As somebody that had breathing problems as a child, I know how limiting it can be. Most can people outgrow their breathing problems within a few years (two years of playing the trumpet really helped me), but when the problems start as an infant with a still-developing body, it can be a serious concern. This was the case for Kaiba, who started being unable to breathe at just six weeks old. After a few weeks in a standard hospital, the family took Kaiba to the University of Michigan's Mott Children’s Hospital in order to check out a possible operation involving 3D printing new parts of his respiratory system. It turns out that implanting 3D-printed organs in the US is currently illegal depending on the material, but the university was able to obtain special permission for a one-time operation. Kaiba had CT scans done, then a new bronchus 3D-printed from PCL (a popular material for studies and these tests as the body seems to accept it and it'll dissolve in 2-3 years) was modeled after the scans. The new tissue was sewn into place successfully. Source I got it before Gahars, yayyyy!