Spinal stenosis

Definition    Return to top

Spinal stenosis is a narrowing of the lumbar (back) or cervical (neck) spinal canal, which causes
compression of the nerve roots.

Causes, incidence, and risk factors    Return to top

Spinal stenosis mainly affects middle-aged or elderly people. It may be caused by osteoarthritis
or Paget's disease or by an injury that causes pressure on the nerve roots or the spinal cord itself.

Symptoms    Return to top

 Pain in the buttocks, thighs or calves that is worse with walking or exercise
 Numbness in the buttocks, thighs or calves, that is worse with standing, walking or
exercise
 Back pain that radiates to the legs
 Weakness of the legs
 Neck pain
 Leg pain
 Difficulty or imbalance when walking

Signs and tests    Return to top

An examination of reflexes of lower legs reveals asymmetry. Neurologic examination confirms leg
weakness and decreased sensation in the legs.

 X-ray of the spine shows degenerative changes and narrowed spinal canal.
 Spinal MRI or spinal CT scan shows spinal stenosis.
 EMG may show active and chronic neurological changes.

Treatment    Return to top

Generally, conservative management is encouraged. This involves the use of anti-inflammatory

medications, other pain relievers, and possibly steroid injections. If the pain is persistent and does
not respond to these measures, surgery is considered to relieve the pressure on the nerves.

Surgery is performed on the neck or lower back, depending on the site of the nerve compression.

Expectations (prognosis)    Return to top

If the nerve roots can be successfully relieved of pressure, the symptoms will not worsen and
may improve.

Complications    Return to top

Injury can occur to the legs or feet due to lack of sensation; infections may progress because pain
related to them may not be felt. Changes caused by nerve compression may be permanent, even
if the pressure is relieved.
 Spinal stenosis
ARTICLE SECTIONS

 Introduction  Screening and diagnosis

  Complications
Signs and symptoms
 Treatment
 Causes
 Risk factors  Prevention

 When to seek medical

advice

Causes

Knowing more about the anatomy of your spine makes it easier to understand how spinal stenosis

Knowing more about the anatomy of your spine makes it easier to understand how spinal stenosis develops
and how it can lead to various problems. The main parts of the spine include:

 Vertebrae. Your spine is made up of 24 bones stacked on top of one another, plus the sacrum
and tailbone (coccyx). Most adults have seven vertebrae in the neck (cervical vertebrae), 12 at the
back wall of the chest (thoracic vertebrae) and five vertebrae at the inward curve of the lower back
(lumbar vertebrae). The sacrum consists of five fused vertebrae between the hip bones. The tailbone
is composed of three to five fused bones at the very end of the spine.

 Ligaments. These tough, elastic bands of tissue help keep the vertebrae in place when you
move.
 Intervertebral disks. These elastic pads of cartilage separate the vertebrae. They keep your
spine flexible and act as shock absorbers to cushion the vertebrae when you move. Each disk
consists of a ring of tough fibrous tissue (annulus fibrosis) surrounding a jelly-like center (nucleus
pulposus).
 Facet joints. Located on the sides, top and bottom of each vertebra, these joints connect the
vertebrae to one another and stabilize the spine while still allowing flexibility. The joints are coated
with a lubricant so that they slide smoothly.
 Spinal cord. This long bundle of nerves extends from the brain stem at the base of your skull to
the second lumbar vertebra in your lower back. When the spinal cord ends, another group of nerves
(cauda equina) continues down the spinal canal.

The nerves within the spinal cord (upper motor neurons) carry messages between your brain and the
nerves that go to all the parts of your body below your head. Two spinal nerves — one leading to the
right side of your body and one to the left side — extend out from the spinal cord between each
vertebra. The nerves exit through openings on either side of the vertebrae (intervertebral foramina).

In all, there are 31 pairs of spinal nerves in your neck and back. Some transmit information from your
body to your brain, and others send messages from your brain to your muscles, skin and other
organs.

 Spinal canal. The spinal cord passed through this channel in your spine. Normally, the spinal
canal is spacious enough to accommodate the spinal cord, but degenerative changes in the spine
can narrow the channel.

How spinal stenosis develops

Doctors categorize stenosis as either primary or acquired. Primary stenosis, which is relatively uncommon,
is present at birth. But most people have acquired spinal stenosis, which develops later in life, usually as a
result of degenerative changes in the spine that occur with aging.

The main cause of spinal degeneration is osteoarthritis, an arthritic condition that affects the cartilage that
cushions the ends of bones in your joints. With time, the cartilage begins to deteriorate and its smooth
surface becomes rough. If it wears down completely, bone may rub painfully on bone. In an attempt to repair
the damage, your body may produce bony growths called bone spurs. When these form on the facet joints in
the spine, they narrow the spinal canal.

Other factors that can cause a narrowing of the spinal canal include:

 Herniated disk. By the time you're 30, your disks may start to show signs of deterioration. They
begin to lose their water content, becoming flatter and more brittle. Eventually, the tough, fibrous
outer covering of the disk may develop tiny tears, causing the jelly-like substance in the disk's center
to seep out (herniation or rupture). The herniated disk presses on the surrounding nerves, causing
pain in your back, leg or both. Sometimes you may also have numbness, tingling or weakness in the
buttock, leg or foot on the affected side.

 Ligament changes. Ligaments in your back can undergo degenerative changes, becoming stiff
and thick over time. This loss of elasticity may shorten the spine, narrowing the spinal canal and
compressing the nerve roots.

Sometimes wear and tear on the disks and ligaments cause one lumbar vertebra to slip over another
— a condition called spondylolisthesis. This often compresses the spinal nerves, leading to
numbness, tingling and weakness in your legs, especially when you stand for long periods or when
you walk.

 Spinal tumors. In the spine, abnormal growths can form inside the spinal cord, within the
membranes (meninges) that cover the spinal cord, or in the space between the spinal cord and the
vertebrae — the most common site.

Tumors may also spread (metastasize) to the spine or the spinal cord from other parts of the body.
Primary or metastastic tumors can occur anywhere along the spine, including the sacrum and
thoracic spine, where osteoarthritis is rare.

Growing tumors may compress the spinal cord and nerve roots. This can cause severe back pain
that may extend to your hips, legs or feet; muscle weakness and a loss of sensation — especially in
your legs; difficulty walking or even paralysis; and sometimes loss of bladder or bowel function.

 Injury. Car accidents and other trauma can profoundly affect the spine and spinal cord.
Sometimes the spine or spinal canal may be dislocated, putting pressure on the cord and lower
motor neurons. In other cases, fragments of bone from a spinal fracture may penetrate the spinal
canal. Swelling of tissue after back surgery can also put pressure on the spinal cord or nerves.

 Paget's disease of bone. Bone is living tissue engaged in a continuous process of renewal.
During this remodeling process, old bone is removed and replaced by new bone. In Paget's disease,
your body generates new bone at a faster-than-normal rate. This produces soft, weak bones that are
prone to fractures. It can also create bones that are deformed or abnormally large.

When unusually large bones develop in the spine, they compress the spinal cord or the nerves
exiting your brain and spinal cord. The resulting pain is often severe and may radiate from your lower
back into your legs. You also may experience numbness, tingling or weakness in the legs or, in some
cases, double vision.

 Achondroplasia. This genetic disorder slows the rate at which bone forms during fetal
development and in early childhood. As a result, people with achondroplasia are of short stature —
often no more than four feet tall when fully grown. They often have small hands and fingers and
 unusually short upper arms and thighs. They also have a narrow spinal canal, which puts pressure
on the spinal cord.

This can cause severe back and leg pain and may even lead to paralysis of the legs. In some cases,
babies or children with achondroplasia die suddenly — often in their sleep — when compression of
the upper end of the spinal cord interferes with their breathing.

Signs and symptoms

Spinal narrowing doesn't always cause problems. But if the narrowed areas compress the spinal cord or
spinal nerves, you're likely to develop signs and symptoms. These often start gradually and grow worse over
time. The most common include:

 Pain or cramping in the legs. Compressed nerves in your lower spine can lead to a condition
called pseudoclaudication, false claudication or neurogenic intermittent claudication, which causes
pain or cramping in your legs when you stand for long periods of time or when you walk. The
discomfort usually eases when you bend forward or sit down, but it continues if you stand upright.

Another type of intermittent claudication (vascular claudication) occurs when there's a narrowing or
blockage in the arteries in the legs.

Although both types of claudication cause similar symptoms, they differ in two important ways:
Vascular claudication becomes worse when you walk uphill and improves when you stand still.
Pseudoclaudication is usually worse when going downhill and gets better when you lean forward or
sit down.

 Radiating back and hip pain. A herniated disk can compress nerves in your lumbar spine,
leading to pain that starts in your hip or buttocks and extends down the back of your leg. The pain is
worse when you're sitting and generally affects only one side.

You also may experience numbness, weakness or tingling in your leg or foot. For some people, the
radiating pain is a minor annoyance, but for others, it can be debilitating.

 Pain in the neck and shoulders. This is likely to occur when the nerves in your neck are
compressed. The pain may occur only occasionally or it may be chronic, and it sometimes can
extend into your arm or hand. You also may experience headaches, a loss of sensation or muscle
weakness.

 Loss of balance. Pressure on the cervical spinal cord can affect the nerves that control your
balance, resulting in clumsiness or a tendency to fall.
 Loss of bowel or bladder function (cauda equina syndrome). In severe cases, nerves to the
bladder or bowel may be affected, leading to partial or complete urinary or fecal incontinence. If you

Risk factors

Age is the main known risk factor for spinal stenosis.

Also at risk are people with skeletal fluorosis, a sometimes crippling bone disease caused by high levels of
fluoride in the body. Although the disease is rare in the United States, several million people worldwide have
severe skeletal fluorosis.

Screening and diagnosis

Spinal stenosis can be difficult to diagnose because its signs and symptoms are often intermittent and
because they resemble those of many age-related conditions. To help diagnose spinal stenosis and rule out
other disorders, your doctor will ask about your medical history and perform a physical exam that may
include checking your peripheral pulses, range of motion, and leg reflexes.

You are also likely to have one or more of the following tests:

 Spinal X-ray. Although an X-ray isn't likely to confirm that you have spinal stenosis, it can help
rule out problems that cause similar symptoms, including a fracture, bone tumor or inherited defect.

 Magnetic resonance imaging (MRI). In many cases, this is the imaging test of choice for
diagnosing spinal stenosis. Instead of X-rays, an MRI uses a powerful magnet and radio waves to
produce cross-sectional images of your back. The test can detect damage to your disks and
ligaments, as well as the presence of tumors.
 Computerized tomography (CT) scan. This test uses a narrow beam of radiation to produce
detailed, cross-sectional images of your body, including the shape and size of your spinal canal.
Because you receive more radiation from a CT scan than from a regular X-ray, you should avoid this
test if you're pregnant.
 CT myelogram. This may be the most sensitive test for detecting spinal stenosis, but because it
poses more risks than either MRI or CT, it may not be your doctor's first choice. If you're
contemplating surgery, however, your doctor may recommend a CT myelogram to assess the
severity of the stenosis. In a myelogram, a contrast dye is injected in your spinal column. The dye
then circulates around your spinal cord and spinal nerves. A myelogram can show herniated disks,
bone spurs and tumors.
 Bone scan. In this test, a small amount of a radioactive material that attaches to bone is injected
into vein in your arm. The material emits waves of radiation that are detected by a gamma camera.
The camera then produces images of your bones. In a sense, a bone scan is the opposite of a
standard X-ray, in which radiation passes through your body to create an image on film. A bone scan
can detect a number of bone disorders, but often can't distinguish among them. For that reason, it's
usually performed with other tests.
 Other diagnostic procedures. Sometimes your doctor may inject you with a spinal nerve block
or epidural steroids. If your symptoms improve after the injection, spinal stenosis is likely the cause of
your discomfort. The problem with this approach is that a negative finding doesn't mean you don't
have spinal stenosis.

Complications

Depending on which nerves are compressed, spinal stenosis may cause a loss of feeling in your arms,
hands, feet or legs. As a result, cuts or wounds may become seriously infected because you're not aware of
them. In addition, spinal stenosis sometimes interferes with bowel or bladder function — a problem that can
affect your quality of life.

Although treatment can relieve symptoms of spinal stenosis, it doesn't stop degenerative changes. Some of
these changes, such as muscle atrophy, may be permanent, even after the pressure is relieved.

Treatment

Many people with spinal stenosis can be effectively treated with conservative measures. But if you have
disabling pain or your ability to walk is severely impaired, your doctor may recommend spinal surgery. Acute
loss of bowel or bladder function is usually considered a medical emergency and requires immediate
surgical intervention.

Nonsurgical treatments
Before considering surgery, your doctor is likely to recommend trying one or more of the following for at least
three months:

 Nonsteroidal anti-inflammatory drugs (NSAIDs). These include over-the-counter and

prescription medications such as aspirin, ibuprofen (Advil, Motrin, others) or indomethacin (Indocin)
to reduce inflammation and pain. Although they can provide real relief, NSAIDs have a "ceiling effect"
— that is, there's a limit to how much pain they can control.

If you have moderate to severe pain, exceeding the recommended dosage won't provide additional
benefits. What's more, NSAIDS can cause serious side effects, including stomach ulcers that may
bleed. If you take these medications, talk to your doctor so that you can be monitored for problems.

 Analgesics. This group of pain relievers includes acetaminophen (Tylenol, others). Analgesics
don't reduce inflammation, but they can effectively treat pain. Yet chronic overuse of acetaminophen
can cause kidney and liver damage. Drinking alcohol increases your risk of serious side effects.

 Nonproprietary drugs. Nonprescription supplements such as chondroitin sulfate and

glucosamine, either alone or in combination, have shown positive effects on osteoarthritis. But it's not
yet known whether they're effective at treating or preventing osteoarthritis of the spine. Talk to your
doctor if you're interested in these supplements — they may interfere with other medications you're
taking, especially warfarin (Coumadin).
 Rest or restricted activity. Moderate rest followed by a gradual return to activity may improve
symptoms. Walking is usually the best exercise, especially for people with neurogenic claudication,
but biking is also recommended because it keeps your back in a flexed position rather than in an
extended one.
 Physical therapy. Working with a physical therapist can build up your strength and endurance
and help maintain the flexibility and stability of your spine.
 A back brace or corset. This helps provide support and may especially benefit people who have
weak abdominal muscles or degeneration in more than one area of the spine.
 Epidural steroid injections. In some cases, your doctor may inject a corticosteroid medication
into the spinal fluid around your spinal cord and nerve roots.

Corticosteroids suppress inflammation and can be especially helpful in treating pain that radiates
down the back of your leg — in fact, a single dose may provide significant relief. But because
corticosteroids can cause a number of serious side effects, the number of injections you can receive
is limited, usually to no more than three in one year.

Surgery
The goal of surgery is two-fold: to relieve pressure on the spinal cord or nerves, and to maintain the integrity
and strength of your spine. This can be accomplished in several ways, depending on the cause of the
problem. The most common surgical procedures include:

 Decompressive laminectomy. In this procedure, your surgeon removes all of the lamina — the
back part of the bone over the spinal canal — to create more space for the nerves and to allow
access to bone spurs or ruptured disks that may also be removed. A laminectomy is often performed
through a single incision in your back (open surgery), although in some cases, your surgeon may use
a laparoscopic technique. In that case, a tiny camera and surgical instruments are inserted through
several small incisions, and your surgeon views the operation on a video monitor.

Laparoscopic back surgery is complex and requires great skill and is not appropriate for many people
with spinal stenosis. When done properly, however, you're likely to have less pain and to recover
from surgery more quickly with this technique. Risks of laminectomy include infection, a tear in the
membrane that covers the spinal cord at the site of the surgery, bleeding, a blood clot in a leg vein,
decreased intestinal function (paralytic ileus) and neurological deterioration.
  Laminotomy. In this procedure, just a portion of the lamina is removed to relieve pressure or to
allow access to a disk or bone spur that's pressing on a nerve. The risks are the same as for
laminectomy.

 Fusion. This procedure may be performed on its own or at the same time as laminectomy. It's
used to permanently connect (fuse) two or more vertebral bones in your spine and may be especially
indicated when one vertebra slips over another. To fuse the spine, small pieces of extra bone are
needed to fill the space between two vertebrae. This may come from a bone bank or from your own
body, usually your pelvic bone. Wires, rods, screws, metal cages or plates also may be used,
especially if your spine is unstable or the operation takes place to correct a deformity.

Back surgery can relieve pressure in your spine, but it's not a cure-all. You may have considerable pain
immediately after the operation, and you might continue to have pain for a period of time. For some people,
recovery can take weeks or months and may require long-term physical therapy. What's more, surgery won't
stop the degenerative process, and symptoms may return — sometimes within just a few years.

When to seek medical advice

Many people ignore the symptoms of spinal stenosis, believing that the pain and stiffness they experience
are a normal part of aging. But discomfort, especially if it interferes with your mobility, is never normal. Seek
medical advice if you have pain, stiffness, numbness or weakness in your back, legs, neck or shoulders
that's not related to exercise or overexertion.

Spinal stenosis is especially likely if you have leg pain that gets worse when you walk and improves when
you sit or bend forward. Get immediate care if you suddenly have trouble controlling your bowels or bladder.

Prevention

You can't always prevent age-related changes in your back, but the following steps can help keep your
spine and joints as healthy as possible:

 Exercise regularly. This helps maintain strength and flexibility in your spine, joints and ligaments.
For the best results, combine aerobic activities such as walking and biking with weight training and
stretching. Toning and stretching before exercise can help reduce wear and tear on your back. It also
reduces your risk of injury by warming up your muscles and increasing your flexibility. Strength
training can make your arms, legs and abdominal muscles stronger, which takes stress off your back.

If you're not used to exercise, start out gradually and increase the duration and intensity of your
workout as you become stronger. Aim for at least 30 minutes of moderate exercise on most days.

 Use good body mechanics. Being conscious of how you sit, stand, lift heavy objects and even
how you sleep can go a long way toward keeping your back healthy.

To minimize stress when you sit, choose a seat that supports your lower back. If necessary, place a
pillow or a rolled towel in the small of your back to maintain its normal curve.

When you drive, adjust your seat to keep your knees and hips level, and move the seat forward to
avoid overreaching for the pedals.

Before you lift something heavy, decide where you'll place it and how you'll get there. Pushing is
safer than pulling. Always bend your knees so that your arms are level with the object. Avoid lifting
overhead.
 For the best sleep posture, choose a firm mattress. Use pillows for support, but don't use one that
forces your neck up at a severe angle.

 Maintain a healthy weight. Extra weight puts additional stress on your joints and bones.