Volunteers have hands amputated, replaced by bionics

Chuck Bednar for redOrbit.com – @BednarChuck
Three men suffering from severe nerve damage volunteered to have their hands amputated and replaced with mind-controlled bionic prostheses, according to research published Tuesday in the medical journal The Lancet.
The process is known as “bionic reconstruction,” and according to Gizmodo, the procedures were performed by Dr. Oskar Aszmann at the Medical University of Vienna, Austria. Each of the volunteers had suffered damage to a bundle of nerves between the hand and the spine known as the brachial plexus that caused paralysis in their hands.
Teaching old dogs new tricks
All of the patients had reportedly undergone surgical procedures to attempt to repair the damage, but none of those operations were successful, leading them to volunteer for bionic reconstruction as an alternative, the website added.
Prior to surgery, their bodies and brains had to undergo a training procedure, as a section of leg muscle was transplanted into their arms to boost the signals of the few functioning nerves which remained. Nerves were allowed to grow into the muscle for a period of three months.
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Afterwards, the started practicing activating the muscle using an armband of sensors that could detect the electrical activity, New Scientist explained. Next, they moved on to using the signal to control a virtual arm, and finally, Dr. Aszmann amputated their hands and replaced them with a standard prosthesis under the control of the muscle and sensors.
Prosthetic works better than the real thing
The new hand is independently powered and requires only a small amount of input from the nerves of the grafted muscle to operate. The transplant was successful, as each of the patients can now pick up a ball, pour liquids from a jug and do up buttons and clothes fasteners. The simple and functional prosthetic hand outperformed their damaged biological on in all three cases.
“I was impressed and first struck with the surgical innovation,” Dustin Tyler of the Louis Stokes Veterans Affairs Medical Center in Cleveland, Ohio, told New Scientist. “There’s something very personal about having a hand; most people will go to great lengths to recover one, even if it’s not very functional. It’s interesting that people are opting for this.”

The patients went through a series of limb function tests, including one called the Southampton Hand Assessment Procedure, following the surgery. On this test, which is graded on a scale of 100 (with 100 being a normally functioning hand), the patients saw their scores improve from a nine to a 65. However, while the transplant restores functionality, it cannot restore touch.
“There are about 70,000 nerve fibres to a normal hand, and the majority of these are sensory fibres carrying hand-to-brain information. Only 10 per cent are motor fibers,” Dr. Aszmann said. Tyler, on the other hand, told New Scientist that he is working on a prototype prosthetic arm that will provide hand-to-brain information transmission, not just motor control.
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The current version of Tyler’s device uses wires to deliver electronic stimulation to nerves in the arm, but he claims that his team will have a fully implantable wireless version in as little as three years. Even then, the website added, “our technological alternatives to the hand will remain crude compared with fully functional human hands.”
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