25 July 2012
New hope for stroke patients
The world's strongest micromotor could revolutionise stroke treatment, thanks to a partnership between The Royal Melbourne Hospital and RMIT University.
The motor is small enough to fit through the tiny vessels of the brain, and has the equivalent driving power of a small kitchen appliance.
At only 250 microns wide, the motor is about the width of a human hair and the size of a grain of salt.
It has been developed with the aim of treating strokes (caused by blocked arteries) and cerebral aneurysms (weaknesses in brain arteries) in patients who can't be saved with standard neurointervention endovascular tools.
The technological breakthrough came after RMIT School of Electrical and Computer Engineering professors James Friend and Leslie Yeo and neurointerventionist, Associate Professor Bernard Yan, from The Royal Melbourne Hospital, recognised the need to drastically improve the surgical equipment used to manage these life-threatening conditions.
Associate Professor Yan said current neurointervention procedures were unsuccessful about 15 per cent of the time, so the need to develop better tools was pressing.
"To treat patients who have suffered a stroke or cerebral aneurysms, we use microcatheters of flexible plastic with permanently bent tips to navigate through a patient's arteries and into their brain in order to reach the target and allow for treatment," he said
"The process is akin to navigating wet paper tubes with a half-boiled piece of spaghetti, and because the current tools are not flexible to guide through the tiny brain vessels, it can, on rare occasion, lead to puncturing an artery, which can result in disability or death.
"This tiny motor means we can now look to develop instruments which can be steered with precision, guiding the catheter to its destination more quickly and accurately.
"This will have a dramatic improvement in stroke survival rates and improve our patients' quality of life."
Professor Friend said others had tried bicycle-cable pulling schemes, advanced electroactive polymers, magnetic fields, and even plastic that expands on exposure to light, with little success.
"These methods are either too risky, need too much time to work, are too large to navigate 0.5mm diameter arteries of the brain, or offer poor control," he said.
"The first step in solving the problem was to develop a motor small enough to pass through the vessels that had sufficient torque to drive itself and the catheter along.
"Now we plan to place it on the tip of the micro-guidewire that is first inserted during endovascular procedures, allowing the tip to bend in whatever direction the neurointerventionist needs.
"We have shown that the patented micromotor technology works and are now aiming to deliver the micro guidewire with the motor."
The motor was developed over the past six years at the Melbourne Centre for Nanofabrication with National Health and Medical Research Council, Australian Research Council and CASS Foundation funding.
The research breakthrough has been published by the American Institute of Physics.
Professor James Friend.
Professor Leslie Yeo.