Machine Design

3D-Printed “Exoskeleton” Helps a Young Girl Use Her Arms

Researchers at the Alfred I. duPont Hospital for Children in Wilmington, Del., have created a medical device called a Wilmington Robotic Exoskeleton (WREX) that a little girl named Emma Lavelle calls her “magic arms.” The device helps the girl overcome the limitations of a congenital disorder called arthrogryposis multiplex congenita (AMC), which causes stiff joints and underdeveloped muscles. The custom-designed exoskeleton helps the child move her arms about more freely. A Dimension 3D printer from Stratasys in Minneapolis provided the 3D-printing technology.

The girl’s family members first encountered the WREX at a conference where the device helped an eight-year-old AMC patient lift his arms and move them in all directions. Researchers at the hospital had worked for years to make the device progressively smaller, serving younger and younger patients. Attached to a wheelchair, the WREX worked for kids as young as six. But at two years old, the girl was too young and, making things worse, small for her age. What she needed was a scaled-down version.

Problem was, parts were too small and detailed for the hospital’s shop CNC to fabricate. So the researchers turned to a Stratasys 3D Printer. It can build complex objects from computer designs — like an inkjet printer, but in three dimensions. Researchers 3D-printed a prototype WREX in ABS plastic. The device was light enough that the child could wear it as a little vest.

The 3D-printed WREX turned out to be durable enough for everyday use. The girl wears it at home and preschool as well as during occupational therapy. The design flexibility of 3D printing lets the researchers continually improve on the device, generating ideas in CAD and building them the same day.

Fifteen children now use custom 3D-printed WREX devices. Because prolonged disuse of the arms can affect children’s cognitive and emotional growth, researchers are watching the children closely for the benefits of earlier arm use.


Nemours/Alfred I. duPont Hospital for Children,


TAGS: 3D Printing
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