Seventeen years after losing the use of his hand in a motorcycle crash, Marcus Kemeter volunteered to have it amputated and replaced with a bionic version.
“It wasn’t hard for me to decide to do the operation,” said Kemeter, 35, a used-car dealer in Austria. “I couldn’t do anything with my hand. The prosthesis doesn’t replace a full hand, but I can do a lot of stuff.”
Kemeter’s artificial hand was made possible by a new medical procedure developed at the Medical University of Vienna, which combines reconstructive surgery with advances in prosthetics and months of training and rehabilitation, according to an article published Wednesday in the Lancet, a U.K. medical journal. The researchers performed the procedure on three Austrian men from 2011 to 2014.
The technique, called bionic reconstruction, offers hope for patients like Kemeter who have brachial plexus injuries, which can result in severe nerve damage and the loss of function in the arms.
The nerves of the brachial plexus start in the neck and branch out to control shoulder, arms and hands. They can be damaged in collisions from car and motorcycle accidents, and in sports like football and rugby. In the past, surgical reconstruction for brachial plexus patients could restore some function in their arms but not hands.
The injuries result in an “inner amputation,” permanently separating the hands from neural control, said Oskar Aszmann, a professor of plastic and reconstructive surgery at the Vienna university who is the lead author of the Lancet study.
The damaged limbs “are a biologic wasteland,” Aszmann said in a telephone interview. The solution is transplanting nerves and muscles from the legs into the arm, creating new avenues for signals from the brain.
“We can establish a new signal and we can use these signals to drive a prosthetic hand,” he said.
The process represents a significant step for patients with brachial plexus injuries, said Levi Hargrove, a researcher in prosthetics at the Rehabilitation Institute of Chicago.
“It provides them with an option,” he said. “As mechanical prosthesis become more advanced and more functional, this should only improve.”
The ultimate success of the procedure won’t be known for years and will depend on how often patients use their new hands, said Simon Kay and Daniel Wilks in a Lancet article accompanying the study. Kay is a hand surgeon at the Leeds Teaching Hospital, while Wilks is at The Royal Children’s Hospital in Melbourne.
“Compliance declines with time for all prostheses, and motorized prostheses are heavy, need power and are often noisy,” they wrote.
Kemeter, who lives in the Lower Austrian town of Hollabrunn, damaged his shoulder in a 1996 motorcycle accident. That year, he had surgery that grafted new nerves to his arm, which restored some function to his shoulder and elbow. Over the next decade and a half, his arm withered and atrophied, with his fingers permanently clenched.
“I could feel everything but I couldn’t do anything with the hand,” he said.
In 2011, Aszmann transplanted Kemeter’s nerves from his lower leg and muscle from his thigh to his injured forearm. After waiting three months for the nerves to grow back, Kemeter’s arm was connected to a computer, where he could practice manipulating a virtual hand.
“The brain has forgotten to use the hand,” Aszmann said. “We have to retrain them.”
The next step was connecting the prosthesis to the new nerves, with Kemeter’s biological hand still in place, to train him to use the device. That helps patients with the decision to amputate, Aszmann said.
“When it’s obvious this mechatronic hand can be of great use to them, then the decision to have the hand amputated is a very easy one,” he said. “If I have to convince someone, they’re not a good patient.”
Finally, after the amputation wounds healed and the prosthesis was fitted, the adjustment to the new appendage took only a few days.
“I can do much more than before,” Kemeter said. “Carrying big things, for example, wasn’t possible with only one hand. Now I can do it.”
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