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Osteoporosis is weakening of the bones due to consumption of
calcium mineral stored in the bone matrix. This results in overall
weakening of the bones making them susceptible to fracture or
collapse under normal stresses. Osteoporosis affects all people with
age, especially those with smaller amounts of stored calium, women
more than men, and Caucasian and Asian women more than African
Americans. Back pain is a common and costly problem in Western
countries. It is estimated that back pain periodically incapacitates
up to 20% of the American workforce at an annual cost of more than
$24 billion in lost productivity and treatment. Pain of spinal
origin has a lifetime prevalence of greater than 60% and an annual
incidence of 5%. It is estimated that 25% of American women over the
age of 50 will suffer at least one vertebral fracture.1 Compression
fractures represent a common cause of life-threatening disability in
the elderly and are now readily treated using minimally invasive
techniques.
Anatomy of the Spine
The spine is a flexible column which consists of a series of bones
stacked one on top of the other. These bones are known as vertebrae.
There are usually 33 vertebrae in the spine, divided into five
categories: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4
coccygeal.
Discs comprised of fibrous and cartilaginous tissue separate
the vertebra from the second cervical level to the sacrum. Their
purpose is to permit and cushion normal movement.
The spinal cord connects the brain to the rest of the body. It is
a thin column of nerve tissue protected within the spinal canal. The
spinal cord terminates usually at the L1 (first lumbar) vertebral
level.. Dorsal and ventral nerve roots arise from the spinal cord at
each vertebral level and exit the spinal canal through foramena, or
openings, between each vertebra. Sensory and motor nerves extend
throughout the body to connect them with the central nervous system.
Thoracic and lumbar vertebrae are most commonly affected by
compression fractures. This region of the spine is ordinarily
subjected to significant loading forces. Extreme, sudden, or
abnormal movements can lead to injury. Fractures of the vertebrae
can be due to several causes. An accident or trauma can lead to
fractures. Vertebral fractures may also be due to
osteoporosis—decreased bone strength due to lack of calcium. Tumors
within the vertebrae are also a cause of bone weakening and can lead
to spinal fractures fractures and severe pain.
When an accident or trauma causes a spinal fracture, the spinal
column may be unstable, or bone fragments may compress the spinal
cord or the nerve roots exiting the spinal foramena. In such cases,
treatment may require surgery with spinal fixation or immobilization
braces. However, when osteoporosis or tumors cause generalized
weakening and fracture of the vertebra, surgery with spinal fixation
is often not possible or involves considerable risk. Severe pain may
limit mobility, but bedrest is notan effective treatment, as it can
exacerbate osteoporosis and lead to other medical complications such
as pneumonia. These very painful fractures are often treated through
a procedure called vertebroplasty. “Vertebro” refers to the
vertebrae and plasty mans “to form.” Vertebroplasty forms a support
for the fractured vertebrae Percutaneous treatment is used for two
common causes of spinal pain: facet joint arthropathy and
osteoporotic vertebral compression fractures. Vertebroplasty, the
use of cement to stabilize vertebral fracture fragments to palliate
spinal pain, may become the new standard of care for management of
pain and disability due to either osteoporotic or neoplastic
compression fractures. Vertebral collapse most commonly occurs
during normal exertion and loading forces in elderly persons with
osteoporosis. 1.5 million osteoporotic fractures occur each year
including 700,000 vertebral fractures. The lifetime risk of
symptomatic vertebral compression fractures is 16% for white women
and 5% for white men. Vertebral compression fractures are defined by
15% loss of vertebral height and classified by morphologic
deformity. The most commonly compressed vertebral bodies are T8,
T12, L1, and L4. Symptomatic fractures cause severe pain and
hospitalization in 8%, and prolonged nursing care in 2%. The result
can be life-threatening pneumonia, immobilization and deep venous
thrombosis, loss of independence, and depression. Mortality rates
are 1.23 times higher in women with compression fractures than in
age-matched controls.
Vertebroplasty was introduced in Europe in 1984, first published in
the medical literature in 1987, and has been performed in the United
States since 1995. It is a very effective procedure with a high
success rate and very low probability of risk.2,3 This technique
entails the insertion of a needle, under x-ray guidance, throught
the skin and into the vertebral body under local anesthesia. Medical
cement (PMMA, polymethyl-methacrylate) is injected which stabilizes
the fracture to prevent pain and strengthens the bone to prevent
further collapse. In properly selected patients, the end result is
usually rapid pain relief and and greatly improved mobility . This
procedure comes with low risk (less than one percent in my
experience and in most published series), although potential
complications such as infection, nerve injury, bleeding, and
pulmonary embolism should be discussed with the physician.
Candidates for vertebroplasty
Although postmenopausal women are at greatest risk of developing
osteoporosis, a thinning and fragility of the bones, men are also
affected. When osteoporosis occurs, calcium and other substances
become lost from the bones. Eventually, they may become so weak that
they cannot support themselves and will ultimately collapse. This is
known as a compression fracture. Although compression fractures are
most commonly due to age-related osteoporosis, bone weakening can
also be caused by long-term steroid use, benign blood vessel tumors,
and malignant tumors that often metastasize to the spine.
Compression fractures frequently but do not always heal over
time, and the process of waiting for recovery may be prolonged and
can be extremely debilitating. Other illnesses may develop while one
is immobile and awaiting recovery. Painkillers, back bracing, and
bed rest may not alleviate the discomfort.4 Mortality rates are
increased 1.23 times in women compression fractures compared with
age-matched controls.
People who suffer from pain due to compression fractures
typically experience a sudden onset of back pain localized to one
spot. Vertebroplasty can usually alleviate such pain. The pain may
also radiate to the front. Sciatica, which involves low back pain
radiating down the buttock and leg, may also be present.
Not everyone with these symptoms is a candidate for
vertebroplasty. The procedure should not be performed on people who
have an active infection, coagulopathy (a bleeding condition in
which the blood does not clot normally), or certain forms of
fractures in which bone fragments press on the spinal cord or the
nerve roots exiting the spinal cord.4
What to Expect when Undergoing Vertebroplasty
The day of the procedure, you will be brought to the operating room
suite. The procedure will usually be performed with the patient in
the prone position (lying on the stomach). For someone with severe
back pain, this could be painful, so some anesthesia is useful to
control any discomfort related to lying in the prone position with a
pillow under the chest or stomach. Your arms will be placed straight
outover your head in the “Superman” position. Sedatives and pain
medications are administered intravenously by a nurse or an
anesthesiologist who also monitors heart rate, blood pressure,
breathing and oxygen levels. Most patients tolerate this procedure
very well while awake and do not find it painful. However, spinal
fractures can be very painful. Sometimes, general anesthesia is
warranted to control the pain until the vertebroplasty has been
performed.
To begin, the skin on the back immediately covering the fractured
vertebrae will be washed with special soap. Sterile sheets and
towels will then be draped over the area. A numbing medication
(usually a combination of lidocaine, marcaine, and sodium
bicarbonate) will be injected into the skin overlying the fractured
vertebra. Then, a special needle will be placed into the fractured
vertebrae under x-ray guidance using a fluoroscope – a special
low-dose x-ray machine. Once the needle is in place, the physician
may confirm needle position by injecting a small amount of x-ray
dyeto allow the doctors to see the tiny veins (the blood vessels
within the vertebra) and to make sure there are no abnormal blood
vessel connections. This helps to ensure that the doctors have
placed the needle in the appropriate place before administering the
cement. As soon as the needle is confirmed to be in the appropriate
location, treatment will begin.
The PMMA cement is mixed with barium or tungsten powder which
makes it visible on the fluoroscope. Once the cement and
accompanying ingredients are all mixed together, it becomes
liquefied. The doctors will be able to watch the mixture entering
into the bone. An antibiotic is usually also added to the mixture to
reduce any risk of infection. The cement hardens very quickly, so
the doctors need to proceed accurately and rapidly. Only a tiny
amount of cement is needed to perform the procedure. Usually,
between 2 and 5 cc of cement are instilled into a single vertebra,
and the results do not appear related to the overall amount of
cement instilled. Once they have determined (by viewing the
injection on the x-ray screen) that a sufficient amount of the
cement has been injected into the fracture, the needle is removed.
The only visible evidence that the procedure took place is a
band-aid; no stitches are required. The puncture hole is usally 1-2
mm and usually heals in 24 hours.
The vertebroplasty procedure, the injection of cement, is very brief
and may take only minutes. The total length of time for the entire
procedure takes one to two hours, depending on specific
circumstances. Most of the time is required to make the patient
comfortable and covered with the sterile drapes and towels. Patients
who may have several affected vertebrae or who need general
anesthesia will require a longer procedure.
Following the Procedure
Once the procedure is completed, the patient is placed in the supine
position (lying on the back) for approximately two hours while the
cement hardens. During this time, patients often visit with friends
or family, enjoy a meal and watch television. Unless the procedure
is performed late in the afternoon or the patient has other medical
problems that require other treatments, patients are usually able to
go home the same day.
A friend of family member must be available to bring you home.
Strenuous activity will be limited at first, but normal activities
will gradually be increased. Some patients feel so well after the
procedure that they are at risk to injure another vertebra, It is
important to remember to limit activity, especially heavy lifting. A
good rule of thumb is to not lift anything heavier than a purse or
small bag of groceries for at least one week.
Follow-Up Care
Your doctor may recommend rehabilitation following the procedure.
This may take the form of supervised physical therapy or independent
exercise. Your doctor may give you written suggestions for exercises
you can do at home. Regardless of the recommendations, your
physician may want to see you several times in the weeks following
the procedure. Most patients will eventually be able to resume
normal activity and discontinue or reduce their use of pain
medication. Dietary modifications, vitamin therapy, new medications,
and judicious exercise are all necessary to curtail or reverse the
bone loss (demineralization) causing osteoporosis.
Many patients report feeling relief from back pain within a few
days. No prospective, randomized trial has been completed. In
retrospective case series, immediate pain relief was achieved in
70-90% with complication rates less than 1%. In one series, 12% of
treated patients developed additional fractures requiring
intervention, but there was no increased risk of new spinal
compression fractures in treated patients. In a small prospective
trial, 21 patients had vertebroplasty and 19, medical therapy, early
results suggested a benefit to vertebroplasty.
If this is not the case, reevaluation is warranted to determine
if other causes may be contributing to the pain. Back pain is often
caused by many different factors at the same time. Another
possibility is a new compression fracture at a different location.
Whatever the cause, open communication with your doctor is extremely
important. |