Future Trends in Upper Extremity Prosthetics: What Do the Experts See?
March 2003 Issue
The O&P EDGE:
In your opinion, what are the most exciting future trends in upper-extremity prosthetics?
Alley: I believe the ability to perform remote diagnosis, adjustments, and other remote consulting services offers tremendous promise for the patients and families, as well as the other members of the rehabilitation team. Of course, the Internet as a whole-with all its potential to educate in a variety of formats and to promote greater communication-will only become a more refined instrument over the next several years.
I also see a much greater depth and breadth of written material intent on invalidating many misconceptions that have stigmatized the field for years.
Finally, there is a great deal of interest in developing clinical standards for upper-extremity prosthetic care, and as chairman of the Upper-Limb Prosthetic Society, one of my most significant projects is to work with the Academy [American Academy of Orthotists and Prosthetists] in hopes of organizing the first "Clinical Standards of Practice" Conference on upper-extremity prosthetic initial and post-delivery assessment. As best practices are identified and adopted, outcomes studies can begin to have more credibility and offer real-world results, which in turn will offer many new insights to patients, prosthetists, and other allied health providers.
Atkins: Occupational therapists need to remain aware that they need to enhance and update their knowledge and skills with respect to current state-of-the-art prosthetic practice, technology, and components.
Expedited fittings is another area where experienced UE prosthetists have significantly reduced the amount of time required to complete a complex, technically advanced UE prosthesis. Ultimately, the sooner an amputee is fit with a prosthesis, the better his functional outcome will be when learning to use a prosthesis. This is a proven fact in a retrospective study of hundreds of upper-limb amputees.
Billock: We need better controls. Myoelectric control is without a doubt the best form of neuromuscular control we have for a prosthesis-and the most natural. But it is possible-and has been proven in other research circles-that you can monitor EMG patterns. This is called EMG pattern recognition. If we can do that-and utilize it for multifunction control of a prosthesis-that's what I would hope to see in the future.
That would allow individual finger movements-and coordinated movements of the hand, wrist, and elbow-unlike the robotic movements allowed by the "six degrees of freedom" we find in today's totally powered arm prostheses.
Going beyond myoelectric, there is also neuroelectric control, in which the impulses between the motor nervous system and the brain are monitored. There's a lot of information traveling there. If we can understand and access that information, we'll be able to achieve multifunctional control of a prosthesis this way, as well.
Some of the techniques being applied to enable Christopher Reeve are similar to what we've used in preprosthetic training for some of my own upper-limb patients-teaching them how to facilitate the muscle contractions without implants.
Brenner: Because we're dealing with fewer and fewer numbers, upper-limb prosthetics is being identified as a specialty area of practice within the field of prosthetics. We've done a demographic analysis trying to determine where our patients come from-particularly pediatric patients with congenital limb deficiencies. In analyzing data from the Centers for Disease Control, and comparing that data with the Canadian Congenital Anomalies Surveillance system and data from Sweden and the UK, we find that the incidence is maybe one child with a limb deficiency out of every 9,000 or 10,000 live births. That means that in this country we're seeing at most about 400 newborns per year that have an upper-limb deficiency that would require or benefit from some kind of prosthetic intervention.
When we look at other data related to the overall number of prosthetic fittings-such as the 2000 Business Survey from AOPA-it appears that the number of upper-limb fittings to lower-limb fittings is about 1 in 15.
One of the trends I believe we'll continue to see is that upper-limb fittings will become an even smaller portion of the overall prosthetic experience. There are several reasons for this: OSHA [Occupational Safety and Health Administration] has definitely had an impact on creating a safer workplace. There are a lot fewer people involved in agriculture (down from 30 percent in the last century to currently 2 percent or less). The advances of replantation and other surgical technology are getting better and allowing more limbs to be saved.
Miguelez: The evolution of some of the terminal devices from a couple of the manufacturers. We are very involved in beta testing and product design with all the major manufacturers. We always get to try the new stuff to help them refine new componentry to suit the patients' needs, and I think that's really important.
Previously they designed and delivered new items for us to use. Now, our relationship with the manufacturers is such that they're seeking feedback from us in order to help them design better products. Instead of making the product and trying to integrate it into the patient's scheme, we now have the patient contributing input regarding what he's looking for and allowing the manufacturer to respond.
Meier: From my perspective, there's very little research going on in the upper-extremity field, possibly because there are not many UE patients, and hence, not much money available from this patient base.
Perhaps more emphasis should be placed on designing a better hook-design terminal device rather than more exotic and less cost-effective high-tech solutions. And with regard to high-tech solutions, I don't feel that sensory feedback is going to be the most useful possibility, despite its popularity as a topic for speculation. Instead, I see a future with lighter prosthetic designs, self-suspending designs, accurate and workable outcomes measures, and hands that come closer to imitating natural function.
Judith Otto is a freelance writer based in Holly Springs, Mississippi.