Lumbar Spinal Stenosis

Topic Overview

Is this topic for you?

This topic is about spinal stenosis of the lower back, also known as the lumbar area. If you need information on spinal stenosis of the neck, see the topic Cervical Spinal Stenosis.

What is lumbar spinal stenosis?

Lumbar spinal stenosis is a narrowing of the spinal canal in the lower back, known as the lumbar area. This narrowing occurs when the growth of bone or tissue or both reduces the size of the openings in the spinal bones. This narrowing can squeeze and irritate the nerves that branch out from the spinal cord . It can also squeeze and irritate the spinal cord itself. This may cause pain, numbness, or weakness, most often in the legs, feet, and buttocks.

What causes lumbar spinal stenosis?

Lumbar spinal stenosis is most often caused by changes in the shape and size of the spinal canal as people age. For example:

• Connective tissues called ligaments get thicker.
• Joint disease called osteoarthritis leads to the growth of bony spurs that push on the spinal cord.
• Discs between the bones may be pushed backward into the spinal canal.

These conditions can lead to problems that narrow the space in the spinal canal.

What are the symptoms?

If the spinal cord or nerves become squeezed, symptoms may include:

• Numbness, weakness, cramping, or pain in the legs, feet, or buttocks. These symptoms get worse when you walk, stand straight, or lean backward. The pain gets better when you sit down or lean forward.
• Stiffness in the legs and thighs.
• Low back pain.
• In severe cases, loss of bladder and bowel control.

Symptoms may be severe at times and less severe at other times. Most people will not be severely disabled. In fact, many people do not have symptoms at all.

How is lumbar spinal stenosis diagnosed?

Your doctor can tell if you have lumbar spinal stenosis by asking questions about your symptoms and past health and by doing a physical exam. You will probably need imaging tests such as an MRI, a CT scan, and sometimes X-rays or an EMG.

How is it treated?

You can most likely control mild to moderate symptoms with pain medicines, exercise, and physical therapy. Your doctor may also give you a spinal shot of corticosteroids, a medicine that reduces inflammation.

You may need surgery if your symptoms get worse or if they limit what you can do. In these cases, surgery to remove bone and tissue that are squeezing the spinal cord can help relieve leg pain and allow you to get back to normal activity. This surgery is not likely to relieve back pain.

Frequently Asked Questions

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	Should I have surgery for spinal stenosis?

Cause

The most common cause of lumbar spinal stenosis is age-related changes of the spine. These changes include thickening of soft tissues and a gradual deterioration of spinal discs and joints that connect the spine's vertebrae. Any of these conditions can narrow the spinal canal. Spinal stenosis usually develops gradually and may begin to squeeze the spinal cord or its nerve roots .

Age-related degeneration often occurs in association with certain disorders:

• Osteoarthritis of the spine wears away joint cartilage and causes bony growths (spurs).
• Certain bone diseases, such as Paget's disease, ankylosing spondylitis, rheumatoid arthritis, and diffuse idiopathic skeletal hyperostosis, may soften the spinal bones or cause too much bone to grow.

Other conditions that may cause spinal stenosis include:

• An abnormally narrow spinal canal, which can be an inherited condition.
• Spondylolysis, which is a defect or fracture on one or both of the wing-shaped parts of a vertebra. A vertebra may slide forward or backward over the bone below and may squeeze the spinal cord or a nerve root.
• Spinal fracture.
• Cancer.
• Fibrosis-which is excess, ropy tissue much like scar tissue-from having spine surgery in the past.

Symptoms

Many people older than age 50 have some narrowing of the spinal canal (spinal stenosis) but do not experience symptoms. If the nerve roots or spinal cord become squeezed, symptoms may include:

• Numbness, weakness, cramping, or pain in the legs, feet, or buttocks. These symptoms get worse when you stretch or extend your back, such as when you walk (especially downhill), stand straight, or lean backwards. The pain gets better when you flex your spine forward, such as when you sit down, lean over a grocery cart, or walk uphill.
• Stiffness in legs and thighs.
• Low back pain.
• In severe cases, loss of bladder and bowel control.

The nerve roots that pass through the lower (lumbar) spine extend to the legs, so spinal stenosis most commonly affects the legs. The classic symptom of lumbar spinal stenosis is leg pain that is present when you walk or stand and that is relieved by sitting. Leg pain is often present when the spine is extended, as while standing straight or leaning backwards, and is relieved when the spine is flexed, as in a sitting position or when walking uphill or leaning over a grocery cart. Some people find bicycling more comfortable than standing or walking. People with severe lumbar spinal stenosis may develop a habit of leaning forward in a stooped position to relieve symptoms.

See a picture of nerves commonly affected by spinal stenosis .

In some cases, the severity of symptoms may not relate to the degree of the narrowing of the spinal canal as seen on imaging tests. You may have very severe symptoms, but tests show relatively little narrowing of the spinal canal. Or you may have mild symptoms, but tests show a significant narrowing of the spinal canal. Therefore, treatment is based not only on imaging test results, but also on how bad your symptoms are and how they impact your normal daily activities and quality of life.

Several other conditions have symptoms similar to spinal stenosis.

What Happens

Spinal stenosis usually starts gradually and develops over a long period of time. Narrowing of the spinal canal can squeeze and irritate the nerve roots that branch out from the spinal cord, or it can squeeze and irritate the spinal cord itself. This may cause pain, cramping, numbness, or weakness, most often in the legs, feet, and buttocks. Symptoms may be severe at times and less severe at other times. You may be able to relieve pain by changing positions. For example, leaning forward or sitting may relieve pain, because it often reduces pressure on the spinal cord or nerve roots. For mild to moderate cases, nonsurgical treatment (such as medicines and exercise) can help relieve symptoms and allow you to do normal daily activities.

Spinal stenosis occurs most often in the lower back (lumbar) area. When it does occur in the neck (cervical spinal stenosis) region, it may cause pain, numbness, or weakness in the arms, hands, and legs. If it is severe, you may also have trouble controlling your bladder or bowels.

The course of spinal stenosis varies-it may stay the same, get better, or get worse. Severe disability is not common. But if symptoms become severe, they may not improve without surgery. Severe symptoms may restrict your normal daily activities and affect your quality of life. If symptoms are still severe after a period of time of nonsurgical treatment, surgery may be considered. Surgery may not be an option for some older adults who have other serious health problems that make surgery too risky.

What Increases Your Risk

The risk of having lumbar spinal stenosis increases if you:

• Are older than age 50.
• Have a history of spinal injury.
• Have osteoarthritis (spondylosis) of the spine, which results in disc deterioration, development of bony growths (spurs), and damage to the joints that connect the spine's vertebrae.
• Have a bone disease, such as Paget's disease, ankylosing spondylitis, rheumatoid arthritis, or diffuse idiopathic skeletal hyperostosis, which may soften the spinal bones or cause calcium deposits to form.
• Are born with a defect or fracture of one or both of the wing-shaped parts of a vertebra (spondylolysis), which may allow a vertebra to slide forward or backward over the bone below, sometimes squeezing the spinal cord or a nerve root. This slipping, called spondylolisthesis, usually happens at the base of the spine.
• Have an abnormally narrow spinal canal, which may be inherited or may develop in curvature of the spine (scoliosis).
• Have a genetic (inherited) disorder in which the bones of the arms and legs do not grow to normal size and the vertebrae of the spine do not grow normally (achondroplastic dwarfism).
• Have had lower back surgery, which may cause swelling that puts pressure on the spinal nerves. Progressive spinal stenosis may occur, even after successful back surgery.

When To Call a Doctor

Call 911 or other emergency services immediately if:

• A fall or injury-even a mild one-has caused numbness or weakness in one or both arms, or one or both legs.
• Low back pain is accompanied by an inability to move the legs (paralysis), confusion, or shock.
• You have a loss of bowel or bladder control.

Note: If you suspect that someone has had a spinal injury, call 911 or other emergency services immediately. Do not move the person unless there is an immediate threat to life, such as a fire. If there is immediate danger, keep the head, neck, and back supported and aligned while you move the person to safety.

Call your doctor if:

• Leg pain is accompanied by persistent weakness, tingling, or numbness in any part of the leg from the buttock to the ankle or foot.
• Low back pain is accompanied by vomiting and/or fever.
• Leg pain, weakness, numbness that comes and goes (intermittent), or tingling persists longer than 1 week despite using home treatment.
• Significant back pain either does not improve or gets worse over 2 weeks.
• A back injury is work-related, and symptoms do not improve in 2 to 3 days.

Watchful Waiting

Lumbar spinal stenosis usually develops gradually over months to years. If you have symptoms that come on suddenly, you may have another serious condition and should call your health professional.

If you begin to regularly experience leg pain when walking and standing, call your health professional.

Who To See

The following health professionals can diagnose and treat spinal stenosis:

• Family medicine physician
• Internist
• Nurse practitioner
• Physician assistant
• Emergency medicine (ER) doctor

Specialists who can treat spinal stenosis include the following:

• Orthopedist/orthopedic surgeon, including surgeons who specialize in the spine
• Neurologist or neurosurgeon
• Rheumatologist
• Physiatrist
• Physical therapist

To prepare for your appointment, see the topic Making the Most of Your Appointment.

Exams and Tests

Lumbar spinal stenosis can usually be diagnosed based on your history of symptoms, a physical examination, and imaging tests.

Imaging tests that may be used to evaluate the condition of the spine include:

• Computed tomography (CT) scan of the spine, which is used to evaluate bones and joints.
• Magnetic resonance imaging of the spine (MRI), which shows the soft parts of the spine better than the bones. With spinal stenosis, the position of the spinal nerves and evaluation of the space available for them is easier to see on an MRI. Disc problems show up better on MRIs than on CT scans. MRI may also show tumors, infections, and other disorders.
• X-rays of the spine, which is used to measure the extent of arthritis or injuries to the vertebrae.
• Myelogram, which may detect narrowing of the spinal canal or abnormalities of the nerves branching off the canal. Myelography is rarely used to diagnose spinal stenosis.
• Bone scan, which is used to rule out cancer and other bone diseases.
• Electromyogram and nerve conduction tests are sometimes done to help diagnose spinal stenosis and also to see if you might have problems other than or in addition to lumbar spinal stenosis. For example, these tests can help detect underlying nerve damage that sometimes develops in people with diabetes (neuropathy).¹

Your health professional may try nonsurgical treatment, such as pain-relieving medicines, exercise, and physical therapy, for a period of time before ordering imaging tests. If this treatment is effective, you may not need tests.

In some cases, the severity of symptoms may not relate to the degree of the narrowing of the spinal canal as seen on imaging tests. You may have very severe symptoms, but tests show little narrowing of the spinal canal. Or you may have mild symptoms, but tests show a lot of narrowing of the spinal canal. So, treatment is based not only on imaging test results, but also on how bad your symptoms are and how much they impact your normal daily activities and quality of life.

Treatment Overview

Lumbar spinal stenosis is narrowing of the spinal canal that usually starts gradually and develops over a long period of time. As the spinal canal narrows, it can squeeze (compress) and irritate the nerve roots that branch out from the spinal cord , or it can squeeze and irritate the spinal cord itself. The goals of treatment for spinal stenosis are to relieve pain, numbness, and weakness in the legs, to make it easier for you to move around (improve function), and to improve your quality of life. Treatment includes pain-relieving medicine, exercises, and other nonsurgical measures, and in some cases, surgical treatment.

Initial treatment

Unless your lumbar spinal stenosis is severe, initial treatment usually is aimed at relieving your symptoms without surgery. Most cases do not require surgery. Nonsurgical treatment often works to allow most normal activity and relieve mild to moderate symptoms of pain, numbness, and weakness in the legs.² Nonsurgical treatment includes:

• Education about the course of your condition and how to relieve symptoms.
• Medicines to relieve pain and inflammation, such as acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs).
• Exercise, to maintain or achieve overall good health. Aerobic exercise-especially riding a stationary bicycle (which allows you to lean forward)-can relieve symptoms.
• Weight loss, to relieve symptoms and slow progression of the stenosis.
• Physical therapy, to provide education, instruction, and support for your self-care. Physical therapy helps you learn stretching and strength exercises that may lead to a decrease in pain and other symptoms.

If you have symptoms of cervical spinal stenosis, testing and treatment may be done earlier than in treatment for lumbar spinal stenosis.

Ongoing treatment

Lumbar spinal stenosis often requires nonsurgical treatment on an ongoing basis. Treatment may include:

• Medicines to relieve pain and inflammation, such as acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs).
• Exercise, which is important for overall good health. Aerobic exercise-especially riding a stationary bicycle (which allows you to lean forward)-can relieve symptoms.
• Staying at a healthy body weight, which may relieve symptoms and slow the progression of the stenosis.
• Physical therapy, to provide education, instruction, and support for your self-care. Physical therapy helps you learn stretching and strengthening exercises that may lead to a decrease in pain and other symptoms.

If medicines, exercise, and physical therapy do not relieve your symptoms, your health professional may recommend an epidural steroid injection (ESI). This injection includes a combination of a corticosteroid and a local anesthetic pain relief medicine. These injections are used for pain that occurs mostly in the legs.

Treatment if the condition gets worse

The course of lumbar spinal stenosis varies: symptoms may be severe at times, and less severe at other times. If you feel numbness, weakness, or have trouble standing or walking, it may mean that your condition is getting worse. Problems with bladder and bowel control also may mean your spinal stenosis is getting worse.

If you are experiencing a flare-up of severe low back pain that is not relieved by other forms of treatment and you are unable to engage in daily activities, your health professional may prescribe hydrocodone or other opioid medicines.² But these medicines do not work well for symptoms that occur in the legs. Also, the side effects of opioids-such as mental confusion, drowsiness, and constipation-can be more of a problem than the pain of lumbar spinal stenosis.

If you have tried nonsurgical treatment for a period of time as determined by your health professional but your symptoms have not improved, you may want to consider surgery. Imaging tests (such as MRI) will be done to find out the amount and location of spinal canal narrowing. You and your health professional will want to discuss the severity of symptoms, along with imaging test results, before making a decision about surgery.

Back surgery (decompressive laminectomy with or without spinal fusion) may be considered when you:

• Have severe symptoms of pain, numbness, or weakness in the legs that restrict normal daily activities and have a negative impact on your quality of life.
• Are in otherwise good health and do not have other medical conditions that might make it harder for you to have and recover from surgery.

The goal of surgery for spinal stenosis is to relieve pain, numbness, or weakness in the legs-not to relieve back pain. People who are operated on solely for back pain are less satisfied with outcomes than are those who are operated on for nerve root symptoms and pain in both the back and legs. Back pain associated with spinal stenosis is often not relieved by surgery. In addition, numbness, weakness, and pain may return after surgery.³

Should I have surgery for spinal stenosis?

What To Think About

Epidural steroid injections (ESIs) are usually only used to treat symptoms of lumbar spinal stenosis that occur in the legs. This treatment only relieves symptoms for a short time, and experts are not sure about the long-term effects. Talk to your doctor about the risks related to the number of injections he or she expects you will need.

Surgery is usually not recommended for an older adult who is able to manage symptoms with nonsurgical treatment and is able to do normal daily activities. Surgery may be considered if the severity of symptoms and the decrease in quality of life outweigh the risks of the procedure. Surgery may not be an option for some older adults whose other serious health problems increase the risks from surgery.

Prevention

Lumbar spinal stenosis is most commonly caused by age-related changes of the spine, which can squeeze the spinal cord or its nerve roots. Some of these changes cannot be prevented, but you may be able to control the severity of spinal stenosis by keeping your back healthy. Regular exercise and flexibility stretches, a healthy body weight, and good posture are all important to the condition of your spinal column.

Don't smoke-smoking has been linked to back pain and disc problems. It decreases your bone density and increases your risk of fracture and bone deterioration. Also, smoking can make it more difficult for the bone to heal after a spinal fusion.

If you have spinal stenosis, you can take steps to prevent the condition from getting worse. You may have symptoms of pain, weakness, and numbness in the legs, which increase your risk of losing your balance. If you fall, you may aggravate your spinal stenosis. You can reduce your risk of falling by:

• Limiting your use of alcohol and sedative medicines, such as flurazepam (Dalmane) or diazepam (such as Valium), which cause drowsiness or dizziness.
• Removing obstacles in your house that may cause you to fall. Household hazards that can cause falls include slippery floors, poor lighting, electrical cords, cluttered walkways, and throw rugs.
• Taking medicines only as directed by your health professional. Review medicines periodically with your primary care doctor, especially if you have more than one doctor prescribing them. You may increase your risk of falling if you take medicines such as sleeping pills or pain relievers.
• Wearing low-heeled shoes that fit well.

Home Treatment

Lumbar spinal stenosis is narrowing of the spinal canal that usually starts gradually and develops over a long period of time. This narrowing can squeeze and irritate the nerve roots that branch out from the spinal cord, or it can squeeze and irritate the spinal cord itself. Nonsurgical treatment may be helpful in relieving or reducing the symptoms of spinal stenosis. Some forms of nonsurgical treatment can be done at home, including:

• Taking medicines to relieve pain, such as nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen.
• Participating in physical therapy. Physical therapists can teach you which movements will help, such as proper lifting positions, and which movements will aggravate your stenosis, such as standing erect for lengths of time.
• Exercising. Aerobic exercise as well as stretching and strengthening exercises for the lower back and stomach muscles can relieve symptoms and improve muscle strength, especially when done 4 to 5 times a week. The most beneficial aerobic exercises include riding a stationary bicycle (with the spine flexed in a forward position) and walking on a treadmill with an incline.
• Restricting activities that make your symptoms worse. Depending on the severity and location of your stenosis, these activities might include walking (especially walking downhill) and standing for a length of time.

Be sure to talk with your health professional before beginning home treatment.

Spinal stenosis may cause pain and numbness in the legs, which increases your risk of losing your balance. You can reduce your risk for falling by:

• Removing any obstacles in your house that may cause you to fall. Household hazards that can cause falls include slippery floors, poor lighting, electrical cords, cluttered walkways, and throw rugs.
• Limiting your use of alcohol and sedative medicines, such as flurazepam (Dalmane) or diazepam (such as Valium), which cause drowsiness or dizziness.
• Taking medicines only as directed by your health professional. Review medicines periodically with your primary care doctor, especially if you have more than one doctor prescribing them. You may increase your risk of falling if you take medicines such as sleeping pills or pain relievers.
• Wearing low-heeled shoes that fit well.

Medications

Treatment for lumbar spinal stenosis is done to relieve pain, numbness, and weakness in the legs and improve your ability to function and your quality of life. Medicine may be used to relieve the pain and inflammation caused by spinal stenosis. Taking medicine in conjunction with other nonsurgical treatment is often enough to relieve pain and allow you to do normal daily activities.

Medication Choices

Medicines used to relieve the symptoms of spinal stenosis include:

• Nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, naproxen, and ibuprofen, which may relieve pain and reduce inflammation.
• Acetaminophen, which may relieve pain but does not reduce inflammation.
• Opioids, to relieve severe lower back pain that does not respond to other medicines. Opioids are usually used only for short periods of time, to help avoid side effects from the medicine.
• Epidural steroid injections (ESIs), which may be used to reduce inflammation and pain in the legs.

What To Think About

Tell your doctor about any other health problems you have and all the other medicines you take. This will help him or her choose the pain medicine that will work best for you.

Some doctors don't like to give epidural steroid injections (ESIs). The symptom relief does not last long and their long-term effects aren't well understood.

Surgery

Surgery for lumbar spinal stenosis is done to relieve pressure on the spinal cord or the nerve roots. During surgery, damaged parts of your spine are removed or adjusted. When successful, surgery enlarges the spinal canal and relieves pressure on the nerves. This can help reduce pain, numbness, and weakness in your legs.

If you have tried nonsurgical treatment for a period of time as determined by your health professional but your symptoms have not improved, surgery may be considered. Imaging tests such as CT scan or MRI will be done to find out the amount and location of narrowing of the spinal canal. Before making a decision about surgery, discuss the severity of your symptoms and the imaging test results with your health professional.

Surgery may be recommended if you:

• Have severe symptoms of pain, numbness, or weakness in the legs that restricts normal daily activities and quality of life.
• Are in otherwise good health and do not have other medical conditions that might make it harder for you to have and recover from surgery.

Should I have surgery for spinal stenosis?

In general, up to 80% of people are satisfied with the results of surgery for spinal stenosis.⁴ For people with severe symptoms, surgery usually reduces leg pain and improves walking ability.⁵ But symptoms may return after several years. About 10% to 20% of people who have had surgery need to have surgery again.⁴

Surgery Choices

The main type of surgery for lumbar spinal stenosis is decompressive laminectomy, which relieves pressure on the spinal cord or the spinal nerve roots. Laminectomy removes part of the vertebra (bone and/or fibrous tissue) to create space for nerves. In some cases, spinal fusion will be done at the same time to stabilize the spine. Spinal fusion might relieve your pain and make it easier for you to move around (improve function). It can also help keep the bones from moving into positions that squeeze the spinal canal and put pressure on the spinal cord.

What To Think About

Surgery does not often relieve back pain associated with lumbar spinal stenosis. Surgery is most likely to relieve pain, numbness, or weakness in the legs.⁴

Other Treatment

Physical therapy is an important part of nonsurgical and postsurgical treatment for spinal stenosis. Physical therapy can reduce pain, improve function, and build muscle strength. Your physical therapist may teach you exercises to strengthen your abdominal muscles, which will help support your spine. You may also learn exercises to help maintain flexibility and reduce inflammation.

Other types of treatment, such as alternative and complementary medicine therapies, are used by some people to relieve pain from spinal stenosis. These therapies include acupuncture, ultrasound, and transcutaneous electrical nerve stimulation. There are no studies that prove these therapies are effective in controlling symptoms of spinal stenosis.⁶

Other Places To Get Help

Organizations

Related Information

• Herniated Disc
• Low Back Pain
• Neck Pain
• Osteoarthritis

References

Citations

1. Haig AJ, et al. (2005). The sensitivity and specificity of electrodiagnostic testing for the clinical syndrome of lumbar spinal stenosis. Spine, 30(23): 2667-2676.

2. Sengupta DK, Herkowitz HN (2003). Lumbar spinal stenosis: Treatment strategies and indications for surgery. Orthopedic Clinics of North America, 34(2): 281-295.

3. Phillips FM, Cunningham B (2002). Managing chronic pain of spinal origin after lumbar surgery: The role of decompressive surgery. Spine, 27(22): 2547-2553.

4. Isaac Z, et al. (2005). Lumbar spinal stenosis. In WJ Koopman, ed., Arthritis and Allied Conditions: A Textbook of Rheumatology, 15th ed., vol. 2, pp. 2087-2092. Philadelphia: Lippincott Williams and Wilkins.

5. Sheehan JM, et al. (2001). Degenerative lumbar stenosis: The neurosurgical perspective. Clinical Orthopaedics and Related Research, 384: 61-74.

6. Truumees E, Herkowitz HN (2001). Lumbar spinal stenosis: Treatment options. AAOS Instructional Course Lectures, 50: 153-161.

Other Works Consulted

• Atlas SJ, et al. (2005). Long-term outcomes of surgical and nonsurgical management of sciatica secondary to a lumbar disc herniation: 10-year results from the Maine Lumbar Spine Study. Spine, 30(8): 927-935.

• Hu SS, et al. (2006). Cervical spondylosis section of Disorders, diseases, and injuries of the spine. In HB Skinner, ed., Current Diagnosis and Treatment in Orthopedics, 4th ed., pp. 238-242. New York: McGraw-Hill.

• Hu SS, et al. (2006). Stenosis of the lumbar spine section of Disorders, diseases, and injuries of the spine. In HB Skinner, ed., Current Diagnosis and Treatment in Orthopedics, 4th ed., pp. 249-252. New York: McGraw-Hill.

• Resnick D, et al. (2005). Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine-Part 9: Fusion in patients with stenosis and spondylolisthesis. Journal of Neurosurgery, 2: 679-685.

• Resnick DK, et al. (2005). Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine-Part 10: Fusion following decompression in patients with stenosis without spondylolisthesis. Journal of Neurosurgery, 2(6): 686-691.

• Spengler DM, ed. (2005). Lumbar spinal stenosis. In LY Griffin, ed., Essentials of Musculoskeletal Care, 3rd ed., pp. 774-777. Rosemont, IL: American Academy of Orthopaedic Surgeons.

• Weinstein JN, et al. (2007). Surgical versus nonsurgical treatment for lumbar degenerative spondylolisthesis. New England Journal of Medicine, 356(22): 2257-2270.

• Zucherman JF, et al. (2005). A multicenter, prospective, randomized trial evaluating the X STOP interspinous process decompression system for the treatment of intermittent claudication. Spine, 30(12): 1351-1358.

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