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Toddler calls 3-D-printed medical exoskeleton her 'magic arms'

Emma wearing her custom WREX
Emma wearing her custom WREXStratasys / YouTube

The field of prosthetics is perhaps the best example of humanity and technology coming together. For proof, consider this video of 4-year-old Emma, born with a muscular condition that prohibited her from moving her arms freely — until modern technology built a pair of "magic arms" customized just for her.

Original WREX modelStratasys / YouTube

Emma's condition, called Arthrogryposis Multiplex Congenita, affects her joints and muscles, making her arms extremely weak. There are devices that can aid in limb movement for people affected by this and similar conditions, but historically they have not been designed for young children. One such device is the Wilmington Robotic Exoskeleton, or WREX, a set of powered joints that assists in natural movement.

For Emma, the machine was very empowering, but its bulk and weight (it is normally attached to a wheelchair) meant her ability to use it in everyday life was very limited. So Nemours/Alfred I. duPont Hospital for Children, which treated her, looked into creating a custom version. They used a Stratasys 3-D printer to create a special harness and fittings out of strong ABS plastic (the same used in LEGO bricks).

Whitney Sample, a research design engineer at Nemours, describes the advantage of the printed parts in the video, recently published by Stratasys:

This is one of those industries that matches perfectly with 3-D printing, additive manufacturing, because we need custom everything. We can answer a need in a heartbeat. I don't have to worry about lead time to machine something, order supplies. I can just basically go back to my program and print out another one.

Emma herself outgrew her first one and they simply printed out another better suited to her new size. The process has proven effective and popular: Since it was first tried with Emma, more than a dozen kids with similar conditions have been given custom WREX builds.

3-D printing is also useful in other areas of prosthetic treatment; in fact, it could be said that it is revolutionizing the field, and is in the process of being applied to the replication of many other body parts. Artificial limbs can be made and adjusted with more speed and precision than ever before, turning the once one-size-fits-all prosthesis into a more patient-centered treatment.

Watch the full video from Stratasys below:

— via CNET

Devin Coldewey is a contributing writer for NBC News Digital. His personal website is