In EU 3.18 million people have an amputated lower limb, and each year 295,000 undergo lower-limb amputation. Commercially available leg prostheses do not give any sensory feedback to the user (i.e. they do not give any information about the movement of the prosthesis itself or about the interaction with the ground). As a consequence, (1) prosthetic leg users risk falls and lose trust in the device, (2) overuse the healthy leg, developing an asymmetric gait, (3) which results in low mobility and fatigue. Finally, since there is not a physiological connection between the extremity and the brain, the amputated nerves send unphysiological signals to the brain, which interpret that as phantom limb pain. Amputees need a prosthesis that restores natural sensations from their missing leg.
SensArs Neuroprosthetics, one of the industrial partners of the consortium, has developed the solution to amputees’ problems. In 2017, the company developed and tested (in collaboration with Ossur, the other industrial partner of the consortium) on 3 transfemoral amputees the first worldwide neuroprosthesis restoring sensory feedback by the electrical stimulation of the sciatic nerve through electrodes implanted transversally in it. SensArs’s product - consisting in A) a sensorized insole to place under the foot of a commercial prosthesis provided by Ossur and B) an implantable stimulating system injecting current in the sciatic nerve of the user, driven by the instructions of the insole – was added to the commercial prosthesis provided by Ossur. In all the subjects the intraneural stimulation elicited tactile and muscular contraction sensations over the whole phantom foot and lower leg. Also, SensArs showed that the subjects, using the prosthesis restoring sensory feedback, (1) fell less on surfaces with obstacles and were faster on stairs, (2) had fatigue reduction, (3) reported pain relief.
The main aim of the GoSafe project is to optimize SensArs’ solutions, to manufacture it in certified facilities (e.g. ISO standards), with the purpose to prepare the regulatory pathway to gather CE mark which will allow its penetration into the European market (and after the USA one). To realize this disruptive goal, two industrial and two non-industrial partners with multidisciplinary expertise (SensArs: neuroprosthetics, Ossur: prosthetics, UCSC and CHAR: clinical and surgical aspects) have created the GoSafe consortium, through 7 Work Packages (WPs).
