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Form, Function Combine in New Hand Prosthesis
By Miki Fairley
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Photo courtesy of LIVINGSKIN |
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For years, conventional wisdom said
that passive hand prostheses were non-functional; their only value
was cosmetic. This was the assumption prosthetists, occupational
therapists, and physicians, and others were taught in school.
However, the real world of unilateral arm amputees and their daily
activities reveals that passive cosmetic hands are anything but
"passive."
A study done in England and the experiences of noted upper-limb
prosthetics specialists in the US shows that "passive" prostheses
are very much used for the many non-manipulative functions involved
in everyday life, such as supporting, stabilizing, pushing, and
balancing.
The study by C.M. Fraser, published by the Occupational Therapy
Services, Aldenbrooke's NHS Trust, Cambridge, didn't rely on
amputees' self-reporting alone. Researchers went to the homes of
amputees and videotaped them performing prescribed everyday tasks,
such as making and serving a hot beverage, buttering and slicing a
piece of toast, writing on a piece of paper, sealing it into an
envelope, and then removing it from the envelope.
Fraser's paper states, "Using video analysis, the study
demonstrates that for non-manipulative actions, cosmetic prostheses
are actively used in the performance of everyday tasks as
frequently as functional prostheses. The study provides evidence
for a cosmetic prosthesis to be presented to an amputee as a
realistic initial prosthesis and not as the option of last resort
if a functional prosthesis is rejected."
In his study, Fraser gave a heads-up for occupational therapists
to not only train prosthetic users to grasp and manipulate objects
such as small blocks on a table, but also to help prosthetic users
to master the large number of real-world non-manipulative tasks
they do each day. Fraser said, "It is also recommended that
training is provided in the use of cosmetic prostheses in
two-handed tasks."
"Facility with the prosthesis was mostly about manipulation and
grasping, when in reality they often don't use it for that--they
use it for other things," said Tom Passero, CP, president and
clinical director, Aesthetics Concerns Prosthetics Inc.,
Middletown, New York, makers of LIVINGSKIN® silicone
prosthetic products. "That was a revolutionary thing for me to
learn, and it verified my experience in trying to make a usable
tool, which is what a prosthesis is. It's put on to perform certain
activities or, in the case of LIVINGSKIN, to blend into certain
activities, so that other people aren't focusing on the amputee's
prosthesis, but rather on the person's eyes, words, or the
presentation they're making during a meeting."
New Knowledge Sparks Innovation
This revelation is sparking an innovative revolution in cosmetic
hand design at Aesthetic Concerns/LIVINGSKIN.
The new hand being developed at LIVINGSKIN combines both
function and appearance, flying in the face of the traditional view
of cosmetic prostheses, said Passero.
Information from the Fraser study, experiences and observations
of upper-limb prosthetic specialists, and amputees themselves "made
it very clear that new assumptions need to be generated about
prosthetic restoration for unilateral arm amputees and innovation
in the thinking of prosthetists who fit them--and that there needed
to be development in the design of terminal devices that really
reflect people's use patterns," Passero said.
The innovative hand is currently being used by a select number
of patients "who understand the developmental nature of the
device," Passero explained. Current plans are for the hand to be
commercially available in early 2006.
New Armature
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Photo courtesy of LIVINGSKIN |
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"One of the demands by unilateral arm amputees we
have seen in the last ten years is for an armature mechanism inside
the silicone to make the prosthesis look more real and that would
duplicate the function of the bones, so that people can do various
activities," Passero continued. He noted that unilateral amputees
comprise by far the largest number of arm and hand amputees, and
that the prosthetic needs of bilateral amputees are much
different.
Although all LIVINGSKIN hand prostheses currently use an
armature, the armature puts the fingers in a curve shape. "However,
our natural fingers don't bend in a curve; they bend at the
joints," Passero commented. The new hand uses an armature which
bends fingers at the joint, thus more accurately reproducing the
anatomical shape of the hand. The joints are able to lock and
unlock. The joints of the fingers and thumb are pre-positioned,
that is, placed in the desired position by the amputee's other hand
in order to perform certain tasks, thus increasing the
functionality of the device.
Patients contributed to the design of the new hand by discussing
the tasks they wanted to be able to do. For instance, one patient
said, "I want to do push-ups, and I want to be able to lift a
curling bar."
"We had to be innovative," said Passero, "so she could flatten
her hand out completely to do push-ups, then stand up and bend her
fingers back to lock around a curling bar and lift weights." He
added, "Nothing we had at the time or that was commercially
available was able to do this."
Current LIVINGSKIN hand prostheses use a strong braided
stainless steel for the armature. The new hand's various armature
parts are machined from a lightweight stainless steel and aluminum,
Passero said. "We're also experimenting with plastics that can be
machined, to make a very light and durable prosthesis."
"So the combination of function and form evolved into this
particular development for partial and full hand amputees," Passero
summed up. "It's been both fun and complicated, like all
breakthroughs are."
For more information, call 800.208.SKIN or e-mail: inquiry@livingskin.com 
Table Of Contents - November 2005
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