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Restoring complete sensory ability for natural walking of amputees

Periodic Reporting for period 3 - GoSafe (Restoring complete sensory ability for natural walking of amputees)

Reporting period: 2022-05-01 to 2023-04-30

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 perform preclinical and clinical validation 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).
- SensArs has completed the design, development and preliminary tests of the intraneural electrode according to Grant Agreement schedule (Deliverable D1.1).
- The customization of the stimulating platform from Med-Ally to fit with SensArs’ specifics has been conducted according to Grant Agreement. The design of the device has been completed. The supply chain and manufacturing plan has been executed. In order to counteract the shortage of electronics components due to Covid-19, an external (non-implantable) device prototype has been developed. The firmware for the stimulator has been developed and tested (design verification).
- The software optimization for the External controller and GUI have been executed according to plan (Deliverable D1.4).

WP2 consists of 2 tasks that are both related to adaptation of prosthetic devices to be compatible with SensArs Neuroprosthetics’ device. This includes communication method and preparing the prosthetic devices to be tested in clinical trials. During Reporting Period 2 most of the work has been focussing on the prosthetic part (task 2.2) but some minor updates have been done on the Bluetooth communication protocol as well to accommodate ongoing technical development.

Acute and chronic study protocol have been done.
In order to comply with both non-GLP and GLP standards, the facility that was forecasted for the studies (Scuola Superiore Sant’Anna) has been replaced with Shamir Health Corporation (Tel Aviv, Israel). The reason for this change is the enter into force of MDR, for which CE mark most likely will be released only after GLP animal studies.

A cadaver study was executed at Washington University in July 2021 to finalize the implantation procedure. The reason for the location was the proximity with our supplier Med-Ally.
After this, the consortium has started the discussion of the clinical protocol and the informed consent. A first draft is linked in this document.

- The consortium has organized periodic meetings to update on activities and agree on future actions. These happened on-line after the COVID-19 pandemic started.
- The consortium has agreed on and requested an amendment to the EC in order to being able to deliver what agreed in the Grant agreement.
- SensArs and consortium have updated the data management plan

- The consortium has conducted a market entry study based on quality, regulatory and reimbursement aspects and Key Opinion Leaders interview (Deliverable D5.2)
- SensArs has interviewed 10+ Key Opinion Leaders, published 3 articles acknowledging GoSafe, presented the GoSafe technology and business plan at 6 events
- SensArs’ patent (US10974043B2, EP3522773B1) has been granted in EU and USA
- SensArs has executed fund raising activities and obtained a term sheet from a Swiss investor (Occident)

A request for approval for the execution of the acute and chronic studies have been forwarded to the Shamir Health Corporation facility. The approval was given (Deliverable 7.1).
Since the GoSafe prosthesis will restore symmetric walking and standing of amputees (details in the next section), long-term use of the device will help prevent the occurrence of associated illnesses, such as osteoporosis, osteoarthritis and back pain. This further contributes to long-term health benefits and quality of life for amputees. The technology is expected to result in stronger prosthetic acceptance and thus more prosthetic use and social participation.

The long-term health benefits of GoSafe will be an important driver for reimbursement of GoSafe for insurers, in turn favouring the growth of the prosthetics market and companies providing such prosthetics (or elements thereof). Furthermore, since many limitations with currently available commercial devices will be reduced by the market launch of GoSafe, the phenomenon of prosthesis abandonment will be reduced and sales of prosthetic devices will be propelled.

The GoSafe technology (i.e. the neuroprosthesis) would represent a new product in the prosthetics market (which was already estimated at €1.4 billion in 2016) which would allow its further expansion. Also, it would create a new European actor in the global neuroprosthetic market (estimated value of €4.6 billion), being today of exclusive leadership of the USA.

The innovations from GoSafe and the innovation potential they bring will help to consolidate the leading position of European companies in this market, such as Össur. It also accelerates growth of SMEs such as Sensars, who greatly benefit from the collaboration with a big player as Össur. Sensars will augment the personnel, especially in high-tech production sites in Italy and Germany (again, with the creation of new working places) to manage the serial production of the sensory feedback restoration device and the sales activities.
Schematic of the GoSafe system