3D-printed custom orthosis helps disabled man get a grip TECHNOLOGY 2016

With this 3D printed rehabilitation orthosis a disabled man can perform physical activities. Prototype of the device was manufactured on ZMorph hybrid 3D printer.

Medical 3D printing has many applications in various fields. In orthotics, industrial 3D printers are used to manufacture custom-sized orthoses, braces as well as prosthesis and parts for powered exoskeletons. First two helps patients with broken bones while the latter are used for amputees. There’s still a lot of untapped potential for helping the patients with cases of mild and partial paresis who need lighter and more comfortable 3D printed rehabilitation orthosis which won’t harm their existing but weak extremities.

Eliza Wrobel faced this problem during her Biomedical Engineering studies under Bogdan Dybala, PhD. Eng. at the Faculty of Mechanical Engineering of Wroclaw University of Technology. She was asked for help by a 33 years old man suffering from tetraplegia (the limb paresis) after being in an accident a few years back. He needed a light, yet durable orthosis that could help him grab objects during the rehabilitation and other physical activities as he couldn’t hold even the lightest dumbbells. In order to play his favorite table tennis, someone had to tie a paddle to his hand which wasn’t too comfortable.

Answering the needs

The 3D printed rehabilitation orthosis had to answer the patient’s needs which meant that Eliza have had to reverse engineer it. She started with making a plaster cast of the patient’s hand which was later filled with liquid ceramic mass and supported by a metal bar inside, so the model itself was easier to hold. After 24 hours, the hand’s model was grinded and then 3D scanned using the ATOS II machine available at Wroclaw University of Technology.

With a 3D model of the patient’s right hand ready, the actual designing of the orthosis have started. In CAD software Eliza tried different mechanical solutions for the rehabilitation device. The biggest challenge was to bring together both the device and the flesh. Solutions used in prosthetics could harm the man’s tissues while standard orthosis used for broken bones would keep his hand in only one setting – open or clenched.

3D Printing of the design

The design of the rehabilitation orthosis consisted of over 70 different parts. They were all exported as an STL files, checked for any shortcomings in Netfabb Basic and then imported to the Voxelizer software in order to prepare them for 3D printing. The parts for the orthosis were later 3D printed on ZMorph 2.0 S hybrid 3D printer with single head extruder 1.75 mm using ABS filaments of different colors