Engineers develop pulley system to improve hand function after nerve trauma

Engineers at Oregon State University have developed a simple pulley mechanism that may offer new options to people who have lost the use of their hands due to nerve trauma, according to a press release.

“Many people have lost the functional use of their hands due to nerve damage, sometimes from traumatic injury and at other times from stroke, paralysis and other disorders,” Ravi Balasubramanian, PhD, assistant professor in the College of Engineering at Oregon State University, stated in a press release. “The impact can be devastating since grasping is a fundamental aspect of our daily life. The surgery we are focusing on, for instance, is commonly performed in the military on people who have been injured in combat.”

In the study, the researchers compared a suture-based procedure to their pulley-based procedure and found that the pulley-based procedure reduced the actuation force required to close all four fingers around an object by 45%. They also found, during the grasping process, the pulley-based procedure improved the fingers’ individual adaptation to the object’s shape and reduced slip by 52% after object contact.

“We will 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. But working at first with hands – and then later with other damaged joints such as knees or ankle – we will help people recover the function they have lost due to illness or injury,” Balasubramanian stated.


Mardula KL. Hand. 2014;doi:10.1007/s11552-014-9676-0.

Disclosure: Funding was provided by Oregon State University.

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