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Vertebroplasty
Southern Sydney angiography has pioneered the use of vertebroplasty in Australia for osteoporotic spinal fractures. We have performed more than 2,000 vertebroplasties over the last 10 years which makes us the most experienced vertebroplasty unit in Australia.

Vertebroplasty is a treatment for painful vertebral fractures. It is usually reserved for fractures occurring in abnormally weak bone due to osteoporosis. It can also be used for spinal pain associated with "pathological" fractures due to tumour or myeloma. However the most common use of vertebroplasty is for painful spinal fractures in patients with osteoporosis.

Osteoporosis is an extremely common condition especially in patients more than 60 years of age. It is the result of progressive loss of one substance which results in fragile bones. Osteoporosis of itself does not cause pain but can result in fractures (broken bones) which do cause pain. These can be the result of a fall, of a continuous strain on the bones for example coughing, from certain sports such as bowling or golf or just from everyday life when the bones are severely affected.

Recent fractures cause pain due to instability and motion of the fracture fragments. The bone requires 6 to 8 weeks to knit and regain its strength. This healing process is often retarded by osteoporosis. In most patients the pain will settle itself with time. In a minority the pain is unbearable or immobilizes the patient. In other patients the side-effects of the pain killing medications (such as constipation and confusion) becomes a problem. In these kinds of patients, vertebroplasty can be very effective in reducing the back pain. Vertebroplasty is not useful for old healed fractures or for chronic (long-standing) back pain.

The vertebral body is a square shaped piece of bone and its main function is in sustaining the weight of the head, chest and upper limbs which are transmitted through the spine into the legs. It is surrounded by cortical (hard) bone on all sides and consists of spongy bone in the centre. Vertebroplasty uses a needle to inject bone glue into the spongy centre of the vertebral body. The hard cortical bone on the outer of the vertebral body serves to constrain the glue within the vertebral body. The glue sets hard within 20 minutes and restores integrity to the bone by sticking its parts together into one functional building block. This "internal fixation" will abolish the majority of pain in 90% of patients.

Vertebroplasty is performed using intravenous sedation to render the patient relaxed and sleepy. The patient is lying in the prone position (on the stomach) with an oxygen mask and with an oxygen finger monitor to ensure that the oxygen levels in the blood are always normal. Local anaesthetic is administered to the area of injection and then a needle is passed into the vertebral bone using x-ray guidance. The imaging machine is an interventional fluoroscope which provides real time imaging of the needle movement and the vertebral bones on a TV screen. When the needle is in good position, the glue is injected and forms a cast inside the vertebral body. This is all watched in real time on the screen which makes the procedure safe. The whole procedure for one fracture takes about 30 minutes. For additional fractures extra time may be needed.

The cement or bone glue used is most commonly a polymethyl - methacrylate. These are the glues which have been extensively used for gluing hip replacements etc over the years. They have a long track record of safety. The glue has a powder and a liquid component. These are mixed to the consistency of toothpaste and then slowly injected into the bone under real time imaging as the doctor watches it distribute in the vertebral body.

The overall risks of a major complication are very low when the operator is experienced and the imaging equipment is good. Glue can extravasate outside of the vertebral body. When this happens it is seen by the radiologist and the injection is ceased. This provides the safety factor. If the fractured bone is irregular or if cement extravasates into the disc above or below the vertebral body then the adjacent bone may be at increased fracture risk. In this case a preventative or "prophylactic" injection of the adjacent bone may be undertaken at the time.

We believe that vertebroplasty is best used for fractures which are less than 8 weeks old and have not healed. The best evidence for this application comes from the VERTOS2 study from the Netherlands which is a randomized controlled clinical trial of vertebroplasty. Five hospitals randomly allocated patients with painful osteoporotic spinal fractures less than 6 weeks old to either receive vertebroplasty or conservative therapy. The vertebroplasty group had significantly less pain than the conservative therapy group at 24 hours, 1 week, 1 month , 6 months and 12 months following the procedure. The vertebroplasty patients had significantly better maintenance of height in the fractured bones following vertebroplasty rather than ongoing collapse in the conservative group. There was no increase in new vertebral fractures caused by the vertebroplasty. There are two other randomized controlled trials which showed vertebroplasty not to be effective in patients with fractures older than 8 weeks (Buchbinder et al and Kallmes et al). We agree with these trials and do not offer the procedure to patients with fractures more than 8 weeks unless an MRI shows that they have not "united" or healed.

Vertebroplasty is funded by the medicare system. Medicare pays for the procedure but not for the bone glue kits which are required. The private health funds pay for the bone glue kit, so there are no out of pocket expenses for patients in private funds or DVA. Uninsured patients will be required to pay a gap to cover the cost of the cement kit.

Links
http://www.sirweb.org/patients/vertebroplasty-osteoporosis
http://www.cirse.org/index.php?pid=98

 

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