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Category: History

Prosthetic split-hooks are by far the MORE MODERN concept than prosthetic hands and they did not take long to get vilified [what you all got wrong about history]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Prosthetic split-hooks are by far the MORE MODERN concept than prosthetic hands and they did not take long to get vilified [what you all got wrong about history]; published March 3, 2019, 23:01; URL: https://www.swisswuff.ch/tech/?p=9423.

BibTeX: @MISC{schweitzer_wolf_1573560712, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Prosthetic split-hooks are by far the MORE MODERN concept than prosthetic hands and they did not take long to get vilified [what you all got wrong about history]}}, month = {March},year = {2019}, url = {https://www.swisswuff.ch/tech/?p=9423}}


We are told by prosthetic R&D aficionados, by film makers, fiction authors, popular culture and whatnot, that a prosthetic hook (i.e., split-hook) is "old", and a prosthetic hand is "new". Also, we get told that myoelectric arms are very modern in terms of control technology, whereas some recent media and prosthetic manufacturers even called myoelectric control "brain control".

None of that is true, quite obviously, while we realize that reality is rather different. Rather strikingly different, in fact.

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Case-study of a user-driven prosthetic arm design: bionic hand versus customized body-powered technology in a highly demanding work environment [article out]

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Wolf Schweitzer: Technical Below Elbow Amputee Issues - Case-study of a user-driven prosthetic arm design: bionic hand versus customized body-powered technology in a highly demanding work environment [article out]; published January 4, 2018, 14:29; URL: https://www.swisswuff.ch/tech/?p=8066.

BibTeX: @MISC{schweitzer_wolf_1573560712, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Case-study of a user-driven prosthetic arm design: bionic hand versus customized body-powered technology in a highly demanding work environment [article out]}}, month = {January},year = {2018}, url = {https://www.swisswuff.ch/tech/?p=8066}}


 


This is a blog post of one of the rare focused and well based scientific journal articles that really explains how real work, body powered and myoelectric arms relate and go together for a unilateral right below elbow amputee in a physically demanding work environment.

The prior presentation of this paper [poster at Cybathlon symposium 2016], which had been more pragmatically worded (with me thinking people would know anyway), this was now written up as article and published. During that process, the reviewers clearly made great points of all kinds of aspects I never knew were not sky clear to everyone.

So maybe, writing a ~ 30 page case study with > 210 references does clarify stuff, at least potentially and for those that actually read it. But possibly, it still requires attention to even just read it.

Knowledge does not come easy, Highlander! (Nakano, in: Highlander III The Final Dimension)

 

If you are more interested in visionary posts, read about the gadget features of the prosthetic arm in Kingsmen: The Golden Circle [link]. And technically, myoelectric control did have it coming. That technology remained uncool for four decades [link].

Publication [link]

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Russian prosthetic arm [about the history of myoelectric arms]

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Wolf Schweitzer: Technical Below Elbow Amputee Issues - Russian prosthetic arm [about the history of myoelectric arms]; published November 23, 2013, 18:00; URL: https://www.swisswuff.ch/tech/?p=2366.

BibTeX: @MISC{schweitzer_wolf_1573560712, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Russian prosthetic arm [about the history of myoelectric arms]}}, month = {November},year = {2013}, url = {https://www.swisswuff.ch/tech/?p=2366}}


Myoelectric prosthetic arms nowadays represent a rather stale technology that remains getting built mostly according to the schematics of the sixties.

It remains being sold at absolutely screaming prices, and we are continuously told that the very complex wiring and mind boggling technology actually warrants prices of 45'000 to 120'000 for one prosthetic arm of that type, despite its clear and massive functional deficits. However, cars with loads of highly evolved technology sell for such prices, and cars are built and sold under free market assumptions (where build a car for, say, 1500 CHF and selling it for, say, 25000 CHF, would be absolutely in order).

But myoelectric arms never saw that type of technological break through. As that and as of today, that technology should be avoided by users (with only a few exceptions). And not surprisingly, rejection rates remain rather high: in terms of function and overuse prevention, one might be better off not wearing a myoelectric arm. It is surprising to see how little the industry, how little researchers and how little prosthetic technicians overall seem to care by, say, addressing the issues in a manner that does in fact address the issues  that this technology not only has, but, always had.

After all, a colloquial slang expression saying "myo arms with hard sockets suck" does not quite nail it now, does it. Because more literally, they don't. Hard suction sockets do not work well as they may slip off, lose electrode contact, restrict motion and can be painful to wear,  localized surface EMG is problematic as it tends to be unreliable due to a range of reasons including sweat, hard socket slip and others, and energy consumption as well as component stability lead to a poor overall performance. Read up on it elsewhere.

And yet, for over seven decades, mechanic,  robotic and engineering labs have been mesmerized with the myoelectric arm concept. Institutions of all kind realized that portraying a prosthetic hand on their annual report or logo would attract funding. So they found that taking funding that was actually dedicated for health and rehabilitation could be branched off into their own funds if they played that card right. To this day, however, not much came out of this. Nothing at all, really, if one is to examine the papers  that were written back in the days and then examine what is being sold and built today. And when the best thing I can buy still is a body powered arm with a hook [how it works][performance], clearly, the last 7 decades of prosthetic arm research point to one thing as a necessary step: there needs to be tight control over these projects.

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Body powered arms [technical design overview]

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Wolf Schweitzer: Technical Below Elbow Amputee Issues - Body powered arms [technical design overview]; published November 21, 2013, 07:05; URL: https://www.swisswuff.ch/tech/?p=2371.

BibTeX: @MISC{schweitzer_wolf_1573560712, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Body powered arms [technical design overview]}}, month = {November},year = {2013}, url = {https://www.swisswuff.ch/tech/?p=2371}}


Body powered arms are not the same. Despite everyone saying they understand what these are, these arms are not the same.

My setup explained, a generic setup explained. To show similarities and differences. For those in need to learn about this, technical differences to myoelectric arms are explained.

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Carnes arm getting re-engineered by an Australian [news]

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Wolf Schweitzer: Technical Below Elbow Amputee Issues - Carnes arm getting re-engineered by an Australian [news]; published June 19, 2011, 19:27; URL: https://www.swisswuff.ch/tech/?p=444.

BibTeX: @MISC{schweitzer_wolf_1573560712, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Carnes arm getting re-engineered by an Australian [news]}}, month = {June},year = {2011}, url = {https://www.swisswuff.ch/tech/?p=444}}


The Carnes arm here has some previous entries, check them out.

Now, Mark actually visited the man that sold him the Carnes arm 'over Internet connection and friends' (Mark: anytime again : ) Turns out things are now really going in the right direction.

Particularly for transhumeral amputees, I believe the Carnes arm has a lot going for it, but it definitely needs a tune up both in terms of materials and ease of clockwork. With osseointegration, you want light weight and as much integrated function as ever possible. Combining elbow flexion and supination is one really good example of a possibly sensible integration over several joints.

As far as I am aware, even combined hand and wrist motion, leave alone hand - wrist - elbow combinations, are really nothing our current commercial consumer product designers do consider in their current "all things are called now 'bionic'" rage. So as every now and so often, amputees have to look out for themselves.

It really appears that the Carnes arm re-engineering now is underway as I read this hot off the press news. Great stuff.

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Learning from the past I - Muirhead Little [literature review]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Learning from the past I - Muirhead Little [literature review]; published April 22, 2011, 17:54; URL: https://www.swisswuff.ch/tech/?p=401.

BibTeX: @MISC{schweitzer_wolf_1573560712, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Learning from the past I - Muirhead Little [literature review]}}, month = {April},year = {2011}, url = {https://www.swisswuff.ch/tech/?p=401}}


1 Comment

It appears that today and in these days, nowadays and in our modern times, below elbow amputation is very rare and while no ergotherapist, physiotherapist, orthopedic surgeon, dermatologist or psychiatrist will see an arm amputee in practice in thirty years here, the "rare disease" community also (!) fails to acknowledge the fact that a realistic incidence estimate of below elbow amputation of around 1/50'000 entails the exact same consequences that other rare diseases and orphan drugs entail.

Yet there are miles to go before we sleep.

In the olden days, arms were removed more often, and knowhow was generated and documented by people that may not have had as much gadgetry and immediate networking opportunity as nowadays but who were just as clever, curious and differentiated as one would ever wish.

I now will type up some short summary points of a handbook published after World War I by Muirhead Little [1].

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Historical prosthetic arm

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Wolf Schweitzer: Technical Below Elbow Amputee Issues - Historical prosthetic arm; published October 4, 2010, 08:14; URL: https://www.swisswuff.ch/tech/?p=357.

BibTeX: @MISC{schweitzer_wolf_1573560712, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Historical prosthetic arm}}, month = {October},year = {2010}, url = {https://www.swisswuff.ch/tech/?p=357}}


Via Science Museum, Object number A602817:

Made from steel and brass, this unusual prosthetic arm articulates in a number of ways. The elbow joint can be moved by releasing a spring, whereas the top joint of the wrist allows a degree of rotation and an up-and-down motion. The fingers can also curl up and straighten out. The leather upper arm piece is used to fix the prosthesis to the remaining upper arm. The rather sinister appearance of the hand suggests the wearer may have disguised it with a glove. Among the most common causes of amputation throughout the 1800s were injuries received as a result of warfare.

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Categories: History Prosthetics

Carnes arm - history and current status [update]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Carnes arm - history and current status [update]; published July 14, 2010, 06:35; URL: https://www.swisswuff.ch/tech/?p=243.

BibTeX: @MISC{schweitzer_wolf_1573560712, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Carnes arm - history and current status [update]}}, month = {July},year = {2010}, url = {https://www.swisswuff.ch/tech/?p=243}}


Carnes arm and function

The Carnes arm is a sophisticated and mechanical prosthetic arm. It was developed by William T. Carnes and patented from the year 1911 on under the US Patents 760102 (artifical limb), 1046966 and 10469672287781 (artificial arm and hand). Interestingly, the more intricate mechanism that the Germans bought from William Carnes (see below) does not appear to surface in the US Patent files until 1942 (US Patent 2287781).

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Carnes arm - hand function

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Wolf Schweitzer: Technical Below Elbow Amputee Issues - Carnes arm - hand function; published January 30, 2010, 22:46; URL: https://www.swisswuff.ch/tech/?p=268.

BibTeX: @MISC{schweitzer_wolf_1573560712, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Carnes arm - hand function}}, month = {January},year = {2010}, url = {https://www.swisswuff.ch/tech/?p=268}}


After I discussed the history of the Carnes arm, here is a description of one of the more intricate mechanisms found in later Carnes hands [4]. I find it absolutely fascinating to also consider how history seems to repeat itself.

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The Monestier-Lescoeur hand

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - The Monestier-Lescoeur hand; published December 2, 2009, 22:59; URL: https://www.swisswuff.ch/tech/?p=239.

BibTeX: @MISC{schweitzer_wolf_1573560712, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - The Monestier-Lescoeur hand}}, month = {December},year = {2009}, url = {https://www.swisswuff.ch/tech/?p=239}}


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(C) Copyright Jacques Monestier

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