Stress management skills such as planning ahead, organizing what they need to take to the hospital and arranging for schoolwork is a solid way to give more control to the adolescent as they prepare surgery. Don't tell your teenager to relax. Model how to choose to relax and how to shift deliberately to positive information. Effective stress management includes using relaxation skills which are valuable before surgery and during recovery. Headphones and a tape or CD player can offer privacy in a place were staff comes and goes a lot without asking permission.
Music can help change experiences of pain as well as also provide cues for deep relaxation.
Consider taking something which makes them laugh. Others will too, and people laughing around them is a better atmosphere than worry and dread. This may be the perfect time for washable tattoos.