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Additive manufacturing, commonly known as 3-dimensional (3D) printing, has been billed as the new industrial revolution. It is a lofty prediction; but we are seeing this prognostication materialize. Everyday consumer products ranging from children’s toys to running shoes are being 3D printed, sometimes right in consumer stores or at home. More and more manufacturers have begun or are exploring additive manufacturing options for their products. 3D-printed products even won an Oscar, when Ruth Carter won Best Costume Design for her work in the movie Black Panther, where portions of Carter’s costumes were 3D printed. From everyday consumer products, to its appearance on the red carpet, 3D printing has arrived.
Recognizing the potential advantages, endless possibilities, and unique manufacturing capabilities offered by 3D printing, more and more medical device manufacturers are entering this new field of technology. However, industry standards and regulations lag behind the pace of innovation. The unique aspects and potential availability of additive manufacturing raise novel products liability issues that may impact traditional product liability litigation doctrines. This article examines the current status of additive manufacturing as well as potential issues and uncertainties it raises for the future of product-liability litigation.
Additive manufacturing is defined by FDA as “a process that builds an object by sequentially building 2-dimensional (2D) layers and joining each layer to the below, allowing device manufacturers to rapidly produce alternative designs without the need for retooling and to create complex devices built as a single piece.” It differs from traditional manufacturing, also known as subtractive manufacturing, in that it builds up by layer, rather than machining down a solid block of material.
Broadly speaking, additive manufacturing of medical devices can be categorized into two production models. The first, following the more traditional mass-production model, is when device companies mass-produce 3D-printed products at a central manufacturing facility, using a single design model, and then sell the products as they would any other traditionally manufactured products. This model follows the traditional chain of distribution. The second model is referred to as “point-of-care” printing, in which medical devices are printed at hospitals or nearby printing hubs and often times individually customized to meet a specific patient’s anatomy.
The primary advantage to additive manufacturing is that it allows manufacturers to more easily provide point-of-care solutions to patients. 3D printers require a digital model of the part to be produced. Through scanning of the patient, models of joints or organs are created, required dimensions precisely are calculated, and then a precise, custom, digital blue print can be sent to the 3D printer for on-location manufacturing.
Another advantage of additive manufacturing is the potential to produce a finished product as a single, unified whole product, as compared with traditional manufacturing methods that might require multiple steps to assemble separate parts. For example, using additive manufacturing, Renovis Surgical Technologies offers an acetabular cup for use in hip replacement surgery that has a porous coated backing that is directly built into the product through printing, during a singular manufacturing process. (At press time, Kyocera Corp. had agreed to purchase Renovis. Here is a link to the technical brochure for the product.) Traditional manufacturing methods required such coatings to be applied to the back of the cup, in a separate manufacturing stage, as a plasma spray or sintered beads.
Despite its unique advantages, additive manufacturing does have potential drawbacks, primarily as a result of the relatively early stages of this technology. Currently, even the top printers have slower build rates, and higher production costs than those for mass production parts. Also, additive manufacturing introduces different variables into the manufacturing process that could affect the mechanical and geometric properties of the finished part. For example, in powder-bed printing (a type of additive manufacturing that uses powder—often for metals—as the material that is then heated and fused together layer by layer), concerns arise that powder residue may remain from one print to the next or that separate material powders could cross contaminate and result in structural defects. In addition, the volatile nature of some printing raw materials adds new hazards to the manufacturing process, particularly when located outside of traditional manufacturing facilities. Developers continue to try to mitigate these variables as 3D printing technology advances.
Standards and Regulations
Innovation is moving quicker than industry standards and regulations, although guidance on additive manufacturing is emerging. FDA and leading industry standards committees have drafted guidance and standards relating to additive manufacturing. In May 2016, FDA issued its initial draft guidance document on 3D printing entitled “Technical Considerations for Additive Manufacturing.” The guidance was issued in final form on December 5, 2017. The guidance does not establish specific requirements,but rather describes issues to be considered and addressed by manufacturers during product testing and manufacturing development stages,as well as the premarket submission process. The FDA’s guidance is limited to 3D printing by manufacturers under the more traditional mass-production model,and does not address point-of-care 3D printing at hospitals (although it is expected that draft guidance directed to hospitals will be released soon).
ASTM International has developed consensus standards for additive manufacturing. In 2009, ASTM International formed a committee, F42, to create standards for manufacturing processes and applications. Committee F42 has formed more than twenty subcommittees on test methods, design, materials, and various applications such as aviation, electronics, and medical products. There are currently standards for testing and evaluation methods for the materials used as well for the manufacturing processes. Committee F42 met during its bi-annual meeting on March 26, 2019, and further announcements and standards information can be expected. ASTM’s Committee on Medical and Surgical Materials, Committee F04, is also considering standards specific to additive manufacturing of medical products, and industry experts expect Committee F04 to draft guidance specific to 3D printing of medical devices in the near future.
Additive manufacturing of medical devices has the potential to raise distinct new questions regarding how such products will be treated under products liability law. With endless possibilities offered by 3D printing, the potential issues and impact on products liability are unknown and unlimited when considering the three primary theories of products liability law—design defect, manufacturing defect,and failure to warn.
The prospects of point-of-care printing and even mass production 3D printing raises as-yet unanswered legal questions involving potential design-defect claims. For example, a key element of a design-defect claim is the availability of a feasible alternative design. With 3D printed products, plaintiffs’ counsel might argue that the same product could be designed using traditional manufacturing processes. Manufacturers might need to identify a distinct design advantage from 3D printing a product, as opposed to using traditional methods. Revisiting the Renovis acetabular shell, for example, one benefit of 3D printing might be to create the porous coated backing in a singular step, fully integrated into the product, versus introducing a separate step and fixation variable into the process by use of a plasma spray or other added feature. By recognizing the justification for utilizing additive manufacturing in the early design and development stage, manufacturers may best position themselves to defend against this potential feasible alternative design argument.
Point-of-care printing for a specific patient, performed on or near the site of a hospital, raises other novel questions relating to design-defect claims. For example, plaintiff counsel might argue that appropriate testing of customized and necessarily unique 3D printed components was not performed. For customized 3D printed devices, where the variations are unlimited due to unique patient anatomies, it will be impossible for a manufacturer to test every scenario. Developing ASTM standards on additive manufacturing may help shape the future case law on this issue.
As to manufacturing-defect claims, one of the biggest questions for point-of-care printing at hospitals or by entities other than the design company is who is deemed the manufacturer. While traditional mass-produced manufacturing occurs at the sight of the design company, point-of-care printing may occur at hospitals, using software designed by another company, and printed on a printer owned and maintained by a third entity. It is unclear which of these entities might be deemed to be the “manufacturer” for the purposes of products liability. The anticipated FDA guidance on point-of-care printing at hospitals may indicate how regulations will implicate each participant in the printing process and preview subsequent products liability developments.
The number of new manufacturing variables introduced by 3D printing may also provide plaintiffs’ counsel with numerous avenues to consider a manufacturing defect claim. Variables unique to 3D printing, such as recycling unused powder or materials from one print to the next, clearing materials or powders from a previous print, and printing or software glitches, increase the potential that deviations from design specifications may occur during the manufacturing process.
3D printing also raises new issues for failure-to-warn claims. Under current FDA framework, instructions for use are submitted to, and either reviewed or approved by FDA prior to the marketing of a device. But with 3D-printed products, especially in the point-of-care setting, will instructions for use be required where the implant is being manufactured at a hospital or nearby printing hub? If so, should those warnings and labels accompany a CAD file, for example, that contains the printing specifications? Or will the designers of software used to image the patient’s anatomy be required to issue warnings? Or perhaps the 3D printers will be required to have warnings and instructions for use? The absence of regulatory or consensus guidance and standards on these issues may open new avenues of argument for legal liability.
Advancements in additive manufacturing have the healthcare industry understandably excited about future possibilities. But as innovation continues to progress, industry standards, federal regulations, and case law lag behind, creating some uncertainties regarding liability. We will continue to keep a close eye on FDA guidance and emerging ASTM standards as they relate to additive manufacturing, as such developments will likely serve as a barometer for the treatment of 3D-printed devices in products liability law.
The author would like to thank Dana J. Ash, chair of the Products Liability and Toxic Torts practice and team lead for the Duane Morris Life Sciences/Biotech industry group, who contributed to this article.