Mechanized Human Hands Could Improve Function After Surgery and Injury

There may be a way to help people regain more function in their hands after surgery: mechanization. Engineers have developed and successfully demonstrated the value of a simple pulley mechanism that can actually improve hand function.

The new device will, in theory, offer a significant improvement on surgery now used to help restore the gripping capabilities in hands following nerve damage. The current procedure, called tendon-transfer surgery for high median-ulnar palsy, reattaches finger tendons to a muscle that still works. Unfortunately, the hand function is still largely impaired, requiring a large amount of force.

"This technology is definitely going to work, and it will merge artificial mechanisms with biological hand function," said Ravi Balasubramanian, one of the researchers, in a news release. "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, 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."

So how does the mechanism work? It's not really robotic since it has no sensory, electronic or motor capabilities. Instead, it's a passive technology that uses a basic pulley that's implanted within a person's hand to allow them more natural grasping function with less energy.

"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 or other disorders," said Balasbramanian. "The impact can be devastating, since grasping is a fundamental aspect of our daily life. The surgery we're focusing on, for instance, is commonly performed in the military on people who have been injured in combat."

The new technology provides a potential way to help improve hand function in individuals suffering from damage. In addition, it paves the way for future technologies to be used in joints and other limbs.

"There's a lot we may be able to do," said Balasbramanian. "Thousands of people now have knee replacements, for instance, but the knee is weaker after surgery. With mechanical assistance we may be able to strengthen and improve that joint."

The findings are published in the journal HAND.