Perforated Appendicitis

In a study of 200 CT scans reviewed by 6 surgeons (including 2 fellows) and 2 radiologists, reviewers correctly diagnosed perforated versus non-perforated appendicitis in 72% of cases, with cases containing abscesses excluded.

In a study of 110 surgeons (62 attendings, 48 fellows) from university, community, and children's hospitals assessing images of appendices, agreement on whether an appendix was perforated was 27% among attendings.

Inter-observer and intra-observer variability in assessing appendiceal perforation was close to chance alone, with surgeons not agreeing even with themselves when shown the same image rotated and flipped later in the study.

When patients without a hole in the appendix or stool in the abdomen were grouped together, the incidence of postoperative abscess was less than 5%.

In the two years before applying a 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 for non-perforated appendicitis dropped and the rate for perforated appendicitis rose from 14% to 18%, indicating that some perforated cases had previously been misclassified as non-perforated.

In a prospective study comparing 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), there was no difference in abscess rate, length of hospitalization, hospital charges, or operative time.

A retrospective study from University of Minnesota (2007-2017, 432 patients, 105 perforated) found that standardized large-volume irrigation (3-12 liters in small focused aliquots) resulted in 0% abscess rate versus 19% with surgeon preference irrigation.

A 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, the surgeon using high-volume irrigation performed focused irrigation in small aliquots with a push-suck technique, never irrigating the whole belly, using approximately 100cc at a time.

In the standardized definition study, the presence of exudate everywhere did not correlate with abscess risk when there was no actual hole or stool present.