Perforated Appendicitis

In a 2010 study from Journal of Pediatric Surgery, 200 CT scans were reviewed by 6 surgeons (including 2 fellows) and 2 radiologists who were blinded to diagnosis, and reviewers correctly identified perforated versus non-perforated appendicitis in 72% of scans that had no abscesses.

Cases with abscesses were excluded from the CT scan accuracy study.

In Doctor Ponsky's 2009 study on inter-observer variation in assessment of appendiceal perforation, 110 surgeons (62 attendings and 48 fellows) from university, community, and children's hospitals reviewed images, and agreement among attendings in defining perforation was 27%.

Inter-observer and intra-observer variability in identifying perforated appendicitis from images was close to chance alone; when one image was turned upside down and flipped, surgeons did not agree with their own previous assessment.

When patients with stool in the abdomen or a hole in the appendix were grouped together as perforated, those without either finding had an abscess incidence of less than 5%.

In the two years before applying the standardized perforation definition, 292 non-perforated appendicitis cases had a 1.7% abscess rate and 131 perforated cases had a 14% abscess rate.

After applying the standardized definition for two years, the abscess rate dropped to 0.7% for non-perforated appendicitis and rose to 18% for perforated appendicitis, indicating that some perforated cases had been misclassified as non-perforated before the definition was used.

Doctor Saint Peter's prospective randomized study compared irrigation and suction versus suction alone during laparoscopic appendectomy for perforated appendicitis, with 110 patients in each arm and a minimum of 500cc irrigation (average 850cc) in the irrigation group.

A 2017 University of Minnesota retrospective study (432 patients over 10 years, 105 perforated) compared standardized large-volume irrigation (3-12 liters in small focused aliquots) by one surgeon to surgeon preference for irrigation by others, finding 0% abscess rate with standardized irrigation versus 19% with surgeon preference.

The irrigation study found no difference between groups in abscess rate, length of hospitalization, hospital charges, or operative time, concluding there was no advantage to irrigation during laparoscopic appendectomy for perforated appendicitis.

A 2018 meta-analysis of irrigation versus suction alone for laparoscopic appendectomy included 3 randomized trials and 2 retrospective studies with 2500 patients (4/5 adults) and found no difference in abscess development, wound infection, or length of hospitalization.

In the Minnesota study showing benefit from irrigation, the surgeon used a focused push-suck technique with small volumes (100cc at a time) rather than irrigating the whole abdomen.

In studies using the standardized perforation definition, the presence of exudate everywhere (without a visible hole or stool) did not correlate with increased abscess risk.