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World Premiere of Muscle- and Nerve-Controlled Arm Prosthesis
For the first time, surgeons at Sahlgrenska University Hospital in Gothenburg, Sweden, have performed an operation in which electrodes have been permanently implanted in nerves and muscles of an amputee to directly control an arm prosthesis. The result allows natural control of an advanced robotic prosthesis, with motions similar to those of a natural limb.
Two major issues have hindered the advancement of robotic prostheses: 1) how to firmly attach an artificial limb to the human body; and 2) how to efficiently control the prosthesis in order for it to regain lost functionality.
“This technology solves both of these problems by combining a bone-anchored prosthesis with implanted electrodes,” said Dr. Rickard Brånemark.
In the new procedure, a titanium screw is used to anchor the prosthesis directly to the stump.
Previous robotic prostheses have relied on electrodes attached to the skin to pick up the muscles’ electrical activity, which is used to drive the actions of the prosthesis. The problem with this approach is that normally only two functions are regained out of dozens of potential movements, Brånemark says. By using implanted electrodes, more signals can be retrieved, thereby allowing more movement control. Moreover, the patient may be provided with natural perception or “feeling” through neural stimulation.
“The next step will be to test electrical stimulation of the nerves to see if the patient can sense environmental stimuli — that is, get an artificial sensation,” Brånemark said. “The ultimate goal is to make a more natural way to replace a lost limb to improve the quality of life for people with amputations.”
Source: Chalmers; February 22, 2013.