Lumbar laminectomy (open decompression)
Similar to a microdecompression, a lumbar laminectomy (open decompression) is
a surgical procedure that is performed to alleviate pain caused by neural
impingement. The laminectomy surgery is designed to remove a small portion
of the bone over the nerve root and/or disc material from under the nerve root
to give the nerve root more space and a better healing environment (see Figure
1).
A laminectomy is effective to decrease pain
and improve function for patients with lumbar spinal
stenosis . Spinal stenosis is a condition
that primarily afflicts elderly patients, and is caused
by degenerative changes that result in enlargement
of the facet joints. The enlarged joints then place
pressure on the nerves, and this pressure may be effectively
relieved with a lumbar laminectomy.
Laminectomy surgical procedure
The lumbar laminectomy (open decompression) differs
from a microdiscectomy in that the incision is longer
and there is more muscle stripping.
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First, the back is approached through a two-inch
to five-inch long incision in the midline of the
back and the left and right back muscles (erector
spinae) are dissected off the lamina on both sides
and at multiple levels (see Figure
2).
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After the spine is approached, the lamina is
removed (laminectomy) which allows visualization
of the nerve roots.
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The facet joints,
which are directly over the nerve roots,
may then be undercut (trimmed) to give the nerve
roots more room.
Post-operatively,
patients are in the hospital for one to three
days, and the individual patient's mobilization
(return to normal activity) is largely dependent
on his/her pre-operative condition and age.
Directly following the procedure, patients
are encouraged to walk. However, it is recommended
that patients avoid excessive bending, lifting
or twisting for six weeks in order to avoid
pulling on the suture line before it heals.
Laminectomy success rate
The success rate of a laminectomy surgery is favorable.
Following surgery, approximately 70% to 80% of
patients will have significant improvement in their
function (ability to perform normal daily activities)
and markedly reduced level of pain and discomfort.
The laminectomy surgical results are much better
for relief of leg pain caused by spinal stenosis,
and not nearly as reliable for relief of lower
back pain. Lumbar spinal stenosis is often created
by the facet joints becoming arthritic, and much
of the back pain is from the arthritis. Although
removing the lamina and part of the facet joint
can create more room for the nerve roots it does
not eliminate the arthritis. Unfortunately, the
symptoms may recur after several years as the degenerative
process that originally produced the spinal stenosis
continues.
In certain instances the success rate of a decompression
for spinal stenosis can be enhanced by also fusing
a joint. Fusing the joint prevents the spinal stenosis
from recurring and can help eliminate pain from
an unstable segment. Fusion surgery is especially
useful if there is a degenerative spondylolisthesis
associated with the stenosis. Generally speaking,
if there is multi-level stenosis from a congenitally
shallow canal a fusion is not necessary; however,
if the stenosis is at one level from an unstable
joint (e.g. degenerative spondylolisthesis), then
a decompression surgery with a fusion is a more
reliable procedure.
Laminectomy risks and complications
The potential risks and complications with a laminectomy
procedure include:
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Nerve root damage (1 in 1,000) or
bowel/bladder incontinence (1 in
10,000). Paralysis would be extremely unusual since
the spinal cord stops at about the T12 or L1 level,
and surgery is usually done well below this level.
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1 to 3% of the time a cerebrospinal
fluid leak may be encountered if
the dural sac is breached. This does not change
the outcome of the surgery, and generally a patient
just needs to lie down for about 24 hours to allow
the leak to seal.
-
Infections happen in about 1% of
any elective cases, and although
this is a major nuisance and often requires further
surgery to clean it up along with IV antibiotics,
it generally can be managed and cured effectively.
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Bleeding is an uncommon complication
as there are no major blood vessels
in the area.
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In approximately 5 to 10% of cases,
postoperative instability of the
operated level can be encountered. This complication
can be minimized by avoiding the pars interarticularis
during surgery, as this is an important structure
for stability at a level. Weakening or cutting
this bony structure can lead to an isthmic spondylolisthesis
after surgery. Also, the natural history
of a degenerative facet joint may lead it to continue
to degenerate on its own and result in a degenerative
spondylolisthesis. Either of these conditions can
be treated by fusing the affected joint at a later
date.
General anesthetic complications such as myocardial
infarction (heart attack), blood clots, stroke,
pneumonia or pulmonary embolism can happen
with any surgery. Although in the general population
these complications are rare, laminectomy
surgery for spinal stenosis is generally done for elderly
patients and therefore the risk of general
anesthetic complications is somewhat higher.
By: Peter
F. Ullrich, Jr., MD
September 8, 1999
(Updated
March 30, 2001
and
December 18, 2003)
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