From MIT News Office
"In the United States, a typical prosthetics specialist who fits
artificial legs for amputees might handle 15 or 20 such patients a
year, fitting them with custom-built legs that can cost upward of
$6,000 apiece. Each patient then gets a series of follow-up visits to
make sure the new limb was properly fitted.
But in India, the
Jaipur Foot Organization handles that many patients every day in each
of its local centers. The charity is the world's largest provider of
prosthetics and has worked with about a million patients since being
founded in 1975.
The JFO, also known as Bhagwan Mahavir Viklang
Sahyata Samiti, is based in Jaipur, a city of more than three million
people that is the capital of Rajhastan in northern India. The
artificial legs they provide, based on a locally developed design, cost
about $40, and the company has little time or funding for follow-up
consultations, or for developing new methods.
A team of MIT
students has been working on a new device that could greatly simplify
the process of fitting these legs, producing a better fit while
eliminating some steps in the process and reducing waste materials. The
hand-powered system, which requires no external power, would also
greatly simplify the fitting of legs in rural areas, where the present
electrically powered fitting system requires bringing along a bulky
generator.
The first step in fitting a leg is to make a mold of
the person's stump to provide a precise fit. This is done by placing
the stump into a container filled with tiny glass beads and covered
with soft silicone rubber, and then creating a vacuum so that the beads
seal tightly around the limb. This "negative" mold is filled with more
glass beads (referred to as "sand") to form a positive mold--an exact
replica of the stump--and the socket of the prosthetic leg is made to
fit that replica. Alternatively, the two steps can be done with plaster
of paris instead of the sand--a process that doesn't require
electricity but does use heavy, non-reusable plaster.
The MIT
system was designed under the auspices of the D-Lab in the Department
of Mechanical Engineering. Mechanical engineering students Philip
Garcia, Maria Luckyanova and Tess Veuthey, physics student Jessica
Schirmer, and D-Lab instructor Goutam Reddy have been working on the
project--some of them for more than a year.
The new fitting
system they devised uses a handcrank to produce the vacuum, eliminating
the need for electric power. And the same device can be used to produce
both the initial negative mold and the positive mold that replicates
the shape of the stump...."
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