Custom designed structural support
Besides prosthetics, many other devices have been 3D printed to help people like Emma, a two-year-old girl who couldn’t use her arms. A congenital disorder (arthrogryposis multiplex congenital, or AMC) made her joints stiff and left her muscles underdeveloped and too weak to even play with toys.
Emma’s doctors at the Alfred Hospital for Children in Wilmongton, Delaware in the United States, were pioneers in the development of devices to support limb movement (orthoses). However, making something to fit her small frame was a fabrication challenge. They contacted the 3D printing company, Stratasys, and together they custom designed a special version of their Wilmington Robotic Exoskeleton (WREX) just for Emma. The WREX provides structural support and assists movement, giving recipients the added strength that they need.
Stratasys printed Emma’s exoskeleton using their fused deposition modelling (FDM) technology from ABS plastic. The device, fitted with rubber bands for balance and to assist movement, has provided the added extra strength she needs to lift her arms and play, leading her to call the exoskeleton her ‘Magic Arms.’ Emma’s WREX was designed to be worn as a jacket. It was special as it could be redesigned, re-printed and replaced as she grew. When the jacket was removed for adjustments, she spoke her first ever full sentence: ‘I want that.’
This examples shows how even the most basic plastics, and the most affordable 3D printers can be used to create functional prosthetics that can change people’s lives. More designs are springing up daily. In particular, a group of over 500 dedicated volunteers, the e-Nable community, are currently working to improve the open-source Robohand design and to adapt it to special cases. In early 2014 they provided one of their designs (the Cyber Beast) to a man named Jose Delgado Jr. After one month of trial, Jose decided the US$50 ABS plastic prosthetic was even more effective than his previous, professionally made, $42,000 device.
These printed prosthetics represent some of the most dramatic and immediate impacts of 3D printing in medicine today. The impact is immediate because ‘conventional’ 3D printing materials (such as metals and plastics) can be used. The task of creating a device which straps on to the outside of the body is of a very different scale than that of creating a device (or replacement tissue) which is to be implanted inside. As we will see, the printing of internal implants or tissue is a much more difficult proposition.
© University of Wollongong, 3D Bioprinting: Printing parts for bodies, 2014, Wallace, G.G., Cornock, R.C., O’Connell, C.D., Beirne, S., Dodds, S., Gilbert, F.