Review of appendicectomies over a decade in a tertiary hospital in New Zealand.

Background: Acute appendicectomy is the most common emergency operation for patients with abdominal pain. In the last decade, computed tomography (CT) scans have increasingly been used to aid in the diagnosis in order to reduce the negative appendicectomy rate. The aim of this study was to evaluate our institution's negative appendicectomy rate and the use of pre-operative imaging.

Methods: A retrospective review was undertaken for all adult patients (>16 years), who underwent an appendicectomy on emergency basis in the years 2004, 2009 and 2014. Cases were identified from the hospital electronic theatre record system. Data were also obtained from the patients records and laboratory reports.

Results: A total of 874 patients were included, 227 in 2004, 308 in 2009 and 339 in 2014. The negative appendicectomy rate was 29.1% in 2004, 20.1% in 2009 and 19.5% in 2014 (P = 0.014). Negative appendicectomies were more common in women (P = <0.001), patients between the ages of 16-30 years (P = <0.001) and were associated with low inflammatory markers (median white cell count of 10.2, C-reactive protein of 8, P = <0.001). The use of CT scan prior to operation increased between 2009 and 2014 (34 (11.0%) versus 64 (18.9%), P = <0.001).

Conclusion: Though the number of appendicectomies being performed in our institution has increased over the last decade, the negative appendicectomy rate remains fairly static and the increased use of CT scans did not further decrease the proportion of negative appendicectomies between 2009 and 2014.