508 Appendicoliths – Time to Operate: The Temporal Relationship Between Pre-Operative CT Confirmed Appendicolith and Time to Develop Complicated Appendicitis

Abstract

Abstract Aim Evidence suggests delaying an appendicectomy for up to 24 hours does not increase the risk of complicated appendicitis. Appendicoliths are a risk factor for perforation. However, no study has explored the temporal relationship between appendicolith presence and time to perforation. This study aims to review pre-operative Computer Tomography (pCT) confirmed appendicoliths and their correlation with a shorter time to complicated appendicitis. Method Retrospective single centre study of patients admitted between 2018-2020. Inclusion criteria: age ≥18 years, appendicitis on histopathology following an operation and pCT scan. Complicated appendicitis was defined intra-operatively as an appendicular abscess, gangrenous or perforated appendix. Results 310 patients were included in the study (45.5% with complicated appendicitis). Appendicoliths were present in 79 (25.5%) patients. Multivariate logistic regression identified an appendicolith as a significant risk factor for perforation (Odds Ratio 4.2, 95% Confidence Interval [CI] 1.3-13.6, p = 0.018). Within the first 12 hours of admission, those with an appendicolith accounted for a significantly greater proportion of patients with complicated appendicitis intra-operatively than those without (57.7% vs 42.3% respectively, p = 0.039). Within 12 hours of admission, those with an appendicolith were 2.2 times more likely to suffer from complicated appendicitis than those without (95% CI 1.4-3.7). Conclusions Patients with an appendicolith found on CT should be prioritised for theatre within 12 hours of admission.