Implanted electrodes allow amputees to regain feeling

As many as two million Americans are living with limb loss.

There’s a new medical breakthrough that may not only improve function for amputees, but restore feeling too.

The Department of Defense is investing millions of dollars to design and build better prosthetics, with the goal of improving the lives of wounded warriors coming home from battle.

New research is showing tremendous promise.

For 13 years after losing his hand in an industrial accident, 45-year-old Shawn Findley has been using prosthetics, which give him three basic motions.

“I can open and close and I’ve got a wrist rotator to turn the wrist. This is a limited prosthetic, but it’s very robust,” Findley said.

Last year as a volunteer in a research project, Shawn, who is also a preacher, was able to do much more, and because of implanted electrodes, he could actually feel his missing hand.

“To be able to trigger those nerves and get feeling in parts of the hand, that was pretty surreal,” Findley said.

“We have a very, very specific approach, which is to place electrical interfaces inside the residual nerves that are still left behind in the residual limb after someone has an amputation,” said Jonathan Cheng, chief of pediatric hand, peripheral nerve, and microvascular surgery at UT Southwestern Medical Center in Dallas, Texas.

The placement of the electrodes and more than 40 wires allowed researchers to send signals to the nerves to control individual fingers of a robotic hand, feel sensations of touch, movement and even a sense of where the hand is in space.

“If you can imagine what that might allow you to do, it would be things like playing the piano or typing on a keyboard,” Cheng said.

Shawn was in the study for three months. FDA approval could be two years away. Shawn knows he’ll have to wait his turn for a long-term fix.

“I think we’ve got a lot of soldier boys that are coming home. They ought to be first in line,” Findley said.

Known now as the one-armed preacher, Shawn Findley served in the Army from 1993 to 1999.

His son now serves with the United States Marine Corps.


REPORT: MB #4454

BACKGROUND: Amputation is the removal of a body part or portion of it that is enclosed by skin, for instance an arm or a leg. Amputation usually occurs at a hospital via surgical procedure and is performed to prevent the spread of complications due to illnesses such as frostbite, diabetes, or others that prevent blood circulation. It may also be performed to control loss of blood or infection due to a traumatic injury, or to prevent the spread of bone cancer. Complications following amputation or limb loss include risk of infections, possible death, heart attack from chest pains, a stroke, pressure sores or wound infections, or even blood clots. Complications may also include a condition known as phantom pain or phantom limb, where many patients experience the sensation of still feeling the limb that has been amputated, as well as related pain to that limb. This varies from person to person, but in most cases, will fade over time.

PROSTHESIS: A prosthesis is an artificial replacement for a missing limb or part of a limb, used as a tool to help patients regain independence after an amputation. Choosing to use one is up to the patient, and each device is different depending on the patient’s needs. The amputee will meet with a prosthetist who will create a device custom-made to fit them personally. The limb can be made purely for mechanical purpose, or can be customized for the patient. Although they can not feel it and it will take time to work with and get comfortable, it can make a world of difference.

NEW TECHNOLOGY: A research study between robotics and amputees is taking place that could change the face of prosthetics. The robotic hand system is state-of-the-art technology that has been around for a few years, but now, researchers have been working to connect these to patients. By placing electrical interfaces inside the residual nerves left behind in the residual limb after the patient has an amputation, the electrodes interact with the nerve in which they are implanted. This allows for the nerves to read out commands for controlling the individual fingers of a robotic hand by decoding the signals that are still inside the nerve. It also “talks” to the nerves by electrically stimulating them, and actually giving them various sensations of touch and movement. Currently three different motions are available, without sensation. Research is still being conducted on expanding the technology to hopefully one day give these amputees their sense of touch back.
(Source: Jonathan Cheng, MD)