Wednesday, September 19, 2012
from komaza aummer 2012
A prosthetic socket – the part of the prosthetic limb that attaches to the wearer’s residual limb – needs to fit perfectly. An ill-fitting socket can lead to pain, sores and blisters, and can also cause the prosthesis to feel heavy and cumbersome, compromising mobility. So sockets are designed to fit very tightly and are usually made from a cast mold. But the shape of a person’s residual limb can alter with weight gain or loss, changes in muscle composition, and age. A difference of just 2% in body weight – 3 pounds for a 150-pound person – will be enough to rotate the socket or cause the limb to piston within the socket, requiring a replacement. Even small fluctuations in fluid retention during the day can affect the socket’s fit.
In the US, a prosthetic socket is replaced on average every few years, due to changes in a wearer’s body or general wear and tear. But in developing countries, such frequent replacement is usually impossible. Sockets can be prohibitively expensive and there are few technicians skilled in the labor-intensive process of making custom-fitted sockets.
Elizabeth Tsai (MSc candidate in Media Arts and Sciences) and her collaborators in The BETH Project (Benevolent Technologies for Health) have innovated a way to circumvent this problem entirely: they have created an adjustable socket.
The Universal Readjustable Prosthetic Socket consists of a standard four-screw attachment plate, a protective outer casing and an inner sack filled with granular material. The granular material interior is the key piece of innovation. When placed in a vacuum, the material is extremely hard, much like an unopened bag of coffee. But when the seal is released, the material becomes soft and malleable, allowing the sack to be reformed on demand around the user’s shape. An inexpensive hand pump is used to release and return the vacuum seal. Once the socket is locked and solid, it performs the same function and has the same mobility as a regular socket.
A cheap adjustable socket would not only be useful in a developing country where people require regular replacements for prosthetic limbs; it would also be incredibly valuable in an emergency situation. The Red Cross donated many pylons (prosthetic legs) following the earthquake in Haiti. Unfortunately, most of these could not be used since it was not possible to donate ready-made custom-built sockets. The BETH Project’s adjustable socket is designed to attach to most pylons, so it could be used with donations like those from the Red Cross.
This creative and potentially transformative idea was developed at a weekend-long conference held in February 2012 run by Hacking Medicine, which encouraged participants to think way outside the box and hack conventional wisdom about healthcare. It was the second such event held by Hacking Medicine (the inaugural conference was in Fall 2011), whose mission is to create a community of physicians, entrepreneurs, engineers and other professionals who are passionate about improving healthcare.
Hacking Medicine is led by two MIT graduate students – Allen Cheng (MD-PhD candidate at MIT and Harvard) and Elliot Cohen (Sloan School of Management MBA candidate) – and Zen Chu, an Entrepreneur in Residence for the Trust Entrepreneurship Center at MIT. The trio founded Hacking Medicine on the belief that system disruption can be a good thing.
“To me, hacking is about clever engineering,” explains Cohen. “It is about looking at a system and thinking, I understand that the system is supposed to function according to these rules, but I’m going to make it function in a different way that achieves something we thought we couldn’t get – making the system quicker, cheaper, more effective”.
Rather than iteratively improving an existing system, the Hacking Medicine team believes in reevaluating the premise behind a system’s original design.
“The more traditional way [to approach system improvement] is to look at the process, take one part and improve it by 10%,” explains Cohen. “But the idea of our approach is to look at the system as a whole and see if it needs to exist as it does.”
Tsai participated in both the inaugural Hacking Medicine event last Fall and the recent Spring event. She was attracted to it because she has always been interested in medicine and felt that her engineering skills could be useful in that field.
“As an engineer, you think you have all these skill sets that can help other people, but you don’t know what the problems are. This event brings together engineers who want to solve problems and doctors who can identify problems,” Tsai says.
Prior to the weekend event, Tsai had never met the two other people she worked with to develop the prototype for the adjustable prosthetic socket. Asa Hammond is a pre-med physiology student at UCLA with a background in graphics and robotics, and Jason Hill is an industrial designer and graduate from the Art Center College of Design. A major goal of Hacking Medicine is to facilitate unusual collaborations like this, between people who might otherwise never meet but who have complementary skill sets relevant to healthcare innovation.
Having quickly moved from initial concept to preliminary prototype over the course of the weekend conference, The BETH Project team is working to advance their adjustable socket. Tsai says, “So far we’ve built a prototype, explored different business plans and reached out to potential
All photos: Elizabeth Tsai
Most items we wear on our bodies are static. Shirts, pants and shoes are not made to change shape or size, even though our bodies can alter substantially over very small timescales (witness the ritual unbuttoning of pants after Thanksgiving dinner). For wearers of prosthetic limbs, this discrepancy can be extremely problematic.
partners. There’s plenty left to be done on all fronts!”
The Hacking Medicine team is also moving forward with their mission. They are working on ways to help the community they created to interact and continue developing disruptive ideas. They are also designing a Healthcare Ventures course to be taught at MIT this Fall, which will teach the Hacking Medicine methodologies and strategies. Cohen says that the team is happy to provide advice to other students working on healthcare projects, and that Hacking Medicine is always looking for people with energy and passion to join the team.
For more information on Hacking Medicine, or to ask the team for advice or mentorship,