The negative appendicectomy rate at Charlotte Maxeke Johannesburg Academic Hospital - a 10-year review

Background: The negative appendicectomy rate (NAR) is defined as the proportion of surgically removed appendices that are pathologically normal. The acceptable NAR has been a debated issue. Previously, a higher rate was accepted, whilst newer thinking favours a lower rate. Diagnosing appendicitis is often a clinical challenge and may require crosssectional imaging to assist in the diagnosis. Methods: A retrospective review was conducted at the Charlotte Maxeke Johannesburg Academic Hospital. Appendix histopathological reports were retrieved for patients older than 18 years over a 10-year period. Reports of ultrasound (US) and/or computed tomography (CT) scans were analysed in the last 18 months. Results: One thousand two hundred and seventeen appendicectomy specimens were included. The overall NAR was 19%. This demonstrated a significant downward trend over the period (p < 0.003). Per gender, the female NAR showed a significant decline (p = 0.002) while the male decline was not significant (p = 0.517). Reproductive-age females were found to have significantly higher NAR as compared to other age groups. The overall perforation rate was 17% which demonstrated a significant increase over the study period (p = 0.012). In the last 18 months, 240 appendicectomies were performed. One hundred and eleven patients underwent imaging (46%), of which 78 underwent ultrasound (70%), 14 CT (13%) and 19 US and CT (17%). Conclusion: The overall NAR declined significantly over the period. Females under the age of 45 were found to have significantly higher NARs. Further prospective studies are needed to determine the benefit and feasibility of preoperative CT in resource-limited settings, particularly in reproductive-age females to reduce the NAR.