Spinal stenosis is narrowing of the spinal canal. This can
develop as you age from drying out and shrinking of the disk spaces. (80% of the disks are
made up of water) If this happens, even a minor injury can cause inflammation of the disk
and put pressure on the nerve. You can feel pain anywhere along your back or leg(s) that
this nerve supplies.
Information about Spinal Stenosis
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
and/or the spinal cord itself.
Spinal stenosis is a progressive narrowing of the opening in the spinal canal. The
spine is a long series of bones called vertebrae. Between each pair of vertebra is a
fibrous intervertebral disk. Collectively, the vertebrae and disks are called the
backbone. Each vertebra has a hole through it. These holes line up to form the spinal
canal. A large bundle of nerves called the spinal cord runs through the spinal canal. This
bundle of 31 nerves carries messages between the brain and the various parts of the body.
At each vertebra, some smaller nerves branch out from these nerve roots to serve the
muscles and tissue in the immediate area. When the spinal canal narrows, nerve roots in
the spinal cord are squeezed. Pressure on the nerve roots causes chronic pain and loss of
control over some functions because communication with the brain is interrupted. The lower
back and legs are most affected by spinal stenosis. The nerve roots that supply the legs
are near the bottom of the spinal cord. The pain gets worse after standing for a long time
and after some forms of exercise. The posture required by these physical activities
increases the stress on the nerve roots. Spinal stenosis usually affects people over 50
years of age. Women have the condition more frequently than men do.
Cervical spinal stenosis is a narrowing of the vertebrae of the neck (cervical
vertebrae). The disease and its effects are similar to stenosis in the lower spine. A
narrower opening in the cervical vertebrae can also put pressure on arteries entering the
spinal column, cutting off the blood supply to the remainder of the spinal cord.
Symptoms of Spinal Stenosis
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
Back pain that radiates to the legs
Weakness of the legs
Difficulty or imbalance when walking
Spinal stenosis causes pain in the buttocks, thigh, and calf and increasing weakness in
the legs. The patient may also have difficulty controlling bladder and bowel functions.
The pain of spinal stenosis seems more severe when the patient walks downhill. Spinal
stenosis can be congenital, acquired, or a combination. Congenital spinal stenosis is a
birth defect. Acquired spinal stenosis develops after birth. It is usually a consequence
of tissue destruction (degeneration) caused by an infectious disease or a disease in which
the immune system attacks the body's own cells (autoimmune disease). The two most common
causes of spinal stenosis are birth defect and progressive degeneration of the tissue of
the joints (osteoarthritis). Other causes include improper alignment of the vertebrae as
in spondylolisthesis, destruction of bone tissue as in Paget's disease, or an overgrowth
of bone tissue as in diffuse idiopathic skeletal hyperostosis. The spinal canal is usually
more than 11.5 millimeters in diameter. A smaller diameter indicates stenosis. The
diameter of the cervical spine ranges is 15-25 millimeters. Any opening under 13
millimeters in diameter is considered evidence of stenosis. Acquired spinal stenosis
usually begins with degeneration of the intervertebral disks or the surfaces of the
vertebrae or both. In trying to heal this degeneration, the body builds up the spinal
column. In the process, the spinal canal can become narrower.
Diagnosis of Spinal Stenosis
The physician must determine that the symptoms are caused by spinal stenosis.
Conditions that can cause similar symptoms include a slipped (herniated) intervertebral
disk, spinal tumors, and disorders of the blood flow (circulatory disorders). Spinal
stenosis causes back and leg pain. The leg pain is usually worse when the patient is
standing or walking. Some forms of spinal stenosis are less painful when the patient is
riding an exercise bike because the forward tilt of the body changes the pressure in the
spinal column. Doppler scanning can trace the flow of blood to determine whether the pain
is caused by circulatory problems. X-ray images, computed tomography scans (CT scans), and
magnetic resonance imaging (MRI) scans can reveal any narrowing of the spinal canal. Electromyography, nerve conduction
velocity, or evoked potential studies can locate problems in the muscles indicating areas
of spinal cord compression.
Treatment of Spinal Stenosis
Mild cases of spinal stenosis may be treated with rest, nonsteroidal anti-inflammatory
drugs (such as aspirin) and muscle relaxants. Spinal stenosis can be a progressive
disease, however, and the source of pressure may have to be surgically removed (surgical
decompression) if the patient is losing control over bladder and bowel functions. The
surgical procedure removes bone and other tissues that have entered the spinal canal or
put pressure on the spinal cord. Two vertebrae may be fused, to eliminate improper
alignment, such as that caused by spondylolisthesis. For surgery, patients lie on their
sides or in a modified kneeling position. This position reduces bleeding and places the
spine in proper alignment. Alignment is especially important if vertebrae are to be fused.
Surgical decompression can eliminate leg pain and restore control of the legs, bladder,
and bowels, but usually does not eliminate lower back pain. Physical therapy and massage
can help reduce the symptoms of spinal stenosis. An exercise program should be developed
to increase flexibility and mobility. A brace or corset may be worn to improve posture.
Activities that place stress on the lower back muscles should be avoided.
Prognosis of Spinal Stenosis
Surgical decompression does not stop the degenerative processes that cause spinal
stenosis, and the condition can develop again. Nevertheless, most patients achieve good
results with surgical decompression. The patient will probably continue to have lower back
pain after the surgical procedure.