Singaporean researchers have developed a robotic sock that mimics tentacle movements of corals to stimulate muscles of bedridden patients to prevent dangerous thrombosis.
Offering an alternative to blood-thinning drugs, administered regularly to patients who can’t move their legs to reduce the risk of deadly blood clots, the actuators-equipped sock induces contractions in lower leg muscles, thus promoting blood circulation.
“We chose to use only soft components and actuators to increase patient comfort during use, hence minimising the risk of injury from excessive mechanical forces,” said Low Fanzhe, a PhD researcher at the Department of Biomedical Engineering of the National University of Singapore.
“Compression stockings are currently used in hospital wards, so it makes sense to use a similar sock-based approach to provide comfort and minimise bulk on the ankle and foot.”
The researchers believe the robotic sock provides a safer alternative to pharmaceutical blood-thinners, which, although effective in reducing the risk of blood-clotting, could on the other hand lead to excessive bleeding.
The method is also believed to be more efficient than compression stockings, used similarly to assist blood flow.
When looking for a novel solution for the deep vein thrombosis problem, the team found inspiration in the natural function of human ankle joint muscles, which facilitate blood flow back to the heart.
Surprisingly, the researchers found similarities between human ankle movements and the design of coral tentacles, used by the invertebrates to catch food.
Using a sort of push and pull mechanism, the corals bring food closer to them. The robotic sock, equipped with a programmable pneumatic pump-valve control system, induces a similar contracting motion to make the ankle joint move.
“Given its compact size, modular design and ease of use, the soft robotic sock can be adopted in hospital wards and rehabilitation centres for on-bed applications to prevent deep vein thrombosis among stroke patients or even at home for bedridden patients,” said Assistant Professor Raye Yeow Chen Hua. “By reducing the risk of DVT using this device, we hope to improve survival rates of these patients.”
Six-month clinical trials of the device will commence in March, involving about 30 patients at the National University Hospital in Singapore. The researchers hope to gather enough clinical data for further improvements and eventual commercialisation of the device.
The researchers believe the sock could become a valuable addition to conventional physiotherapeutical procedures as it allows physicians to track the motion of the ankle joint, thus monitoring whether exercises are being done properly.
The robot assisted exercises would also allow increasing the amount of time the patients spent on their ankle work-outs in the absence of a therapist, leading to further improvements.