Perforated appendicitis: an evidence-based definition

Papers that cause the coveted “ahah!” feeling are very few and far-between. But this one certainly made me go ahah!

In this paper, the authors set out to unify the definition of perforated appendicitis. They pointed out that since the definition of perforation was all over the board, no true conclusions could be made of studies looking at outcome.

The authors defined perforation as the presence of a visible hole in the appendix or the finding of an extruded appendicolith (this definition was used for a prior study they performed). Patients with purulent fluid in the peritoneal cavity who did not have a visible hole as well as patients with a gangrenous appendix were considered non-perforated. Patients in the perforated appendicitis group received a prolonged course of postoperative antibioitcs while those in the non-perforated group received only preoperative antibiotics. The authors then studies the effect of this strict definition on patient outcome, including the rate of intraabdominal abscess formation.

The results were very interesting. Expectedly, the rate of postoperative abscess formation in the perforated group increased from 14% to 18%. This made sense since the denominator in the perforated group was smaller with this strict definition. More importantly, the rate of abscess formation in the non-perforated group decreased, from 1.7% to 0.8%. This was the most important finding in this study. This confirmed that withholding postoperative antibiotics from patients with a gangrenous appendix, or those with “puss” in the abdomen but no true hole, did not result in worse infectious complications.

Defining perforation in clear simple terms, and showing that this definition works, should help prevent unnecessary antibiotic administration, waste of resources, as well as inter-study inconsistencies.

St Peter et al. An evidence-based definition for perforated appendicitis derived from a prospective randomized trial. J Ped Surg (2008) 43:2242-45