Prosthetic hands printed by students bring hope to kids
Nine-year-old Rafael Esquivel is just like any other third grader — except that he was born with part of one hand missing.
He was always treated differently by his classmates because of his hand, Rafael’s mother Maria Sanchez said. He was unable to do many things by himself, and even playing with other kids proved difficult. Rafael often cried in sheer frustration.
But then, one of Rafael’s teachers put the family in contact with e-NABLE, a national non-profit organization that prints 3-D mechanical prosthetic limbs for children and adults missing portions of their hands or forearms. Using the technology of the University of Houston chapter, Rafael received a prosthesis, or a prosthetic limb, earlier this year.
“I thank e-NABLE every day,” Sanchez said. “Daniel and Jalal’s work, doing what they did for me when I lost hope, they gave it right back to me.”
The organization had five members when it started, but mechanical engineering sophomore Jalal Yazji and engineering technology sophomore Daniel Bahrt mainly founded the UH chapter in Spring 2016. Yazji serves as president and Barht, vice president.
Yazji met e-NABLE members in high school when he had his first brush with prostheses during a school project, and he brought his connections to college with him. Yazji and Bahrt also enlisted the help of other students in their residence hall, Cougar Village II, to start the organization.
“When I came to UH, I brought the idea and the passion with me,” Yazji said. “Over a casual college dinner with Daniel and some other guys, I brought up this idea. They were like, ‘No, that’s not gonna work, this is crazy,’ but I convinced them, somehow, and we got it to work. Now, we’re swamped with prosthetic hand recipients.”
Yazji and Bahrt meet with the parents of the children who receive the prosthetic limbs. Yazji said parents usually find them through the e-NABLE website or on Facebook. During the meeting, they assess the children to determine what kind of prosthesis they need.
E-NABLE has 24 members with five officers. Each officer heads a different project, Bahrt said, because they are usually working on multiple prostheses at a time.
‘Where we come in’
The prostheses begin as nothing more than a 3-D blueprint built through software called computer-aided design (CAD). The UH group measures the dimensions of each recipient’s limb and modifies the blueprint to fit each person. The process forms a CAD file, which can be used to print models in a 3-D printer.
“Depending on the extent of modification, it can take quite some time and be quite tricky,” Bahrt said. “It might only take a few hours, but we’re college students, so we have to spread it out.”
Bahrt said that finishing a prosthetic takes about a month. After the CAD file is completed, the printer takes about a week to print the model. The group uses the 3-D printers at the Cullen College of Engineering to print the prostheses for free, but they have to supply the filament.
The UH e-NABLE chapter prints roughly 30 pieces simultaneously that will become the models. Then, they separate the parts, shave them of excess plastic and assemble the models. One of the primary functions of the e-NABLE general members is to help with this process because it requires a significant amount of labor hours and knowledge of the modeling software is not needed.
Most commonly, e-NABLE prints a model for children missing about 40 percent of one hand, usually without fingers. The prosthetic fingers bend with the flexing of the wrist by using a mechanical pulley system that requires no electronics to work. Because of this, the fingers can grip items as forcefully as the recipient can bend their wrist.
The type of grip is adjustable with a screw. For example, if the hand needs to pick up a set of keys, it can be adjusted so that only the pointer finger is closed with wrist motion.
“The entire purpose of the hand is to provide a very cheap, temporary solution until you have reached an age in your life when you will no longer outgrow a prosthetic,” Bahrt said. “It costs, on average, about $10,000 for every prosthetic hand. If you’re a 6-year-old going through these hands every six to 12 months, it’s wholly impractical for a family to continue buying them. That’s where we come in.”
The majority of the recipients of e-NABLE’s UH chapter are children, but Yazji said they have had one adult recipient so far. Other chapters of e-NABLE have also helped military veterans who lost limbs in combat while they were on waiting lists for proper prostheses.
The national e-NABLE organization has a library of CAD files that are free for members to use and modify to fit recipients’ needs. They also have forums online that members can use to ask for help in designing prostheses.
Recipients choose the colors for their prostheses. Yazji said a girl wanted hers to be themed after the Disney movie “Frozen.” Another boy wanted a prosthesis that looked like Iron Man’s suit.
Rafael’s mother said he chose three colors based on things he likes: Baby blue for the sky. White for God. Gray because he loves sharks.
“It’s boosted his self-esteem, it’s made him more secure,” Sanchez said. “He loves all the attention.”
The UH e-NABLE chapter has delivered four completed prostheses; by the end of the semester, they will have completed seven prostheses total, including Rafael’s.
With his new prosthetic, Rafael is able to do things with his prosthesis that he was never able to do before, like open water bottles, use his phone, and play with his Beyblades. Sanchez said that Rafael’s classmates never ask about his hand.
“They’re just amazed by it, and they want one,” Sanchez said. “He’s so cool because he has a robot hand.”