Acute appendicitis is a common surgical emergency, with a prevalence of 112 per 100,000 people per year in Europe. Negative appendicectomy is defined as a pathologically normal appendix removed from patient suspected with appendicitis. Negative appendectomy rate (NAR) has been reported to be around 15-25%. We aimed to evaluate our unit's negative appendectomy rate and the effect of pre-operative imaging on NAR.
A retrospective study including all patients who underwent both open and laparoscopic emergency appendicectomy in a single district general hospital from 2017-2018. Clinical information including cost was calculated based on the 2017/18 national tariff payment system. Patients under 18 years old were excluded from this study.
Two hundred thirty-two patients were included in this study, of which 69 (29.74%) had a pre-operative CT scan. The mean length of stay was 2.57 days. The sensitivity, specificity, positive predictive value and negative predictive value for CT were 77.8%, 100%, 87.5% and 100%. The negative appendicectomy rate with and without pre-operative CT scan were 7.25% and 22.09% respectively. Based on the 2017/18 national tariff payment system, a CT abdomen and pelvis with contrast and emergency appendicectomy with CC score of 0 cost 92 and 2370 pounds respectively. The total cost of patients who underwent appendicectomy without imaging was £ 322,320. If all patients undergo pre-operative CT, with a reduction of 15% in negative appendicectomy rate, the overall total cost would significantly lower to £ 36,212.