The prosthetic foot worth millions - Le Soir

We all have in our minds an image of an old pirate limping on a wooden peg to replace his lost foot in a fierce battle. But did you know that since the pirate's wooden foot and the prostheses currently offered to below-knee amputees, there has been almost no evolution? Most ankle prostheses designed for walking are rigid, simply covered with latex mimicking the foot.

Replicating the movement of the ankle is indeed extremely complex. However, in his small laboratory, a robotics doctoral student at VUB has found a mechanism to best mimic ankle articulation. The hope for improved mobility for thousands of patients.

The story began 12 years ago. Pierre Cherelle began his doctorate in robotics. He found himself in a group specialising in lower limb rehabilitation at the VUB. « They were mainly working on prototypes of exoskeletons and prostheses and were quite advanced in the world », explains the entrepreneur. « It's fascinating to see how such technology can improve people's daily lives. By the end of my PhD, I had several working prototypes of a bionic ankle. I was then offered the chance to continue working on it with the goal of producing it. This was a unique opportunity for me ».

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A question of mechanisms

For Pierre Cherelle, everything is a matter of engineering: "For a knee, the principle is very simple: it's just a spring. For an ankle, you need to provide the walking impulse. This joint is the most complex in the human body. Imitating the ankle joint is extremely challenging to achieve natural walking for an amputee. No technology on the market allows this to date."

In practice, during walking, an ankle generates a lot of energy, and using a single motor is not sufficient. "If we used only one motor, it would be too bulky to be incorporated into a prosthesis. Our solution to this problem is to combine a motor with springs and a freewheel mechanism. This robotics innovation is now also enhanced by artificial intelligence, making it absolutely unique in the world."

The first prototype has attracted attention from the entrepreneur's thesis readers. VUB has asked him to continue the work and also to file patents, especially because two of the readers from China and the United States seemed very interested in this new technology. Currently, only about ten research groups worldwide are working on the subject.

At this stage, the prosthesis is conceptually viable, but it still needs technical improvement. Miniaturizing the object is, of course, necessary, and this is typically done fairly quickly since reducing circuits is a well-known technique. The challenge lies in ensuring that the foot can function perfectly for three years (the average lifespan of a limb prosthesis) and cover the recommended 10,000 daily steps by doctors. "The challenge of the prosthesis's lifespan is crucial," acknowledges Pierre Cherelle. "Our goal is to guarantee maximum performance and safety, as well as optimal comfort for the patient. Axiles Bionics aims to offer better bionic prostheses on the market at more affordable prices."

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Combining robotics and artificial intelligence

Two years ago, Pierre Cherelle launched a worldwide appeal to find a partner capable of working on artificial intelligence. In the end, he found him in the building next door: Felipe Gomez Marulanda, a specialist in artificial intelligence. « Today, it's the patients who adapt to their prosthesis. Our aim is for the prosthesis to adapt to the patient's gait. The combination of our skills in robotics and artificial intelligence has enabled us to develop a prototype which, unlike any other device on the market, is capable of restoring patients' natural gait and posture. It also adapts to and assists the patient's efforts by compensating for the muscles of the lost leg ».

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Economical viability

If Axiles Bionics has made significant progress with its prosthetic foot, it is equally crucial for the start-up to secure the means to continue its work. "The initial trials are very satisfactory. However, we still need to improve our product before bringing it to market. To achieve this, we must ensure the financial viability of the company." The entrepreneur embarks on an equally complex quest: securing funding.

In June 2017, thanks to the Lifetech program from Hub.brussels, the company received €1,500 by winning the MedTech award. This medical device acceleration program highlights entrepreneurs innovating in the medical sector, representing recognition from the Brussels Region for the project.

This award provides a new argument to attract investors. At the end of January this year, Axiles Bionics officially came into existence with four founders. The two doctoral students were joined by a finance specialist and a medical certifications specialist. "We are fortunate because a prosthesis is non-invasive and remains with a Type 1 approval for medical devices."

By the end of the year, the start-up aims to raise a significant amount of funds, but Pierre Cherelle prefers to remain discreet about the amount due to the high stakes. In Western Europe, approximately 45,000 feet are sold each year, and in Belgium alone, between 900 and 1,200 prostheses are needed annually.

If all goes well, the first Brussels bionic foot should be commercialized in 2022. If Axiles Bionics succeeds, it could become the next Belgian unicorn.

Today, it's the patients who adapt to their prosthesis. Our aim is for the prosthesis to adapt to the patient's needs. - Pierre Cherelle

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The right price will depend on INAMI

Developing technology is one thing; bringing it to market is another. Before moving to this stage, determining the selling price remains. Existing American mobile prostheses are priced at around €50,000. However, Axiles Bionics aims to market its product at a much lower price. "It needs to be accessible to as many people as possible. We also hope that, soon, particularly thanks to the reform of the reimbursement codes from INAMI, our foot can be a reimbursed device," explain the designers.

"For this, we need to prove that its use improves patients' health. With our prosthesis, we can demonstrate that people suffer less from back problems and gain autonomy, for example." In the meantime, the company cannot rely on reimbursements but hopes to increase its sales volume to reduce production costs. This achievable challenge involves exporting to foreign markets. "We aim to create a bionic center of excellence in Brussels. This is important to us because the Brussels Region, particularly Innoviris, has supported us, and we also want to invest in it." - V.LH.

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