Today, the Washington Post reports that a new life is within reach for the first woman with bionic arm (free registration required). Claudia Mitchell lost an arm in a motorcycle accident, but she's now using a 'bionic' arm that she can control with her thoughts. This bionic arm was designed at the Rehabilitation Institute of Chicago with funds from DARPA. And in a separate article, the Associated Press adds that this artificial arm could provide hope for soldier amputees, such as "the 411 U.S. troops in Iraq and 37 in Afghanistan who have had wounds that cost them at least one limb." It would also help many civilians. But read more...
Here is one excerpt from the Washington Post article.
Mitchell and the first person to get a bionic arm -- [Jesse Sullivan,] a power-line technician who lost both arms to a severe electric shock -- will demonstrate their prostheses today at a news event in Washington. The Rehabilitation Institute of Chicago (RIC) is part of a multi-lab effort, funded with nearly $50 million from the Defense Advanced Research Projects Agency (DARPA), to create more useful and natural artificial limbs for amputees.
Below is an illustration showing how the bionic arm works (Credit and copyright: The Washington Post). Here is a link to the original picture.
Let's return to the Washington Post article for another quote.
The particular achievement with Mitchell is that her prosthesis works with her breast intact. With previous versions, surgeons removed some chest tissue so that electrodes in the arm could better detect twitches in the rewired chest muscles. But that would have been particularly disfiguring.
We saw above how such a bionic arm worked. But how do you prepare a patient to use such an unconventional prosthetic limb?
In preparation for the bionic arm, Kuiken and his surgical colleagues first re-create a biological control panel for a hand on the amputee's chest. They use muscle and skin that can be sacrificed -- or, more precisely, hijacked -- for that purpose. They cut the nerves to two chest muscles, the pectoralis and serratus, at a point where those nerves have branched to go to different parts of the muscles, but far "upstream" from the point where the nerves divide into tiny fibers that attach to individual bundles of muscle fiber.
They then sew the stumps of the large nerves that once went to the arm and hand to the cut ends of the chest-muscle nerves. In the same operation, the nerves carrying sensation from the skin over the pectoral muscle are also sewn into the arm nerves. Over several months, the arm nerves grow down the sheaths of the motor fibers and attach to the muscles.
For more information, please follow all the links above. You also can see several pictures of Jesse Sullivan or visit the Boston Digital Arm System page at Liberating Technologies, Inc., which participated in the development of the bionic arm used by four people today.
Sources: David Brown, Washington Post, September 14, 2006; Bill Poovey, Associated Press, via The Lubbock Avalanche-Journal, September 13, 2006; and various web site
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