Early or mild appendicitis on CT imaging and its correlation with a negative appendicectomy: an observational retrospective study

Background: A computerized tomography scan is frequently performed to confirm or exclude appendicitis. The interpretation of such CT scans is crucial in determining which patients should be offered surgery. In a subset of patients with undifferentiated abdominal pain, the radiological diagnosis of “early” or “mild appendicitis” is encountered. It is unclear, based on the current literature, how to manage this entity and hence it may be exposing patients to unnecessary surgery. This raises the question if “early” or “mild appendicitis” on CT imaging correlates with an increased rate of negative appendicectomies. Methods: All laparoscopic appendicectomies from 2018 to 2023 at a single Australian tertiary hospital were reviewed retrospectively for pre-surgical imaging, appendix histopathology, age, gender, and white cell count. The CT early/mild appendicitis group was compared with the CT uncomplicated appendicitis group. Results: Of 599 patients who had uncomplicated appendicitis on CT imaging, 63 of these patients received a diagnosis of early or mild appendicitis. Twenty-two in this group had a normal appendix on histological assessment. The “early” or “mild” appendicitis group had a significantly increased likelihood (OR>10, p<0.001) of having a normal appendix on histology, compared to the CT uncomplicated appendicitis group. Women and lower WCC were associated with early appendicitis (p<0.05). Conclusions: Results of this study suggest that the diagnosis of “early” or “mild appendicitis” on CT imaging results in a greater number of negative laparoscopic appendicectomies.