Considerations for Point of Care (POC) 3D Printing
The global 3D printing medical device market is expected to generate $2.34 billion in revenue by the end of 2024.1 Research and design investment, a rapidly expanding customer base, and increased scope of biomedical application are three factors anticipated to fuel market growth.2 The medical community primarily leverages 3D printing, also called additive manufacturing, for two purposes. Manufacturers use 3D printers to develop economical medical devices, such as hip and knee implants and porous spine cages, on a large scale. They also use 3D printers to create patient-specific implants that utilize computed tomography scans or radiograph data for use in complicated surgical procedures. Although implants have traditionally been produced by manufacturers in centralized 3D printing facilities, there is growing demand by clinicians to have implant production in or near hospitals, at the point of care.
Point of care 3D printing has been growing as a training vehicle for 3D visualization for physicians as well as manufacturing non-implanted medical devices, such as surgical models and cutting guides or instruments.3,4 Now we are beginning to see increased focus on point of care AM for implants. This will be an important discussion at the Exponent-organized 4th International PEEK Meeting in Washington, D.C. on April 25-26, 2019.
Why point of care additive manufacturing of Implants?
Point of care additive manufacturing of implants is driven by the urgent desire of clinicians to quickly treat complex surgical cases that demand a unique, patient-specific approach. Currently, 3D printing of patient-specific implants is a clinical reality, but it can be time consuming, involving weeks or even months of back-and-forth between a clinical team and a remote manufacturing facility. The resulting 3D printed implants are expensive compared with traditional “off the shelf” devices. In addition to saving time and cost, placing an additive manufacturing facility at the point of care has the benefit of driving not only training and education but also innovation by immersing technologists, engineers, and clinicians in a collaborative environment.5
Two models of point of care additive manufacturing have already emerged. In one model, which I refer to as the “Starbucks” model, an established 3D printing implant manufacturer reaches an agreement with a hospital to operate a manufacturing facility on their premises. For example, in January 2019, the Hospital for Special Surgery and Lima Corporate announced “provider-based” 3D printing of complex, personalized orthopedic implants on the upper east side of Manhattan.6 In this example, the implant manufacturer of record is Lima Corporate, not the hospital. The medical technology company Stryker has also announced a five-year, $9.3 million partnership in Australia to deliver 3D printed patient-specific implants for people undergoing tumor removal and bone cancer treatment.7
In a second model, the hospital or medical services provider is the point of care manufacturer and builds a dedicated additive manufacturing facility on their premises. Over the past five years, the number of U.S. hospitals with an in-house 3D printing department has increased from one to roughly one hundred.8 Still, thousands of hospitals across the United States can benefit from considering point of care 3D printing to drive operating efficiencies, cost reduction, and improvements in time to treat their complex patients. Additive manufacturing in hospitals has already focused on load-bearing prosthetics for pediatric patients and veterans.9,10
Hospitals can also create 3D training models for physicians to train with or practice on pre-surgery. The process of reattaching an appendage, for example, requires several surgeons to work together as a team to reattach muscles and ligaments and connect blood vessels. By practicing on patient-specific models before surgery, the team can be better prepared to deliver a positive outcome. Similarly, a surgeon who is preparing to separate conjoined twins can use point of care 3D printing to color code one twin’s brain or organs from the other and practice the complex surgical procedure in advance.11
3D printing facilities in hospitals have the most familiarity with low-temperature extrusion-based printers for plastics. However, in 2019, high-temperature plastic printers will be commercially introduced, opening the door for load-bearing point of care implants manufactured out of polyetheretherketone (PEEK).12 3D printer manufacturers such as Apium and Kumovis are producing printers tailored specifically for PEEK implant production in hospitals.13,14 We are still in the early stages of understanding the structure-property relationships for implants fabricated using PEEK printers.15
The demand for additive manufacturing point of care implants has created a need for careful preclinical testing and evaluation to ensure such devices are reasonably safe and effective before clinical introduction. In the United States, the regulatory pathway for additive manufacturing products has been described in a U.S. Food and Drug Administration (FDA) Guidance Document.16 Patient-specific implants fall under a category of patient-matched devices, which require an entire envelope of designs to be verified and validated under the regulatory framework overseen by the FDA. The regulatory situation for point of care additive manufacturing is unclear at present in the United States, because the FDA has not issued formal guidance yet on this specific topic.
The regulatory landscape for point of care additive manufacturing will likely continue to evolve over time. Like medical devices made using other manufacturing processes, devices made using 3D printing technology are classified into Class I, II, or III and subject to FDA regulatory requirements.17 Currently, most point of care 3D printed medical devices go through the 510(K) process, which includes factors to be considered when commercializing an in-hospital solution that impacts patient care. Manufacturers are expected to address questions about what biomaterial they use; how they know the material has been validated for that particular application; and how they know that the software will provide an accurate model of what is happening with the patient at the time of surgery. For example, if a hospital takes an image of a cancer patient on day one and prints it on day four, how does the surgeon know that the state of the patient’s body is unaltered when the procedure is performed on day eight? U.S. regulations stress the importance of images being not only accurate but also relevant at the time of the actual surgery.
In Europe, the situation is currently more lenient than in the United States, with hospitals falling outside medical device regulations, provided they produce implants using standardized biomaterials. Surgeons are aware of this exemption and are encouraging the manufacture of patient-specific implants in hospitals, at least so long as the regulatory exemption still exists.17 It is expected, that European regulators will eventually modify this exemption, but its existence might explain why the first producers of medical implant printers, Apium and Kumovis, are in Europe.
Our European colleagues can provide important learning on specific biocompatible, high-performance polymers (e.g., PEEK) that may be well suited for permanent implants. They can also lend insights on how to develop 3D printers that are specifically designed for hospital printing and how to train medical professionals on the new technologies. Those interested in learning more may attend the Exponent-organized 4th International PEEK Meeting in Washington, D.C., on April 25–26, 2019. Engineers, scientists, regulators, and clinicians from academia, industry, and government agencies will present leading-edge research on advancements in medical grade PEEK technology and clinical applications. Learn more at http://www.medicalpeek.org/pub_reports/view/194.
How Exponent Can Help
Exponent’s multidisciplinary team of engineers, scientists, and physicians are at the forefront of PEEK research and routinely evaluate 3D printing technologies in our biomedical engineering laboratories. We currently provide technical and practical expertise for 3D printers and clients seeking to adopt 3D printing technology. Our staff can assist with the regulatory concerns, manufacturing validation, material selection and characterization, and facility development related to additive manufacturing.
Sources / Further Reading
5 Liu A, Xue GH, Sun M, Shao HF, Ma CY, Gao Q, Gou ZR, Yan SG, Liu YM, He Y. 3D Printing Surgical Implants at the clinic: A Experimental Study on Anterior Cruciate Ligament Reconstruction. Sci Rep 2016;6:21704.
12 Honigmann P, Sharma N, Okolo B, Popp U, Msallem B, Thieringer FM. Patient-Specific Surgical Implants Made of 3D Printed PEEK: Material, Technology, and Scope of Surgical Application. Biomed Res Int 2018; 4520636.
15 Basgul C, Yu T, MacDonald DW, Siskey R, Marcolongo M, Kurtz SM. Structure-property relationships for 3D printed PEEK intervertebral lumbar cages produced using fused filament fabrication. Journal of Materials Research 2018;DOI: 10.1557/jmr.2018.178.
18 Otero JJ, Vijverman A, Mommaerts MY. Use of fused deposit modeling for additive manufacturing in hospital facilities: European certification directives. J Craniomaxillofac Surg 2017;45:1542–546.