This is a retrospective observational study in the form of a cohort study evaluating the use of pre-operative imaging for the diagnosis of acute appendicitis in a tertiary centre during the first and second waves of the COVID-19 pandemic in the United Kingdom. The study group includes all patients who underwent emergency appendicectomy for suspected acute appendicitis between March 2020 and February 2021, while the control group includes all patients who underwent emergency appendicectomy for suspected acute appendicitis between March 2019 and February 2020. The final histology will be used as primary outcome, as the study hypothesis is that increasing the use of pre-operative imaging will reduce the negative appendicectomy rate.

Inclusion Criteria:

• Patients of all ages who underwent emergency appendicectomy (either laparoscopic or open) for suspected acute appendicitis
• Patients of all ages who underwent partial ileo-caecectomy or right hemicolectomy for suspected acute appendicitis

Exclusion Criteria:

• Patients who underwent elective interval appendicectomy for a previous appendiceal phlegmon
• Patients who underwent appendicectomy or right hemicolectomy for appendiceal tumours
• Patients who underwent diagnostic laparoscopy for suspected acute appendicitis, where the appendix was not removed

All consecutive patients operated at a tertiary centre