When his high school in Hudson, Massachusetts got a new MakerBot Replicator 2X 3D printer, engineering instructor Ryan Dailey could hardly wait to use it. He’d worked on small 3D printing projects with his students in the past and wanted to move on to something more ambitious.
That’s when he read a story about a boy in Marblehead, Mass. whose father had created a prosthetic hand for him using a 3D printer. “As soon as I saw that,” says Dailey, “I knew I was printing one no matter what.”
But what started out as simply a “cool project” turned into a life-changing experience when Ellen Schuck, the Hudson district’s director of technology, introduced Dailey to McKayla Shutt, a Quinn Middle School fifth-grader born without a full-sized left hand or fingers on her left hand. She had an uncomfortable and difficult-to-operate prosthesis that she rarely used.
Although she was getting by with what her parents refer to as her “little hand,” McKayla and her family jumped at the opportunity for a customized 3D printed prosthesis in the hopes that it would improve the 10-year-old’s quality of life.
“Traditionally, children with upper limb differences are given a hook because it’s the least expensive of the prosthetic devices and it’s pretty durable,” says Jean Peck, an occupational hand therapist who is part of a research team at Creighton University that creates and studies the use of 3D printed prosthetic hands on children. “But it’s not attractive, it gets in their way, and they can actually be pretty functional without it.”
“3D printed prosthesis may be less durable, but they are way more attractive,” Peck continues. “The kids get to choose what colors the prosthetic is and they are very proud of their device. So, in that sense, they’ll wear it more than the hook because it looks cool and they can be proud of it.”
Peck’s research team, led by Dr. Jorge Zuniga, developed one of the most popular designs for a 3D printed hand called the Cyborg Beast, and made its files available for free on Thingiverse for research and personal use. McKayla’s hand ended up being based on the Cyborg Beast’s design.
Daily created PTC Creo CAD files from Cyborg Beast’s original blender files and then inserted the measurements of McKayla’s “little hand”, wrist, forearm, and her full-grown hand to create the prosthetic. He then 3D printed a gauntlet, the wrist component of a prosthetic hand, and a palm piece to test the fit.
“Once those parts were sized properly with the padding and the strapping it was just a matter of printing the fingers, getting cabling, and putting on the small mechanical pieces that are involved to make the hand move,” explains Dailey. “Once all of that was ready it took two sessions of fine tuning to get the grip to close properly. After the second session, McKayla was able to pick up a bottle—which I think was down to about 1 1/2 inch diameters—hold it in her hand and take a drink.”
After all the fittings and re-configuring, McKayla was finally presented with her new hand about one month after her initial meeting with Dailey. The prosthetic, made of ABS plastic and costing around $35 to make (a traditional prosthetic starts at about $3,500), is attached with straps at the palm and wrist. When McKayla bends or flexes her little hand the fingers of the prosthetic pull close. When she releases her hand, the prosthetic opens back up.
McKayla has customized her new hand by having it printed in her two favorite colors: pink and teal.
“We offered her any color she wanted and said we could make it as close to natural as possible, but she was adamant about pink and teal as the colors,” explains Dailey. “The kids around her are used to her having her ‘little hand,’ so for her to suddenly have this giant, plastic prosthetic that looks natural would probably have been more shocking to them than having a plastic prosthetic that was pink and teal and looks more like a glove. I do know some people want the natural look, but others want to have as much fun with it as possible.”
McKayla got her new hand in June, and Dailey asked her to keep a journal over the summer detailing her feedback on the hand’s functionality. The journal information is still being collected, but McKayla has already reported the myriad benefits of using her new prosthetic.
“It helps me carry my school books and do many things at home like play Legos with my brother, or carry out a box of markers or crayons with my sister,” she says. “But some improvements I would like to have in my next version are to be able to carry more books and to write/hold a pencil.”
For Dailey, it’s clear the first version of this 3D printed hand is just the beginning of a much larger project. “After McKayla talked to me about what she’s interested in and we got the chance to learn about who she was, it became a question of ‘what can we do to make these future iterations of her hand more functional for her?’” Daily explains.
An improvement Dailey is already working on: creating a three-digit hand. “As of right now the fingers are two digits—where the top and middle knuckle are solid and then there’s the bottom knuckle that’s flexible—and there are certain limitations that we’ve seen for her,” he says. “It doesn’t quite close tight enough onto objects for her to be able to be manipulative with things, so right now we’re looking for a hand design that’s more than two digits so that she can brush her hair or hold a pencil. And if there’s not, we are going to start taking the current design and break it down.”
McKayla also plays softball (she’s a catcher), so another future prosthetic is planned to allow her to use two hands when she bats instead of having to hold it with one hand, which limits her control over the bat and how hard she can swing.
For Dailey and the students involved in the project, being able to create these ‘cool’ new iterations of a 3D printed hand is only a small part of the take away.
“The process itself was one of the more rewarding things I’ve done in teaching. This was something where you got to really see the result of your work first-hand,” says Dailey.
“I got to see the look on her face when she picked up a bottle for the first time with her left hand; it was a very overwhelming experience. And seeing the impact it had on the people around me, not even the people who were directly involved, but the admins and those who were around during the course of the process. Just seeing the impact it had on them it was a really exciting and rewarding opportunity that I was glad to be a part of.”
Photo courtesy of Ellen Schuck, Director of Technology for Hudson Public Schools