Three Austrian men have undergone a new technique called bionic reconstruction, enabling them to use a robotic prosthetic hand controlled by their mind. The technique involves selective nerve and muscle transfers, as well as amputating the affected limb. The limb was then replacing with a prosthesis containing sensors that respond to electrical impulses in the patient’s muscles.
The new technique was developed by professor Oskar Aszmann, director of the Christian Doppler Laboratory for Restoration of Extremity Function at the Medical University of Vienna, together with engineers from the University Medical Center Goettingen. “Existing surgical techniques for such injuries are crude and ineffective and result in poor hand function”, explains Aszmann. “The scientific advance here was that we were able to create and extract new neural signals via nerve transfers amplified by muscle transplantation. These signals were then decoded and translated into solid mechatronic hand function.”
All three patients each had brachial plexus avulsion, a condition which Aszmann describes as an “inner amputation” that makes it impossible to control the hand with the brain. Before amputation, the patients spent months doing cognitive training, first to activate the muscles, and then to use the electrical signals to control a virtual hand. Once they had mastered the virtual environment, they practiced using a hybrid hand—a prosthetic hand attached to a splint-like device fixed to their non-functioning hand. Video of the men completing exercises, shows how much they improved in simple skills, such as pickup up and placing small objects.
Three months after the accident, considerable gains had been made in daily living and the patients also reported a reduction in pain. For the first time since their accidents, all three men were able to accomplish various everyday tasks such as picking up a ball, pouring water from a jug, using a key, cutting food with a knife, or using two hands to undo buttons, according to research published recently in The Lancet.
“So far, bionic reconstruction has only been done in our center in Vienna. However, there are no technical or surgical limitations that would prevent this procedure from being done in centres with similar expertise and resources,” says Aszmann.