Otto Bock Michelangelo hand DEMO [Gonzo report]

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Otto Bock Michelangelo hand DEMO [Gonzo report]; published May 27, 2011, 12:01; URL: https://www.swisswuff.ch/tech/?p=416.

BibTeX: @MISC{schweitzer_wolf_1571445466, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Otto Bock Michelangelo hand DEMO [Gonzo report]}}, month = {May},year = {2011}, url = {https://www.swisswuff.ch/tech/?p=416}}


[Find all articles about the Otto Bock Michelangelo hand]

Zurich, May 27th 2011.

Dipl.-Ing. Martin Wehrle presented the Otto Bock Michelangelo hand starting at 9:00 AM in a presentation at our local technical orthopedic service, Balgrist Tec. To that purpose he was wearing one on his right arm. This is my Gonzo report about the event.

At 8:50 AM, I was sitting in the presentation room observing before the real show would start. As he was setting up his computer, Martin Wehrle appeared to seriously pull up his right shoulder wearing the Michelangelo hand arm as if the arm was really heavy. The whole arm looked as stiff and as prosthetic as ever one would look. He used his mouth to hold on to cables and stuff as any self respecting amputee would do. And he had trouble grabbing soft springy cables as one usually has with prosthetic hands and cables - hooks work a lot better there. So, while watching him set up his presentation while he was wearing the Michelangelo hand, I would never ever have guessed that hand was a modern new bionic hand but a heavy piece of really limited use. Which, in my view, it probably is.

However, the presentation started at 9:00 AM and Martin Wehrle seemed to present himself with a symmetric body and shoulder posture and a selection of seemingly well coordinated moves he repeatedly called "natural" and "the prosthetic felt natural" and "as part of himself". The Michelangelo hand was shown with a semi transparent white glove. There was a tiny degree of impression of "natural motion" that I got from the wrist as it sometimes - but by no means consistently - appeared "relaxed". However that "natural" impression was quickly corrected by what seemed to me a rather loud motor noise, as well as its striking white appearance, and so the hand appeared to be most natural when not actually used.  The hand is really rather noisy, with only the iLimb appearing even louder than the Michelangelo hand. Another member of the audience asked questions regarding that issue as well. Martin Wehrle said Otto Bock has no plans to actually remove the noise or to seriously muffle the hand. There was another Michelangelo hand with a new Otto Bock cosmetic glove on. On that hand, only the dorsal side and back of the hand looked halfways acceptable in my opinion - the flexor side and inside of palm contained rather heavy creases of the cosmetic glove and so it appeared the glove was not even a halfways reasonable fit - even the Centri glove on my Becker hand is a better fit. In my opinion these creases took away all of the elegance of the hand. So the cosmetic glove appears to be a major issue as also it seems that the hand's dimensions do not match existing cosmetic gloves that can be easily ordered in. So one will have to rely on Otto Bock for these gloves, and so far best to really wait and see.

Also, Martin Wehrle now used the hand's wrist flexibility to have the wrist bend a little and overall seemed to highlight how useful the hand was when he would be walking back and forth in front of the audience and swing or wave his arms. Indeed the arm looked as prosthetic as arms with elbow encasing Munster sockets just look (i.e., cramped), but he came across as a really nice person, and made up for it with stories and smiles. He squeezed a knife between thumb and index finger to cut up something. While he tried to cut up something that way, the knife fell out - as it does also with some of my gear and not paying attention. I have the same experience, and so the Michelangelo hand may not add too much in terms of function for everyday life - but then, there are really better ways to cut up food using knife, fork and a prosthetic hand that work perfectly well even with a cosmetic arm. Opening a tiny cream container came across to me as quite tedious and not different from trying it with a Becker hand or hook, yet, most self respecting unilateral amputees probably would spritz these open one-handedly. The audience was asserted that the hand could push up to 25 kg so that is a benchmark right there. He did not show push ups however, as the hand obviously is too fragile for that - at least I would not think the Michelangelo hand and wrist is built for that. Apparently some "aerospace aluminum" was used for the hand, or, fingers, and Martin Wehrle pointed out some metal looking part. He said there was no warranty on putting load on the hand and no warranty cover for driving a car, say, with a stick shift. After the presentation that lasted about 30 minutes, he appeared to be dripping wet from sweat.

As far as I understood from where I was sitting when he got asked about the weight, he said the arm was quite a bit heavier than the previous Otto Bock arm. So he said it was about 1,5 kilos but one would get used to it. He was wet, dripping, not just moist. But, no sweats - I probably would have been dripping too.

To me (as disabled person) and when I asked him, Martin Wehrle explained there would - as far as I understood - be no plans for a multi electrode Michelangelo hand allowing for more advanced grip patterns even within the next 5 to 10 years. Strange, because really, technology is there. - A few minutes later and to a researchers group (a few robotics researchers were there as well) he explained, however, to the best of my understanding, that Otto Bock was running a Michelangelo hand already on a multielectrode control in their laboratory. Cool, because that matches the rumors and expectations a lot better.

Furthermore, Martin Wehrle said there was absolutely no way Otto Bock was selling that hand for cable controlled / body powered arms. Inasmuch, that is great news as with that, other folks can get to it and build the new bionic mechanical hand that we are all really waiting for.

When asked what part would be the first to fail, Martin Wehrle revealed they were still field testing, and not selling the hand but would not tell what parts would fail. To me, it appears that field testing is a rather extensive procedure here. After all, Otto Bock has a well established track record of products that are both relatively fragile, in my experience not overly well designed in aspects of measurements and part assembly, in terms of material choice and build, as well as their customer service that recommends ergotherapy when in fact they could have admitted they get stuff manufactured in China and don't do proper quality control. With a MovoHook product they describe the joint as "service free" in their product sheet, place a "CE conformant" engraving onto the product, and then actually place a small plastic disc into the hook joint that wears down over a few months enough for the hook to wiggle - and now, we are surprised that same company has problems field testing the Michelangelo hand.


a) Bionic? If Otto Bock create a "bionic" hand, they do so with the intent to make the wearer blend in more, appear more anatomically whole. Why they then neglect to optimize for a virtually perfect appearance and why they refrain from complete noise removal but instead, go about it with a seriously ill fitted cosmetic glove and why they assert to maintain their IMHO high noise level is beyond me. Also, an even heavier weight than previous prosthetic arms takes a toll on both asymmetry and energy usage of the wearer - as proven today. In that context and on that day, I was wearing an about 600 gram cosmetic arm - and I also got orange juice and coffee, and also opened cream containers. My cosmetic arm is so realistic even a neurologist once assumed it was a real hand, and it has a deadly silence. But let's not talk about my cosmetic arm now.

b) Multi-electrode control is near, and it is coming. Now that Otto Bock and TouchBionics offer such multiarticulated hands, best to wait for intuitive complex prosthetic hand control. They all must be working on it. That is the next step to have a good look at when it comes. A stump appears to be able to control single digits or at least a lot more complex movements than just open/close - as a lot more information is provided by a stump than currently exploited by so-called "state of the art" prostheses (Reilly et al., 2006 and Castellini @ DLR) - and with that, systems should be built that allow the user to intuitively control the prosthetic hand without implants or further surgery. A female Otto Bock representative of Otto Bock Switzerland tried to tell me that aside from targeted reinnervation there was no complex control anywhere close - but then we may all benefit from keeping up to date with recent developments. And robust complex intuitive hand control will be the absolutely necessary step in innovation that warrants the purchase of a multiarticulated prosthetic hand.

c) Too big, too long, too heavy. Size is humongous. The Michelangelo arm contains heavy batteries and the wrist gearbox, and so all it all it is too large for quite a number of folks. And probably a bit heavy, so heavy that one is better off using the mouth than the prosthetic hand. Better power supplies will be a hard requirement, as well as low profile wrists and compatibility with Ossur or other companies' pin lock systems. No one wants elbow encasing Munster sockets - that painfully limit elbow flexion and extension - if they can have a silicone liner mounted arm instead. Absolutely no one.

d) Money, honesty? It is unclear for what amount of money a customer service representative or marketing specialist of that company will actually provide a straight answer. When targeting customers with a top product, as the Michelangelo hand appears to be, and when advertising these new items a "part of the customers' body", I fail to see the reason why that company does not fight more to come across as more open and honest, and ultimately, trustworthy. If Michelangelo hand parts fail I  want to know which parts of our future body parts fail, I really do, after all they want me to obtain insurance funding and buy one of these suckers, no. If cosmetic gloves - that are all that separate human from artifical appearances - have a really bad fit, I see that and go, hm. If a shoulder is pulled up and a Trapezius muscle is painful, any specialist can see that - but an amputee like me expects it and goes looking for it. If the weight of the prosthetic arm is high, I need a true figure: how much. If the hand is, as it was claimed, built using "aerospace aluminum" and in fact ready to be used for anything, it does not convince to not see at least one push-up. Whatever was wrong with admitting that gloves were a huge issue, what the technical problems were, admitting the hand was for light office type application and not for household, garden work or sports? Whatever was wrong with admitting the product was heavy and despite resembling a human hand a tad bit more still had an only limited type of adaptive grip (even a Becker hand wraps better), non-articulated fingers and as that, only very limited everyday advantages over previous products?

e) Customer service of Otto Bock. Kerstin Fiedler of Otto Bock wrote to me they would recommend occupational therapy - a type of therapy used to introduce me to how to use the device - when I confronted them with ill-fashioned Otto Bock connector bolts they had sold me. Obviously representatives of Otto Bock are blissfully unaware of Swiss laws: instructions for use are regarded as part of the product and a duty of the manufacturer or reseller (KHMI Kreisschreiben of the Bundesamt für Sozialversicherungen, Article / Paragraph 1044, "Kosten für Gebrauchstraining - Die Instruktion zum Umgang mit dem Hilfsmittel ist grundsätzlich im Kaufpreis inbegriffen und gehört zu den Leistungspflichten der Lieferanten und Lieferantinnen").  Instead of her acknowledging their deficient user instruction and their fundamental technical issue that I confronted her with, and instead of her apologizing for charging 80 CHF for crappy Otto Bock parts, she recommended Ergotherapy. That is like having a car mechanic being confronted with missing out on replacing the motor back into the car and suggest the customer take Aspirin for the headache. Given that situation, it is a special privilege to see Otto Bock's current prime Michelangelo method actor hold cables with his mouth and pull up the shoulder due to a heavy anchor type prosthetic arm they try to market as end-all be-all bionic part. Don't get me wrong - I have no problems with any self respecting amputee using mouth, remaining limbs or other means to do whatever. But as a company, do *not* try to pull clients over the table and then miss out on Ergo-therapying your own. Ultimately, Otto Bock prosthetic part quality and the rough charm of their customer service is legendary. All arm amputees that I know speak in glowing colors of these qualities. You may very well think I may be kidding you but I could not possibly comment ; P

Final remarks. Most likely you will end up - one way or another - wearing some prosthetic arm that looks one way or another. Guy at the gas station, woman in super market, person on the teller tells you "compliments your arm looks quite real and I had a hard time recognizing it as prosthetic". WTF, such a compliment can be had for 3'000 bucks without insurance problems - no need to go "bionic", round up 80'000 bucks and cash in unknown problems of repair and terror all the way to these compliments. And of all companies we are talking about Otto Bock. And it is not that the Michelangelo hand really makes it look more real. I have not seen that poor a quality of a cosmetic glove since a long time. If you want something realistic looking, get a 600 gram cosmetic arm - *that* had a few people around me not notice at all.

3 Replies to “Otto Bock Michelangelo hand DEMO [Gonzo report]”

Comments are closed.

Do NOT follow this link or you will be banned from the site!
HTML Snippets Powered By : XYZScripts.com
I footnotes