A novel 3D printed implant solution has emerged, poised to enhance patient care in the field of neurosurgery.
A novel 3D printed implant solution has emerged, poised to enhance patient care in the field of neurosurgery.
Ever since inventor Chuck Hull filed the first patent for stereolithography (SLA) in the late 1980s, 3D printing has evolved significantly. Today, tailored pharmaceuticals and even the potential for organs crafted from living cells are possible to the imagination, with the potential of 3D printing promising further groundbreaking developments in medicine.
In fact, this April, the Food and Drug Administration (FDA) gave additive manufacturing solutions provider 3D Systems – which Hull also co-founded – 510(k) clearance for its 3D-printed, patient-specific cranial implant solution: VSP PEEK Cranial Implant. Such clearance enables widespread adoption of the company’s self-contained, cleanroom environment-based printing system, the EXT 220 MED, with implant-grade PEEK (polyetheretherketone) materials to deliver patient-specific cranial reconstruction solutions.
According to the Director of Medical Devices at 3D Systems, Stefan Leonhardt, the technology can produce patient-specific cranial implants with up to 85% less material than similar implants produced by traditional machining, which can lead to significant cost savings for expensive raw materials such as implantable PEEK. The cleanroom-based architecture of the printer, combined with simplified post-processing workflows, also makes it an ideal technology for producing patient-specific medical devices at the hospital site with faster turnaround, while keeping the overall cost under control.
PEEK Performance
The VSP PEEK Cranial Implant is the first FDA-cleared, additively manufactured patient-specific PEEK implant intended for cranioplasty procedures to restore defects in the skull. This implant-grade, high-performance polymer has a well-known clinical history in medical device applications as it possesses properties close to that of the human bone. In addition, PEEK has great biocompatibility, resistance to bodily fluids, and stability in a wide range of temperatures, making it an ideal choice for many medical device applications.
Moreover, the durability and strength of the material and the implant’s contoured fit make it an ideal choice for reconstruction. 3D printing in PEEK is also quicker than using traditional milling processes and is more compatible with diagnostic imaging. Meanwhile, the material is lightweight and eliminates temperature sensitivity, improving patient comfort.
The printing process
Leonhardt explains the process in creating the implant, stating that it all starts with a CT scan. “Based off that CT scan done at a hospital, the next workflow step is segmentation,” he says. “Here, we use software called D2P to create a three-dimensional model of the skull and the defect. In a second software called Freeform the implant is designed to fill the patient’s skull defect.” 3D Systems also offers guidelines to help users of the system design an implant to ensure it perfectly fits the patient at the end of the process.
Medical experts can then import the model onto 3D Systems’ EXT 220 MED open filament 3D printer to print the implant. Formerly known as Kumovis R1, the printer is equipped with a global laminar air flow which allows users to heat the build chamber homogenously up to 250°C. The additional local airflow helps users improve the mechanical properties of the device. The platform is also designed to control temperature during production.
“High-performance polymers such as PEEK need to be processed at extremely high temperatures, as we have to ensure that each layer shows a good bonding to the next layer ,” Leonhardt explains. “The layer bonding is determining the mechanical properties of the final part. Our proprietary temperature management system ensures that we are processing PEEK at optimal conditions to produce printed parts that show mechanical properties comparable to machined implants.”
The EXT 220 MED printer includes a filter system which creates a clean-room environment inside the build chamber. Particle measurements show that an environment equal to an ISO class 7 cleanroom can be achieved. “This filtration system ensures that there’s no contaminations or particulates between the layers that are printed – that is a major advantage of our machine,” Leonhardt says. Moreover, depending on the size of the implant, the printer can print an implant in up to four hours, with capabilities to print a smaller implant within an hour, he adds.
Endless opportunities
Leonhardt states that the company sees growing interest in the technology from hospitals directly. To date, the solution provided by 3D Systems has been used to enable nearly 40 successful cranioplasties in Switzerland at University Hospital Basel, in Austria at Salzburg University Hospital, and in Israel at the Tel-Aviv Sourasky Medical Center. “We also see the FDA thinking about how we [3D Systems] can do point-of-care printing in hospitals in the US,” Leonhardt adds. “We are also seeing more traction from industry partners across Europe as well as patients with skull defects.”
Leonhardt envisions that the FDA clearance will herald in a new era of implant technology. “With this technology, we can enhance implants with features like bone or lattice structures, tailored to each patient,” he explains. “Moreover, we’re able to achieve this while reducing costs, shortening lead times, and revolutionising the supply chain by enabling on-site printing in hospitals.”
Placing 3D printing systems within hospitals fosters closer collaboration with surgeons, Leonhardt notes, while ongoing innovation expands the array of medically compliant materials available. “This technology empowers us to craft cutting-edge implants, democratising access to advanced healthcare,” he emphasises. “Ultimately, patients benefit from faster, more affordable, and high-quality implants, enhancing their quality of life.”
CASE STUDY: a successful cranioplasty using 3D printing tech
Rainer Trummer from Salzburg, Austria, embodies the transformative impact of 3D printing in medicine. Born with a skull anomaly, Trummer faced prohibitive costs and technological limitations hindering corrective surgery. However, Salzburg University Hospital leveraged additive manufacturing, utilising 3D Systems’ point-of-care printing technology, to create a custom skull implant for Trummer – this marked the first use of the hospital’s own EXT 220 MED 3D printer for such a purpose.
The implant development involved using an expander. And over several months, the expander was filled with a total of 260ml of saline solution over one and a half years to stretch the scalp for full implant coverage. The surgical procedure entailed expander removal, fixation with mini plates and screws, and wound care, culminating in the formation of a natural tissue layer for added stability.
Throughout the process, Trummer reported minimal discomfort, primarily from the expander. Post-surgery, his physical and psychological wellbeing significantly improved, bolstering his self-assurance and overall quality of life.
