Does the Use of Diagnostic Imaging Reduce the Rate of Negative Appendectomy?

In February 2010, the Dutch Society of Surgeons introduced a guideline for diagnosis and treatment of acute appendicitis. This guideline suggests that, with the standardized use of imaging (ultrasound and computed tomography), the percentage of negative appendectomies can be reduced. With this study we evaluated the effect of the implementation of this guideline. Primary outcome is the percentage of negative appendectomies. Diagnostic imaging might result in a delay of surgery and a higher rate of perforated appendices. Therefore, our secondary outcome is the perforation rate.

Retrospectively all pathology results in our hospital were studied, which were classified as "appendicitis acuta" or "appendix sana" from January 2007 until October 2012. To evaluate the perforation rate in acute appendicitis, surgery reports of all patients included in the study were studied. Both percentages of negative appendectomies and perforation rate were compared for the periods before and after the introduction of the new guideline (i.e. 2007-2009 vs. 2010-2012).

A significant decline in the percentage of negative appendectomies was found from an average of 18.0% before implementation of the guideline towards an average of 9.2% after implementation of the guideline (p<0.001). The percentage of patients with appendicitis in which the appendix perforated remained about the same; 20.9% before implementation of the guideline compared to 19.2% after implementation of the guideline (p=0.527).

Our data show a significant decline in negative appendectomies without an increase of perforation rate after introduction of the new diagnostic guideline for acute appendicitis.