Postoperative delirium (POD) is a known complication of inhalational agents used to anaesthetise patients for surgery with potential long term implications.The incidence of postoperative delirium in spine surgery is 3.3% to 3.8%.The purpose of this study is to compare the occurrence of postoperative delirium with inhalational anaesthetics namely isoflurane and desflurane in spine surgery patients.