The Future of 3D Printed implants: Promise and Challenges

The promise is incredible but the pathway isn’t clear

On our Facebook and Twitter feeds yesterday, we posted about the incredible news from Spain late last week that a man with cancer was provided a custom rib cage by Australian medical device company Anatomics and the team of doctors at Salamanca University Hospital.

The rib cage, 3D Printed in titanium, was designed for the customer using CAT Scan data converted into a CAD design, and then printed on an Arcam Electron Beam Melting 3D Printer.

This incredible story sets the stage for a broader discussion of 3D Printed prosthetics.  What are they?  Are they better than traditional implants?  If so, why?  And for those of us with creaky knees or hips, can I get one?

In this post, we aim to outline a brief history of metal prosthetics, note some of the key benefits of 3D Printing for orthopedic surgery, and discuss a few hurdles to adoption that 3D Printed prosthetics face.

3d printed sternum, 3d printed ribs, 3d printed prosthetic
Illustration of 3D Printed Illustration. Source: Anatomics/CSIRO

A brief history of metal “bone mimicry”

Ever since people have experienced failing joints, doctors have tried to develop new and better ways to stabilize and revitalize them.  In recent decades, that has taken the form of prosthetic implant devices which effectively mimic the behavior of failing or failed bone.  Companies like Medtronic and DePuy have mass produced replacement joint components of varying shapes and sizes, which are implanted into the body during surgery.  The inherent risk of an implant, however, is that the patient’s body rejects it.  If it’s dimensionally inaccurate in the wrong place or made of the wrong material, for example, it can lead to a host of complications tied to the body’s rejection of the implant.  Recognizing these challenges, actions have been taken and advances made.  Still, there aren’t perfect solutions.  Mass produced implants can effectively serve the bulk of the population, but when a part doesn’t quite fit, it’s forced to fit by way of bone sawing and other surgical techniques.  Once the implant is in, getting it to integrate with the patient’s skeletal system is another issue.  Dr. Peter Sculco, an orthopedic surgeon with New York City’s Hospital for Special Surgery, spoke to some of the progress of the past two decades in combating this issue: “First there was a metal mesh, then small cobalt chrome metallic beads, then a titanium plasma spray.”  Still, he noted the key shortcoming of those advances: “These techniques encourage bone to grow onto, but not into implants.”

Custom matching at the macro and micro level

3D Printing addresses both of these lingering issues.

For those cases where a size S, M, L, or XL implant doesn’t quite fit, 3D Printing allows for custom designed implants to match a patient’s unique anatomy.  This minimizes the impact that the surgery needs to have on surrounding muscular systems, expediting the time it takes for the muscles to reform around the implant and shortening recovery times.  The story from Salamanca is a perfect case example of this – the patient’s cancer called for a unique geometry that simply wasn’t available in mass produced form.

Additionally , 3D Printing opens the door to bone growth into the implants themselves.  Bone is inherently porous, and will grow into metallic structures that can match its porosity.  Prior to the advent of 3D Printing, creating such porous structures via traditional manufacturing methods was extremely time and labor intensive.  “The manufacturing process was restricted to a predetermined structure [which] limited the shapes and porosity of the designed metal,” Sculco said.  3D Printing allows for this porosity to be integrated into the design at the time of its manufacture.  So not only can prosthetic designs be matched to the specific body geometry of the patient in question, but different microstructures can be embedded into the prosthetic to match the desired porosity and stiffness of the bone in question.  As Sculco notes, this is very advantageous in a complex surgery with varying amounts of bone loss.  “The microscopic 3D structure and overall porosity can be carefully calculated to reflect the surrounding bone environment and such biomimicry optimizes bone ingrowth and implant fixation.”  In sum, with 3D Printing, a patient’s bone and the implant become a single functioning part rather than two separate parts that find a way to cohabitate, as with traditional prosthetics.

Hurdles for 3D Printed Prosthetics

While 3D printed implants offer tremendous promise for the reasons outlined, don’t sign up for your new knee or hip just yet.  There are a few barriers that limit custom prosthetics from becoming commonplace in the immediate term.

Demonstrated Performance

The first hurdle to clear is demonstrated performance.  3D Printed prosthetics are fairly new phenomena – while skulls, vertebra, and jaws have all been printed, for instance, the rib cage and sternum case was a world first.  So while the possibilities for improved patient care seem tremendous, there is still a lot of testing and learning to be done.  It will be important to watch how cases like the cancer patient in Spain unfold, to see whether ongoing performance in these special case exemptions are positive.  It’s worth noting that 3D Printed parts are not as inherently strong as forged parts – which is the current process for traditional metal medical implants.  While they are stronger than cast parts, they simply wear down faster than forged parts in a lab testing environment.  This may not matter if the implant integrates with the existing skeletal system, but this tradeoff of osteointegration vs. impact resistance over time is at the crux of demonstrating the superiority of printed implants or traditional options.

Regulation

Presuming data favorable to 3D Printing continues to come back, you can assume more companies will push into the sphere of registering products tailored for 3D Printing.  As Matthew DiPrima of the FDA told participants at the IPQC Summit for Additive Manufacturing in Life Sciences, more than 70 3D printed devices have been cleared via the 510(k) pathway, including patient matched implants (e.g., skull), patient-matched surgical guides, dental devices, and orthopedic devices.  While those approvals have taken place, DiPrima noted that draft technical guidance for medical device companies is still to be published by the FDA later this year.  Until then, companies exploring 3D Printed innovations face a fairly uncertain approval pathway.  Once that guidance is provided, it remains to be seen how narrow or broad the guidance will be.  The default means of 3D Printing metal prosthetics is by selectively fusing grains of metal powder – something that is subject to the inherent variability of a laser, among other variables.  How directive the FDA wants to be remains to be seen.

And that is just approval in America.  There is no governing body worldwide.  So 3D Printed innovations will need to go through separate approval processes for the governing body in each market where it would like to sell 3D Printed solutions en masse.

Conclusion

3D Printed prosthetics hold a world of promise and developments in this space should be watched closely.  In conjunction with 3D Printed assays for drug testing, they represent two fairly near term game changing 3D printing applications in the life sciences space.  With all of that said, keep being nice to your knees!  Custom 3D Printed implants for all are coming as fast as they can, but there’s still a bit of ways to go.

 

Cullen Hilkene is CEO of 3Diligent, the Sourcing Solution for Industrial Grade Rapid Manufacturing. He is an alumnus of Princeton University, the UCLA Anderson School of Management, and Deloitte Strategy and Operations Consulting. For more information about 3D Printing and to access 3Diligent’s marketplace of 3D Printing vendors, visit www.3Diligent.com.

Meet 3Diligent at Westec in Los Angeles!

3Diligent experts in Booth 2540

This time next week and for two days following, 3Diligent will be at Westec, the West Coast’s premier manufacturing event!  We’ll be there along with hundreds of other industry experts showing off some of the latest innovations from the manufacturing industry.

Come pay us a visit in Booth 2540!  If you’re looking for landmarks on the floor plan, we’re about halfway between the Stratasys and Concept Laser booths, near the cafe and foosball section (pictured below).  If you don’t have a pass, just let us know ASAP and we should still be able to arrange a free pass for you.  You can email us at customersupport@3Diligent.com.

We’ll be there to answer any questions you might have about 3D Printing, Rapid Manufacturing, and Sourcing Smarter through the 3Diligent platform.  If you have specific questions about a particular project you’re undertaking, we’re happy to weigh in and offer our perspective.

It’s a fantastic opportunity to also see some of the industrial equipment we carry – which typically pretty huge – on display.  Manufacturers represented on our platform including Stratasys, 3D Systems, Concept Laser, Arcam AB,  in the booths of the manufacturers

Lastly, we will be accepting foosball challenges if there’s ever a lull in the action!

We’ll hope to see you there!

 

The Details

Who: Your friends at 3Diligent

What: Westec Manufacturing Trade Show – the West Coast’s premier manufacturing event

When: Tuesday, September 15 to Thursday, September 17

Where: Los Angeles Convention Center

Where1201 S Figueroa St, Los Angeles, CA 90015

Why: You’re interested in 3Diligent, 3D Printing, Rapid Manufacturing, and/or would enjoy taking a stroll amidst some of the most cutting edge manufacturing equipment in the world

 

WESTEC FLOOR PLAN (GENERAL)

3d printing trade show, trade show, 3diligent

 

WESTEC FLOOR PLAN (DETAIL)

3Diligent, trade show, 3d printing, 3d printing trade show

 

Key Considerations For Any Company Buying a 3D Printer

As a tidal wave of 3D Printing news has crashed across the headlines of news outlets, corporate leadership has taken notice.  Whether a company has a pressing need or application for 3D Printing, it has become an increasingly common Chief Officer mandate to “take stock of what 3D Printing is, how it can/will impact our company, and come up with a strategy of what to do about it.”

Because 3D Printing already provides a fundamentally more efficient way to prototype most products and increasing ability to print end-use parts on-demand, most companies find that there is a place for 3D Printing in their strategic plans.  Often, the decision boils down to buying a 3D Printer (or several), utilizing a service provider or providers, or some hybrid of the two.

In this three-part series “3D Printing – Buy Then Build vs. Buy Built,” we set out to provide a framework to consider purchasing printers and utilizing service providers to fill your needs.

In this first post, we set out to discuss the topic of buying a printer and then building parts in-house.  Below are some of the considerations companies should take into account when assessing whether they should buy a 3D Printer.

 

Hard Costs

This is the most obvious one.  While the most basic desktop printers can be had for a few hundred bucks, industrial grade equipment starts in the tens of thousands of dollars.  For top of the line plastics equipment, you’re looking at several hundred thousand dollars.  Investigating metal printing?  Regularly those machines cost in excess of a million.

You might be thinking, why such a broad range of prices?  It comes down to functionality, reliability, speed, and size.  Industrial printers are capable of printing in a broader range of materials, more accurately and reliably, faster and often with bigger build trays.

But do those differences matter to you?  Can you get what you need or want out of a desktop printer?  Or some percentage of what you need/want out of a desktop printer and the rest from a service provider?  Beyond the hard cost of purchasing, there are also the costs of feedstock and maintenance, so weigh them all.

Get a sense of the hard dollars you have to spend first to make sure you’re looking in the right ballpark of options.

 

Soft Costs

Once you’ve got an operating budget, consider the human impacts within your organization of making a purchase.

Do you have the people to operate and maintain a machine effectively?  Do you have a culture that supports CAD design and will keep that printer humming?

It’s important that you can either carve out time from existing personnel’s schedule to develop expertise on the system, or to hire new staff that can take ownership of making the most out of your 3D Printing investment.  Realize that there is both art and science to operating a machine – we’re not to push button parts yet – and there’s a significant learning curve that comes along with a printer purchase.

Make sure you have the manpower and organizational commitment to support your investment.  The last thing you want is a high-dollar investment growing cobwebs in the corner of the shop floor.

Breadth/Application

Once you’ve got a sense of what you can spend and how much staffing up will bite out of your budget, then consider how you’d like to use your equipment.  Different machines are capable of different types of printing, and no single printer can do it all.

First, are you looking to print in metal or plastic?  If metal, there are powder bed and blown powder options to consider.  All are capable of end use parts, but different machines and processes lend themselves to different applications.

If plastic, do your prints need to be functional?  Or are you simply looking for accurate models?

If you need functional models with some durability, a Fused Deposition Modeling (FDM) or Selective Laser Sintering (SLS) machine might be best for you.  Those machines offer a range of thermoplastics, some of which are quite durable.  Ultem 9085, for instance, is an FDM thermoplastic that has received FAA certifications for its high resistance to heat and fire.

If your models don’t need to be durable, PolyJet or Stereolithography might be a better fit.  Those printer types use resin as the “ink” to build their 3D Printed parts.  As a result of this, they are incredibly accurate – PolyJet can print in 16 micron layers – but not especially durable over time.

Also, what sort of geometries are you trying to achieve?  SLS, for instance, has virtually no limitations on design freedom.  That process works by laying down one layer of fine powder at a time, selectively fusing together those particles in the layer that it wants solid, and leaves the rest of the layer alone.  Then another layer of powder, another run of the laser, again and again, until the part is made.  Because the “extra powder” still sits in the bed, it serves as a support to whatever is being built above.  This extra powder can also be recycled for future parts.

PolyJet can achieve something near this level of freedom, as some machines are capable of  printing both end material and dissolvable support material.  Meanwhile, stereolithography machines require supports for overhanging areas, and FDM parts do as well.  These supports require manual removal.

Do you need color in your prints?  How big do your prints need to be?  Do you need to produce in a very specific material?  All are worth considering.

Build out a list of “need to haves” and “want to haves” (and possibly “can’t haves”), then figure out whether there’s a machine or collection of machines in your budget that fit the bill.

 

Obsolescence

We call out some of the capabilities and limitations of different technologies in the previous paragraph with a hint of hesitation.  That’s because the market is evolving so fast.  Market fixtures like Stratasys, 3D Systems, EOS, SLM Solutions, and Arcam AB who’ve put those products into market may introduce new functions or features to next generation models to refine existing processes.  After all, the list of potential innovators and competitors in the space is growing.  We’ve seen traditional names like Dremel, Renishaw, Mitsubishi, and Cincinnati recently enter the ranks of the 3D Printing world.  As of Wohlers and Associates last count, there are more than 300 “FDM Knockoffs” that utilize plastic extrusion.  Beyond those who’ve already entered the market, every couple weeks we’re also hearing about another “breakthrough innovation” that claims it will soon render existing equipment obsolete.  Many of these innovations are currently still in development, but HP, Carbon3D, and Gizmo3D have all offered compelling prototype videos to announce technologies that may massively accelerate the speed of printing, especially in plastics.

Now, it remains to be seen whether any company’s innovation renders your printer obsolete in the truest sense of the word.  Printers will continue printing as long as the manufacturer continues providing technical support, and probably a good while longer depending on the model.  Consider the implications of this for you and your business.  If a printer with markedly faster speed, accuracy, material breadth, or build size hit the market, would you need it, or could you keep getting by with this investment without being put at a competitive disadvantage?  If you would want or need that new printer, how quickly do you need to recoup your investment vs. utilizing a service provider during that time?

Make sure that you’re going to be comfortable with your purchase when the “next big thing” hits the market.

Consider Alternatives

So you’ve considered cost, printer options, and obsolescence risks.  And now you have a plan reflecting the fixed and variable costs of your investment, a few target printers in the right range, an estimate of the time/resources required to staff the printer(s), and a degree of comfort with the state of that machine on the obsolescence curve.

If you didn’t hit any snags along the way, you’ve got yourself a viable option.  You could call it the Buy Then Build Option.

But is it necessarily the right option?  Better take a second to consider alternatives.  You could do some core printing in-house and outsource the rest.  Or you could outsource all of it as you wait for the market to mature.

An exploration of the “Hybrid” and “Buy Everything Built” options will appear in our next posts.

 

Cullen Hilkene is CEO of 3Diligent, the Sourcing Solution for Industrial Grade Rapid Manufacturing. He is an alumnus of Princeton University, the UCLA Anderson School of Management, and Deloitte Strategy and Operations Consulting. For more information about 3D Printing and to access 3Diligent’s marketplace of 3D Printing vendors, visit www.3Diligent.com.