Artificial Limbs Are Set to Get Some 3-D Assistance

A new project aims to deliver better prosthetic sockets at a fraction of the cost—and to a country that desperately needs it.

(Photo: Courtesy CBMCanada.org)

Feb 5, 2015· 2 MIN READ
Katharine Gammon has written for Nature, Wired, Discover, and Popular Science. A new mom, she lives in Santa Monica.

Three-dimensional printing has myriad uses, from printing pizza and car parts to smartphone cases and even guns. But an ambitious new project looks to set the bar higher by using the technology to print custom sockets for artificial limbs.

Christian Blind Mission, a nonprofit supporting disabled people in the developing world, received a $90,000 grant in December from the Grand Challenges Canada fund to print custom sockets at a fraction of the cost and make them widely available to low-income countries in need.

“There are more than 10 million people in the world with amputations, most of whom live in developing countries,” Mitch Wilkie, CBM’s director of international teams, told SciDev.net. He added that 300,000 of those people have lost a limb due to land mines, and the number creeps up by 26,000 each year. There’s also a shortage of about 50,000 prosthetic technicians based on demand, he told Global News.

Titled 3D PrintAbility, the project will first launch in Uganda, where there are more than 2.46 million disabled people, according to the International Monetary Fund. Of those, more than 250,000 are children, many of whom lost limbs from land mines or debilitating diseases such as polio. There are only 12 trained prosthetic technicians on record in the country of more than 37 million.

(Photo: GlobalNews.ca)

While aid agencies can distribute artificial limbs, those limbs need custom sockets to attach to their owners—and those sockets take time and money to create. Custom sockets make artificial limbs usable; they have to fit perfectly to the user’s remaining body part, and they can be uncomfortable if they don’t work just right. Currently, doctors make a plaster mold of a person’s limb to create a unique socket. The molds can take days to dry, harden, and cure before a patient gets the custom socket.

The software-guided PrintAbility project is far more precise and can be completed in as a little as six to 12 hours. A field worker measures a patient’s remaining limb with a handheld laser scanner to create a digital image in minutes. The scan is then sent to a 3-D printer to create the prosthetic limb using cornstarch-based PLA plastic, a type of bioplastic commonly used in 3-D printing. The software also allows researchers to change the pressure points of the socket to design a fit around the limb that maximizes comfort, University of Toronto researcher Matt Ratto told an interviewer.

The project hopes to reduce the cost of printing a socket from about $5,000 to $250—a far more affordable solution that could change the lives of children who require multiple sockets to accommodate their limbs as they grow (up to 25 over a lifetime). CBM estimates that the material used to create each socket costs only $3, and the whole system can be set up for less than $12,000 in equipment.

Researchers at the University of Toronto have already been working for a few years on the system. They started by using a $200 Microsoft Xbox gaming system, which typically follows a player’s movements, to scan a limb; together with a sophisticated piece of software, the scanner can map out the socket’s dimensions.

CBM will collaborate with Comprehensive Rehabilitation Services Uganda and the University of Toronto’s Faculty of Information (iSchool) to field-test the system at a children’s hospital in Uganda early this year, starting with 35 patients over the next six months.