Dr Nicola Vitiello explains how robotic artificial limbs and exoskeletons can help amputees stay mobile.

The amputation of a leg or foot significantly diminishes the overall health and quality of life of millions of people worldwide. The primary causes of lower-limb amputation are peripheral artery diseases (PADs), such as atherosclerosis, which causes a person’s arteries to harden and narrow. In the worst cases, it may be necessary to carry out lower-limb amputations. As PADs are more common in older individuals, and Europe’s population is currently ageing, it is likely that such amputations will become more and more frequent in the years to come. Society needs to find ways of helping amputees to live lives that are as active as possible.

The vision of the Horizon 2020 CYBERLEGs Plus Plus project is to develop innovative robotic artificial limbs and exoskeletons to restore amputees’ mobility and autonomy, making it easier for them to perform daily tasks such as walking on different surfaces and terrains, climbing and descending stairs, and transitioning between sitting and standing. This restored mobility will allow amputees - in particular, older persons - to remain more physically active, thus counteracting physical decline and improving their overall health and quality of life.

model of prosthetic foot showing inner mechanics

Solving everyday challenges

Lower-limb amputation can range from partial foot amputation to (in rare cases) the removal of a person’s whole leg from the hip joint downwards. Although all amputations make a patient’s life much harder, amputations of the leg above the knee present a significantly greater challenge, as the knee joint is very important to normal walking. People who have undergone this kind of amputation (transfemoral amputees) consume significantly more energy than their healthy counterparts while walking, as their bodies move differently to compensate. For instance, an influential 1976 study found that, on average, amputees whose amputations were the result of vascular diseases walk at 40% of the speed of non-amputees, while consuming 2.5 times more energy. Furthermore, negotiating common features such as stairs and slopes is particularly challenging and hazardous for people with transfemoral amputations. Finally, walking involves a heavier cognitive burden. The neurological processes of normal walking are largely automated, under the control of the neural tissue in the spinal cord, but transfemoral amputees must compensate cognitively to achieve unnatural (asymmetrical) patterns of neuromuscular activation, and to maintain their balance without using their knee and ankle joints to help them stay upright.

Unfortunately, the physical, metabolic, and cognitive challenges posed by transfemoral amputation are not adequately addressed by any artificial limb. As a consequence, only a small proportion of transfemoral amputees – about 20% – use their artificial limbs for at least several hours a day and manage to walk. Most do not use any limb substitute at all, resorting instead to alternative means of mobility such as wheelchairs. CYBERLEGS Plus Plus is trying to change that.

CYBERLEGs: past, present and future

This initiative was launched by a multidisciplinary, international, and quintessentially European consortium in 2012, when the previous CYBERLEGs project was sponsored by the European Commission. Building on the robotic artificial limb and exoskeleton prototypes developed in this first project, a multidisciplinary team of experts in wearable robotics and sensing technologies, medical doctors, psychologists, and physical therapists from Italy, Belgium, Slovenia, and Iceland is now committed to further developing and validating these next-generation CYBERLEGs technologies.

Currently two years into the second project, the consortium is now in the delicate phase of analysing clinical data collected in 2018 and finalising the designs of a new generation of CYBERLEGs prototypes, to be tested in Italy and Belgium in 2020.

The ultimate goal of this consortium is not simply to advance scientific knowledge. Thanks to the involvement of two companies, Össur (Reykjavik, Iceland) and IUVO (Pontedera, Italy), the team is also aiming to deliver an affordable, safe, and easy-to-use family of products that will reach the market in the near future. Major efforts are also being devoted to investigating how these exoskeletal technologies could benefit other people with lower-limb mobility impairments, such as those suffering from neurological injuries, or frail elderly people.

Both the CYBERLEGs projects are clear demonstrations of the crucial role that the European Commission plays in fostering the evolution and innovation of our society. Fulfilling the high-risk/high-reward challenges addressed by the CYBERLEGs project has been possible only by combining a variety of expertise across multiple EU countries and sectors, from academia, large industry, small and medium-sized enterprise, and clinical practice. Horizon 2020 has offered this consortium the necessary resources and opportunities to dream of a better quality of life for lower-limb amputees, and to realize this vision together.

You can also watch this Euronews video about the work of the CYBERLEGs Plus Plus project.

Consortium

SCUOLA SUPERIORE SANT'ANNA, Italy

UNIVERSITÉ CATHOLIQUE DE LOUVAIN, Belgium

VRIJE UNIVERSITEIT BRUSSEL, Belgium

UNIVERZA V LJUBLJANI, Slovenia

FONDAZIONE DON CARLO GNOCCHI, Italy

ÖSSUR, Iceland

IUVO S.R.L., Italy