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A Repeatable 3D Printing Process for Low-Cost Prosthetics

Dr. Ryan Schmidt leads the Design and Fabrication group at Autodesk Research and has been working with CBM Canada and Dr. Matt Ratto's Semaphore Lab at the University of Toronto to create a repeatable and inexpensive process for childrens’ prosthetics. The pilot for this project is taking place at CoRSU Hospital in Uganda. Dr. Ratto talks about the project in the following short video.

This project is currently focusing on trans-tibial (below the knee) prosthetics. Above the knee is known as trans-femoral and you may have heard of the complementary prosthetic knee project D-Rev is working on with the Autodesk Foundation. Both of these projects are helping the developing world by reducing costs from thousands or even tens of thousands of dollars down to tens of dollars. 

The team recently went to Uganda to visit the prosthetists at CoRSU hospital to familiarize them with the latest tool developments, get their feedback and test the tools beyond the home lab.

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The prosthetics lab at the hospital is a workshop with a lot of familiar hand tools. Here we see Dr. Ratto from the University of Toronto.

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Prosthetics have two primary parts – the socket for the limb to fit into and the prosthetic limb. Here we see some lower legs with feet. These parts can be reused as the patient grows. 

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The current process is both time-consuming and produces more waste than necessary. The current process requires creating a plaster mold of the residual limband then creating a plaster positive of the limb to vacuum form a plastic socket around. Here we see some plaster positives ready to be discarded.

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Once the plastic socket is created, the hand tools are used to improve the fit and comfort for the patient. Using a 3D scanner (the team is using Sense for this project) provides a better fit without the waste and lets the team go straight to 3D printing a socket.

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The team has taken advantage of the API in Meshmixer to create a wizard to streamline the process of cleaning the scan and preparing it for printing. This can now take as little as thirty minutes.

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This brings the process down from a week to a day. Here Moses Kaweesa from CoRSU inspects a 3D printed socket and the bolt assembly that attaches the prosthetic limb.

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Dr. Schmidt works on the digital tools at a more traditional workstation.

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And then takes a break from coding to untangle some filament for the 3D printer. 

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And then returning to code again in a more relaxing location. 

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Here is Ruth trying on the first 3D printed socket. She is not only a patient but also a volunteer at the hospital helping to develop this process while pursuing a degree in architecture.

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Ruth`s socket fits and everyone is happy!

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If you look closely at the socket Dr. Schmidt is holding you can see a horizontal line in this socket as it was printed in two pieces to increase the delivery time. The two pieces were connected with a mirror welder at the hospital.

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This is Rosaline trying out her new leg. 

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It was a successful trip and the results show that the process is working. In thinking about the predictions of needing 40,000 prosthetists across the developing world, reducing the time for a new limb from a week to a day is very significant. This helps the doctors work with more patients but it also helps the patients save money on travel costs and lodgings during treatment. The time for 3D printing is the longest part of the process so as 3D printers get faster, the process will get even faster. 

All Photos: Semaphore/ginger coons

License: Creative Commons Attribution-ShareAlike 4.0 International License

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