Patients left paralysed by injury or illness could be back on their feet again, thanks to a breakthrough by Melbourne researchers who have designed a revolutionary bionic spine.
With human trials set for next year, the device implanted into the brain will enable patients with spinal cord injuries to control a robotic limb by harnessing the power of thought.
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'Bionic spine' breakthrough in Melbourne
The 'holy grail' of creating movement via thought may about to be realised, thanks to a stent the size of a paper clip that can be implanted into brains of paralysed patients.
"It's the holy grail for research in bionics," said Terence O'Brien from the Royal Melbourne Hospital where patient trials will begin late next year.
Professor O'Brien is overseeing the groundbreaking project, which involves a team of 39 neurologists and biomedical engineers from the hospital, Melbourne University and the Florey Institute of Neuroscience and Mental Health.
Key to the bionic spine is a stent the size of a small paperclip. With the aid of a catheter, the stent is inserted into the jugular vein in the neck and pushed up the vein until it reaches the motor cortex - the part of the brain at the top of the head which controls movement.
Using a vein as a highway to transport the stent means patients will avoid invasive brain surgery and hospital stays, with the technique instead requiring little more than a day procedure accounting for a few hours.
The vein also cocoons the stent, allowing it to slip under the immune system's radar. This means the body does not try to expel the stent, as it would a splinter or another foreign object.
Clive May, from the Florey Institute of Neuroscience and Mental Health said sheep trials showed the stent emitted a signal throughout the 190-day test period - and that the signal became stronger once tissue grew around the stent, locking it in place. He said the animal trials also showed the chance of blood clotting around the stent was minimal.
Containing 12-electrodes, the stent is like a recording device which collects the electrical activity from neurons in the patient's motor cortex before translating the activity into commands. The commands are carried via 12 wires to a transmitter implanted just under the skin on the chest. The transmitter then sends the commands wirelessly to an exoskeleton - or to a wheelchair.
"Our vision, through this device, is to return function and mobility to patients with complete paralysis," said Thomas Oxley from the Royal Melbourne Hospital and the Florey.
Melbourne University biomedical engineer Nicholas Opie designed the metal stent, which has elastic properties to allow it to bend and compress as it travels through the twists and turns of the vein.
Once in place, the stent expands so the 12 electrodes press against the walls of the blood vessel.
Outlined in the journal Nature Biotechnology on Tuesday, Dr Opie said he expected the stent would prove transformational for other areas of bionics, including the quest to build a bionic eye, not least because the stent did not involve electrodes being implanted in the brain.
"There are also a lot of blood vessels in the brain and a lot of other areas that can be accessed so that means there is a lot of potential," he said.
Patients participating in the trial next year will be selected from Austin Health's Victorian Spinal Cord Unit. Three paraplegic patients will be selected first, as they have the most to gain from a bionic spine.
Professor O'Brien said in future, the stent could also play a role in the treatment of neurological conditions such as epilepsy, Parkinson's disease and Motor Neuron disease by serving as a neural stimulator.
Just three years in the making, the project was funded partly by $1.6 million from the National Health and Medical Research Council and the US Army, which provided US$1.3 million in the hope it will enable soldiers injured in the field to regain their mobility.
According to the most recent Australian study, conducted in 2007-08, the average age for spinal cord injury was 41 years for males and 44 years for females, with the majority of injuries acquired by males.