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Cervical Spinal Fusion Surgery
Considering spinal fusion surgery as treatment for a spinal
condition like degenerative disc disease? Call the
specialists at United Back Specialists. Contact us to
determine what option is best for you, what your insurance
will cover and any additional surgery costs.
What is Cervical Spine Fusion?
Cervical
spinal fusion (arthrodesis)
is a surgery that joins selected bones in the
neck ( cervical
spine). There are different methods of performing
a cervical spinal fusion:
- Bone can be taken from elsewhere in your body or
obtained from a bone bank (a
bone graft). The bone is used to make a bridge
between vertebrae
that are next to each other (adjacent). This bone
graft stimulates the growth of new bone. Man-made
(artificial) fusion materials may also be used.
-
Metal implants can be used to hold the vertebrae
together until new bone grows between them.
- Metal plates can be screwed into the bone,
joining adjacent vertebrae.
- An entire vertebra can be removed, and the spine
then fused.
- A
spinal disc can be removed and the
adjacent vertebrae fused.
This procedure can be performed through an incision
on the front (anterior) or back (posterior) of the neck.
This surgery usually requires a short stay in the
hospital. You may need to wear a brace on your neck
(cervical collar) during recovery.
Cervical spinal fusion may be done:
Cervical spinal fusion is usually successful in
relieving symptoms. But it does not appear to work
better than nonsurgical treatment. Complications
sometimes occur. Repeat surgery is sometimes needed to
address complications or recurrence.
Although cervical spinal fusion stiffens part of the
neck, this does not reduce neck flexibility for most
people.
It is important to stress that the decision to undergo a
fusion procedure for
low back pain is entirely the patient’s decision and he
or she needs to carefully weigh the risks and possible
complications along with the potential benefits of surgery,
as well as consider the full range of alternatives to a
spine fusion surgery.
It is often a good idea for patients to get a second (or
third) opinion from other
surgeons and/or other types of spine specialists prior
to deciding whether or not to have spinal fusion.The
decision to have a spine fusion procedure to treat low back
pain from degenerative disc disease is a very personal one.
Degenerative disc disease is for the most part a
non-crippling, non-progressive type of back condition,
although in a minority of cases it can cause severe back
pain and can significantly impact on an individual’s ability
to function.
History of Spinal Fusion Surgery
Fusion surgery for the treatment of
lower back pain has been done since the early 1900’s. At
that time, spine fusion procedures were done to limit the
deformity created by tuberculosis infections, and it was
found that not only did the fusion procedure limit the
deformity, it also reduced the patient’s low back pain as
well.
Since then, spine fusion procedures have had variable
popularity for the treatment of pain from
lumbar degenerative disc disease and remain somewhat
controversial in the medical community.
Surgeons and researchers span the spectrum in terms of
their beliefs as to how useful spine fusion surgery is and
when and how it should be performed.
- Some spine surgeons do not believe fusion surgery is
at all useful and is never indicated for the treatment
of low back pain from lumbar degenerative disc disease.
- Some
spine surgeons are very willing to offer patients a
fusion procedure, and some are even willing to do
multiple level fusion surgery.
As with most things in medicine, the truth lies somewhere
in between the two far ends of the spectrum of beliefs about
spine fusion surgery as a
treatment for low back pain from degenerative disc
disease. In general, when done by a skilled surgeon for a
patient with the right indications, spinal fusion surgery is
usually an effective treatment that brings significant
relief from severe, ongoing low back pain caused by
degenerative disc disease.
Each patient has to weigh the risks of a major surgical
procedure and a long healing process with the potential
benefits. The spine fusion surgery works best for treating
one level of the spine, although two levels can be fused if
the patient has
severe low back pain. As the number of levels fused
increases, the risks of the procedure increase (e.g. a
nonunion) and the potential benefits decrease. Only rarely
and in extreme cases would most
spine surgeons recommend or even offer a three or
four-level spine fusion surgery.
Who is a good candidate for Spinal Fusion Surgery?
The biggest risk for spine fusion procedure is continued
pain, meaning that the surgery did not substantially reduce
or eliminate the patient’s pain. The number one reason this
occurs is that the fused disc was improperly identified as
the cause of the patient’s pain, so fusing the disc was
unnecessary and irrelevant. This is why getting an accurate
diagnosis is critical.
One of the most difficult and crucial parts of any type
of low back surgery is selecting the patients who will do
well with a certain procedure. It is especially critical to
select the right patients for a lumbar spine fusion surgery
for two reasons:
- Lumbar spine fusion is an extensive surgery and the
healing process takes a long time (about 3 to 6 months,
and up to 18 months)
- The spine fusion forever changes the biomechanics of
the back and is thought to increase the stress placed on
the other (non-fused) joints in the lower spine and
possibly lead to degeneration of the adjacent levels of
the spine.
Lumbar spine fusion surgery is generally not recommended
until a patient has tried 6 to 12 months of adequate
non-surgical care. Spinal fusion is best for treating
low back pain caused by severe degenerative disc changes
and is best for treating one, or maybe two, levels of the
lower spine (typically the L4-L5 level and/or L5-S1 level).
Prior to recommending or offering spine surgery, a
surgeon must also consider other causes of low back pain
that can closely mimic the symptoms of degenerative disc
disease. These conditions include:
If a patient’s
low back pain and other symptoms do not improve with
extensive conservative (nonsurgical) treatment and other
causes of low back pain have been ruled out, then he or she
may be considered for a spine fusion surgery. Importantly,
while failing conservative treatment is a necessary
prerequisite for spine fusion surgery, it is not sufficient.
Prior to recommending spine fusion surgery, a
spine surgeon has to be confident that he or she is
fusing the segment of the spine that is generating the
patient’s pain (the “pain generator”). Obviously, fusing a
structure that does not cause pain will not reduce the
patient’s low back pain or lead to a successful outcome.
MRI scans have greatly increased the spine surgeon’s
ability to diagnose degenerative disc disease.
Unfortunately, a lot of the changes that are seen on MRI
scans are more related to normal aging than to a pathologic
and painful disc. Differentiating a painful disc from an
aging disc is often difficult but there are some clues that
help. In general, a painful disc will be severely
degenerated whereas the rest of the discs will be well
preserved. Other characteristics of a painful disc on an MRI
scan include:
- Disc space collapse, which means that the disc has
gotten shorter/flatter
- Endplate erosion, which is erosion of the top and
bottom outer material of the disc
- Edematous changes in the vertebral body (Modic
changes), which is when the MRI shows irritation of the
bone marrow, may be an indicator of a painful disc.
There is a characteristic bright signal on the MRI scan
when this occurs.
If a
spine surgeon is uncertain as to whether or not a disc
is painful, a CT-discogram may be ordered.
A discogram is a direct pain provocation test that is
designed to try to elicit the patient’s pain by injecting a
dye into the disc space. If the test creates the patient’s
normal pain, it can be assumed that the test is positive and
the disc is generating the patient’s pain. Some major
drawbacks of the procedure are:
- It involves an injection into the spine, which has
several risks (albeit rare)
- It is usually painful
- It is a subjective test, and both false positives
and false negatives can occur
- Accuracy of the test is largely dependent on the
skill of the discographer
Discograms are used by some
surgeons before every spine fusion, and it is certainly
warranted to gather as much information as possible before
undergoing a fusion procedure. However, discograms are
probably not necessary on a routine basis, and the test
itself is somewhat controversial. The test should only be
used if the results are going to change the surgeon’s
recommendations (e.g. if negative, spine surgery will not be
recommended). If the results are ignored and the surgical
choice is made off of the MRI findings, then a discogram
does not serve any useful purpose.
Increasing Success of Spine Fusion Surgery
Once a correct diagnosis has been made and the patient
has decided to proceed with spinal fusion surgery, then
obtaining a solid fusion is the next focus.
Pseudoarthrosis, which means lack of a solid
fusion, is becoming a less common outcome of spinal fusion
surgery thanks to modern instruments and surgical
techniques. However, there are a number of fusion risks that
can adversely create this outcome, including the patient’s
own health and personal habits (host factors) and the
technique of the spine surgeon.
Factors that Affect Spinal Fusion
There are a number of factors that negatively impact on
obtaining a solid fusion following spinal fusion surgery,
including:
Of all these factors, the one that most negatively
impacts the fusion rate and is under the control of the
patient is smoking. Nicotine has been shown to be a bone
toxin and it inhibits the ability of the bone growing cells
in the body (osteoblasts) to grow bone. A fusion is
basically a race between the bone growing cells and the bone
eating cells (osteoclasts). Continuing to smoke after a
spine fusion surgery, especially immediately after surgery,
favors the bone eating cells and significantly undermines
the body’s ability to grow the bone need to create a fusion.
Since having a spinal fusion surgery for
low back pain is almost always the patient’s decision,
it only makes sense for patients to make a concerted effort
to allow the body its best chance possible of allowing the
bone to heal by not smoking. While
quitting smoking is difficult, it is definitely worth it
when considering a
lumbar fusion surgery.
In addition to not smoking, most
surgeons will restrict a patient’s activity level for
several months following the surgery. Typically, mild
activity such as walking is encouraged as it promotes
healthy circulation and aids in the healing process.
However, activities such as repetitive bending, lifting, and
twisting, are usually not permitted. Once the bone fuses,
the patient is encouraged to gradually resume normal
activities as bone is a living tissue and will become
stronger when appropriate stress is applied to it over a
period of time.
Another factor that may contribute to obtaining a solid
spine fusion is the type of bone that is used. Typically,
bone graft is taken from the patient’s hip. Several types of
bone graft substitutes and supportive materials are
currently either in use or in various stages of development,
and researchers are hopeful that new materials will help
improve the success rate of obtaining a solid fusion,
especially for patients who are at high risk for non-fusion.
Spinal Fusion Approaches
Technically, there is a wide variety of surgical procedures
that can be done to fuse the spine. The spine fusion surgery
can be done with the following approaches:
With any type of spine surgery, the specific technique
used is largely dependent on the spine surgeon’s experience
and his or her comfort level with the approach.
There has been a recent trend in spine surgery toward
trying to do more minimally invasive types of procedures.
Anterior fusions—approached from the front—are done through
a laproscope or a mini-open incision and carry less
morbidity (unwanted aftereffects) than spine fusion surgery
done through a posterior incision. However, there are a
number of considerations with
anterior spine fusion, including:
- Some types of pathology do not lend themselves well
to an anterior fusion alone
- Not all spine surgeons are comfortable with the
approach or do not believe it is the best approach
- There are some unique risks associated with
approaching the spine fusion surgery from the front
No matter how the spine fusion surgery is done, the goal
is to obtain a solid fusion and stop the motion at the level
fused.
Spine Fusion Alternatives
There are a couple of alternatives to spine fusion
surgery that may be considered for patients with
low back pain from lumbar
degenerative disc disease. Currently, the main fusion
alternatives include:
- IDET, or
Intradiscal electrothermal coagulation (or annuloplasty).
This procedure involves inserting a needle into the
lumbar disc space, passing a catheter through the
needle, and heating up the annulus (the outer core of
the disc space). The exact mechanism by which the
procedure relieves pain has not been clearly
established, but it is theorized that the heat contracts
and thickens collagen fibers in the disc wall, which in
turn seals up painful tears and cracks and reduces pain.
The procedure also cauterizes nerve endings which is
thought to make them less sensitive. Not all patients
benefit from IDET, and the treatment is more likely to
help people with less severe
degenerative disc disease than people with
significant disc degeneration. IDET is minimally
invasive and usually done on an outpatient basis (no
overnight hospital stay) under mild sedation and a local
anesthetic. Although the procedure is minimally invasive
it has largely fallen out of favor in the spine world as
it has marginal clinical efficacy. Most insurance
companies no longer cover the procedure.
- Artificial discs.
Disc replacement surgery involves replacing the
painful disc in the spine with an
artificial disc. As of August 2006, two brands of
lumbar artificial disc are available for use in patients
in the U.S.: the Charite lumbar artificial disc and the
PRODISC-L lumbar artificial disc. A number of other
artificial disc brands are in the clinical trial testing
phase. The goal of artificial disc replacement surgery
is to preserve the normal motion of the spine (unlike
fusion, which eliminates motion at the painful spinal
segment). Artificial disc surgery has two primary
theoretical advantages over spinal fusion; 1) it is
thought that preserving spinal motion reduces the risk
that other segments of the lumbar spine will wear down
prematurely; 2) it is believed that artificial disc
surgery may achieve better pain reduction than fusion.
However, these potential benefits come at the expense of
greater risk with the surgery. Any motion preservation
device can fail by extrusion or wearing out with time.
Revision surgeries are expensive and extremely
dangerous. The risk/benefit ratio of artificial disc
versus fusion is still largely unknown, and currently
many insurance companies are not covering the procedure.
- Posterior dynamic stabilization.
This treatment is different from fusion in that
posterior dynamic stabilization seeks to preserve motion
in the spine while also taking pressure off the diseased
vertebral disc. The theory is that removing pressure
from the painful disc will create a favorable healing
environment and
reduce pain. The devices used in the surgery are
designed to unload pressure from the vertebral disc in
the same way a dynamic (moveable) brace unloads pressure
from an
injured knee or ankle to allow it to heal. Various
forms of posterior dynamic stabilization devices are
still in the investigative or testing phase or early in
use, and their efficacy and potential risks and
complications have not yet stood the test of time.
- Disc regeneration. Researchers in
cellular and molecular biology are exploring ways to use
gene therapy to stimulate regeneration of the vertebral
disc and/or to slow or prevent degeneration of the disc.
The hope is that this therapy could prevent the need for
surgery. For example, in animal studies, the BMP-12 gene
(bone morphogenetic protein) has dramatically increased
the generation of cells in both the nucleus and the
annulus of the vertebral disc. BMP-12 is a molecule
that, among other duties, promotes formation of
embryonic joints. Research is also being performed on
gene therapy that could inhibit the degeneration
process. Gene therapy for treatment of the
intervertebral disc is still in the early stages of
research.
Patient's Decision: Spinal Fusion
The decision to have a spine fusion procedure done to treat
low back pain is a very personal one, and it is entirely
the patient’s decision. Degenerative disc disease is for the
most part a non-crippling, non-progressive type of back
condition and does not lead to neurological deficits or
result in a progressive crippling condition.
The natural history is for the low back pain to improve
with time (although it may take many years) as the natural
aging process leads the disc space to have less motion. With
continued degeneration, bony growth around the disc will try
to capture the excess motion. Therefore, continuing
non-surgical treatments (such as medication, exercise) to
manage the painful symptoms and living with the discomfort
is always an option.
Unlike many other types of surgery, with spinal fusion
surgery only the patient can decide if the pain and
inability to complete one’s normal daily activities is bad
enough to warrant spinal fusion (or any other) type of
surgery. And the best way for a patient to make an informed
decision about whether or not to have spinal fusion
is to fully understand the trade-offs between spinal fusion
and other non-surgical and surgical treatment options.
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