In my previous post, I considered the applications of technology for external medical devices. Since then, the Food & Drug Administration (FDA) in the US has published draft guidelines for Technical Considerations for Additive Manufactured Devices. The main thrust of these guidelines currently is not definitive, but rather provides direction both for medical device manufacturers and for FDA staff. Importantly, it does serve to illustrate the growth and acceptance of this application of 3D printing.
Growing Demand for Implants
Here, though, I’d like to take a closer look at the 3D printing ecosystem for implantable devices. It is a sub-sector of the medical device industry that is considerably more stringent in its regulation due to the critical nature of placing these devices within the human body to fulfill the function of body parts that no longer work and cannot be repaired, whether as the result of catastrophic injury or worn out through longevity. When such a prognosis is delivered it is invariably amid the suffering of ongoing physical pain that has a tremendous negative impact on an individual life and a permanent resolution is beyond desirable.
Moreover, global demographics continue to show an ageing population that is significantly contributing to increasing demand for replacement implants and the wider socio-economic implications of healthcare costs cannot be overlooked. Across the medical field, considerable research is being undertaken into the development of superior, cost-effective medical implants and the 3D printing ecosystem is contributing notably to these developments with many positive outcomes through design optimization, customized manufacturing operations and approved material production.
3D printing Meets the Need
As I alluded to previously, for a non-medical person, wrapping one’s head around all of the different medical disciplines can cause a brain fry. Let’s take away the soft tissues for a moment and just consider the skeleton, the area where 3D printed implants have had the most success to date. An adult skeleton consists of 206 bones, which — broadly speaking — comes under the ‘orthopedics’ banner in medical speak, with the more specialized areas of the skull/face defined as ‘cranio-maxillofacial’ (CMF).
In the last decade both of these disciplines have forged ahead with advanced techniques utilising 3D printing and its application is becoming increasingly widespread for both standard and custom-manufactured implants tailored to individual cases. These advanced techniques have also demonstrated clear cost and time efficiencies as well as adherence to the highest quality demands.
The dominant (but not exclusive) process in this specialized medical field is metal laser melting / sintering and electron beam melting. These metal processes allow for the manufacture of the complex mesh structures of innovative implants that reduce production costs and lead-times compared with conventional manufacturing techniques of such products.
The complexity involved in the production of an orthopedic / CMF implant is inherently linked to the ability to simulate bone structure, porosity, and a surface texture that produces high-friction and allows for bone ingrowth around the implant.
And this is where 3D printing excels, in a way that no other single process ever has previously. Add in the personalization benefits, whereby implants are designed specifically in relation to CT scans of the patient, and the positive results in terms of personal anatomy, stability and mobility can be immeasurable.
The more recent proliferation of 3D printed implant applications often belies the difficulties of the process, including but not limited to micron level accuracy and contamination risks. As a result, it is not just the hardware that has evolved to meet the demands of this application area but also validated quality assurance processes — for the powder material, the build process itself and post processes such as sterilization. Structural orientation within the build chamber is also a parameter that must be understood and utilized for optimum output results.
Effort & Application
In general terms, 3D printed acetabular systems for hip replacements is a stand-out example here and it was also one of the first 3D printed medical implants to receive approval and accreditation. Other 3D printed orthopedic implants include specific knee and spinal devices implanted during reconstructive surgeries and the last couple of years have seen numerous other applications proliferate as well as with CMF implants developed to treat injuries, trauma, and birth defects.
More specifically, today there are numerous companies that are working directly to develop 3D printed implants for different parts of the body. Each one demands anatomical research conducted in parallel with process development, meaning it is not something that happens fast.
A couple of stand-out organisations are acknowledged here, but this is by no means an exhaustive overview.
There are also specialist medical device manufacturers that have developed proprietary 3D printing materials / processes for implant development and production. Oxford Performance Materials is one notable company in this area, with its OsteoFab process that combines laser sintering with its proprietary material formulation for patient-specific implants. To date, the company has had a number of implants (cranial, facial and spinal) approved by the FDA.
More traditional (multi-national) medical device companies are also becoming more visible in their use of 3D printing as a production method for implantable medical devices. This year alone news has come out of Stryker and Smith & Nephew in this vein.
I believe this application area is only going to get bigger and better. While that might mean more teeth-grinding headlines with the “world’s first” clause in it, it’s worth putting up with. More often than not, what those headlines can point to is a new medical breakthrough for a different problem. And if one more medical problem has been solved by 3D printing, that should raise a smile and a cheer for the improved lives behind the headline rather than a roll of the eyes at the headline itself.
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