The amputations affect two categories of persons: the civilians (accidents, vascular issues…) and the military (artillery wounds, accidents).

They are more frequently located on lower limb^[1] (Figure 1).However, bionic prostheses are nowadays developed mainly for the arms. In fact, the prehension and the hand’s control are a huge challenge for the prosthetic industry, because it requires control by a set of nerves. We took this into consideration when building our 3D model and our scenario for a trans-humeral amputation. Nevertheless, NeuronArch’s system is transposable for different anatomical amputation locations.

Following a serious accident, the patient arrives at the hospital. The doctor diagnoses that the injury is too severe and that amputation is inevitable. If the conditions allows for it, the hospital staff presents the patient with the different relevant options available to him. The first option is a classic amputation procedure which would allow the patient to have, at best, a myo-electrical prosthesis. The second option is the NeuronArch solution. The NeuronArch solution allows a bionic prothesis, and in addition is partially supported by Social Security. After weighing both his options, the patient therefore obviously chooses the NeuronArch option!

The first step for a new NeuronArch holder is to have the implantosteointegrated by an orthopedic surgeon. The latter receives the internal device in a sealed package. During the surgery, the surgeon drills the bone in its center along its longitudinal axis, while a nurse lifts the NeuronArch system out of the package and drains the culture liquid of the biofilm with a syringe. The part which contains the liquid will serve as protection in order for the surgeon to be able to grasp the stem with the surgical clips without fear of damaging the biofilm or the membrane (Figure 2). He inserts the stem into the bone. The orthopedist places some screws to hold the device in place (they will be removed subsequently). The surgeon can now take the protection out (quarter turn system) and complete with stitches around the stump.

Before the release from the hospital, the surgeon assist the patient in configuring the medical data which the former will have access to, always with the patient’s agreement.

On leaving the hospital, the NeuronArch holder starts the process with a rehabilitation phase. A complete healing and implant-bone adhesion is indeed necessary before the patient can fix his NeuronArch interface device and the bionic prosthesis. During this period the nerve regrowth will take place and thanks to an integrated optical system in a sleeve, the production of neutrophins is stimulated in the biofilm, enhancing the nerve growth towards the stump area. Even though we didn't have the opportunity to test this technique during our lab experiments, with its local and targeted action, the optical system is more interesting than the chemical inducer medication system.

During the night, the amputee took off his prosthesis. So, in the morning, the NeuronArch holder connects his interface device to the stem with the quarter turn system. After this, he puts his bionic prosthesis.

He controls and moves in an intuitive way thanks to the connection between nerves and prosthesis allowed by NeuronArch. He can consult the NeuronArch app to either take an appointment with the doctor, check the battery status of his interface device, or his health data.

In the evening, the amputee removes his prosthesis and put the interface device on the charging station. During the night, the device is recharged and the data are synchronized with NeuronArch servers.

To maintain the patients data’s security, the patient has a QR code on his NeuroArch application. When he goes to the doctor, the NeuronArch holder shows it to the doctor who scans it. The QR code is used as a “key” to enter in the patient’s NeuronArch files.

We also thought about the NeuronArch’s post-implantation maintenance. Indeed, we created an interface device locked by eight screws. In this way, a prosthetist trained for the NeuronArch maintenance can open it and check the electronics parts such as the battery. If something is defective, the prosthetist will proceed with repairs or replace the part. The data on the SD card inside is encrypted, therefore safe. NeuronArch is conceived to last a life time.

• JM. André and J. Paysant, Les amputés en chiffres : épidémiologie, Cofemer, 2006