Bono's back surgery has derailed U2's plans for a 16-city jaunt across North America, which now won't happen until next year, the band announced today. The tour, part of U2's larger 360° world tour, was supposed to kick off next month, but doctors are prescribing a DL stint of at least 8 weeks for Bono, EW reports. Fans are urged to keep their tickets, which will be valid whenever the tour is rescheduled. (More Bono stories.)