The implant has taken place in Sweden, involving a patient with a hand amputation. The technology, developed at Chalmers University of Technology, is an osseo-neuromuscular implant designed and built to control a dexterous hand prosthesis.
To fit the implant, advanced surgery was required, which involved fitting titanium implants placed in the two forearm bones (radius and ulnar). From this, electrodes were fitted to nerves and muscle, and these were extended to extract signals designed to control a robotic hand and to enable tactile sensations.
The implant is the world’s first clinically operational, dexterous and sentient prosthetic hand that can be used in ‘real life’.
The new technology cover comes a weakness with conventional prosthetic hands, which require electrodes to be placed over the skin in order to extract control signals from underlying stump muscles. Such electrodes can only provide limited signals and these can only permit the user to control a few simple operations, like opening and closing the hand.
The researchers were able to provide more reliable information to permit a greater range of movements by implanting electrodes in the complete muscle. For this, sixteen electrodes were required, and post-surgery activities showed how improved dexterous control could be obtained.
A further enhancement was with connecting electrodes to the lost biological sensors of the hand, which enabled the scientists to electrically stimulate particular nerves in the same manner by whuich information conveyed by the biological hand.
The patient is currently undertaking a rehabilitation program to regain the strength in her forearm bones so that she will be able to carry the prosthetic hand. In addition, she is working out how to control her missing hand through the use of virtual reality. These steps are being taken to enable her to use the prosthetic hand with increasing function and sensations.
According to lead researcher Dr. Ortiz Catalan: “The breakthrough of our technology consists on enabling patients to use implanted neuromuscular interfaces to control their prosthesis while perceiving sensations where it matters for them, in their daily life.”
