Mechanized Human Hand Improve Function Lost To Nerve Damage

New technology might improve hand function
lost to nerve damage. (Source: meltmethod.com)
Engineers have developed and successfully demonstrated the value of a simple pulley mechanism to improve hand function after surgery. The device, tested in cadaver hands, is one of the first instruments ever created that could improve the transmission of mechanical forces and movement while implanted inside the body. This technology may offer new options to people who have lost the use of their hands due to nerve trauma, and ultimately be expanded to improve function of a wide range of damaged joints in the human body.
 
The research will offer a significant improvement on surgery currently used to help restore the gripping capability of hands. That procedure, called tendon-transfer surgery for high median-ulnar palsy, essentially reattaches finger tendons to a muscle that still works. But the hand function remains significantly impaired, requiring a large amount of force, the stretching of tendons, and fingers that all move at the same time, instead of separately as is often needed to grasp an object.
An implanted pulley system may one day
 help people with nerve damage regain a better
 grasping function.
(Source: Oregon State University)

The new mechanism is not really robotic since it has no sensory, electronic or motor capabilities. Rather, it's a passive technology using a basic pulley that will be implanted within a person's hand to allow more natural grasping function with less use of muscle energy.
 
The new research showed, in cadavers, that the mechanism developed can produce more natural and adaptive flexion of the fingers in grasping. The needed force to close all four fingers around an object was reduced by 45 percent, and the grasp improvement on an object reduced slippage by 52 percent. Such progress can be an important step to improve function beyond the existing surgical procedure, by providing an alternative to the suture which has been the previous mainstay. The hand, experts say, is amazingly complex, with 35-38 muscles and 22 joints all working together, innervated by three nerves between the elbow and fingertip.
 
The long-term potential of such mechanized assistance is profound. In some cases it may be possible to create joints or limbs that mechanically function as well or better than they did originally.


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