In decompression surgery, the surgeon removes bone from the back of the spinal canal to open up more space. Bone spurs or protruding disks that are pressing on nerves also will be removed.
If the vertebrae have slipped and are unstable, spinal fusion may also be required. In this procedure, two or more disks are fused together with a bone graft from the hip, a bone substitute, or an artificial material such as metal, wires, rods, or screws.
Spine surgery entails the risks common to all surgery (bleeding, infection, blood clots, reactions to anesthesia). Other potential risks include a bone fusion that doesn’t heal, inadequate or short-lived symptom relief, damage to nerves, or the need for further surgery. With decompression surgery alone, a person in good overall health may be hospitalized for only a day or two and may be able to resume normal activities within several weeks.
Patients who undergo fusion surgery will spend several days in the hospital, will undergo intensive physical therapy for a few months, and will usually achieve full recovery in two to three months. Full recovery can take as long as six to nine months for elderly individuals or those with chronic health problems.
Bottom line advice on spinal stenosis: If you have osteoarthritis and want to prevent spinal stenosis, here are some guidelines:
- Avoid weight gain, or lose extra pounds
- Commit to a comprehensive exercise program -- aerobic, strength-training, and stretching)
- Learn and practice good posture and proper body mechanics
- Avoid smoking. It accelerates disk degeneration
