MIT - Massachusetts Institute of Technology

New amputation procedure offers promise

Not anymore.

A first-of-its-kind amputation procedure, conducted in July, was shared during a news conference at Brigham and Women’s Faulkner Hospital in Boston. “Dynamic-model amputation” may allow the brain to interact with and power a prosthetic — and sense where a limb is without the patient having to look. With a preserved relationship between muscles in concert with prosthetic innovations, Dr. Matthew Carty explained, patients may enjoy restored limb function in new and more natural ways.

The idea of what could be possible was a welcome one for Jim Ewing, 52, who underwent the experimental procedure. An engineer by training, he liked the idea of being part of something visionary.

About two years ago, Ewing, of Maine, fell 50 feet while rock climbing in the Cayman Islands. He landed on his left side and received multiple injuries, including a shattered ankle. No matter the excruciating work he did in physical therapy, severe nerve damage blocked meaningful progress.

He could not walk barefoot. Stepping on a simple grain of sand would fire off sharp and stabbing pain. In shoes, he couldn’t travel 100 feet without stopping in exhaustion and agony. He plowed through medical journals and researched clinical trials, but nothing suggested that his ankle could be saved. He couldn’t bear to live with this sort of pain.

A longtime climber, he reached out to Hugh Herr, a man he’d met 30 years before.

Jim Ewing takes his first steps after his amputation.
Herr, himself a climber whose legs were amputated below the knees after he was rescued from a 1982 winter climb, had become head of biomechatronics research at the MIT Media Lab. Biomechatronics is a field that combines human physiology with electromechanics in developing bionic limbs. Ewing told Herr he wanted to know what life would look like if he decided to amputate his foot.

Ewing said Herr told him of those who’d struggled for years, only to have their limbs amputated in the end. He also told him how surgeons had generally viewed amputation as a failure.

“Finally,” Ewing said, “he told me about the research he and Dr. Carty were doing. … I was intrigued.”

Soon after meeting with Carty, director of the lower extremity transplant program at Brigham and Women’s Hospital, he was sold.

“It’s now been four months since I had my foot removed. It’s been challenging. I won’t lie,” Ewing said. Nonetheless, he’s “100% certain I made the right decision.”

‘The Ewing Amputation’

A standard amputation cuts feedback between muscles, Carty said. But by creating a tendon pulley system through “the Ewing Amputation” — as this new procedure will be called — muscles can work in relation to one another, and patients can maintain a better connection to the nervous system and to the feeling of limb control.

Carty has been collaborating with other plastic, vascular and orthopedic surgeons as well as Herr’s team at the MIT Media Lab. His work was bolstered in 2014, when he was awarded the first Stepping Strong Innovator Award, established by the The Gillian Reny Stepping Strong Center for Trauma Innovation to fund projects in innovative trauma treatment and recovery. (Reny was 18 when her legs were critically injured — and later saved — during the 2013 Boston Marathon bombing.)
Jim Ewing is rock climbing again after an experimental surgery that could change the future of amputation.

On the MIT Media Lab team is Tyler Clites, a Harvard-MIT doctoral candidate in health sciences and technology. He shared a video to demonstrate how sensors on Ewing’s left leg track the electrical activity in his muscles, showing results unseen in previous methods of amputation. Within the next few months, Clites said, Ewing should have wireless sensors implanted in his muscles, which will integrate with the robotic prosthetic being created for him.

Ewing will be able to point and flex his prosthetic foot and rock his ankle from side to side — a range of motion made possible by the new surgical approach.

Without knowing the intricate details, Mike McLoughlin is intrigued by what Carty and the MIT Media Lab are doing. He’s the chief engineer for the research and exploratory development department at Johns Hopkins University’s Applied Physics Laboratory. In this role, he serves as the principal investigator for the Revolutionizing Prosthetics Program.

McLoughlin said his team has made similar strides with upper extremity prosthetics, using electrodes and computers to detect muscle movement and help the brain communicate with the prosthetic. People can imagine opening and closing their hands, for example, and see it happen.

What’s new here, McLoughlin believes, is the focus on lower extremities. What a hand does is complex, he said, and when we use our hands, we’re generally aware of what we’re using them for. With feet, we walk and run without thinking about them in the same way.

With issues like balance and the need to hold significant weight, he said, what Carty and the MIT Media Lab are attempting involves a different set of challenges.

“It’s a really exciting thing they’re doing here,” McLoughlin said. “I’m anxious to see where they’re going with it.”

A better quality of life

Carty’s procedure to restore the natural dynamic of limbs should work for both lower and upper extremities, the surgeon said. And though the team hasn’t implemented a way to revise the procedure for those who’ve already experienced an amputation, he said, “We have an idea of how that would work.”

Rather than see amputation as a failure, the result of “throwing in the towel,” he and others hope this procedure will help people view amputation as a choice, a possibility that may restore a better quality of life.

That’s certainly been the case for Ewing, who — even though he hasn’t gotten his final robotic prosthesis — is already grateful.

With his temporary prosthesis, he went on a 2-mile walk recently and has returned to climbing indoors.

“I’m even relearning how to run, though they don’t want me running yet,” he said. “It’s so liberating to be moving so quickly and easily.”

To be a part of this milestone experiment motivated him, he said. It gave him “a chance to give back to society” in a meaningful way.

“I literally fell into this situation,” Ewing said. “I consider it a great honor to have this new protocol bear my name.”

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