Fans of Aerosmith are being given the chance to study singer Steven Tyler's famous vocal cords in a new TV documentary. The rocker's recent throat surgery will feature as part of an upcoming medical special, Incredible Human Machine, on the National Geographic Channel. Tyler's doctors were also interviewed about the 2006 procedure to save the frontman's voice.Aerosmith had to scrap a series of shows when Tyler suffered damage to one of his vocal cords.He underwent surgery in March to repair a popped blood vessel in his throat. The operation was a sucess and Tyler re-joined his band in May to begin work on their new album. Aerosmith formed in 1970 and in that time they have sold 150 million albums worldwide 65.5 in America alone.It was their thrid album Toys in the Attic that was to be their breakthrough and is widely considered a rock classic.