3D-Printing Our Way to Safer Medical Devices

The US Food and Drug Administration (FDA) recently released a new draft document intended to guide medical device manufacturers who are using additive manufacturing methods in the design and construction of their products. The new document is only a set of initial guidelines, but the conditional green light from the FDA will likely encourage more device manufacturers to explore what can be done with this new technology.

Flexible, Quickly-Advancing Technology

Additive manufacturing is more casually known as 3D printing. Small printers are available at surprisingly affordable prices for consumers to buy and use at home to build anything they can get (or draw up) blueprints for. NASA even has a 3D printer installed on the International Space Station so that astronauts can print out specialized tools when they need them, instead of waiting for a rocket to arrive with the nuts and bolts they need. It’s a very flexible technology that can build almost anything a person can design, and that has inspired many innovators in the medical devices industry.

Currently, medical devices used inside the human body aren’t generally custom-made for each unique individual. New hip and knee joints, for example, may come in a small array of sizes, and the surgeon selects a model that is the closest fit for the patient. This can be a problem when devices aren’t easily available in the necessary sizes – for example, tiny devices for pediatric patients. 3D printing technology allows device manufacturers to customize their devices, often using high-tech medical imaging to design perfect matches for a person’s anatomy.

The FDA guidance document (PDF link) for additive manufacturing, published in May 2016, isn’t legally binding; it isn’t a set of federal regulations that manufacturers must adhere to or risk sanctions. It’s what they call a “leap-frog” document, outlining the agency’s initial thoughts and concerns on the subject. With technology moving so quickly, the FDA relies on drafts and leap-frog guidance in order to give manufacturers interim guidelines to follow.

Safety and Standardization

The current guidance document was drafted with the input of various stakeholders in the medical device industry. A 2014 FDA workshop on additive manufacturing collected opinions and expertise from academics, device  manufacturers, and physicians. The attendees weighed in on the quality and safety of the materials involved in 3D printing, as well as the design, printing, and post-printing validation and assessment of the physical and mechanical properties of the final devices. Perhaps most importantly, they discussed the biological impact of 3D-printed medical  devices.

Because of the “relative lack of medical device history” behind 3D-printed medical devices, they carry an uncertain amount of patient risk. It is important that device manufacturers assess the biocompatibility of the materials they are using, especially as the technology advances and some manufacturers explore the addition of antimicrobial agents to the materials they print with.

It’s also essential that manufacturers test their original device design in order to know which parameters can be modified and customized for individuals and which are essential to the correct function of the device. It might seem that a custom-fit sternum designed for a patient’s chest would be better than trimming the patient’s ribs to make space for an off-the-shelf model, but if changing its thickness and size compromises its integrity and lessens its function, perhaps the patient isn’t better off with the custom device.

Through this draft document, the FDA hopes to standardize the industry somewhat by outlining what quality systems a manufacturer must have in place before developing and implementing design processes. While the devices themselves may all be different, the processes behind their design and construction and the way that their risks are assessed should be the same across the board.

Biological 3D Printing Needs A Closer Look

3D printers don’t only build with plastic and metals. Researchers all over the world are working towards printing entire replacement organs using a matrix of living cells. Unfortunately for those companies who might want to get started 3D printing skin grafts and coronary arteries, the FDA has decided to delay publishing specific guidance for that particular subset of the technology, saying, “Biological, cellular or tissue-based products manufactured using [3D printing] technology may necessitate additional regulatory and manufacturing process considerations and/or different regulatory pathways.”

The FDA, for now, is referring questions about biological 3D printing of tissues and organs to the Center for Biologics Evaluation and Research (CBER).