His limbs are paralysed although he can breathe and eat unaided. He has been moved from a university clinic in Germany to a specialist centre in Switzerland.
"While there may be slight improvements in the coming years he will never be able to walk unaided again," said Dr Michael Baumberger, the head of the clinic treating Mr Koch.
Robbie Williams, Phil Collins, Cameron Diaz, Justin Bieber, Oscar-winning actor Christoph Waltz, supermodel Sara Nuru and Cher were among the guests when Mr Koch's stunt went wrong on the Wetten Dass! (Want to Bet) show. He bet host Thomas Gottschalk that, using springs on his feet called power jumpers or kangaroo shoes, he could leap over five cars driving towards him at 15mph.
However, after his fourth attempt where he tried jump over a car driven by his father Christoph, the 23-year-old landed face-down and the show was taken off air.