Our lumbar spine (lower back) provides a foundation to carry the weight of the upper body. It also houses the nerves that control the lower body. With aging, degenerative changes in the spine can occur. The disks between the vertebrae (bones) may become dehydrated, and the joints may become overgrown due to arthritis. Over time, these changes can also lead to narrowing, or stenosis, of the spinal canal.
Narrowing of the lumbar spinal canal pinches the nerves that go to the skin and muscles of the legs. Sometimes, the pinched nerves become inflamed, causing pain in the buttocks and/or legs.
Degenerative changes in the lower back also can diminish the ability of the spine to carry the load of the upper body. This can lead to forward slippage of one vertebra on another, a painful condition called spondylolisthesis.
Lumbar spinal stenosis usually affects middle-aged and older adults. People who are born with narrower spinal canals are more likely to develop this problem.
Symptoms
Typically, patients with lumbar spinal stenosis have a long history of pain in the back, buttocks, and/or legs that gradually worsens over time. Standing or walking upright usually increases the symptoms, resulting in an achy pain, tightness, heaviness, and a sense of weakness in the buttocks and/or legs. These symptoms are generally relieved by sitting down or leaning forward.
Although patients with lumbar spinal stenosis are unable to walk for long periods of time, they may be able to ride an exercise bicycle for much longer. Some patients also find that it is easier to walk while leaning forward on a shopping cart. This position tends to create more space in the spinal canal and can relieve some of the pressure on the nerves. Leaning on the handlebars of a bicycle creates the same effect.
Diagnosis
An orthopaedic surgeon can diagnose lumbar spinal stenosis using a combination of:
Symptoms
Physical examination
Plain radiographs (X-rays)
Magnetic resonance imaging (MRI)
Radiographs can show the presence of arthritis and slippage of vertebrae. An MRI scan can show whether nerves are being pinched.
For people who cannot get an MRI (for example, people with pacemakers), a special test called a computed tomography myelogram may be necessary. In this test, dye is injected into the spine to make the nerves visible. The doctor can then determine whether the nerves are being pinched.
Treatment
Nonsurgical Treatment
Most patients with lumbar spinal stenosis do not require surgery. However, if a patient is experiencing severe pain that limits the activities of daily living, surgery may be recommended.
Generally, nonsurgical treatment for lumbar spinal stenosis consists of:
Physical therapy A program of physical therapy usually includes aerobic conditioning and exercises for strength and flexibility. The exercise bike is a good way for patients to exercise without pain. Pool exercises can be useful for people who cannot do aerobic exercises on land.
Anti-inflammatory medications Medications such as ibuprofen and naproxen may be prescribed to decrease pain and inflammation; however, they can have serious side effects. Prolonged use can lead to gastrointestinal ulcers, bleeding, and kidney problems. Some anti-inflammatory medications may also increase the risk of heart attack and stroke.
Epidural steroid injections These injections deliver anti-inflammatory steroid medication directly into the spinal canal—straight to the pinched nerve roots. The injections can provide relief for weeks to months, and may allow the patient to participate in more aggressive rehabilitation. In some cases, they may enable the patient to postpone or avoid surgical treatment altogether. Epidural steroid injections are more effective than anti-inflammatory medications taken by mouth, and they may also have fewer side effects.
Bracing A lumbar brace or corset can provide some support and help the patient gain some mobility, but bracing is generally not recommended for long-term use. If used for too long, bracing can lead to deconditioning of the muscles that support the back. Acupuncture or chiropractic manipulation can also be attempted.
All of these nonsurgical treatments are aimed at decreasing inflammation and providing relief of symptoms. However, nonsurgical treatment will not improve the narrowing of the spinal canal.
Surgical Treatment
In general, surgery is only considered as a last resort if all attempts at nonsurgical therapies are unsuccessful, and if the overall potential benefits of surgery are greater than the potential risks. Surgery may be recommended on an urgent basis if a patient has severe weakness or loss of bowel and bladder control.
Decompression
The surgical procedure for lumbar spinal stenosis involves removing the bone and soft tissues of the spine that are pinching the nerves. This procedure is called a "decompression" or a "laminectomy."
Spinal Fusion
Some patients with lumbar spinal stenosis require only a decompression. However, if there is also forward slippage of a vertebra or curvature of the spine, a "spinal fusion" may be needed. In this procedure, two or more vertebrae are permanently fused together, using a bone graft harvested from the hip. Fusion eliminates motion between vertebrae and prevents the slippage or curvature of the spine from worsening after surgery, which would cause more back and/or leg pain. The surgeon may use screws and rods to hold the spine in place while the bones fuse together.
The use of rods and screws makes the fusion of the bones happen faster and speeds postoperative rehabilitation. Overall, the results of spinal fusion are good to excellent in approximately 80% of patients. Patients tend to see more improvement of leg pain than back pain. Most patients are able to resume a normal lifestyle after a period of recovery from surgery.
Complications of Surgery
There are some risks to surgery for lumbar spinal stenosis, including:
Bleeding
Infection
Blood clots
Reaction to anaesthesia
Tear of the sac covering the nerves (dural tear)
Failure to relieve symptoms
Return of symptoms after some time
Failure of the bone fusion to heal
Failure of screws or rods
Need for further surgery
Injury to the nerves
The risks of surgery depend on the patient and the exact procedure being performed. Elderly patients have higher rates of complications from surgery. So do overweight patients, diabetics, smokers, and patients with multiple medical problems.
Rehabilitation
After surgery, patients may be hospitalised for several days, depending on the patient and the procedure performed.
Relatively healthy patients who undergo only decompression may be discharged from the hospital the same day, and may return to normal activities after only a few weeks.
Patients who undergo spinal fusion are hospitalised for several days. They usually receive an outpatient physical therapy program.
A lumbar corset or brace may also be prescribed after surgery. Patients generally return to normal activities after 2 to 3 months.
Older patients who need more physical therapy may be transferred from the hospital to a rehabilitation facility.
Prevention
The best way to avoid lumbar spinal stenosis is to stay as physically fit as possible. Regular exercise can improve endurance and keep the muscles that support the spine strong.
Avoiding weight gain can decrease the load that the lumbar spine has to carry.
Patients should also avoid cigarette smoking. Both the smoke and the nicotine cause the spine to degenerate faster than normal.
