A man who lost his leg in a motorcycle accident has made history by using a thought-controlled bionic leg to reach the top of one of the world’s tallest skyscrapers. By simply thinking ‘climb stairs’ – Zac Vawter, made his way up 103 flights of stairs to the top of Willis Tower in Chicago on the revolutionary prosthetic leg. The robotic leg responds to electrical impulses from muscles in his hamstring, with his thoughts triggering motors, belts and chains to synchronise the movements of the prosthetic ankle and knee.
Researchers from the Rehabilitation Institute of Chicago (RIC) monitored his progress but believe the incredible technology is still a few years away from being marketable.
Mr Vawter had to leave the experimental leg behind with them afterwards to run more testing – but the climb signals major strides forward in this type of pioneering medical technology.
Thought-controlled prosthetic arms have been available for years but with leg amputees outnumbering people who have lost arms and hands, researchers are focusing more on lower limbs.
The 31-year-old, who reached the top of the tower in under an hour with no breaks, said: ‘One of the reasons I wanted to do this was because I was so thankful for everything the RIC have done for me – I wanted to pay them back.
‘Before the accident I loved to run and afterwards I didn’t think I would ever be able to be so active again.
‘Mentally and physically I felt prepared for the climb, so it was kind of what I expected. I got a real kick out of it and felt really strong. I made it in excellent time with no issues.
‘The doctors and team who have come this far with me have been great and their support has helped me the whole way.
‘Standing up the top of the tower I really wasn’t expecting such an incredible view at the finish line. It was a fitting way to end the climb.’
To prepare for the climb, Zac and the scientists spent hours adjusting the leg’s movements. Eleven electrodes placed on the skin of Vawter’s thigh fed data to the bionic leg’s microcomputer and researchers turned over the ‘steering’ to him.
Behind closed doors he was able to kick a football, walk around a room and climb stairs.
He was able to take part in the test thanks to the foresight of surgeons who amputated his leg after the accident in 2009.
During the operation, a surgeon repositioned the residual spaghetti-like nerves that normally would carry signals to the lower leg and sewed them to new spots on his hamstring.
The surgery, called ‘targeted muscle reinnervation’, would allow Zac to one day be able to use a bionic leg, even though the technology was years away.
Researchers insist safety is incredibly important – as if a bionic hand fails, a person drops a glass of water but if a bionic leg fails someone falls down stairs.
The $8m project is funded by the U.S. Department of Defense and involves Vanderbilt University, the Massachusetts Institute of Technology, the University of Rhode Island and the University of New Brunswick.