Implanted pulley device could aid those with nerve damage to their hands

The arrow illustrates the tendon and pulley movement.--Courtesy of Oregon State University

Thanks to engineers at Oregon State University, people who have lost the use of their hands due to nerve trauma or stroke might get their grip back with a simple pulley mechanism.

The device, which was transplanted and tested in the hands of cadavers, is one of the first of its kind and could improve the transmission of mechanical forces and movement, according to a press release. The mechanism is considered passive technology because it has no sensory, electronic or motor capabilities. It uses a basic pulley that when transplanted in a person's hand provides a more natural grasping function with less use of muscle energy.

The findings were published in the professional journal Hand. The research was done in conjunction with the School of Medicine at the University of Washington.

"We'll still need a few years to develop biocompatible materials, coatings to prevent fibrosis, make other needed advances and then test the systems in animals and humans," Ravi Balasubramanian, an expert in robotics, biomechanics and human control systems, and assistant professor at Oregon State's College of Engineering, said in a statement. "But working at first with hands--and then later with other damaged joints such as knees or ankles--we will help people recover the function they've lost due to illness or injury."

The device can produce more natural and adaptive flexing of the fingers while grasping, the researchers said. The force needed to close all four fingers around an object was reduced by 45%, and slippage when grasping an object was reduced by 52%. The human hand is a very complex mechanism with between 35 and 38 muscles and 22 joints that need to work together.

Earlier this month, the U.S Defense Advanced Research Projects Agency (DARPA) awarded Harvard University engineers up to $2.9 million to develop a robotic suit to make walking easier for soldiers and potentially civilians with disabilities.

- read the Oregon State news