A new research made by Flinders University uncovered other possible causes of slipped disc injuries other than the commonly blamed bending and twisting.
According to a recent report, this finding will lead to a better understanding of which motions put people at greatest risk of a slipped disc and help develop more robust guidelines for safe lifting.
With access to a lab using more advanced technology, a PhD candidate at the Flinders University Medical Device Research Institute tested the theory of bending and twisting as the mechanism for a slipped disc.
Slipped discs, which are technically known as lumbar disc herniations, are a common source of sciatica in the young and middle-aged. Sciatica is the radiating pain down the legs.
The ‘discs’ are made of an elastic casing around a jelly-like material, called the nucleus, which helps absorb shock and keep the spine stable by slotting between the vertebrae.
They found that a slipped disc could be likened to squeezing a jam donut, when the jam oozes out.
When a disc is pressurised and bended, the nucleus bulges out of its casing, thereby impinging the nerves coming out of the spinal cord.
This would then cause radiating pain down the legs and even potential back pain.
The University’s robotic hexapod was used by the team. It simulated a year’s worth of ‘lifting’ a 20kg box, with bending and twisting movements on sections of cadaveric human spine.
The hexapod robot was able to mimic human movements that were not possible previously with the standard mechanical testing devices.
The biomedical engineering researchers tracked the disc failure patterns and found that only half of the spines failed because of slipped discs, while the others failed through bone injuries.
This led the team to believe that there are other motions that can cause a slipped disc, which may be worse than just bending and twisting.
Further research on other combinations of motions will aid in better understanding what causes a slipped disc.
The prevalence of lumbar disc herniation is estimated at 3% – 5%. Lumbar disc herniation often presents with acute low back pain, followed by severe leg pain. These symptoms can persist for some time, resulting in work absence with significant cost to the economy.
Research like this is crucial if incidence of disc herniation is to be reduced. It is significant for those involved in manual handling tasks to be educated in safe lifting practice.
It is hoped to help develop better prevention protocols for safe lifting techniques, with a focus on manual labour workers and people within industries that involve repetitive heavy lifting.