Although patients wear a prosthesis, many feel a pain where none can arise - the so-called phantom pain. Painkillers only help to a limited extent. Now researchers are teaching the prosthesis how to feel and trick the brain, so that the pain will disappear.
Following the development of the world's first mind-controlled arm prosthesis, the market launch of the "feeling" leg prosthesis is now imminent. The marketability was realized by the Austrian start-up company Saphenus Medical Technology. About 50 percent of prosthesis wearers suffer from phantom pain. Until now, only heavy painkillers (such as opiates, morphine) have been able to provide temporary relief. Long-term and sustainable forms of therapy have not yet established themselves.
Four years ago, Prof. Dr. Hubert Egger presented the feeling leg prosthesis as a prototype. A test user with the first functional model was shown at that time, which attaches to surgically diverted and reactivated sensory nerves. After four years of development work, the Austrian company Saphenus took over the bionics concept and developed the prosthetic add-on "Suralis" based on it to series maturity: This means that any existing prosthesis can be retrofitted - regardless of the manufacturer. Toni Innauer, Saphenus co-founder, is pleased that the market launch can start in a few weeks: "The bionic approach improves the quality of life of patients enormously," says Innauer.
Many people with amputations suffer from very special pain, the phantom pain: Because the brain - in vain - tries to retrieve information from the foot that no longer exists, this pain intensifies. To date, no therapy has been successful in the sustained treatment of phantom pain.
With the invention of the feeling prosthesis, the brain again receives sensory information. Together with a team of doctors, Hubert Egger has developed a method in which those affected feel their foot lost through amputation again.
Suralis has some technical subtleties in it: a sensor inner shoe records the rolling movements when walking. A radio transmission transmits the rolling movements to the amputation stump.
The actuator unit transmits the information of the rolling movement to the nerves of the skin area that has been surgically prepared to receive the rolling information. This non-invasive information transfer is perceived by the brain as information from the lost foot. The result: phantom pain is reduced or even completely eliminated. Another advantage is that the authentic feeling recognizes the different characteristics of the floor. This improves gait stability and makes walking safer. The prosthesis add-on Suralis is adapted by a certified orthopaedic technician and can also be used in combination with another interchangeable prosthesis.
The Suralis prosthesis add-on is a patented feedback system that can be retrofitted to any existing prosthesis (regardless of manufacturer). It was designed by Andreas Mühlenberend, industrial designer and professor at the Bauhaus University Weimar. The prosthesis with the additional part Suralis has "tactile properties".