Vertebroplasty and Kyphoplasty, FDA Warning
Medical Disclaimer
Vertebroplasty
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Vertebroplasty is a technique where a bone cement is injected
into the vertebral bodies of the back. The procedure is performed
to treat painful compression fractures of the spine that have not
responded to simpler methods such as bedrest, bracing or analgesia.
The fractures typically are caused by osteoporosis, but occasionally
tumors such as breast cancer, hemangiomas, and other types can be
treated to reduce the pain. In some cases traumatic fractures of
the vertebral bodies can be treated. The procedure is not used to
treated ruptured discs
or other types of degenerative spine disease.
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Vertebroplasty consists of placing a needle through the skin and
into the bone under X-ray guidance. This allows us to see the position
of the needle at all times. Once it is positioned a small amount
of X-ray dye is injected to insure the needle is in the proper place
in the bone. A bone cement called methylmethacrylate
is injected through the needle into the vertebral body. Usually about a teaspoon
of the bone cement is used. Methylmethacrylate is a medical grade
substance that has been used for over 30 years in artificial joints.
It has a very good safety record. The cement is mixed with an antibiotic
to reduce the risk of infection, and a powder containing barium
or tantalum to allow it to be visible on X-rays. When the material
is injected it is like a thick liquid, but within 20 minutes becomes
rock hard. Usually each vertebral body is injected on both the right
and left sides through the pedicles, just off the midline of the back.
After the procedure is performed, you will normally be kept in bed for about an hour,
and then you can leave about two to three hours after the procedure. The
procedure should not be especially uncomfortable, but to help you
relax, you are given sedative medications and they may make you sleepy. We expect
that your pain will be reduced after this procedure, but it is still
important to be careful in your activities. Other vertebral bodies
are still prone to fractures, even if pain in the treated vertebral
body has been alleviated. It is also important to continue or get
started on medications to treat the underlying problem causing the
weakened vertebral bodies. Osteoporosis can now be effectively treated
with medications. Talk to your primary care physician about these therapies.
Most patients find significant pain relief within hours of the
procedure. However, not everyone gets complete pain relief and you
should understand this before undergoing the procedure. The risks
of the procedure are minimal, but potentially can include infection,
additional pain, or neurological problems such as weakness or pain in the legs.
See Also: Chronic Pain
Vertebroplasty as a procedure is not an FDA approved procedure,
meaning it has not been through a process whereby the government
labels the bone cement and technique specifically for this procedure.
Rather we as your physicians are using this cement and technique
because we think it has the best chance of improving your condition.
This use is termed the "off-label" use of an approved medical device
(the cement). It is not experimental which means you are not part
of a study to evaluate its safety and usefulness.
See FDA Warning
Kyphoplasty
Treatment for vertebral compression fractures caused by Osteoporosis.
Kyphoplasty is a refinement of the vertebroplasty procedure. In addition to the
reduction of fracture-related pain, some or all of the height is restored to
the compressed vertebral body. Normalizing the height of the fractured vertebra
reduces the focally exaggerated curvature of the spine (ie, kyphosis). This
effect, in turn, results in an esthetic improvement, improved posture, and a
reduced risk of fracture of the adjacent vertebra as a result of abnormal
load bearing. The restoration of a more normal appearing configuration of the
vertebral body and improvement in the load-bearing physics is accomplished
with the intravertebral inflation of 1 or 2 high-pressure balloon tamps
(KyphX; Kyphon). As with vertebroplasty, access is via a transpedicular or
peripedicular approach. The procedure distracts the fragments and elevates the
collapsed vertebral endplate. The inflated balloons create cavities in the
vertebral body, the margins of which are lined by the displaced, fragmented
trabeculae.
The degree to which the height of the vertebral body and the angulation of
depressed endplates are corrected appears to vary from case to case. The maximum
volume of the balloon and the pressure required for inflation determine the
inflation of the balloons, and therefore, the degree of height restoration.
Once height is improved, the balloon catheters are deflated and withdrawn. A
preparation of methylmethacrylate (bone cement) thicker than that used in
vertebroplasty is then injected under relatively low pressure into the cavities
created by the inflated balloons. This procedure is used to maintain the
elevation of the endplate and stabilize the fracture fragments, thereby reducing
or eliminating pain and promoting healing. Because this acrylic is more viscous
that that used for vertebroplasty and because it is injected under lower
pressure that in vertebroplasty, the risk of intravascular extension of acrylic
is thought to be lower.
The compact 4d trabeculae at the periphery of the acrylic acts as a bone graft,
providing a dense matrix of bone upon which endosteal healing can occur.
Kyphoplasty is most effective with acute compression fractures secondary to
either trauma or osteoporosis, but it is not recommended for the treatment of
fractures secondary to infection, most solid tumors, and vascular lesions. The
presence of a burst fracture with loss of integrity of the posterior vertebral
cortex and retropulsion of a fracture fragment into the spinal canal is
considered exclusionary. Kyphoplasty is not indicated for the treatment of
degenerative disk or joint disease.
As with vertebroplasty, patients must exercise caution in subsequent activities
because other osteoporotic vertebral bodies also may be prone to fracture.
Medical management of the underlying disorder that weakens the vertebral bodies
should be initiated. This procedure does not eliminate the need for aggressive
treatment of osteoporosis, without which other fractures may ensue. Ideally,
treatment should include Actonel; Fosamax; Miacalci; calcium supplements; and
multivitamins, including vitamins C and D. Hormonal replacement therapy should
also be considered in female patients. Alterations in the medications and
dosage of drugs that predispose patients to osteoporosis (eg, steroids) should
also be evaluated. Progress should be monitored with serial DEXA scans.
In 1998, the Food and Drug Administration (FDA) approved (FDA Warning) the use of this
acrylic in kyphoplasty. To the author’s knowledge, no investigators from
long-term outcome studies have reported the breakdown of the acrylic over
time. Preliminary clinical 2-year follow-up data from approximately 4,000
kyphoplasties in more than 3,000 patients is favorable.
Methylmethacrylate is an FDA-approved (see FDA Warning below) medical-grade
tissue adhesive that has been used for more than 30 years in the fixation of
artificial joint prostheses. Its use in vertebroplasty, however, is not
approved by the FDA, which means that it has not been reviewed in the process
whereby the government approves the bone cement and technique specifically
used for this procedure. In vertebroplasty, the acrylic cement, which the FDA
considers a medical device, is used in an off-label application.
FDA Issues Bone Cement Warning - November 7, 2002
The U.S. Food and Drug Administration warns that a type of bone cement used to
treat spinal fractures may cause serious side effects, reports United Press
International.
According to the FDA alert, two procedures, vertebroplasty and kyphoplasty,
have been linked to tissue damage and nerve root pain due to the bone cement,
called polymethylmethacrylate, leaking into the body. Without releasing
numbers, the agency also said it had received reports of blood clots in the
lungs, respiratory and cardiac failure and even death.
But Dr. Thomas A. Einhorn, chairman of orthopedic surgery at Boston University
Medical Center, said doctors around the world perform these two procedures
daily and rarely see serious complications.
Dr. Steven Garfin, chairman of orthopedic surgery at the University of
California, San Diego, said the operations have had a 90 to 95 percent
success rate. According to Dr. Garfin, the problems may lie with where needles
were placed during surgery, rather than with use of the bone cement.
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