Inclusion Criteria:

• Age: There are no age restrictions, although, if appropriate participating hospitals can choose to only include children or only adults, based on an age cut-off of their choice.
• Procedure: All patients undergoing appendicectomy for suspected or confirmed appendicitis by any surgical approach should be included. This includes patients who went theatre with suspect appendicitis even if the intraoperative or pathology results found a different diagnosis, so long as an appendicectomy was performed. It also includes patients who went to theatre for reasons other than suspected appendicitis but were found to have appendicitis intraoperatively and underwent appendicectomy. This includes interval appendicectomy and right hemicolectomy if performed for acute appendicitis.
• Approach: Both open and minimally invasive (laparoscopic and robotic) interventions are eligible for inclusion. Laparoscopic and robotic converted to open cases are also eligible.

Exclusion Criteria:

• Indication: Appendicectomy for any indication other than suspected or confirmed appendicitis should be excluded. For example, patients having appendicectomy for known appendiceal neoplasm.
• Procedure: Patients having appendectomy as part of another surgical procedure should be excluded. For example, patients having removal of appendix as part of a colon cancer procedure are not eligible for inclusion.
• Approach: Natural orifice surgery and endoscopic treatment for suspected appendicitis are excluded.
• Previous appendicectomy: Patients having surgery for stump appendicitis are excluded.
• Return to theatre: Patients should be entered into study only once. A patient returning to theatre after appendectomy should not be re-entered as a new patient.