Varying negative appendectomy rates after laparoscopic appendectomy: a systematic review and meta-analysis

Purpose Appendicitis is a common cause of acute abdominal pain, and treatment with laparoscopy has become increasingly common during the past two decades. Guidelines recommend that normal appendices are removed if operated for suspected acute appendicitis. It is unclear how many patients are affected by this recommendation. The aim of this study was to estimate the rate of negative appendectomies in patients undergoing laparoscopic surgery for suspected acute appendicitis. Methods This study was reported following the PRISMA 2020 statement. A systematic search was conducted in PubMed and Embase for retrospective or prospective cohort studies (with n ≥ 100) including patients with suspected acute appendicitis. The primary outcome was the histopathologically confirmed negative appendectomy rate after a laparoscopic approach with a 95% confidence interval (CI). We performed subgroup analyses on geographical region, age, sex, and use of preoperative imaging or scoring systems. The risk of bias was assessed using the Newcastle-Ottawa Scale. Certainty of the evidence was assessed using GRADE. Results In total, 74 studies were identified, summing up to 76,688 patients. The negative appendectomy rate varied from 0% to 46% in the included studies (interquartile range 4–20%). The meta-analysis estimated the negative appendectomy rate to be 13% (95% CI 12–14%) with large variations between the individual studies. Sensitivity analyses did not change the estimate. The certainty of evidence by GRADE was moderate due to inconsistency in point estimates. Conclusion The overall estimated negative appendectomy rate after laparoscopic surgery was 13% with moderate certainty of evidence. The negative appendectomy rate varied greatly between studies.