- Historically, urgent surgery was advocated in patients with suspected appendicitis for fear of perforation and possible complications. Although recent studies have shown that it is safe to delay surgery under certain circumstances, many studies do not report adjusted data and exclude patients based on risk factors. Furthermore, it is unclear if an ultrasound based diagnostic work-up is sufficient to safely delay surgery. The aim of this large retrospective study was to analyze the risk adjusted association of delayed appendectomy with perforation and complication rate.