The Bionic Leg

For the last five years, Hailey Danisewicz has learned to deal with not having two healthy legs to walk on.

Diagnosed with an aggressive form of bone cancer when she was just 12 years old, Hailey endured years of chemotherapy and unsuccessful surgeries until her disease-ravaged leg became a burden.

“I wasn’t able to bend my knee. My leg was pretty much functionless. I was walking on crutches for two years,” she says.

It was then that she made the bold decision to have her left leg amputated above the knee. But it’s something she says she doesn’t regret.

“When I was 14, I went through with that and it ended up being the best decision I’ve ever made because my quality of life has just improved immensely,” she says.

Now a sophomore at Northwestern University studying Human Development and Psych services, Hailey is part of a research program at the Rehabilitation Institute of Chicago.

“When I moved to Chicago, I started to see a prosthetist at RIC,” she explains. “When I came in for my first appointment, they told me about some of the research that was going on here and it sounded very appealing.”

The Bionic Leg

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That research has been at the cutting edge of creating prosthetics that amputees can control just by thinking about the intended movement. Using a pioneering technique called muscle reinnervation the remaining nerves from the arm are surgically implanted into chest muscle.

“The idea behind targeted reinnervation is that you can use those healthy nerves and just transfer them onto healthy muscle,” explains Levi Hargrove, Research Scientist at RIC’s Center for Bionic Medicine.

“And then the patient just has to think, move their hand and the nerves signal, instead of moving to hand muscles, move to chest muscles. Our electrodes pick up that activity and our computers tell the bionic arms what to do.”

But now, with the help of people like Hailey, the Institute is moving forward into research that would demonstrate real-time neural control of knee and ankle motions for lower limb amputees.

“There are very few groups doing it,” Hargrove says.

Results from the early-stage research of RIC’s Center for Bionic Medicine, were published today in the Journal of the American Medical Association.

“I think it’s pretty groundbreaking,” says Hailey. “When I first had my amputation, I was told that a lot of the research was being done with arms controlling things with muscles and the fine motor control, that that wasn’t really possible for legs.”

But that’s changing.

Since January Hailey has been working with the research team at RIC where she is learning to control a virtual reality leg just by thinking about it.

During this process, Hailey is ordered to think about moving her virtual leg a certain way.

When she thinks about the movement that has been ordered, the electrical impulses her brain is sending to her nerves are recorded by the computer, and in turn controls the virtual leg.

“The signals are very similar, explains Hargrove. “There is some variability but we can train the computer to recognize that variability. What Hailey is doing right now is making motions that she would have normally made. She’s not doing anything that’s unintuitive.”

The next step in the research is translating that data in a form that would be able to control an actual motorized prosthetic leg.

Hargrove says right now research scientists are using a powered knee as a prototype.

“We’re working to incorporate a powered ankle to the design,” he says flexing the motorized leg. “We’ll have many enhancements when it’s ready for widespread patient use. But right now it’s a great tool to do our research with.”

Hargrove says the goal is to have Hailey move from controlling the virtual leg to controlling the motorized leg by the end of the year. It’s an ambitious goal.

What makes this research so exciting, say scientists, is that it’s believed to be the first time an amputee would be able to control both the knee and ankle of a prosthetic limb just by using neural signaling.

Hailey says she’s just excited to be a part of it.

“I think that’s what’s the coolest part about it, just knowing that this is going to change so many people’s lives, especially now, you know with all the veterans that are coming home,” she says. “I think it’s really great that I’m able to use what’s happened to me, to kind of give back in a certain way.”

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