November 29, 2011

UT Designing, Building O&P Devices for Injured Service Members

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Richard R. Neptune, PhD, associate professor of mechanical engineering in The University of Texas at Austin Cockrell School of Engineering, and a team of graduate students are designing and building lightweight O&P devices for injured service members. The prosthetic devices and AFOs that not only improve functional mobility, they increase patient comfort, are customized to each patient’s need, and could reduce costs.


Richard Neptune displays the prosthetic foot he designed and built with his team of students. Photograph courtesy of The University of Texas at Austin Cockrell School of Engineering.

“We’re having them walk over uneven ground, going up and down stairs, running a whole battery of other tests, to be able to understand how they adapt to the different stiffness levels of these orthotic and prosthetic devices,” Neptune said. “One of the challenges though is that everybody has a different injury.”

Neptune and his team have been working through research collaborations with the Department of Veteran Affairs (VA) Center of Excellence for Limb Loss Prevention and Prosthetic Engineering,Seattle, Washington, and the Center for the Intrepid (CFI), San Antonio, Texas.

“It’s rewarding to be able to give back to the people who have done so much for our country,” said U.S. Army Colonel Rachel Evans, research director for the CFI, who recently returned from a six-month deployment in Afghanistan. “When you watch a patient who’s been injured, walk or run again for the first time, and you see the look on their face, it’s very moving.”

The goal of the center is beyond restoring functional mobility, Evans said. She and others aim to restore soldiers to the highly active lives they had prior to their injuries, and which were a part of their jobs in the military.

That’s where Neptune comes in.

Using an AFO designed by Ryan Blanck, CPO, with the CFI, Neptune and his students are creating struts—the part of the AFO that acts like a muscle.

Struts and prosthetic devices built by Blanck, Neptune, and his students store and release elastic energy—giving patients the ability to run and jump—and they’re customized to meet the specific needs of a patient unlike many struts and prosthetic devices commonly used. For instance, depending on how tall a patient is and how quick and spread out his gait is, he may need an orthotic device that’s longer or more elastic.

Neptune and his students can account for these specific needs through cutting-edge design technology developed at UT. Known as selective laser sintering (SLS), the technique allows Neptune and his students to design a prosthetic limb or orthotic device on a computer, and then replicate the 3D design with a laser process that melts, or “sinters” a special nylon powder. The powder is transformed layer by layer into a hard, but elastic prosthetic device that is specific to each individual’s physical characteristics and gait.

“In the end, we want to be able to understand the relationship between these design characteristics and the gait performance of the individual, so that clinicians are better informed when prescribing an appropriate orthotic device or prosthetic device for each patient,” Neptune said.

While the research is currently focused on O&P devices for military personnel, its applications are far-reaching given that the number of diabetes-related amputations are projected to increase dramatically over the next 40 years.

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