FDA published its guidance on additive manufacturing technical considerations, outlining the Agency’s long-awaited position on use of the technology for medical devices.
Like you, we’ve eagerly awaited the finalization of this guidance. Few topics have dominated our conversations with device companies, suppliers and surgeons like additive has in recent years. FDA points out that the 31-page document is considered “leapfrog” guidance, a term reserved for FDA’s anticipation that its initial thoughts on an emerging technology will change over time. In short, more questions and answers will continue to arise as the technology is adopted.
What we do know is that FDA outlines its thoughts on the phases of design development, production process, process validation, semi-finished and final finished device testing. While the full guidance, “Technical Considerations for Additive Manufactured Medical Devices,” can be read online, we’ve chosen to highlight three points related to questions with which readers have often approached us: device design, materials and cleaning/testing.
FDA outlines its stance on design from mass produced to patient-specific implants, stating that additive manufacturing may introduce variability into the manufacturing process. To overcome this, “We recommend that you compare the desired feature sizes of your final finished device to the minimum possible feature size of your AM technique and the manufacturing tolerances of the individual machine, given the build parameters and conditions under which the final device is expected to be made. This is to ensure that devices and components of the desired dimensional specifications can be reliably built using the chosen additive technology.”
FDA points out that the starting material may undergo significant physical or chemical changes during the additive manufacturing process, which could impact the properties of the final finished device. FDA proposes that companies document the following with regard to materials:
- Identify the material or chemical name by common name
- Material supplier
- Incoming material specifications and material certificates of analysis (COAs); applicable materials standards and test methods referenced
The guidance provides several examples on the latter point about material specification. If a metal is used, for example, FDA seeks to know the metal’s chemical composition and purity.
Within its material explanation, FDA touches on the reuse of materials, recommending that companies describe the material reuse process, which could include a description of processes such as filtering reused materials, a limit on the percent of reused material, monitoring for changes in chemistry, etc.
FDA outlines its recommendations on mechanical testing, dimensional measurements, material characterizations and removal of material residues and sterilization. Best practices on removal of residues (i.e. cleaning) and sterilization continue to be discussed by industry. As FDA point outs, complex geometries created by additive manufacturing may increase the difficulty of removing residue and create internal voids with limited or no access during sterilization.
FDA recommends that manufacturers establish and maintain procedures for the use and removal of residue to ensure that it is removed or limited to an amount that doesn’t adversely affect device quality. The Agency recommends that the process be documented and included in companies’ premarket submissions.
Additionally, on the topic, FDA says, “It is important to note that many end user facilities may not have routine access to the equipment or materials needed to implement cleaning procedures that are designed to remove residual manufacturing materials and that personnel are likely not adequately trained to perform such cleaning procedures. Therefore, only devices that are sufficiently cleaned of residual manufacturing materials should be provided to the end user.”
To repeat: FDA expects that its thoughts on the technology will change overtime. Similarly, we expect the questions we’ll field from industry will also evolve as companies experience successes and failures with the technology.
For now, we plan to provide expert, real-world insight to industry’s questions on design considerations, material considerations, residue removal, testing and forthcoming standards in the GE Additive Tech Center at OMTEC 2018. FDA, ASTM, device companies, contract manufacturers, machine suppliers, testing companies and material companies have been invited to dissect the aforementioned list of topics and more over the course of one and a half days.
FDA’s guidance is critical to the additive manufacturing narrative. However, standards and best practices surrounding the technology are being discussed globally on a daily basis. OMTEC expects to put those people in one room for one conversation that provides industry with practical, actual guidance.