TP9.2.1Evaluating the incidence, the predictors and the outcomes of patients with negative appendicectomy

Negative appendicectomy (NA) is still a major issue following appendicectomy. We evaluated the rate and predictors of negative appendicectomy in a cohort. Patients and Methods Data of patients who underwent emergency appendicectomies over a year was collected and analysed. The absence of inflammation and/or other significant pathology in the appendix was considered negative by standard definition. A stricter definition of NA was the absence of inflammatory cells in the appendix. Negative appendicectomy rate (NAR) was calculated using the standard criteria (NAR-SDC) and the strict criteria (NAR-STC). Results 372 patients were included, 179 males and 193 females with a median age of 27 (5-94) years. Median duration of symptoms and waiting time to surgery were 2 days and 1 day respectively. The mean admission WBC and CRP were 12,600 (3000-38000)/mm3 and 66.9 (1-323) mg/L respectively. Laparoscopic appendicectomy was performed in 93.5% of patients with a conversion rate of 4.6%. NAR-SDC was 10.2% and NAR-STC was 25.8%. NAR was significantly higher in females than males (39.4% versus 11.1%; p-value 0.0001). Patients with NA were younger (p-value 0.0001), had lower mean total WBC (p-value 0.014) and CRP (p-value 0.0001) on admission. Independent predictors of negative appendicectomy are female gender, duration of symptoms more than 3 days, and lower total WBC. Conclusion NA is still a major problem in the management of patients with acute right lower abdominal pain. Our NAR compared favourably with reported rates. Female gender, symptoms duration more than 3 days, lower WBC are independent predictors of NA.