Kaiba was six weeks old in 2011 when he stopped breathing and turned blue. His parents rushed him to the hospital, where they learned that his left bronchial tube had collapsed because of a birth defect. The attacks recurred for weeks until January 2012, when surgeons implanted a 3-D-printed tube to hold the baby's airway open. The tube will dissolve after a few years inside the boy's body, giving his bronchus time to grow strong enough for normal breathing. This is the first use of such an implant to aid tissue reconstruction and was reported in a May edition of the New England Journal of Medicine.

The trachea's 20 interlinked rings of cartilage keep a newborn's airway open as it branches into the lungs, rather like the steel rings that support a vacuum cleaner hose. But rarely, a portion is floppy and collapses. Implanted stents can prop open the airway from within but often still result in compromised breathing from the irritation they cause. Kaiba's doctors contacted Glenn Green, a doctor who, along with his colleagues at the University of Michigan, was developing custom-fit tubes to wrap around a collapsed trachea as an irritant-free way to hold the airway open.

Green and his colleagues thought 3-D printers could make an artificial trachea because of the ease of manufacturing the rings that make up the organ's tubular structure. The researchers printed tracheae from biocompatible plastic and tested them in piglets.

For Kaiba, the team first took a CT scan of the infant's airways and used the data to print a cast. Using that cast, the scientists next created a fitted, flexible sleeve to stabilize the airway. The final step was to sew the tissue of Kaiba's bronchus to the inside of the sleeve, which required an emergency-use approval from the U.S. Food and Drug Administration. “When we put the splint on, we saw his lungs move for the first time,” Green says. Like Kaiba, the use of 3-D-printed medical devices and body parts is still in its infancy, but Green believes the technology has “gigantic potential.”