Selective Laser Melting for Medical Implants

Brochure Selective Laser Melting for Medical Implants
Brochure Selective Laser Melting for Medical Implants

If individually adapted bone and joint replacements or medical implants had greater functionality, e.g., through integrated and defined pore structures, physicians could significantly improve medical care. The additive manufacturing process, Selective Laser Melting is particularly suitable to manufacture such complex and individualized implants.

Trends and Challenges in Medical Technology

Both demographic change and the need for ever improving medical care have placed new challenges upon healthcare research. In particular, personalized medical technology is considered one of the most promising fields of the future. By taking the individual medical needs of the patient into consideration, e.g. when planning an operation or designing the implant, physicans can improve minimally invasive surgery, thereby guaranteeing the patient optimal medical care. On the one hand, this can considerably increase a patient’s sense of well-being, and, on the other, reduce the costs for the health care system and the economy systematically.

The use of resorbable implants as bone replacements is also setting new standards. These implants dissolve in the bones of the patient and are successively replaced by the body’s own bone. This way, implants can be created that “grow” in children as they grow, thus making it unnecessary to remove an implant after bones have healed, or for an implant to remain in the body permanently.

Individual and Functional

In SLM, component parts are built layer by layer from a fine powder that is melted by laser radiation according to a CAD model. Since it manufactures parts without tools and does so in layers, SLM lends itself well to cost-effective individual fabrication of complex geometries. Tailor-made implants can be designed on the computer directly from medical image data (CT, MRT) for a patient and subsequently manufactured with SLM cost-effectively. If needed, these patient-specific implants can be provided with additional functions that cannot be achieved with conventional manufacturing methods, or only at a very high cost. On the one hand, when an implant’s pore structures are carefully defined, for example, technicians can improve how well the implant is integrated into the tissue (osseointegration) and how well new tissue (vascularization) is supplied to the implant. On the other, SLM enables technicians to set optimal mechanical properties that are desirable for the particular patient and site of implantation.

In particular, with resorbable implants, defined pore structures are a decisive advantage compared to non-porous implants. The total volume that needs to dissolve can be reduced significantly and an effective transport of the dissolved products can be guaranteed by a complete vascularization of the implant. At the same time, the bone can form inside the implant so that the implant is strengthened by new autologous bone while it decomposes.

Medical Implants Manufactured with SLM

SLM is already being used commercially with many metallic biomaterials (e.g. titanium alloys, cobalt-chromium alloys or stainless steel). For applications in medical technology, the Fraunhofer ILT has already put this process into practice in cooperation with partners from medical and industrial companies for the individual series production of coronal caps and bridges in the dental industry, for joint replacement (e.g., hips, knees) in orthopedic surgery and for bone replacement in dental, oral and maxillo-facial surgery. In addition to individual implants, highly specialized surgical instruments and spinal fusion cages with enhanced functions can also be manufactured with SLM. These SLM components fulfill all the requirements of the corresponding regulatory standards upon mechanical properties and biocompatibility.

The Fraunhofer ILT also offers promising solutions to current research questions. As an example, we were able to successfully test resorbable bone replacement implants that have interconnected pore structures – made on the basis of a polylactide-calcium phosphate composite; they were used in small animal experiments for an area of the skull under low biomechanical stress. At the same time, we are researching the use of the technology for resorbable implants made on the basis of resorbable magnesium alloys for higher load-bearing areas.

From Idea to Product

The Fraunhofer ILT developed the SLM process in the middle of the nineties, and since then has constantly refined it in close cooperation with leading industry companies and research institutions while taking the whole process chain into consideration. Thanks to our expertise and many years of experience, our experts can assist you individually from the very first idea, through feasibility studies, process and system development all the way to implementing the results into your production chain. You can fall back upon our comprehensive range of equipment, consisting of various commercial systems and highly flexible laboratory plants, but also upon our knowhow in the area of laser beam source and optics development.

Thanks to our close cooperation with other Fraunhofer Institutes, the FH Aachen University of Applied Sciences, the University Hospital RWTH Aachen and the RWTH Aachen University, you can also profit from the bundled competence this location, Aachen, offers in the sector of additive manufacturing.