24 June 2008
A new technique is being developed to measure the variation in bone density within spinal bones which may improve the ability to identify people at special risk of spinal fractures – one of the most common fracture types in osteoporosis.
Dr Andrew Briggs, an Australian National Health and Medical Research Council (NHMRC) Postdoctoral Research Fellow from Curtin’s School of Physiotherapy, is developing the technique along with colleagues from the Department of Medicine at the University of Melbourne and the Institute for Medical and Veterinary Sciences in South Australia. He explained its workings and the development progress.
“The technique involves modifying the analysis of routine bone density (DXA) scans for bone thinning or osteoporosis to provide an assessment of bone density distribution in the back,” Dr Briggs said.
“We have shown this modification is reliable, valid and easy to use and are finishing off this phase of the testing. We need to conduct a large clinical study to verify initial findings, and if all goes well the new technique could be in clinical practice within ten years.”
In 2001, nearly two million Australians were suffering from osteoporosis, according to Access Economics, resulting in one fracture every five to six minutes at a staggering cost of $1.9 billion, or $389 for every Australian. By 2021 Access estimates the number of sufferers will rise to three million.
Osteoporosis affects about 30 per cent of women and 8 per cent of men over 50. It causes a decrease in bone strength, so fractures are a common outcome. Spinal fractures account for almost half of all osteoporosis-related breaks and result in pain, mobility problems, breathing problems, postural changes, diminished strength, reduced balance and emotional disturbances.
Even worse is once an initial break is sustained, the risk of further back fractures increases by between four- and seven-fold. This is known as a fracture cascade and is devastating for the patient.
“While we can easily measure bone mineral density, it only provides us with an estimate of bone strength,” Dr Briggs said.
“We cannot use it to predict with confidence who is at risk of sustaining a broken back or a fracture cascade.”
Dr Brigg explained the shortcomings of the routine DXA scan.
“Bone mineral density is routinely measured using the DXA scanner as it is cheap, efficient and already subsidised by Medicare for certain patient groups. But at present, DXA scans only provide a gross or ‘average’ measure of bone mineral density in the spinal bones,” Dr Briggs said.
“Such measures don’t describe how the bone mineral density is distributed within spinal bones, and this may be the key to identifying patients at risk of spine fracture.”
Dr Briggs’ research team will investigate ways to improve the routine DXA scans so the pattern of bone mineral density can be measured easily.
The research team has already proven that DXA can reliably identify differences in bone density distribution within spinal bones. They have also collected preliminary data which suggests that the technique can better identify patients who have sustained spinal fractures than routine DXA methods.
Testing of the technique will be done on donor spines before rolling out the method in a large clinical study. If successful, the technique may have major implications for clinical practice in the field of osteoporosis.
Dr Andrew Briggs is one of 16 early-career scientists chosen for Fresh Science, a national program sponsored by the Federal and Victorian governments. He presented his research to the public for the first time at the Melbourne Museum on 18 June 2008.
Modified: 24 June 2008