Based on a regional cohort, this study we will try to demonstrate the superiority of routine laparoscopic appendectomy vs. leaving an intraoperative assessed normal appendix in situ in cases of normal findings at diagnostic laparoscopy. If routine laparoscopic appendectomy is not superior, we will recommend leaving the "normal" appendix in situ.

The study is a retrospective cohort study with a superiority design. It will be carried out at the surgical departments of the four public university hospitals providing emergency surgical service to the entire population of 1,8 million in the Capital Region of Denmark.

On March 17, 2017, a new electronic health record (EHR) had been implemented at three of the hospital, while it was implemented at Copenhagen University Hospital - Bispebjerg on May 20, 2017. These dates mark the start of the inclusion period for each hospital, while the inclusion period ended April 1, 2021 for all four hospitals.

The "snap boards" covering the relevant operation rooms at the four hospitals will be systematically review. For all cases, where diagnostic laparoscopy was performed on suspicion of acute appendicitis, the EHR will be reviewed.

Inclusion Criteria:

• Diagnostic laparoscopy with normal intraoperative findings (including mesenteric adenitis
• Laparoscopic appendectomy and a histopathological normal appendix and otherwise normal intraoperative findings (including mesenteric adenitis)

Exclusion Criteria:

• Diagnostic laparoscopy with abnormal intraoperative findings.
• Laparoscopic appendectomy and a histopathological non-normal appendix.
• Laparoscopic appendectomy and a histopathological normal appendix and abnormal intraoperative findings.

Patients undergoing diagnostic laparoscopy on suspicion of acute appendicitis