Jerlena was born with her left hand not fully developed. She is dependent on her right hand to perform daily tasks, particularly when carrying objects. Her family has sought out a prosthetic for Jerlena from local prosthetic clinics, however they haven’t found an option that suits her partial hand. Colin Pischke heard about a group of high school students 3D printing a prosthetic for Jerlena on CBC, and wanted to help improve upon some limitation of the design. Particularly, Jerlena was looking for a hand that can carry heavier objects.
Colin pitched the story at the the 2019 Innovation 4 Health hackathon at the University of Calgary. A group of 8 students who were touched by the story took on the challenge of building a functional prosthetic for Jerlena in six weeks. This group consisted of students studying engineering, kinesiology, and medicine. Members from this team would eventually form the AICP Foundation.
When asked what attributes were most important to her, Jerlena listed that function, comfort, and weight were her top priorities. Jerlena had tried wrist actuated 3D printed prosthetic before. These require wrist flexion to close the hand. However, one of the biggest limitations that Jerlena faced with these designs was her inability to maintain flexion for an extended period of time. Imagine having to flex your wrist the whole time you brush your teeth for instance…
The team got to work brainstorming ideas for the custom prosthetic for Jerlena. Many hours were spent on the computer, modelling ideas using 3D scan of Jerlena hands donated by Rapid3D. The scan of her fully developed hand became the foundation for our prosthetic. This provided realism to the aesthetic and anatomical consistency between her hands while wearing the prosthetic.
We eventually decided to make a wrist actuated design with a locking mechanism. The mechanism uses a ratchet to hold the hand closed when grasping objects and reduces the strain on Jerlena’s wrist. We also introduced a thumb that has multiple positions. This allows her to have multiple different grips, such as a fine pencil grip.
To improve the comfort of a 3D printed device, we thermoformed the forearm piece and fitting soft textile attachment to perfectly contour her arm. We then secured her arm in the prosthetic using a weaving pattern, similar to tying a shoelace, rather than more abrasive velcro. Finally, the hand was printed with carbon fibre material to improve the strength while keeping the device lightweight.
After six weeks, many iterations and hours, our final designs and prototypes were showcased at the Innovation 4 Health Demo Day. While this was the end of the competition, our motivation for helping Jerlena and other children in need was only starting.
Although we had fully design and made a prosthetic for Jerlena, there were still several limitations to the design which we wanted to resolve. Particularity,
- The locking mechanism added resistance when flexing the wrist to close the hand, making it difficult for Jerlena to close without assistance from her other hand.
- We weren’t able to get her arm secured tight enough in the prosthetic to carry heavy objects.
Ultimetely, this was just the beginning of our journey. Since the competition, we received a small grant to continue our work and sought this opportunity to expand our impact through not only helping Jerlena, but to eventually become a non-profit organization.
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