Spinal stenosis is a narrowing of space inside the spine that may compress the spinal cord or nerve roots. It typically develops later in life as a result of degenerative changes in the spine that occur with aging.

People with spinal stenosis may experience a variety of symptoms. Some patients have cramping, pain or numbness in their legs, back, neck, shoulders or arms. Others have problems with bladder or bowel function.

Methods of diagnosing spinal stenosis include imaging tests such as MRI.

Treatment options may include exercise, physical therapy, medications, injection therapy or nonsurgical spinal decompression. In more serious cases, a physician may recommend spine surgery to create more space for the spinal cord or nerves.

Spinal stenosis is a condition in which one or more areas of the spine narrow, pressuring the spinal cord or the roots of the nerves that branch off it. This impingement causes pain and other symptoms for many patients.

The spine is made up of 33 bones (vertebrae) held together by fibrous bands (ligaments). There are seven cervical vertebrae in the neck and 12 thoracic vertebrae in the middle of the back. The five large lumbar vertebrae in the lower back carry most of the body’s weight. Below the lumbar vertebrae are the sacrum, made from five fused vertebrae, and the coccyx (tailbone). Together, these bones are referred to as the spine, spinal column or vertebral column.

The spine supports the upper body’s weight. It also houses and protects the spinal cord, which along with the brain forms the central nervous system. The spinal cord is made up of nerves and nerve cells that extend the length of the spine. Thirty-one pairs of nerves branch off from the spinal cord and transmit electrical signals between the brain and the nerves in the legs, arms and other areas of the body. The spinal cord extends from the base of the brain to just below the rib cage. A bundle of nerves known as the cauda equina continues from the lumbar region, where the spinal cord ends, and downward. This provides neurologic function to the lower part of the body.

Spinal stenosis is a result of a narrowing of the spine that puts pressure on the spinal cord or nerve roots. It is categorized as one of the following two varieties:

• Primary stenosis. Relatively uncommon, it is the result of congenital disorders (those present at birth), such as being born with a narrow spinal canal.
  
  
• Acquired stenosis. Develops later in life, usually as a result of degenerative changes in the spine that occur with aging. This is the more common source of stenosis.

Spinal stenosis may affect a large or small portion of the spine. It tends to affect one or more of three areas:

• The canal in the center of the spinal column through which the spinal cord and nerve roots run
  
  
• The canals at the base or root of nerves that branch out from the spinal cord
  
  
• The openings between the vertebrae through which the nerves leave the spine on their way to other parts of the body

The spinal degeneration associated with acquired stenosis usually results from aging. Most patients are men and women age 50 or older. As people age, the ligaments of their spine thicken and calcify. This loss of elasticity may shorten the spine, narrowing the spinal canal and compressing the nerve roots.

Aging also contributes to deterioration of the intervertebral discs, which separate vertebrae and act as “shock absorbers.” Wear and tear on the discs, such as from degenerative disc disease, can cause one lumbar vertebra to slip over another, a condition known as spondylolisthesis. This compresses the spinal nerve, leading to numbness, tingling and weakness in the legs when a person walks or stands for long periods of time.

As the intervertebral discs become flatter and more brittle with age, the interior jelly-like substance may poke through the tough, fibrous coating, a condition known as a herniated disc. This may put pressure on the nerves or spinal cord, resulting in spinal stenosis, which may cause excruciating pain.

In addition, aging can cause bones and joints to become larger, and a form of arthritis known as osteoarthritis may leave the body even more vulnerable to spinal stenosis. Osteoarthritis affects the cartilage that cushions the ends of the bones in the joints. Over time, the cartilage deteriorates and the smooth surface becomes rough. If bone rubs against bone, pain results.

 Other sources of narrowing of the spine include:

• Spinal tumor. A mass of abnormal cells can occur inside the spinal cord, within the membranes (meninges) that cover the spinal cord or in the space between the spinal cord and vertebrae. In addition, cancer can spread (metastasize) to the spine from other parts of the body, such as the prostate gland or breasts. These tumors may compress the spinal cord or nerve roots, causing severe back pain that may extend down through the hips, legs or feet. Some patients may also experience muscle weakness and loss of sensation, difficulty walking or paralysis, and loss of bladder or bowel function.
  
  
• Injury. Car accidents or other trauma can dislocate the spine or spinal canal, pressuring the spinal cord and the lower motor neurons. In some cases the spinal cord is partly or completely severed. Spinal fractures can cause fragments of bone to penetrate the spinal canal. Swelling of tissue after back surgery can also put pressure on the spinal cord or nerves.

• Paget’s disease. Although bone seems tough and inanimate, it is a living tissue in which old bone is constantly removed and replaced with new bone. Patients with Paget’s disease have bone that is generated at a faster-than-normal rate. This can create abnormally large bones in the spine that may compress the spinal cord or nerve roots, resulting in excruciating pain that may radiate down into the legs. Some patients also experience numbness, tingling or weakness in the legs, or double vision.
  
  
• Scoliosis. An abnormal sideways curvature of the spine, scoliosis can cause arthritis and structural changes such as stenosis.

• Achondroplasia. This genetic disorder slows the rate of bone formation during fetal development and in early childhood. Patients with this condition have a shorter stature, including a smaller spinal canal that pressures the spinal cord. This can cause severe back and leg pain and paralysis of the legs. Babies and children with achondroplasia may die suddenly from compression of the upper end of the spinal cord that interferes with breathing.
  
  
• Ossification of the posterior longitudinal ligament. This condition occurs when calcium deposits turn fibrous tissue into bone on the ligament running up and down the spine inside the spinal canal. These deposits may cause pain if they press on the nerves of the spinal canal. 
  
  
• Skeletal fluorosis. This disease is caused by high levels of fluoride in the body, which can cause immobilization of the spine and joints. This makes any kind of movement painful. Skeletal fluorosis usually results from long-term inhalation of industrial dusts or gases contaminated with fluorides, long-term consumption of water containing large amounts of fluoride and accidental ingestion of insecticides that contain fluoride. It is rare in the United States. 

In some cases, spinal stenosis does not cause any symptoms. However, it is more likely that patients will experience gradual symptoms that will worsen over time. These may include:

• Leg pain or cramping in the legs. Compression of nerves or spinal cord in the lower spine may lead to a condition known as neurologic intermittent claudication, more commonly known as pseudoclaudication. Pseudoclaudication triggers pain or cramping in the legs of those who walk or stand for extended periods of time.
  
  Patients with pseudoclaudication usually find that bending forward relieves symptoms, as this takes pressure off the nerves. Unlike true (vascular) claudication, a common pain symptom caused by constriction of blood vessels in the leg (typically due to peripheral arterial disease), at least 20 minutes of rest rather than a few minutes may be required to ease leg pain caused by spinal stenosis.
  
  
• Sciatic nerve pain (sciatica). Discomfort that radiates down the back, hip and into the leg. This is usually the result of a herniated disc pressuring the sciatic nerve, which extends down the back of each leg. For most patients, pain usually affects just one leg and worsens during sitting. In addition to pain, patients may experience numbness, weakness and tingling in the leg or foot.

• Neck pain and shoulder pain. Occurs when the nerves or spinal cord of the neck are compressed and may occur either occasionally or chronically. In some patients, pain extends into the arm or hand and can cause headaches, loss of sensation or muscle weakness.

Patients who experience unexplained pain, stiffness, numbness or weakness in the back, legs, neck or shoulders should seek medical care. Spinal stenosis is especially likely when a patient has leg pain that worsens during walking but improves when sitting or bending forward.

Sudden inability to control bladder or bowel movements (incontinence) is a sign of cauda equina syndrome, a serious but rare form of spinal stenosis in which there is compression of the sack of nerve roots below the spinal cord. This condition demands immediate medical attention to prevent neurological damage.

In diagnosing spinal stenosis, a physician will review a medical history and perform a physical examination. Spinal stenosis is sometimes difficult to diagnose, as symptoms may come and go. In addition, symptoms associated with spinal stenosis can sometimes be mistaken for those of routine aging. The patient may be asked to complete a pain assessment.

Spinal stenosis is sometimes difficult to diagnose, as symptoms may come and go. In addition, symptoms associated with spinal stenosis can sometimes be mistaken for those of routine aging. A physician may therefore use various imaging tests to identify the source of symptoms. These tests include:

• X-ray. Though this test is unlikely to reveal spinal stenosis, it can help rule out other conditions that cause similar symptoms, including fractures, bone tumors or inherited defects.
  
  
• MRI (magnetic resonance imaging). The cross-sectional images revealed by this test can highlight damage to intervertebral discs and ligaments, and uncover the presence of tumors.

• CAT scan (computed axial tomography). Producing cross-sectional x-ray images, CAT scans may be used to reveal the shape and size of the spinal canal. However, this test exposes patients to more radiation than an x-ray and is not recommended for women who are pregnant.
  
  
• Myelography. Perhaps the most sensitive test for detecting spinal stenosis, it involves injecting a contrast dye into the spinal column that circulates around the spinal cord and spinal nerves. Myelograms can reveal herniated discs, bone spurs and tumors. However, because the test requires an injection into the spinal column, it poses slightly higher risks than some other procedures.
  
  
• Bone scan. A small amount of radioactive material is injected into a vein in the arm. The material attaches to bone and emits waves of radiation that are detected by a gamma camera. This type of radionuclide imaging can detect many bone disorders but usually cannot specify the type of disorder. For this reason, other tests are usually performed with bone scans to help diagnose bone conditions.

In some cases, a physician may inject a patient with a spinal nerve block or epidural corticosteroids. The patient is monitored for improvement in symptoms.

The degenerative process that leads to spinal stenosis generally cannot be treated. However, nonsurgical and surgical treatments can relieve the nerve compression that leads to pain suffered by those with spinal stenosis.

Nonsurgical treatments include:

• Over-the-counter medications. Nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen or naproxen can reduce inflammation and pain. Analgesics such as acetaminophen relieve pain but do not reduce inflammation.
  
  Supplements such as glucosamine and chondroitin have been shown to have a positive effect for pain relief in some cases of moderate to severe knee osteoarthritis. However, it is not known whether this benefit extends to osteoarthritis of the spine. As with all medications, patients should consult with a physician before using these supplements.
  
  

  

• Moderate exercise or rest. Moderate rest may improve symptoms but should not be overdone. Research shows that moderate exercise is even more beneficial to symptom relief. Walking can especially benefit patients with neurogenic claudication (pseudoclaudication). Biking may also be beneficial, as it keeps the back in a flexed rather than extended position. Patients may be referred to physical therapy for supervised exercise and for pain-relieving modalities such as thermotherapy (heat), hydrotherapy or electrical therapy.
  
  
• Back brace or corset. This can provide support to the spine, and may particularly benefit patients who have weak abdominal muscles or degeneration in more than one area of the spine.
  
  
• Nonsurgical spinal decompression. The U.S. Food and Drug Administration has approved systems in which the patient lies on a special mechanical table designed to relieve pressure on the discs. A patient may have sessions of up to an hour most days of the week for several weeks to relieve conditions such as spinal stenosis, herniated discs or sciatica. But more research is needed on this modality at this point.
  
  
• Injection therapy. Anesthetic injections, also known as nerve blocks, can be used near affected nerves to temporarily relieve pain. With epidural corticosteroid injections, the medication is injected into the spinal fluid around the spinal cord and nerve roots. Corticosteroids suppress inflammation and may be especially beneficial in treating pain that radiates down the back of the leg. However, they must be taken in limited doses to avoid potentially serious side effects, such as osteoporosis. In patients who are not candidates for surgery or do not want surgery, sometimes having epidural steroid injections at reasonable intervals may be the best option.  

In some cases, spine surgery will be necessary to address spinal stenosis. The goal of surgery is to relieve pressure on the spinal cord or nerves while maintaining the integrity and strength of the spine. Examples of surgery include:

• Decompressive laminectomy. Removal of the back part of the bony arch over the spinal canal (lamina) to open more space for the spinal nerves. This procedure also allows the surgeon to access bone spurs or herniated discs that may be removed. In some cases, the procedure is performed through a single incision. In other instances, it may be performed though a series of small incisions in a technique known as laparoscopy (similar to arthroscopy).
  
  
• Laminotomy. Partial removal of the lamina to remove or relieve pressure to allow access to a disc or bone spur that is pressing on a nerve.

Risks associated with laminectomy and laminotomy include infection, a tear in the membrane that covers the spinal cord (the dura), bleeding, a blood clot in a leg vein, decreased intestinal function (paralytic ileus) and neurologic deterioration.

Fusion is another form of surgery used to treat spinal stenosis. In this procedure, two or more vertebrae are permanently connected. It is often used when stenosis causes one vertebra to slip over another. The extra bone may come from a bone bank or from the patient’s own body. A section of pelvic bone is often used when the patient is a self-donor.

Surgery can help relieve pressure in the spine, but patients frequently continue to feel pain for weeks or months after the procedure. In addition, surgery does not halt the degenerative process, and patients may find that their symptoms return within a few years.

In many cases, successful treatment of spinal stenosis will be followed or accompanied by physical therapy. Such treatments can increase strength and endurance, and help maintain the flexibility and stability of the spine. Occupational therapy can benefit patients who have difficulty performing daily tasks. 

The age-related changes to the back that are the primary cause of spinal stenosis cannot be fully prevented. However, people can take various steps to keep their spine and joints healthy for as long as possible. These include:

• Regular exercise. A combination of aerobic activities, weight training and stretching can help maintain strength and flexibility in the spine, joints and ligaments. Stronger abdominal muscles and limbs take stress off of the back. People are generally advised to aim for at least 30 minutes of moderate exercise on most days. However, a person should consult a physician before starting an exercise program.
  
  
• Proper body mechanics. Good posture and ergonomics can relieve the pressure on the back. When standing, maintain the pelvis in a neutral position. When lifting heavy objects, bend at the knees and hips and keep the back straight. Hold objects close to the body while carrying them.
  
  When sitting, choose a seat with good lower back support, arm rests and a swivel base. A rolled-up towel or pillow in the small of the back can help maintain the spine’s normal curve. Keep knees and hips level. Also, sleep on a medium-firm mattress. Recent studies indicate that sleeping on such a mattress is better for the back than sleeping on a firm mattress. Pillows can also offer good support, but only if they do not force the neck up at a severe angle.
  
  
• Maintain a healthy weight. Excessive weight puts additional stress on the joints and bones.

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about spinal stenosis:

1. What exactly happens to my body during spinal stenosis?
   
   
2. What symptoms of spinal stenosis might I experience?
   
   
3. Are some symptoms more serious for me than others?
   
   
4. What tests might I need, and what do they involve?
   
   
5. What is the difference between primary spinal stenosis and acquired spinal stenosis? Which form do I have?
   
   
6. What is the expected course of my condition? 
   
   
7. What are my treatment options, and how do their risks and benefits compare?
   
   
8. Could I need surgery if conservative approaches fail?
   
   
9. Are there ways I can prevent the damage associated with spinal stenosis?
   
   
10. Are there any exercises I can or other measures I can take do to prevent spinal stenosis?