Not that long ago, there was a small group of forward-thinking people who saw how evolving new image processing techniques could intersect with 3D printing to create educational and planning tools to transform surgery preparation. This small group carefully handled patient data and turned them into physical replicas of the anatomy for surgeons and patients to hold in their hands, rehearse, plan, and think through a procedure before going into the operating theatre. Largely, these people and their companies began developing quality control systems to handle their data, validated cleaning and sterilization methods, registered their companies and listed their products with the FDA under a low risk, Class I product code - HWT.
Soon this manufacturing technology of 3D printing was adapted to do more, and early applications of the technology were focused on orthopedic surgical cutting guides allowing off-the-shelf joint arthroplasty implants to be placed with a personalized cut specific to the boney anatomy and mechanical alignment of each patient. These guides originally came onto the market under the same Class I product code, but then in a relatively short amount of time, FDA warning letters were issued and a Class II product code was settled on in line with the Class II device they were deemed to be an accessory to. This required companies to get a substantially equivalent (to traditional methods in this case) determination for clearance of a 510(k).
This approach was then adopted across the anatomy for planning boney anatomy cuts and guiding placement of bone grafts. Maxillofacial, cranial, and other orthopedic applications followed. Each FDA review group for these areas found appropriate Class II product codes, requiring pre-market approval in the form of a 510(k), specific to these types of devices, pairing the digital inputs and software system to create the printable file and the physical printed device into one code.
Simultaneously, companies were pursuing Direct Metal Printing with laser and electron beam-based 3D printing to print high detail, porous and fully dense serialized implants. Those were treated, from a regulatory standpoint, just as traditional methods of subtractive machining, falling under the same product codes as the traditionally manufactured outputs, but with more focus on the process validation, powder handling, and cleaning of the 3D printing systems and parts.
In 2017, the FDA/CDRH/Division of Radiological Health set out some guidelines on how FDA was planning on regulating the increasingly popular and democratized capability of 3D printing anatomic models for the purposes of making diagnostic decisions. That presentation laid out the intent of diagnostic anatomic models to be regulated through the software systems supporting medical image processing to make the digital model that is then 3D printed, under product code LLZ, which is a Class II product code requiring 510(k) clearance. This was a major change in the way companies had been producing anatomic models under the Class I, 510(k) exempt, HWT product code. The framework, documented in a slide deck from the FDA/CDRH–RSNA SIG Joint Meeting on 3D Printed Patient-Specific Anatomic Models, is still the primary documentation indicating the intent of regulation of these software applications and printed physical replicas.
In 2019, the first product was cleared under this new framework under product code LLZ. It was Materialise’s Mimics Medical and included a true turnkey system for printing diagnostic quality anatomic models. This allows a customer to purchase the software system capable of reading and segmenting (editing out only anatomic features desired for the application) medical imaging data, with clear, tested, instruction on which anatomies can be printed, which 3D printers and materials to use, and how to print, post process, and quality check the printed physical replicas. This turnkey method aligned perfectly with the forthcoming framework for classifying higher risk 3D printed devices.
In 2019, the FDA CDRH Additive Manufacturing Working Group set out another framework to guide the regulation of point-of-care and higher risk 3D printed devices. It includes five categories, grouped by risk and associated methods of regulation. This is the current understanding of the way the FDA is anticipating and encouraging the medical device industry to adopt and meet healthcare industry needs while maintaining a structure allowing appropriate FDA oversight and review of the safety and effectiveness of the devices. A Guidance Document formalizing the framework is expected to be released in 2021.
This industry has seen so much growth and expansion over the past three decades that at times it feels like the regulations have not been able to keep up with the technology and scope needed for capable products that are desired by the industry.
The key to advancing the technology further is collaboration with both the FDA and with standards organizations that support and encourage thoughtful requirements while acknowledging risks. This will continue the effort to raise an entire industry up to the level we all demand of ourselves and for ourselves.
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