Discomfort associated with wearing a device continues to be one of the most common complaints from users of prosthetic or orthotic products, according to Hugh Herr, PhD, director of biomechanics and the Center for Extreme Bionics at the Massachusetts Institute of Technology.
In a symposium entitled “Future of prosthetics: Analyzing the tissue socket interface” at the 2017 American Orthotic & Prosthetic Association World Congress, Herr said he and his team at Extreme Bionics are working to develop the “science of comfort” by combining body imaging, soft tissue modeling, regenerative computational design and digital manufacturing.
“In this new paradigm, we take individual patient data — a substantial, comprehensive data representation of the human — and we model the human or a part of the human, such as the residuum, with physics-based modeling,” Herr said. “We then do a digital design with that digital human where we co-model the human-machine interactions and we search digitally, computationally, across many different designs. So instead of cutting and grinding in a physical way, we do that in a simulated world. Then, we use fabrication in the manufacturing.”
According to Herr, the result is “personal bionics” or bionics that is personal to the nuances of the individual patient.
He added that models that measure how a socket affects the skin, with factors such as skin pressure, tissue strain and skin shear forces, can allow researchers to “test hypotheses about what comfort is.”
“What we can do is use the model to predict peak tissue strains that often appear near the soft tissue-bone boundary,” Herr said. “ … It can then come up with a patient’s optimal socket. We could say, ‘This socket minimizes the patient’s tissue trains. It’s optimal. We know it’s optimal.’”
From there, manufacturers can use 3-D printing to fabricate such optimal sockets to meet the exact measurements and specifications.
“This is an exciting time,” Herr said. “We finally have the tools — the imaging, the computational tool, the 3-D printing — to fundamentally change how we are building sockets and mechanical interfaces.” – by Jason Laday
Herr H. Future of prosthetics: Analyzing the tissue socket interface. Presented at: American Orthotic & Prosthetic Association World Congress; Sept. 6-9, 2017; Las Vegas.
: Herr reports no relevant financial disclosures.