D-Pulp, digital process for upper limb prosthetics

What it does

D-Pulp is a new product-service system consisting of software with a simplified interface that crosses current limitations. The optimised process offers more lightweight, sustainable, and affordable prosthetics with increased aesthetic personalization.

Your inspiration

In the coming decades, the number of amputees in the world is expected to further grow, as estimated by the World Health Organization. Currently, the prosthesis manufacturing processes are mainly handcrafted. Production time, costs, and repeatability may vary depending on different factors, such as stump clinical conditions, the orthopaedic technician's experience, and the customization requests of the patient. The good knowledge of technologies like Nurbs and parametric modelling, scanning, and 3D printing allowed a mitigation of the limitations related to the specific handmade process and the use of more sustainable solutions and materials.

How it works

The product-service system consists of software with a simplified and intuitive interface, ad hoc to be managed independently by orthopaedic technicians. After the positive mold generation of the stump and the stylized forearm, the technician does a 3D scan of the outcome. It is imported into the script and modified by the expert to generate the 3D model, which is composed of the socket and the cover. The technician and the patient together choose the prosthetic customization, with 2D and 3D texture, that is printed using an Hp MJF 580, characterised by a coloured technology using recycled PA12 powder. The result is tested by the patient, and, if required, the technician implements small tweaks in order to ensure a more comfortable prosthesis. The optimised process ends with the chemical polishing of the prosthetic, which guarantees the product is water-resistant and usable according to regulations and is therefore delivered to the patient.

Design process

The design process consisted of an initial stage of dialogue with orthopaedic technicians at Centro Protesi Inail in order to examine and observe the traditional process firsthand. This phase was important to understand the main critical aspects due to the craftsmanship of the process: it is not reproducible; duplicate sockets differ from the originals; the orthopaedic technician's experience affects time and cost; and cosmetic customization is limited. Subsequently, the constant collaboration with engineers, experts in technologies such as modelling, 3D scanning, and printing applied to the prosthetic sector, allowed to automate and standardise the most complex and repetitive phases for technicians, replacing them with processes independent from the operator. This led to the definition of a process that enhances the trust relationship between the patient and the technician, overcomes the criticalities of the traditional process, and ensures a high quality of the product. The new process was validated by the technicians in each phase to make the interface intuitive and easy to use, and then it was tested on a patient to verify its comfort.

How it is different

D-Pulp is the first innovative system that allows the 3D printing of upper limb myoelectric prostheses, consisting of socket and cover, affecting the whole process of prosthetic generation. The strength of the system is the simplified interface for technicians, who can easily set the characteristics of the prosthesis, such as the position and orientation of the sensors that capture the electrical signals of the muscles (EMG sensors). The system has several advantages over the traditional production process of prostheses, including: the creation of a digital archive and the consequent printing of copies identical to the original; the reduction of time and costs in the long run; the use of recyclable materials; a high level of customization of the cover in polychrome, with the possibility to choose between preset textures or even drawings made by the patient; and the mitigation of risk to the operator caused by manual processing.

Future plans

In order to get feedback for "User-friendly" and "Human Centred Design" development, we are testing the product on patients. In accordance with the research area of the Centro Protesi Inail, the D-Pulp process will be further optimised and implemented within the structure as a digitalized service/process transferable to the market. This is made possible by ongoing comparisons with industry players and patients. Last but not least, as the final stage of the implementation, we will focus on the automatic alignment of the cover starting from the socket, an aspect currently managed by the orthopaedic technician and complex to digitize.

Awards

Selected product within the ADI Design Index 2022 for Premio Compasso d'Oro 2024