At the University of Waterloo in Canada, researchers have developed a microfluidic pneumatic system that regulates pressure in the socket of a lower limb prosthesis. The goal is to achieve the ideal pressure and adjust the fit of the prosthesis to compensate for changes in the size of the residual limb due to swelling. Modern lower limb prostheses require users to manually change silicone and fabric pads to adjust the fit of their prosthetic device. This is suboptimal, especially in diabetic patients who may have limited sensation in their residual limb, leading to chafing and ulcers. This new device contains miniature pneumatic actuators that can precisely control the fit of the prosthesis, helping to reduce irritation.
Diabetes is a leading cause of leg amputation, and these patients have an added complication when it comes to managing the residual limb. Diabetes can also cause a loss of sensation in the residual limb, making it difficult to know whether a prosthesis is causing a problem or not. The relationship between the residual limb and the prosthesis can become problematic if the limb swells throughout the day, but patients with diabetic neuropathy may not be aware that chafing and chafing are occurring. This can eventually lead to serious problems such as ulcers.
Swelling of the lower limb can be unpredictable, and current prosthetic wearers manually change silicone and fabric pads to adjust the fit as needed. However, in diabetic patients, this technique is not as useful, as limited sensation may mean they don’t know there’s a problem at first. This problem led researchers at the University of Waterloo to develop a new system that can automatically adjust the pressure experienced by the residual limb.
The system consists of miniaturized soft robotic actuators that are controlled by a microfluidic device. The microfluidic component contains ten integrated pneumatic valves that control one actuator each. Actuators align the socket of the prosthesis and help adjust the pressure as needed. “Instead of creating a new type of prosthetic socket, the typical silicone/cloth lining of the limb is replaced with a single layer of lining with integrated soft fluid actuators as the interface layer,” said Carolyn Wren, a researcher involved in the study. “These actuators are designed to inflate to different pressures based on the anatomy of the residual limb to reduce pain and prevent pressure ulcers.”
In the future, the Canadian team hopes to refine the system so that it redistributes pressure from areas of the residual limb that are particularly sensitive to pressure, such as the fibular head, to other areas that are better able to handle the pressure. The hope is that the technology will lead to prostheses that are more comfortable to use and less likely to contribute to problems such as ulcers.
Research in a journal Biomicrofluidics: Soft Robotic Transtibial Prosthesis Socket Lining with Air Microfluidics for Dynamic Management of Limb Residual Contact Pressure and Volume Fluctuation
Through: American Institute of Physics
Pneumatic Prosthesis to Reduce Pressure and Irritation for Amputees