$50 3D-printed hand trumps $42,000 prosthesis

53-year old Jose Delgado, Jr., was born without most of his left hand. With the help of insurance, Jose managed to obtain a number of different prosthetic devices over the years, including a myoelectric device that uses the muscle signals in his forearm to trigger the closing or opening of the fingers. The total cost? $42,000, of which Jose paid about half out of pocket.

Unsurprisingly, Delgado eventually decided to seek a cheaper option and so approached Jeremy Simon of 3DUniverse to inquire about obtaining a simple 3D-printed prothesis. Simon recommended the Cyborg Beast – even though he was initially somewhat skeptical about the basic 3D printed prothesis.

“Jose works in an environment that involves a lot of lifting and moving of boxes, so I was kind of expecting that the Cyborg Beast, which in this case is made of ABS plastic (same material as LEGO blocks), wouldn’t hold up for long. To my surprise, however, Jose says it’s been doing very well, and that he actually prefers it to his far more expensive myoelectric prosthesis,” Simon wrote in a recent blog post.

“Jose provides a unique perspective, as he’s been using multiple types of prosthetic devices, including the myoelectric one, for years, so he’s very familiar with what can or can’t be done with them in terms of day-to-day functionality.”

In short, the simple, mechanical design provides Jose with more day-to-day functionality than his far more expensive myoelectric prosthesis.

“Next, I’ll be printing another Cyborg Beast for Jose using a material called Bridge nylon, which has significantly enhanced strength properties, while remaining very lightweight,” Simon explained. “I’ll also be providing him with an alternate thumb mount that will enable a different kind of grip.”

According to Simon, the 3D printed prosthesis is a completely mechanical design, with a series of non-flexible cords running along the underside of each finger, connecting to a “tensioning block” on the top rear of the device (the “gauntlet”). 

The tension is caused by bending the wrist downward. With the wrist in its natural resting position, the fingers are extended, with a natural inward curve. When the wrist is bent 20-30 degrees downward, the non-flexible cords are pulled, causing the fingers and thumb to bend inwards. A second series of flexible cords run along the tops of the fingers, causing the fingers to return automatically when tension is released.

“I’ve been saying that 3D printing is a transformational technology and this is a great example. It completely changes the possibilities and it makes those possibilities available to anyone, anywhere,” Simon added. “When you combine that kind of technology with the collaborative power of the Internet, the inherent generosity of human beings and a global open source community, truly remarkable things start to unfold.”