Some people want their prosthetic hands to look as natural as possible; others want hands that can do nearly everything; and yet others may wish to have bodies that are intact to the maximum extent possible. To each his own. This is as true for prostheses as it is for anything else. That said, the bionic prosthetic arm really is revolutionary. Arie Rommers, who has used the arm, and EMC researcher/lecturer Ruud Selles will tell students all about it at a lunchtime lecture given on 17 October.

“All fingers can move, and on top of that, each finger has two bending points – two phalanges, if you will,” says Vera van Heijningen, an occupational therapist specialising in hand therapy and a colleague of Selles’ at Erasmus MC. “Which really is unique, because so far, all other myoelectric prosthetic arms (conventional myoelectric prostheses) have only had one point at which they could move, without any phalanges.”

Better grip

reportage protheses Bionische hand 1 – Sanne
Vera van Heijningen shows the bionic hand Image credit: Sanne van der Most

As a result, the thumb and index finger, along with the middle finger, can bend towards each other so as to pick things up. “Using the bionic hand, you can grip things more tightly and hold on to them without their slipping from your fingers,” Van Heijningen explains. “Electrodes on the muscles in your arm will transmit signals that provide motor innervation to the bionic arm.”

reportage protheses Bionische hand 2 – Sanne
All fingers of the bionic hand can move separately and bend in two different places. Image credit: Sanne van der Most

In future, the brain may be able to transmit such signals. “Research on this is currently being conducted in the United States,” says Van Heijningen. “I definitely expect something like that to become available to Dutch patients at some point. Which would be absolutely wonderful.”

Charging your arm

For what it’s worth, Van Heijningen is not saying that conventional prostheses and traditional hooks will no longer be used when this happens. “It depends on what you want your prosthesis to do for you,” she explains.

reportage protheses Hoopje handen – Sanne
The prosthetic hand is covered by a glove in the exact same colour as the patient’s own skin. Image credit: Sanne van der Most

Basically, there are three types of prostheses: passive, body-powered and myoelectric prostheses. Passive prostheses are hands or hooks that cannot be opened or closed. “They make your limbs longer, and as far as arms are concerned, they can look quite real,” says Van Heijningen. “Silicone hands, in particular, look so real it’s hard to tell them from the real thing. They are covered by very tight skin-coloured gloves which make the hands look like they’re real. We could also put something like that on bionic hands, but due to the moveability of such hands, softer silicone gloves would be required, which would break much sooner.”

reportage protheses Lichaamsbekrachtigde prothese – Sanne
Body-powered prostheses are moved using the power of your own muscles. Image credit: Sanne van der Most

Body-powered prostheses can be moved, using the power of your own muscles. As Van Heijningen explains, “Such prostheses are firmly attached to the body, generally by means of a corset of sorts, thus allowing you to get them to move by using the power of your muscles in your good arm, or in another body part on the other side of your body.”

reportage protheses Siliconenarm 1 – Sanne
Silicone arms are much more expensive, but it is very hard to tell them from the real thing. Image credit: Sanne van der Most

Then there are myoelectric prostheses, such as the bionic arm. But there are also more conventional myoelectric prostheses, which can be charged by putting a plug into an electric wall socket. Van Heijningen explains how these work: “Electrodes placed on the muscles of your arm or a different body part will transmit signals that will set the [bionic] arm in motion.”

‘The Future of Prostheses’ is the first lecture in a series of ‘Medical Future’-related lunchtime lectures, organised by SG Erasmus and MFVR. (In Dutch)

Date: Tuesday, 17 October 2017, 12.30-13.30

Location: Lecture room No. 1, Erasmus MC