Dad designs and 3D prints a prosthetic arm for his son

Story highlights

  • Sol Ryan had an arm amputated as a baby
  • His father Ben set out to create a movable prosthetic for very young children
  • He has begun trialling his design on other children

(CNN)Sol was born two years ago on the day of a solar eclipse. But for his parents, the joy of his birth was clouded by news of a severe blood clot in his left arm.

Sol's mother and father had to wait 10 days as his arm slowly decayed before the doctors could amputate it.
    "It was a massive relief seeing this hideous thing that was attached to him and dying suddenly gone," Sol's father, Ben Ryan, tells CNN.
      But the family from North Wales was told Sol would need to wait a year to be issued a prosthetic arm from the United Kingdom's National Health Service (NHS). What's more, he would likely have received a standard issue prosthetic arm with a rigid socket and a rubber or silicone hand, with no hand movement, Ryan explains.
      While there are options for babies to be fitted with such "passive" devices, there are no functioning prosthetic arms on the market for children younger than three, says Ryan. This is owing to the small or electrical parts, as well as the costs involved, because young children regularly outgrow their prostheses.
      Ryan says watching Sol's arm decay for 10 days is something he'll never get over.

      A new arm for Sol

      So Ryan, a former psychology teacher, buried himself in research to find an alternative.
      He came up with a basic design for a 3D-printed prosthetic arm that would let his son grip things.
      The design includes a bulb of fluid -- or actuator -- under the armpit which, when squeezed, creates fluid pressure to open or close the prosthetic thumb.
      "It's only the thumb that moves, so that it can be robust enough to crawl on and put weight on," says Ryan. "It had to be something that could withstand a tantrum."
      Although the arm is still to be perfected, Ryan has had inquiries from 160 families to print prosthetics for their children. He has since established an online prosthetics service, Ambionics, and plans to trial his device by working with 20 families around the world.
      Sol sports his father's prosthetic device.

      Lending hands to children around the world

      Ryan uses an Xbox scanner to create digital scans of the residual limb, so that he can 3D print the socket. The families working with Ryan will send him scans that he will use to model and 3D print their prosthetics.
      Ryan's beta trial began in October when he fitted his first prosthetic on another child in Wales.
      "The trial is really to test that basic assumption -- can a family send me a scan from Ecuador, Australia or Africa and then can I model a socket that will fit?"
      Ryan says he can make a whole arm system for between $150 to $250-worth of materials and time.
      Added to that, he says it would take less than a week to model and print a new socket for a child if they outgrew or misplaced theirs, compared to a few months wait for an NHS prosthetic.
      A much more advanced myoelectric arm -- which uses muscle signals