Microdiscectomy (microdecompression) spine surgery
In a microdiscectomy or a microdecompression spine
surgery, a small portion of the bone over the nerve
root and/or disc material from under the nerve root
is removed to relieve neural impingement and provide
more room for the nerve to heal. A microdiscectomy
spine surgery is typically performed for lumbar
herniated disc.
Microdiscectomy helps leg pain
A microdiscectomy surgery is actually more effective
for treating leg pain (radiculopathy) than for
lower back pain. The impingement on the nerve root
(compression) can cause substantial leg pain, and while
it may take weeks or months for the nerve root to fully
heal and any numbness or weakness get better, patients
normally feel relief from leg pain almost immediately
after a microdiscectomy surgery.
Microdiscectomy spine surgery procedure
A microdiscectomy spine surgery is performed through
a small (1 inch to 1 1/2 inch) incision in the midline
of the low back.
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First, the back muscles (erector spinae) are lifted off
the bony arch (lamina) of the spine. Since these back
muscles run vertically, they can be moved out of the
way rather than cut (see Figure
1).
-
The surgeon is then able to enter the spine
by removing a membrane over the nerve roots
(ligamentum flavum), and uses either operating
glasses (loupes) or an operating microscope
to visualize the nerve root.
-
Often, a small portion of the inside facet
joint is removed both to facilitate access
to the nerve root and to relieve pressure
over the nerve.
-
The nerve root is then gently moved to
the side and the disc material is removed
from under the nerve root.
Importantly, since almost all of the joints, ligaments
and muscles are left intact, a microdiscectomy spine
surgery does not change the mechanical structure of
the patient's lower spine (lumbar spine).
When to have microdiscectomy spine surgery
In general, if a patient's leg pain due to a disc
herniation is going to get better, it will do so in
about six to twelve weeks. As long as the pain is tolerable
and the patient can function adequately, it is usually
advisable to postpone back surgery for a short period
of time to see if the pain will resolve with conservative
(non-surgical) treatment alone.
If the leg pain does not get better with conservative
treatments, then a microdiscectomy surgery is a reasonable
option to relieve pressure on the nerve root and speed
the healing. Immediate spine surgery is only necessary
in cases of bowel/bladder incontinence (cauda equina
syndrome) or progressive neurological deficits. It
may also be reasonable to consider back surgery acutely
if the leg pain is severe.
Microdiscectomy spine surgery
is typically recommended for patients who have experienced
leg pain for at least six weeks and have not found
sufficient pain relief with conservative treatment
(such as oral steroids, NSAID's, and physical therapy).
However, after three to six months, the results of
the spine surgery are not quite as favorable, so
it is not generally advisable to postpone microdiscectomy
surgery for a prolonged period of time (more than
three to six months).
After the microdiscectomy surgery
Usually, a microdiscectomy spine surgery procedure
is performed on an outpatient basis (with no overnight
stay in the hospital) or with one overnight in the
hospital. Post-operatively, patients may return to
a normal level of daily activity quickly.
Some spine surgeons restrict a patient from bending,
lifting, or twisting for the first six weeks following
surgery. However, since the patient's back is mechanically
the same, it is also reasonable to return to a normal
level of functioning immediately following microdiscectomy
spine surgery. There have been a couple of reports
in the medical literature showing that immediate mobilization
(return to normal activity) does not lead to an increase
in recurrent lumbar herniated disc.
Microdiscectomy spine surgery success rate
The success rate for a microdiscectomy spine surgery
is approximately 90% to 95%, although 5% to 10% of
patients will develop a recurrent disc herniation at
some point in the future.
A recurrent disc herniation may occur directly after
back surgery or many years later, although they are
most common in the first three months after surgery.
If the disc does herniate again, generally a revision
microdiscectomy will be just as successful as the first
operation. However, after a recurrence, the patient
is at higher risk of further recurrences (15 to 20%
chance).
For patients with multiple herniated disc recurrences,
a spine fusion surgery may be recommended to prevent
further recurrences. Removing the entire disc space
and fusing the level is the only way to absolutely
assure that no further disc herniations can occur.
Recurrent herniated discs are not thought to be directly
related to a patient's activity, and probably have
more to do with the fact that within some disc spaces
there are multiple fragments of disc that can come
out at a later date. Unfortunately, through a posterior
microdiscectomy spine surgery approach, only about
5 to 7% of the disc space can be removed and most of
the disc space cannot be visualized. Also, the hole
in the disc space where the disc herniation occurs
(annulotomy) probably never closes because the disc
itself does not have a blood supply. Without a blood
supply, the area does not heal or scar over. There
also is no way to surgically repair the annulus (outer
portion of the disc space).
Following a microdiscectomy spine surgery, an exercise
program of stretching, strengthening, and aerobic conditioning
is recommended to help prevent recurrence of back pain
or disc herniation.
Microdiscectomy surgery risks and complications
As with any form of spine surgery, there are several
risks and complications that are associated with a
microdiscectomy spine surgery procedure, including:
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Dural tear (cerebrospinal fluid leak). This occurs
in 1% to 2% of these surgeries, does not change the
results of surgery, but post-operatively the patient
may be asked to lay recumbent for one to two days
to allow the leak to seal.
-
Nerve root damage
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Bowel/bladder incontinence
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Bleeding
-
Infection
However, the above complications for microdiscectomy
spine surgery are quite rare.
By: Peter
F. Ullrich, Jr., MD
September 8, 1999
(Updated
March 30, 2001 and
December 18, 2003)
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