BRIEF presentation of the research tasks of the VARINEX ZRT. PROJECT No. NVKP_16-1-2016-0022, “Development of a new generation manufacturing process for personalized medical-biological implants and assistive devices using additive technologies”
specified under the above title The research tasks
The project is implemented with the support of the National Research and Innovation Office from the NKIH Fund
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Tasks and results performed by VARINEX Zrt. independently and jointly with its consortium partner:
In accordance with the relevant points of the grant agreement, we have fully completed the tasks assigned to us, primarily the research and tasks related to the "Definition of a technological sample system for the research of polymer products".
We have performed these tasks for both thermoplastic and thermosetting systems. We have examined the full applicability of both technologies and have also gained practical experience in the additive manufacturing of specific models. These models will be used primarily to verify the design of metal implants, and we will also provide modeling of bone defects in a given patient with these polymer systems.
In the project, we defined the entire process required for the production of a unique, patient-specific implant. Taking into account the emerging medical and technical needs and their specificities, the requirements were defined, based on which a CAD format serving as input for additive manufacturing can be produced from the patient's CT, MRI and X-ray images, including their deficiencies, through geometric reconstruction.
The 3D CAD design resulting from the process is produced using additive manufacturing on the successfully implemented EOS M100 additive manufacturing system, made of Ti64 titanium, a material that can be implanted into the human body.
For the purpose of microstructural examination of the produced specimens, a scanning electron microscope (SEM) and a microanalyzer were selected and purchased, the equipment was installed, trained, calibrated, and test measurements were performed. The treatment conditions were established and trial operation tests were also performed. The laboratories of the participating partner departments provided the conditions for the examination of the mechanical properties.
As a result of the project's complex, interdependent research, we have produced a hip prosthesis and prototypes of its components that are suitable for use as a unique, patient-specific implant.
The image shows the stem and ball of the prototype implant – and on the right, the cup and polyethylene insert.
A very important part of the process was the development of the manufacturing technology for the individual, patient-specific implants. The manufacturing was carried out using an EOS M100 Direct Metal Laser Sintering – DMLS – machine. During the layer-by-layer construction of the implants from metal powder, nearly 200 parameters can be changed in order to ensure that the given implant meets all the requirements. An important requirement was that bone ingrowth could be facilitated by surface and various lattice structures.
The entire design and manufacturing process was designed to meet the emerging medical and technical needs as closely as possible. Initially, we used EOS-316L stainless steel for DMLS production, and later we switched to EOS-Ti64, which is a material that can be used for implants in the human body. For both materials, we performed the necessary mechanical tests and determined the material properties that we could use for finite element tests, thus verifying the load-bearing capacity of the designed implants.
The entire design, review and manufacturing process is designed to have branching points that can be entered and exited – for example, if a 3D CAD model of a patient's problem area is available, it can be used to move forward in the process, avoiding having to start the process from scratch.
Another typical case may be that after checking the manufacturability of the implant created in a later phase of the design, the resulting 3D CAD model can be transferred to another manufacturer – for example, to a manufacturer who has a larger workspace for color grading equipment. This way, the process is fully interoperable and can be used flexibly according to the given needs.
The medical fields where this process can be used have been identified. These primarily include various bone replacement cases in orthopedic, oncological and, to a lesser extent, traumatological treatments. Our developed method also seems indispensable in the production of certain unique medical instruments.
We can say that the project has proven to be successful, providing a solid basis for its continuation and clinical implementation. It would definitely be worth continuing the research in the future, as there is an increasing demand for unique, patient-specific implants that ensure faster healing and more secure recovery, when the implant is adapted to the patient's characteristics and not vice versa.
The biggest challenge for the introduction into daily practice is the new EU regulation. The so-called “Medical Device Regulation” – MDR – imposes such complex and at the same time strict requirements on implant manufacturers that they can only be solved at high costs in larger organizations. The production of individual, so-called custom-made implants, which requires compliance with much simpler rules, may be a loophole. The new MDR will enter into force in May 2020 – but there is still no accreditation body in our country that could carry out the conditions for the introduction of an individual implant. Regardless of this difficulty, it is worth continuing the research because the approach we have developed in the production of individual, patient-specific implants can be applied in many new areas.
Total project budget: HUF 837,823,139
Amount of support from the National Research, Development and Innovation Fund: HUF 745,423,139
For further information about the above project: György Falk (falk@varinex.hu)
