Additive manufacturing (AM) broke through the limitations of traditional manufacturing, fundamentally transforming how implants are designed and produced. Much of the success realized to date has come from producing implants using a variety of metals, such as titanium and cobalt chrome. Metal materials offer advantages such as strength and durability. However, there are also drawbacks such as the potential for allergic reactions and the weight of the implant depending on its size. Just as AM enabled breakthroughs for implant production, the technology is also showing promise for producing implants from plastic material—PEEK (polyetheretherketone) in particular.

PEEK offers several advantages over metal in medical applications. First, PEEK is not known to cause any allergic reactions, which can be a concern with certain metals. Second, PEEK’s mechanical properties—such as high strength, durability, and fatigue resistance—are closer to human bone than metals, allowing for better load-bearing performance and reducing the risk of stress shielding. Third, PEEK has a thermal expansion coefficient similar to bone. Patients with metal implants, especially craniomaxillofacial (CMF) implants, often complain about headaches on very cold or hot days due to the different expansion behaviors of metal and bone. Another big differentiator is the radiotranslucent behavior of PEEK. Metals are radiopaque, which can hinder visibility in medical imaging, making it challenging to assess the surrounding tissues or monitor the implant’s performance. This can be particularly relevant in medical applications where regular imaging is necessary, such as in tumor resection surgery. However, while PEEK presents these advantages, it is often viewed as challenging to 3D print.

Overcoming Challenges & Unlocking PEEK’s Potential

Additive manufacturing with PEEK presents a unique set of challenges, primarily due to its high melting temperature and the need for precise control over the printing environment to ensure optimal material properties. As such, there are currently not many commercially available 3D printers optimized to use this material. An extrusion printer with an integrated cleanroom and temperature management protocols might be the answer.

With the selection of an appropriate 3D printing technology, it’s possible to address a breadth of medical applications. PEEK’s excellent mechanical properties, biocompatibility, and radiolucency make it ideal for patient-specific CMF and orthopedic implants. The ability to 3D print in PEEK enables manufacturers to design more complex geometries with integrated lattice structures or porous scaffolds, which have been shown to support bone ingrowth and facilitate osseointegration.¹ It also enables the production of custom implants tailored to a patient’s specific anatomy, based on CT scans or MRI data. This allows for a precise fit and alignment of the implant with the patient’s bone, resulting in improved implant stability and function. Patient-specific implants can also reduce the need for extensive intraoperative adjustments and minimize postoperative complications, leading to better patient outcomes.

READ MORE: Empowering Contract Manufacturing Growth with 3D Printing

Additionally, the capacity for point-of-care printing means hospitals can produce these implants on-site, further enhancing efficiency and patient care.

There are already several successful use cases of 3D-printed PEEK cranial implants. As of now, more than 40 surgeries using these PEEK cranial implants have been conducted in point-of-care settings in Europe, demonstrating the practical benefits and effectiveness of this technology. For instance, the University Hospital of Salzburg in Austria has successfully used 3D-printed PEEK cranial implants in several complex cases, showcasing the technology’s potential to improve patient outcomes through personalized solutions.

Navigating Regulatory Pathways with Advanced Technologies

Introducing new technologies like PEEK extrusion printing into the medical field involves navigating complex regulatory landscapes. The process of obtaining regulatory clearances for such innovative materials can be intricate and time-consuming. However, partnering with experienced companies that understand these challenges can significantly streamline this process. The key is to seek out a partner that offers comprehensive support, including the reuse of data and access to master files, which can expedite regulatory approvals.

This approach not only accelerates time-to-market but also fosters innovation by allowing manufacturers to focus more on product development and less on regulatory hurdles. By leveraging established expertise and resources, medical device manufacturers can bring new products to market more quickly and cost-effectively, reducing internal regulatory costs and resources.

Future Outlook: Expanding Applications of 3D-Printed PEEK

Very recently, we saw the FDA clearance of the first patient-specific, 3D-printed PEEK cranial implant. This is just the beginning of this journey as the technology’s potential extends far beyond CMF applications. Future developments are expected in areas such as thoracic and spinal implants, where the mechanical properties of PEEK can provide significant advantages.

Modified PEEK filaments, such as fiber-reinforced PEEK or calcium phosphate/HA-enhanced PEEK, are already commercially available and offer additional benefits for specific medical applications.Beyond this, there are opportunities for 3D-printed PEEK’s expanded use in many different orthopedic applications, trauma implants, dental implants, and sports medicine applications.

Another growth segment could be hybrid implants. PEEK can be combined with other materials—such as metals, ceramics, or other polymers—to create hybrid implants with complementary properties. These combinations can result in implants with improved performance, such as enhanced mechanical strength, wear resistance, or imaging visibility, leading to more versatile and customized implant solutions. As the medical device industry continues to evolve, the integration of 3D printing technologies with advanced materials like PEEK will undoubtedly lead to new innovations and improved patient care.

Conclusion

The journey to mastering 3D printing with PEEK is challenging but incredibly rewarding. The successful development and regulatory clearance of 3D-printed PEEK cranial implants highlight the immense potential of this technology. By addressing the initial challenges and leveraging strategic partnerships, manufacturers can accelerate innovation, reduce time-to-market, and ultimately improve patient outcomes. The future is bright for 3D-printed PEEK, with vast possibilities across various medical fields poised to benefit from this groundbreaking technology. 

Reference

1. Wixted, CM, Peterson, JR, et al. Three-dimensional Printing in Orthopaedic Surgery: Current Applications and Future Developments. JAAOS: Global Research and Reviews 5(4):p e20.00230-11, April 2021.

Stefan Leonhardt is director of Medical Devices for 3D Systems. In this role, he leads the company’s efforts focused on 3D printing with medical high-performance polymers. Leonhardt joined 3D Systems in 2022 through the acquisition of Kumovis, a company he co-founded with four colleagues in 2017. While at Kumovis, he and his colleagues developed the first 3D printing platform specifically designed for medical device production, now known as 3D Systems’ EXT 200 MED. Leonhardt studied medical engineering at the Technical University of Munich. He holds an MBA with a focus on digital transformation and new business models. Leonhardt also earned a Ph.D. for his work on material development for resin-based 3D-printing technologies for the development of bioreactors.