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Lumbar spinal stenosis is a condition in which
the spinal canal is narrowed, causing the spinal cord or
spinal nerve roots to be compressed. Spinal stenosis is related to
degeneration of the spine, as the facet
joints get larger and place pressure on the nerve roots. The condition
usually affects patients over the age
of 60.
Approximately 75% of spinal stenosis cases affect the lumbar
area of the spine, and most will affect the
sciatic nerve which runs along the back of the leg. Standing upright
further decreases the space available
for the nerve roots, and can block the outflow of blood from around
the nerve. Congested blood then
irritates the nerve and the pain travels into the legs.
Symptoms
The compression of lumbar spinal stenosis can produce the
following symptoms, which radiate into the
buttocks and legs:
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Pain
-
Tingling
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Numbness
-
Weakness (rare)
These symptoms typically develop slowly over
several years (although they do occasionally come on
suddenly), they are intermittent as opposed to continuous,
they occur during certain activities and in
certain positions, and they are relieved by rest or any
flexed forward position. The most common symptom
of lumbar spinal stenosis is pain in the legs while walking,
which is relieved only by sitting and resting (not
simply by stopping walking).
The longer a patient with
spinal stenosis stands or walks the worse the leg pain will get.
Flexing forward or sitting will open up the spinal canal and relieve
the leg pain and other symptoms, but they will recur
when the patient gets back into an upright posture.
Numbness and tingling can accompany the pain.
Weakness is a rare symptom of spinal stenosis.
Diagnosis
The nerve compression of spinal stenosis will vary,
depending on the activity or position of the patient
(standing, sitting, walking). Physical examination
alone will not be enough to correctly diagnose stenosis.
Either
a Magnetic Resonance Imaging (MRI) scan or a Computed Tomography
(CT) scan with myelogram can be useful in diagnosing lumbar spinal
stenosis. Sometimes both are used. A non-enhanced CT scan
(without myelogram) is not useful in diagnosing
this condition.
A spinal stenosis at two or even three levels can
affect a single emerging nerve. If surgery is
considered, a combination of anatomical and clinical
examination is needed in order to make sure one
surgical procedure will address all contributing
components of spinal stenosis. |