From fully operational guns to camera lenses, acoustic guitars, shoes and food, it seems there’s little that 3-D printing can’t churn out — even body parts.
Across the country, doctors and biomechanical engineers are using 3-D printing technology in innovative ways to revolutionize medicine, and some of that revolution is happening right here in Colorado.
Just ask Duane Duggan. The Boulder realtor knew 10 years ago that his knees were going, but he says he felt he was too young for knee replacement.
“I think it’s pretty much instilled in you that [knee implants] last 20 years, which I don’t know if that’s really true or not, but I would think that most people don’t want to go through it twice,” Duggan says. “So I was waiting for the last 10 years, trying to get closer to 60 years old.”
But on New Year’s Eve, out on a ski trip with an old college buddy and that friend’s father, Duggan knew the time had come. Both of his skiing companions were lifelong skiers and both had undergone knee replacements — they were having fun and Duggan was in pain.
Duggan’s brother-in-law had heard about knee replacements being done with customized 3-D-printed joints — not an “off-the-shelf ” joint, but one designed specifically for the patient. Intrigued, Duggan started to investigate the procedure, eventually connecting with Dr. Michael Wertz, an orthopedic surgeon who’s been doing total joint arthroplasty for around 25 years. Wertz is one of only a handful of doctors in the state doing knee replacement with 3-D joints.
Wertz says that he’s “kind of into new technology” and has had some investments in socalled 3-D additive manufacturing companies. So when a representative approached him from a Bostonbased company called ConforMIS, detailing their customizable 3-D-printed knee systems, the doctor’s interest was piqued.
“He introduced me to this system about a year ago and of course I went and read and got more training on it and was impressed by the technology,” Wertz says. “Once I was trained in the techniques and saw how the technology was being used and how exact it was, I was pretty much sold on it.”
Wertz explains that when doctors perform joint replacement, they are trying to correct to the normal mechanical axis of the joint. The closer a doctor can get to correcting a patient’s natural alignment, the longer the life of the replacement joint. To do this, doctors must take images of the patient’s knees, ankle and hip. For the folks at ConforMIS to make a customized joint for a patient, they combine these images and create an implant that fits the patient’s bone almost as closely as their natural joint.
Like Wertz, Duggan was sold on it too.
“It was like, wow, that really makes sense, instead of having the surgeon need to cut on you to fit standard sizes, they make it just for you and it just made sense that the surgery would be less painful and you would recover quicker,” Duggan says.
And not only is the implant designed specifically to the patient, but also the instrumentation to put the implant in are specifically designed for each patient, Wertz adds.
“It allows us to make really precise cuts and restore that patient’s alignment, and the implants themselves are really designed to fit their bone morphology exactly. The ones I’ve put in are truly within a millimeter of the edge of the bone, both the femur and the tibia, and because they fit so well, I think they have less issues with the rehab and they tend to get back on it and walk a little faster, and we’ll see as time goes by whether they last longer, but I think they probably will. I hope.”
While most 3-D printing is done in plastic, Wertz says these joints are constructed from a threemetal alloy.
He also says the process is better for everyone involved.
“It not only makes it easier for the surgeons but for the scrub technicians — there are a lot less parts and pieces to deal with,” Wertz says. “And it’s a less expensive process for the hospital when they don’t have to clean and process, sterilizing all these different instruments between cases. There’s a quicker turnover time, a more efficient use of staff. It just simplifies what we call the back table, which is where [all the surgical equipment] lines up when we do your surgery.”
A cleaner back table might not sound all that interesting, says Richard Weir, a professor in bioengineering at the University of Colorado Denver, but less equipment means less chance of what’s called retained surgical instruments — when the surgical team leaves an instrument in a patient’s body.
“It’s all stuff that you don’t necessarily think of,” says Weir. “It’s not very exciting, like a cleaner back table — who’d think about that? But it’s a big deal, right?”
While Weir’s got experience with 3-D medical printing, it’s very different than Wertz’s experience.
“Our lab, we build artificial hands and limbs. We do everything that’s related to that problem. We’re interested in prototyping and rapid prototyping and 3-D printing of components to make better hands and better limbs,” Weir says.
And with an equipment grant from Veterans Affairs, Weir’s Biomechatronics Development Lab at the Anschutz Medical Campus was able to purchase a 3-D metal printer to help them do just that.
The team has had the printer up and running for about a year, and Weir says the experience has been “exciting.”
“It’s allowed us to prototype parts and finish parts very quickly and we don’t have to wait for the machine shop,” Weir says. “It allows us to turn around stuff. It allows us to make and execute designs that are much more anthropomorphic in design, sort of rounded and smooth rather than all sharp edges and square and stuff. It’s been kind of interesting in that way.”
“So I think the big barrier for the metal printers at the moment is cost. Everyone would like one if they could afford one but they are expensive,” Weir says.
Prices are hard to find on the websites of 3-D metal printer companies — such as EOS e-Manufacturing Solutions, the German company that provided Weir’s 3-D metal printer — but Google searches reveal prices no lower than $100,000, with some machines running in the millions.
As such, most of the 3-D printed prosthetics that are made today, Weir says, are done in plastics, but time has shown that these materials simply won’t hold up over the long haul.
“They’re great for laboratory demonstrations and stuff but once you go out into the world and try to use a hammer or tool, they don’t stand up — at the moment,” Weir says. “But everything is about to change. It just has to go through its design cycle and iteration and stuff. The more of these things we can get out into the world, that we can get out at low cost, at like $1,000, the more exciting things that will happen because suddenly you’ll have all sorts of people all over the place doing all sorts of stuff that no one had ever dreamt of.”
Weir is unwilling to say that 3-D printing is a better process by which to make prosthetics.
“This is what I will always say: People want to hold up 3-D printing as the panacea for everything and it’s not. It’s just a tool. It’s another tool that we will use to help make our parts,” he says. “Three-D printing in and of itself is not the cure all. It’s just another tool in your machining armamentarium. Just like everything else, there are times when it’s appropriate to use it and times when it’s like, ‘Let’s just go and use something else.’”
But Weir says that 3-D printing is here to stay and it’s certainly “revolutionized the way we make stuff,” especially in medicine.
“We’ll be printing organs in like 10 or 15 years,” he says. “Obviously, you’re not going to print an organ with your standard plastic printer — that’s a highly specialized medical application, so you’re going to need far different stuff to do that.”
Weir says he and his colleagues watch the market for soft tissue 3-D printing “because, I don’t know, maybe we’ll print an arm or something at a later date.”
For Duggan, 3-D printing has made all the difference in his quality of life. He and his wife just took a trip to Hawaii where the avid cyclist was able to get five or six rides in over the course of their two-week vacation. They also hiked — a four-mile round trip to see some waterfalls in Hana.
“I hadn’t enjoyed a hike like that in years,” Duggan says. “And I could still walk the next day, so that was pretty exciting.”
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