George Murray of Ladysmith, Wis., loves to hunt, volunteer with the fire department and spend time with his family. Until a few months ago, activities like hunting or holding a ball were difficult or impossible.
He was born without the lower portion of his left arm, which included his hand.
“I have had many problems with my right arm, shoulder and hand because it was being overused,” Murray said. “It started becoming painful, which led to multiple surgeries.”
But now, for the first time in his life, Murray has two hands.
“It’s weird,” he said. “It’s almost in the way for a while until you relearn how to do day-to-day stuff.”
Technology has fueled improvements in prosthetics
Murray, a Marshfield Clinic patient, has been fit with an advanced upper extremity externally powered prosthetic device. Shy Harn, a Marshfield Clinic prosthetist, worked with Murray to find a prosthetic device best suited for him.
“This prosthesis model has 36 grasp patterns, 12 of which can be customized,” Harn said. “It can be as delicate as a slight pinch to hold a piece of paper and is controlled by the strength of the signal. Older versions typically opened and closed and were hard to control. Now you can control how fast you open or close your hand with the specific grasp pattern intended.”
The person also can control these grasp patterns through their cellphone or through an electronic chip. You place the chip on an object, and the chip will communicate with the prosthesis to a preset grasp pattern programmed for that item. These grasp patterns can include typing on a computer, taking a picture and other functions.
Harn says the prosthesis software is faster, stronger and smarter than previous versions and also can vary the speed of opening and closing the hand. The hand has a gyroscope and accelerometer incorporated in it. This means the device knows where it is in space for gesture controls, which allows patients like Murray, to change grasp patterns with a simple specific gesture.
Another key feature is that the thumb has two motors. One is for opposition and the other is for rotation of the thumb. Each digit, which is essentially a finger, has a motor. This allows a compliant grip to conform around an object such as a ball or to shake hands.
Old vs. new
Older versions of upper extremity externally-powered prostheses usually had one motor, which only opened and closed the hand. Some prostheses also didn’t allow operating the thumb in any plane and must be used in either opposition or lateral grip.
Murray’s prosthesis, manufactured by Touch Bionics, offers prosthesis control using opposite muscle groups. One muscle group opens the hand and the other muscle group closes it, which can be as simple as flexing your forearm. The wrist also can rotate 360 degrees. Murray can give a thumbs-up, or unlock a door by holding a key and hang onto objects, like a cup of water.
“It’s phenomenal to have this technology for our patients,” Harn said. “To have so many available grasp patterns, you can pretty much do whatever you’d like. George is a hunter, so he wants to be able to hold his bow. With this device, the possibilities are endless and open an infinite amount of doors for him in the future.”
Murray is excited for that challenge and to start this chapter of his life with his family and new prosthesis.
“My family is so supportive,” he said. “I have to slow down and realize it’s there for good and relearn to do things. But, I’m excited that finally after 39 years, I have two hands.”
“With the all the new features this prosthesis offers, it allows users to perform tasks many people take for granted,” Harn said. “Imagine trying to play ball with your child without being able to pick up the ball, shaking hands with someone and not knowing how much pressure you’re applying or wanting to hold your child without knowing you have a secure hold on them. This technology allows the user to do all these things confidently and effectively, which is greatly impressive.”