The Rehabilitation Institute of Chicago (RIC), Illinois, publicly unveiled what it calls the first “thought-controlled bionic leg.” Developed for individuals with transfemoral amputations, the computerized prosthetic leg has actively powered knee and ankle joints that are neurally controlled by the user’s thoughts via targeted muscle reinnervation (TMR). TMR is a surgical procedure that reroutes brain signals from nerves severed during amputation to intact muscles, allowing patients to control their robotic prosthetic devices by merely thinking about the action that they want to perform.
When Vawter pushes on the prosthesis to stand-up, the device reads his intent and pushes back on him propelling him up. “One of the biggest differences for me is being able to take stairs step-over-step like everyone else,” he said.
Photograph courtesy of RIC.
Seattle, Washington-resident Zac Vawter, 31, debuted the prosthesis on November 4, when he was joined by nearly 3,000 others as he climbed 103 flights of stairs for the SkyRise Chicago fundraising event, which benefits research and clinical care at RIC. Vawter lost his right leg in a motorcycle accident three years ago. He received the TMR procedure when his leg was amputated and became part of RIC’s research trial about a year ago. He travels to Chicago every few months to work with the RIC team to refine the control mechanisms with this leg system.
TMR was pioneered in 2002 by Todd Kuiken, MD, PhD, director of RIC’s Center for Bionic Medicine and director of Amputee Services at RIC. Levi Hargrove, PhD, director of the Neural Engineering for Prosthetics and Orthotics Lab within RIC’s Center for Bionic Medicine, said RIC is leading efforts to improve the neural-interface of the prosthesis for improved control of the robotic leg hardware. “Our interest is primarily in improving the control options for amputee patients,” he said.
This work is a result of a grant from The Department of Defense Army’s Telemedicine and Advanced Technology Research Center (TATRC). This work is a collaborative effort lead by RIC’s Center for Bionic Medicine, also including the University of New Brunswick, Fredericton, Canada; Vanderbilt University, Nashville, Tennessee; Massachusetts Institute of Technology (MIT), Cambridge; and the University of Rhode Island (URI), Kingston. The robotic leg prototype Vawter used was designed by Michael Goldfarb, PhD, the H. Fort Flowers Chair in Mechanical Engineering and professor of mechanical engineering and of physical medicine and rehabilitation at Vanderbilt, and has undergone extensive testing at both Vanderbilt and RIC.
Vanderbilt and Freedom Innovations, Irvine, California, entered a worldwide licensing agreement in 2011 that grants the company exclusive rights to commercialize the prosthesis. A partnership agreement between Freedom Innovations and RIC for development of the neural control is in process.
