Additive Manufacturing in Medical Devices: Innovation, Challenges, and Paths to Compliance

What is Additive Manufacturing in Medical Devices?

Additive manufacturing, also known as 3D printing, has gained prominence in the medical device industry. This technology enables the creation of customised products and the fabrication of complex structures, including porous surfaces and internal channels that are more difficult to achieve using traditional methods. 

However, implementing this process in the medical field presents significant challenges, primarily related to technical and regulatory requirements. Key critical points include material traceability, validation of manufacturing processes, post-processing, and assessment of device biocompatibility. 

What is FDA Guidance for 3D-Printed Medical Devices?

In 2017, the FDA published guide “Technical Considerations for Additively Manufactured Medical Devices”, outlining what critical factors manufacturers should consider during design, production, and validation phases. It includes recommendations on material selection, process validation, machine calibration, and post-processing protocols. The FDA emphasises that the interaction between these parameters plays a key role in determining the final performance of the medical device. 

The guide’s requirements do not change the regulatory process for medical devices. All devices, including additives, must meet the quality and compliance requirements of 21 CFR 820. Manufacturers must meet regulatory requirements for pre-market submissions, such as 510(k), Pre-Market Approval (PMA), and Investigational Device Exemptions (IDE) for devices with additively manufactured components. 

Critical Steps in the Additive Manufacturing Lifecycle

Additive manufacturing is transforming how medical devices are designed and delivered. Offering faster innovation, reduced waste, and patient-specific solutions. But with great opportunity comes complexity. Every stage of the lifecycle must be controlled to ensure safety, consistency, and compliance. 

How is Software Used in 3D-Printed Device Design?

The initial step in the process is the generation of 3D printable models from medical scan images. Evaluating these images using software requires specific validations, which, if not performed correctly, can be detrimental to the geometry and dimensions of the final device. Therefore, the entire digital process must be validated to ensure that the developed model is printed correctly. 

What Materials are Used in 3D-Printed Medical Devices?

The selection of the starting material is a crucial step in the additive manufacturing of medical devices, as it directly impacts the performance of the final product and its biocompatibility. 

The technologies applicable to the process enable the use of a variety of materials, including plastics, metals, and ceramics. Each class of material presents specific benefits and limitations, which must be studied in detail depending on the intended use. Additionally, depending on the methodology applied, it is essential to control characteristics such as particle size distribution, sphericity, chemical purity, and powder flowability to ensure repeatability and predictability in manufacturing. 

A notable feature of 3D printing technology, in turn, is the reusability of material that was not incorporated into the final device. However, reused material can be exposed to heat, oxygen, humidity, and ultraviolet energy, which can alter its original state. Therefore, the FDA mandates that studies must be conducted to confirm that the use of reprocessed material does not interfere with the structural properties, mechanical behaviour, and biocompatibility of the device. Validation evidence must be documented and reflect that the stated maximum reuse amount is validated based on a worst-case scenario assessment and that patient risks remain within acceptable limits. 

How do You Validate 3D Printing Processes for Medical Devices?

3D printing setup involves important parameters that determine the structural integrity and function of the device. Factors such as part orientation in the build chamber, beam power, scan rate, and thermal management need to be well defined, controlled, and characterised within the qualification processes. These factors can influence mechanical and dimensional properties. Therefore, process validation should include qualification through multiple raw material batches, production batches, and printing cycles, ensuring that the resulting devices are consistent with predetermined quality assurance limits, as well as worst-case scenario assessments. 

Each post-processing phase represents a critical manufacturing process that must be independently validated, with a special focus on preserving the mechanical properties, dimensional stability, and biocompatibility of the final product. 

Dimensional and Material Characterisation in 3D Printed Medical Devices

Dimensional conformity to the design must be proven using appropriate metrological methods. Furthermore, characterisation of the printed material, including analysis of microstructure and chemical composition, is mandatory. These properties can be significantly influenced by printing and post-processing conditions and must be consistent with the specified performance parameters.

What Mechanical Tests are Required for 3D Printed Devices?

Mechanical testing should be performed on the final device, applying tensile, compressive, flexural, and strength loads, as well as fatigue tests, as applicable, according to the intended purpose and conditions of use of the device. 

During mechanical testing of these devices, manufacturing alignment and the positioning of the parts on the build platform must be taken into account, as they can affect the final properties. In this context, the build condition (especially the worst-case scenario) of the device or parts should be established in relation to the respective performance test. 

Validating Cleaning and Sterilisation for Medical 3D Prints

The geometric complexity of devices manufactured using additive manufacturing can pose a significant challenge for the effective removal of manufacturing residues and the validation of the sterilisation process. Structural characteristics are conducive to the deposition of particles/dirt that are not easily accessible through cleaning and sterilisation processes. 

To ensure device safety and performance, it is essential to describe in detail the process adopted for residue removal, as well as to demonstrate its effectiveness using sensitive and validated methods. 

Therefore, it is essential that the validation of cleaning and sterilisation processes consider standardised methods and verification using worst-case models under the worst-case conditions to ensure the effectiveness of the processes. 

Assessing Biocompatibility in Additive Manufacturing

Assessing the biocompatibility of medical devices is an essential step in ensuring patient safety against local or systemic adverse effects. The assessment must be performed on the finished device, after all manufacturing, finishing, and sterilisation steps, in accordance with the guide “Use of International Standard ISO 10993, Part 1: Biological Evaluation of Medical Devices in a Risk Management Process” and other applicable standards. 

In the context of additive manufacturing, this requirement becomes even more critical, since each step of the process can significantly alter the surface composition, morphology, and chemical profile of the product. 

The worst-case biocompatibility assessment must be carefully considered, considering the potential for leaching and the need for additional chemical analysis to select representative samples. 

When powder reuse is anticipated in manufacturing, the biocompatibility assessment must consider the cumulative impacts of this reuse, requiring chemical and biological testing to be conducted on the final device manufactured under the worst-case validated reuse conditions.

The Future of Medical Devices: Innovation Meets Regulation

Additive manufacturing represents a revolution in the way medical devices are designed, offering highly personalised solutions aligned with precision medicine. However, its complexity challenges traditional regulatory models, requiring specific and updated guidelines. 

Overcoming these barriers requires collaboration between industry, academia, and regulatory authorities, with a focus on rigorous process validation, quality control, and risk-based assessment. 

References

• Connole, K., & McDermott, O. (2025). The Challenges in the Regulatory Approval of Additive-Manufactured Medical Devices: A Quantitative Survey. Therapeutic Innovation & Regulatory Science.

• Morrison, R. J., et al. (2015). Regulatory Considerations in the Design and Manufacturing of Implantable 3D-Printed Medical Devices. Clinical and Translational Science.

• Di Prima, M., et al. (2016). Additively manufactured medical products – the FDA perspective. 3D Printing in Medicine.

• FDA. (2017). Technical Considerations for Additive Manufactured Medical Devices: Guidance for Industry and Food and Drug Administration Staff.

• FDA. (2023). Use of International Standard ISO 10993-1, “Biological Evaluation of Medical Devices – Part 1: Evaluation and Testing within a Risk Management Process”: Guidance for Industry and Food and Drug Administration Staff.

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