A woman in Sweden became the first person in the world to receive an osseo-neuromuscular hand prosthesis that is impressively accurate and that can even transmit sensations back to its user. The device is integrated with the patient’s remaining natural arm unlike anything else out there. It is the culmination of the DeTOP (Dexterous Transradial Osseointegrated Prosthesis with neural control and sensory feedback) project, which involved the Chalmers University of Technology in Sweden, Scuola Superiore Sant’Anna in Italy, and Integrum AB, a Swedish firm.
The prosthesis is attached to a pair of partially exposed implanted titanium rods, one of which was driven into the radius and the other into the ulnar bone. The rods have electrodes stretching to the nerves and muscles nearby, which are used to read the intentions of the user and to transmit sensations.
Typically, electrodes are positioned over the skin and therefore don’t have access to a clean signal compared to one that can be achieved when the electrodes are implanted. Using external electrodes, a prosthetic hand can’t be much more complicated than being able to simply open and close. With the sixteen electrodes that were implanted into the Swedish woman’s stump, the reading of the neurological signals is a great deal more accurate and the nerves can be directly stimulated to evoke a sense of touch.
The technology to make the new prosthesis possible has already been developed and is ready to be fully tested with the Swedish woman. But it will take time, as the amputee’s arm still has to adjust to the weight of the new prosthesis and the woman will have to spend some time becoming comfortable with controlling the device.