Interobserver Variability in Intraoperative Classification of Acute Appendicitis and Postoperative Antibiotic Management

BACKGROUND: During laparoscopy for suspected acute appendicitis (AA), surgeons classify the appendix as normal, phlegmonous, gangrenous, or perforated, with or without abscess. The surgeon's assessment directly influences postoperative antibiotic treatment and length of hospitalization. There is currently no objective gold standard for this classification. This study aimed to evaluate interobserver variability in the laparoscopic classification of AA. METHODS: Surgeons and surgical trainees viewed video recordings of laparoscopies from 30 patients suspected of AA. Each participant anonymously classified the appendices according to the diagnostic categories and indicated whether they would prescribe postoperative antibiotics. Inter-rater reliability was assessed using Fleiss' κ for dichotomous outcomes, and percent agreement for multivariable outcomes. RESULTS: The study included 89 surgeons and trainees from seven Danish hospitals with varying experience levels. Interobserver agreement was moderate for distinguishing a normal appendix from appendicitis (κ = 0.72, 95% CI 0.61-0.84) and for identifying complex appendicitis (κ = 0.66, 95% CI 0.52-0.80). Agreement regarding postoperative antibiotics was high: 96% for phlegmonous, 81% for gangrenous, and 99.7% for perforated appendicitis. CONCLUSIONS: This study demonstrates moderate to high interobserver agreement among surgeons in the classification of AA and decisions regarding postoperative antibiotics. However, a larger sample size combined with a dichotomous classification (simple vs. complex) may be required to detect potential differences between demographic groups.