POPE Francis has reappeared after chronic sciatic pain forced him to miss the Church's New Year services, and made no mention of his ailment as he delivered his traditional appeal for world peace. The pope was unable to attend services on Thursday and again on Friday morning because of the sciatica - a relatively common problem that causes pain along the sciatic nerve down the lower back and legs. It was believed to be the first time since he became pope in 2013 that Francis, who turned 84 last month, has been prevented by health reasons from leading a major…