Ask upper-limb prosthetics providers about the strengths and weaknesses of myoelectric and body-powered prostheses and the reasons for preferring one or adopting both, and you’ll get a collection of responses as varied as the patients they serve.
Among the factors one must consider when creating a second device or terminal attachment for a patient with an upper-limb amputation is how they will integrate it into their daily life, says Shane Grubbs, CPO/L, FAAOP, director, ProCare Ottobock.care, Georgia. “Some like wearing the myoelectric prosthesis with a bionic hand when they leave home, because they can adapt their grip for function and look more natural. If they use a body-powered prosthesis with a hook, there can be a somewhat cultural negative connotation to its appearance which undermines its utility.”
While each type has its advantages—durability and strength for rugged outdoor work or manual labor with the body-powered, and versatility, bionic precision, and more pleasing aesthetics from the myoelectric—sometimes payers won’t cover both. Grubbs says that payers don’t always understand the need to have versatility between multiple systems and designs to gain the necessary function for the patient’s improved independence and quality of life, especially when one of the devices may only be needed a few times per week.
“There are many tools or devices we use sparingly through the week to maintain our homes and care for ourselves,” he points out. “The amount of time or frequency with which a tool is used is inconsequential when the tool provides a function that is necessary to achieve a desired outcome. When it’s needed, it’s very important. If it’s the patient’s primary prosthesis and they use it a few hours a day and don’t want to wear it all the time, they’re using it for the things they really need it for—so that is successful from their perspective. Sometimes it’s a terminal device to play golf or tennis once or twice a month, and that’s valuable to the patient, and improves their quality of life.
“Some people want the simplest thing possible, and they want it to be lightweight,” Grubbs says. “Even though they’re great candidates for a myoelectric, they may not interested in it due to the weight of the batteries, motors, or maybe don’t like the thought of charging more things. That’s totally okay. They’re usually looking for something that they can quickly don and take care of the one or two tasks that they really want to do every day with a prosthesis. Sometimes it starts simply and opens the door to provide functionality for other tasks they didn’t realize it could, at first.”
While he believes that every upper-limb prosthesis user would benefit from having the opportunity to explore additional options, there are always exceptions—like people who can manage life extremely well with limited resources. “They may have a long transradial limb, and they like the sense of touch it offers, and they don’t want to cover that up with a prosthesis of any kind.”
Different Perspectives, Different Ambitions
Tim Bump, MSPO, CPO, clinic manager, Handspring, Utah, agrees that the way patients are likely to integrate a second device into their lives is key to what is defined as success for them. “Some people don’t want to take extra things with them, or take extra steps to do things, so, like the rest of us, they are always trying to find the simplest step forward for them to accomplish their goals.
“When we start with a brand-new patient with the potential for multiple devices, we will typically start with body-powered because it can be easier to continue wearing that by adding socks to adapt it to their changing shape,” he says. “So the body-powered can last a little longer and continue working. Because the myoelectric has to maintain an intimate fit against the skin, their body shape needs to maintain more stable volume to be able to control it effectively.”
Bump also points out that the body-powered system with hook is still used today with minimal changes, 100 years after its introduction, for sensory reasons. “We use our visual sensory system to guide us as we grab onto things, in conjunction with our sensation from touch. With myoelectric that becomes more difficult, because you can’t see through a prosthetic hand to see what you’re grasping. There’s some level of control that you just don’t quite get without that sensory feedback you experience with a cable and harness. You can’t get that with myoelectric yet.”
Patient preferences for a second device or specialized attachment are as individual as the patient, Bump notes, and often vary with age. “The younger population often (but not always) will be more interested in having something that’s active, where the older population usually trends toward wanting something that’s more passive or cosmetic. Something that blends in.
“I’ve also seen both go the opposite direction—older adults who don’t care about aesthetics, they just want something to go golfing, while younger people care more about appearances and want the look.”
The trend toward showcasing a high-tech bionic look is still popular, he says. “Many people want their myoelectric device to look cool or robotic and enjoy the opportunity to discuss the prosthesis with those who are attracted by its unique bionic look. Conversely, if patients choose a passive cosmetic prosthesis that looks like a hand, with a realistic skin covering, they are less likely to be approached by interested strangers who ask about it.”
Their choice may be as much a reflection of the patient’s own personality as the level of utility the prosthesis offers, Bump says.
“But when you have something like a traditional body-powered prosthesis, some people will show interest and ask how it works, while others are not really sure whether their attention will be welcomed or considered intrusive. Unless the patient is comfortable and confident using it, people are uncertain about approaching them.”
“There’s more to selecting a myoelectric prosthesis than simply preferring it over a body-powered or passive option,” says John M. Miguelez, CP, FAAOP(D), president and senior clinical director, Arm Dynamics, California. “Our initial evaluation gives us a comprehensive picture of the patient, including their injury history, lifestyle, work requirements, and recreational goals. If a myoelectric system emerges as the most appropriate option, there are still important choices to make.
“Many patients want a hand, whether multiarticulating or single-motor, for everyday use, but they may also want to pursue activities that require a different prehension pattern, greater grip strength, or increased durability. In those situations, we incorporate a quick-disconnect wrist into the prosthetic design and provide an electric hook or ETC, allowing the patient to easily switch between the hand and hook as needed.”
Combining Devices
Josh Kinsey, CPO, ForMotion, Indiana, notes that most ForMotion patients use a combination of myo and body-powered devices, with their situation and preference determining which device is used most.
“A construction worker may not be into myoelectric; they’re going to use the body-powered every day at work; then they’re going to go home and do more of their [activities of daily living] with their myoelectric device.”
Brooke O’Steen, OTR, ForMotion, agrees that at the transradial and transhumeral levels, a combination is most often required. “We’re not providing as many of the cosmetic or passive prostheses, except at the partial hand and partial finger level. And at those points, we’re often attaching osseointegrated prostheses.”
As the world becomes better informed and more aware of people with limb loss, are patients becoming less sensitive about having a prosthesis, and therefore less interested in concealing their limb loss with a passive or cosmetic choice?
“It comes and goes in waves,” O’Steen observes. “Sometimes more people seem to want things concealed; at other times we see waves of patients who want to look bionic.”
“We’re also starting to notice a paradigm shift with a lot of our younger patients wanting that robot look, which looks cool,” Kinsey agrees. “They want it to look kind of bionic; so more and more of them are covering up less and less of the prosthesis. At the same time, many patients who have been wearing a prosthesis for a very long time still want a glove and continually ask for gloves as long as they use their prosthesis. Similarly, some cultures just want to hide the prosthesis, restore it, and keep it out of the spotlight.
“I think we’re seeing a great divide between the younger wearers and the longtime older and cultural users,” he concludes.
Back and Forth
Is it challenging for patients with multiple devices to switch from body-powered to myo, or vice versa, perhaps several times in the course of a normal day?
“I don’t think it’s difficult for most patients,” says Miguelez. “We have exceptional therapists, and we never provide a prosthesis without training. If we’re providing multiple prostheses, we provide training for each one.”
How quickly patients become comfortable and proficient varies. “Some are just super users and become remarkably competent within three or four days, while others need more time. The key is keeping them engaged. Our therapists tailor training to the individual and find creative ways to motivate them based on their personality and interests. A competitive patient, for example, may respond well to scored challenges or contests. There are many ways to approach it, but effective training has to be engaging.”
In the final analysis, respondents agree, patients’ success with their choice of multiple devices depends on their commitment to embracing and integrating these tools as a necessary part of their daily lives. Their prosthetist’s challenge is encouraging them to do so.
Judith Philipps Otto is a freelance writer who has assisted with marketing and public relations for various clients in the O&P profession. She has been a newspaper writer and editor and has won national and international awards as a broadcast writer-producer.
