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Broken backs – can we improve assessment for spinal osteoporosis?
Bone breaking tests
Embargo and press conference 10.00 am, Thursday 19 June 2008,
Melbourne Museum
To read the background to this report,
view here.
For images,
view here.
A technique which measures the variation in bone density
within spinal bones may improve the ability to identify people at special risk
of breaking their backs, Curtin University physiotherapist Andrew Briggs has
found.
The method—developed by Briggs and colleagues from the
Department of Medicine at the University of Melbourne and the Institute for
Medical and Veterinary Sciences in South Australia—involves modifying the
analysis of routine bone density x-ray (DXA) scans for bone thinning or
osteoporosis to provide an assessment of bone density distribution in the back.
“We’ve shown this modification is reliable and easy to use,”
Briggs say. “Now it’s a matter of demonstrating its value in a large clinical
study. That would take two or three 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% of women and 8% 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.
Worse, 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 provide us with an estimate of bone
strength,” Andrew says. “We cannot use it to predict with confidence who is at
risk of sustaining a broken back or a fracture cascade.”
Bone mineral density is routinely measured using the DXA
scanner. It’s 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. 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.
The researchers are investigating ways to improve the routine
DXA scans so the pattern of bone mineral density can be measured easily. They
are now testing their techniques on donor spines before rolling out the method
in a large clinical study. If successful, the technique may have major
implications for clinical practice.
Andrew Briggs is one of 16 early-career scientists chosen for
Fresh Science, a national program sponsored by the Federal and Victorian
governments. He is presenting his research to the public for the first time at
the Melbourne Museum.
Media contacts: Andrew Briggs on 0407 479 147, A.Briggs@curtin.edu.au;
Sarah Brooker on 0413 332 489; and Niall Byrne on 0417 131 977 or
niall@freshscience.org
Background
Dr Andrew Briggs
Australian
National Health and Medical Research Council (NHMRC) Postdoctoral Research
Fellow, School of Physiotherapy, Curtin University of Technology, Perth WA;
Physiotherapist, private practice, Perth, WA.
Broken backs – can we improve assessment for spinal
osteoporosis?
What is the problem?
According to an Access Economics
report in 2001 (Access Economics Pty Ltd, Canberra), nearly 2 million
Australians had osteoporosis in 2001 and this was expected to rise to 3 million
by 2021 with a fracture occurring every 3½ minutes. Osteoporosis consumed a
staggering $AUD 1.9 billion in health care costs, representing $389/pa for every
Australian in 2001.
The prevalence of musculoskeletal
conditions increases dramatically with age, so with an aging population, the
burden of these conditions is likely to become more significant both for the
individual and for the Australian community. In recognition of this burden,
musculoskeletal diseases, such as osteoporosis, are recognised as an Australian
National Health Priority Area, while the World Health Organisation and United
Nations declared the 21st century as the Decade of Bone and Joint
Diseases.
Osteoporosis, or ‘thinning of the
bones’, is one of the most common age-related musculoskeletal conditions,
particularly in women. The condition affects about 30% of women and 8% of men
aged over 50. Osteoporosis causes a decrease in bone strength, so fractures are
the most significant outcome of the condition. Spine fractures are considered
the hallmark of osteoporosis, accounting for almost half of all
osteoporosis-related fractures. Spine fractures have several consequences
including pain, mobility problems, breathing problems, postural changes,
diminished strength, reduced balance and emotional disturbances. The direct cost
(a quarter of the total cost) of these fractures in Australia was estimated at $
AUD 227 million/pa several years ago, so the figures today are likely to be
greater. A major problem is that once an initial spine fracture is sustained,
the risk of further fractures increases 4-7 fold. This problem is referred to as
a ‘fracture cascade’ and is devastating for the patient.
Although we can measure bone mineral
density easily, which gives a reasonable idea of bone strength, we cannot
predict with confidence who is at risk of sustaining a spine fracture and the
fracture cascade.
Working towards solving the problem
Bone mineral density is normally
measured with a device called a DXA scanner. It’s cheap, efficient and
subsidized by Medicare under certain requirements. However, routine DXA scans
only make a gross or ‘average’ measure of bone mineral density in the spinal
bones. However, we know that bone mineral density is not distributed evenly in
the spine, so a gross or average measure doesn’t really describe how the bone
mineral density is distributed in a patient. The distribution of bone mineral
density may be the key to identifying patients at risk of spine fracture.
Andrew and his research colleagues
(University of Melbourne Department of Medicine, Royal Melbourne Hospital,
Victoria; and the Institute for Medical and Veterinary Sciences, South
Australia) are investigating ways to improve routine DXA scans so that the
pattern or distribution of bone mineral density can be measured easily in the
clinic. The research team has 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. The team is
currently testing the technique 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 filed of osteoporosis.
Images
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DXA scan of the lower back showing individual spinal
bones. credit |
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Typical X-ray of someone who has sustained a spine fracture due to
osteoporosis.
credit |
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Dr Andrew Briggs at work as a physiotherapist
treating someone with a spine fracture. credit |
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Dr Andrew Briggs at work as a physiotherapist
treating someone with a spine fracture. credit |
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Patient undergoing a DXA scan.
credit |
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