The Shift to Additive Manufacturing
If you were asked, what inventions have changed the world, what would you say? The internet, the wheel, electricity, sliced bread? When it comes to the medical field, it would, surely, have to include 3D printing.
Developed in the 1980s by American engineer Charles ‘Chuck’ Hull, 3D printing is the process of using a digital design to additively manufacture objects by laying down thin layers of material on top of each other.
An early adopter of the technology, the medical world, has been revolutionised by additive manufacturing, from the routine printing of implants, prosthetics, surgical tools and anatomical models to the incredible advancements continually being made in laboratories across the globe. Take for example, The Wyss Institute at Harvard University has invented a 3D bioprinting method that prints vascularised tissue which could make instrumental advancements in tissue replacement and engineering. Or Skåne University Hospital in Sweden, which successfully designed and printed 3D implants on-site. And just this year, The University of Queensland published a study in the International Journal of Pharmaceutics highlighting that the reality of 3D printing medicine customised for individuals’ needs is not as far away as perhaps imagined.
That’s really the crux of it, the shift to additive manufacturing has allowed the medical field to make advancements that previously would have been delegated to the realms of seeming impossibility, something we could have only imagined as a distant reality.
Traditionally, a diagnosis of late-stage avascular necrosis of the ankle meant that treatment was likely to be either amputation or ankle fusion, which would result in a loss of mobility and a subsequent detrimental effect on the patient’s quality of life. Now, however, by harnessing additive manufacturing, Orthopaedic foot and ankle company Paragon 28® have created the Paragon 28® Patient Specific Talus Spacer, the first and only FDA approved patient specific talus spacer that provides a novel alternative for the usual treatments for avascular necrosis of the ankle.
By using images captured by a CT scan, a patient-specific replica of the talus bone can be additively manufactured to replace the damaged bone, thereby sparing the joint, providing pain relief and retaining the motion of the ankle which, naturally, leads to greater independence and freedom of movement.
First approved by the FDA in February 2021 to be printed in cobalt chromium metal alloy by laser sintering, the Paragon 28 ® Patient Specific Talus Spacer was then approved again by the FDA in December of the same year to be additively manufactured from titanium alloy with a titanium nitride coating using electron beam melting. Allowing for the surgeon to select the material best suited for their patient based on any possible allergies or sensitivities to the metals.
The results from clinical studies of patients who have received a Paragon 28 ® Patient Specific Talus Spacer show promise. Patients have seen a reduction in their VAS Pain scores, an improvement in their range of movement and a return to their career, and sporting and recreational activities. For a patient to go from possibly having an amputation or a severe reduction in their mobility, to getting back to walking without pain, is life changing.
No doubt, these would have been the applications that Chuck was referring to, when asked by CNN what had surprised him the most about additive manufacturing: ‘To me, some of the medical applications. I didn’t anticipate that, and as soon as I started working with some of the medical imaging people, it became pretty clear that this was going to work. But, you know, they told me, I didn’t tell them.’