Here are three important things that medical device makers should consider as they examine the pros and cons of 3-D printing, courtesy of Andreas Pfahnl of Devicix.

Andreas Pfahnl, ScD, Devicix

Manufacturing a medical device requires carefully selected materials, controlled fabrication and assembly manufacturing processes, and qualified suppliers and contract manufacturing partners. Incorporating 3-D printing or additive manufacturing process into the overall manufacturing of a medical device requires the same compliance and attention to these details with this fabrication process.

Here are some things to keep in mind:

1. Geometry, Cleanliness, and Biocompatibility

The geometrical features of the medical device design must be controlled along with the cleanliness and biocompatibility, not just of the raw material but also of the finished device. You really need to consider the processes used to achieve the final state. For example, just because the titanium of an implant screw is deemed biocompatible does not ensure the screw is biocompatible. If after it goes through all the machining to incorporate the threads and shapes, it is dripping with machining oil, then the screw is not yet biocompatible even though the titanium is still biocompatible, since it has not changed.

Implants and surgical devices as patient internal tissue contacting require additional considerations and controls for biocompatibility beyond external contacting ones that are outlined in ISO 10993-1.

(See Pfahnl discuss 3-D printing at MEDevice San Diego, September 1-2.)

2. What You Can Learn from the Ortho Sector

The orthopedic space has seen some of the best implementations of 3-D printing, taking all of these aspects into consideration. Ortho device makers have been working on both metal and polymer devices created with controlled additive manufacturing processes.

Orthopedic implants provide mechanical stability during healing (e.g. interbody spine fusion cages) and fixation (e.g. screws and plates). The goal long term is that the implants assimilate themselves to the surrounding bone, requiring that the bulk mechanical properties resemble that of the local bone tissue, and integrate themselves with it as well. This helps mitigate the loosening of the implant that can happen from repeated mechanical forces imposed on the implants. Therefore, good bone ingrowth is important, which has led to the integration of different types of porous bone ingrowth coatings on the surfaces of implants that need to osseointegrate. These relatively thin coatings are applied as a separate process such as on the bone-contacting surfaces of a hip replacement acetabular cup or stem implant. Having separate processes for machining, cleaning, and coating require the physical movement of the component from one set of manufacturing operations to another. 3-D printing now allows the entire device to be created with the bone in-growth surface with one fabrication manufacturing process, eliminating interim processing steps. The bone ingrowth surface can also now not just be a coating but an actual porous scaffold optimized for ingrowth and strength. 

3. Customization

With 3-D printing qualified as a manufacturing method in these applications the process naturally lends itself to customization of the implants to specific patient anatomies. One still needs to consider the lead time or turnaround time to create the proper implant geometry and fabricate it including all the processing steps through packaging and sterilization. But 3-D printing nevertheless creates a new opportunity for the industry, clinicians, and researchers to explore and understand when it comes to the benefits of optimized implant designs.

From a product perspective too, there are other factors that come into play beyond the implant, such as preparation tools like trials and fixtures especially for total knee replacements that also need to be customized and considered. Ultimately it is improved clinical outcomes and total procedure improvements to reduce costs both in component costs and procedure that will justify hypothesized benefits.

(See Pfahnl discuss 3-D printing at MEDevice San Diego, September 1-2.)

Andreas Pfahnl, ScD, is GM & CTO of Devicix, which is an international contract medical device product development and commercialization company with brand divisions: www.iomedx.com and www.orthopedx.com. Devicix is a division of Nortech Systems Inc. His expertise is in business development, commercialization and regulatory strategies, and product architecture development across a broad range of clinical areas including meuromodulation/stimulation, cardiology, mHealth /telemedicine, and orthopedics.