Experts on Creutzfeldt-Jakob disease, a rare but fatal brain disease, say there hasn't been a documented case of transmission from contaminated surgical instruments since the 1970s, when sterilization techniques were more primitive. But there is still a risk. And that's what Novant Health officials are now explaining to 18 patients and their families after apologizing Monday for exposing those patients to surgical instruments that had been used on a CJD patient at Forsyth Medical Center in Winston-Salem. "There's no excuse for this. It should never have happened," said Florence Kranitz, president of the Creutzfeldt-Jakob Disease Foundation in New York. "I know the hospital is apologizing. People are always tragically sorry for what happens."