Stronger at the broken places
Fixing bone fractures has stayed the same for 200 years. These engineering students aim to change that via 3-D printing.
By Cory Phare
A couple of centuries ago, the First French Empire reached its apex. Goethe had just published his “Theory of Colours.” And the plaster cast emerged as the new way to mobilize broken bones for healing.
Since then, we’ve expanded our chromatic comprehension and Napoleon’s dominion has blown apart.
But as for orthotics?
“The biggest surprise is that we’ve basically been using this same medical technology for more than 200 years,” said Michaela Beadles, a senior in mechanical engineering technology (MET).
“We have these common injuries, so why hasn’t the way we treat them changed?”
This was the spark of inspiration that struck Beadles, along with fellow MET students Josh Kenning and Daniel Skousen. And thanks to a direct digital manufacturing course studying the use and implementation of 3-D printing, they had the techniques to embark on their senior project: developing an updated take on healing broken bones.
“Hip replacements can be 3-D printed, so it seemed like a natural approach to innovate on orthopedic support,” said Kenning. “We think of medical technology as cutting edge, but plaster casts and fixed devices that drive steel pins into bones are old school – they work, but they’re heavy, invasive and really uncomfortable.
“We knew there had to be something better.”
Diving into research, they quickly realized they weren’t the only ones trying to improve a technique set in its way. Several years ago, researchers in South Korea experimented with injection-molded outer shells for casts; a company in southern Colorado is also exploring kiosk-based approaches to similar supports.
But the fact remains that, as a new technology, 3-D printing remains largely outside the hospital.
“Comparatively, we saw there was a gap – we needed to talk directly with practitioners to make sure what we’re doing meets medical needs,” said Beadles. “As engineers we need to test and prove our approaches work in variable applied environments.”
Another key to developing a viable solution was shifting away from a purely theoretical perspective, said Ananda Paudel, Ph.D., assistant professor of mechanical engineering technology, who provided tutelage and insight along the way.
“In engineering, we figure out mathematical equations, then implement them; it’s essentially trying to simplify objects," Paudel said.
“With 3-D printing, however, it affords multiple combinations of shapes and sizes. It becomes a complex spatial equation.”
One of the primary challenges the group faced in figuring out this complexity was how to measure specific organic contours of the human arm. They looked at handheld scanners used extensively in manufacturing and MRI equipment to do soft tissue imaging – but with both technologies costing prohibitively into the tens of thousands of dollars, the odds of using of those were slim to none.
“We knew we needed to take a different approach,” said Skousen. “So, we looked at what we had to accomplish and was available on the market with similar technology.”
That led to an unexpected solution: Engineering a common motion sensing commercial video game peripheral, they were able to functionally render information needed to manufacture custom supports.
The group also examined orientation, alignment and sources, as 3-D printed materials tend to be anisotropic, or having more strength in one direction than others. Partnering with local business Peak Additives, they landed on Nylon 12, a durable polymer with antimicrobial properties.
This resulted in small-scale prints to ensure the supports wouldn’t collapse, and the eventual creation of open-structure, spider web-like models on display at the recent Student Impact and Innovation Showcase, put on by the University’s Applied Learning Center.
“This is a totally new concept and design that required them to take a different approach to the problem,” said Paudel. “And here at MSU Denver, we’re set up with the resources and knowledge to help students arrive at those innovative applied solutions.”
For Skousen, improving the practical healing process is personal. Partway through the senior project this past summer, a severe work-related injury left him in an induced coma for nine days from a penetrating head injury and collapsed orbit of the eye. It required doctors to remove half his skull to reduce swelling and cut off a piece of his brain via craniotomy.
After an experience like this, it’d be understandable to think about anything other than academics – but that wasn’t the case.
“The semester was starting when I got out of acute care, and my biggest question was ‘When can I go back to school? I have a project to work on,’” Skousen said.
In addition to his own rehabilitative work with occupational and physical therapists at Englewood-based Craig Hospital, he was able to ask medical professionals in-depth questions about the current technology for orthopedic support and where improvements could be made. He credited their contributions to both his own recovery and for advancing the study's ultimate implications.
“It was inspirational to see other patients with broken bones in a similar or worse state; at an emotional level, I knew there was the opportunity to help,” Skousen said.
And, as a true group effort, Beadles and Kenning were there with him at each step along the way.
“Two of my best friends would come and work literally alongside me in my hospital bed, sharing research and advancing the project,” he added. “I couldn’t have done it without my fantastic team.”
It’s a shared sentiment, as the students credit each other – along with the support of the MET department to enable their applied approach to research.
“This is almost a graduate-level thesis they’ve worked on as undergraduates; it’s remarkable” said Paudel. “And they’ve been able to continue on it even after the project has completed.”
The next steps of that work are refining the algorithm for the shape of the cast and improving the interface to make the process faster, said Skousen. Intensive field testing is also in store to ensure characteristics like waterproof durability, added Kenning.
Their ideas are scalable, too. Though they’ve focused specifically on wrists and arms for this endeavor, it’s theoretically feasible to apply the same concept to healing other parts of the body, said Beadles.
And those are just the challenges – with subsequent opportunities – they plan to tackle next.
“When you finish one project, 10 more doors open,” she said. “It’s a new geometry; we’re just at the tip of the iceberg for what’s in store.”
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