Breakthrough development of child prosthetics with Stratasys 3D printing

Researching infant development with prosthetics, Mr Ryan has developed a prosthetic for infants to wear, enabling a more natural acceptance of prosthetic arms for young children. An unnovation that the company says is unparalleled within this sphere of the medical field, the customised design and production of the 3D printed hydraulic prosthetic has delivered cost savings of up to 76%, as well as time savings in design and production of 90%, compared to traditional methods of manufacture. This crucially permits prosthetics to be used at an earlier developmental stage.

When Mr Ryan’s son was born in March 2015, complications resulted in the amputation of his lower left arm. Although able to keep approximately one inch of his lower arm, Sol would have to wait three years for a myoelectric prosthetic from the NHS, and one year before a cosmetic, non-functional prosthesis would be fitted. Mr Ryan saw his son losing responsiveness and acceptance of his left arm, and decided to act.

Having undertaken extensive research into infant development, Mr Ryan saw that higher rejection rates occur when children are fit after the age of two years and that early fitting of functional devices correlates with continued prosthetic use throughout childhood. Another study also found that children fitted before two years of age tend to accept their powered prosthesis more than those fitted after two years. With this in mind, Mr Ryan first designed a foam arm for his son, and later a hydraulic prosthetic, enabling Sol to move his thumb on his own.

Mr Ryan designed and created his 3D printed hydraulic prosthetic arm on the Stratasys Connex 3D Printer. First practicing with prototypes of his design, Mr Ryan 3D printed flexible actuators and a power-splitting unit (double acting helical bellow or DAHB) for the prosthetic. According to Mr Ryan, the DAHB unit enables the wearer to open and close the thumb in manual mode or with assistive power (using compressed air or a hydraulic pump and reservoir), but the grip continues to operate manually in the event of power interruption.

“The success of my patented DAHB mechanism draws on the advanced capabilities of the Stratasys Connex Printer – the ability to combine rigid and soft materials in a single print was vital to the success of the design,” explains Mr Ryan. “We were fortunate enough to have access to this technology, which enabled us to 3D print a prototype arm so quickly and cost-effectively. In founding Ambionics, it’s now my goal to ensure that other limb deficient children like my son are not faced with the current constraints and delays of traditional prosthetic manufacture.”

To develop the design for the prosthetic, Mr Ryan relied on the use of Autodesk Fusion 360.

“This is a very innovative and ambitious project and it’s been inspiring to work with Ben on it,” said Paul Sohi, a product design expert at Autodesk. “It is amazing that despite Ben having no real background in product design, he’s effectively taught himself enough to create something that will not only help his own son Sol, but in Ambionics, potentially others facing the same challenges too.”

Stratasys www.stratasys.com