PURPOSE: Despite a wide spectrum of severity, perforated appendicitis in children is typically considered a single entity in outcomes studies. We performed a prospective cohort study to define a risk stratification system that correlates with outcomes and resource utilization.

METHODS: A prospective study was conducted of all children operated for perforated appendicitis between May 2015 and December 2016 at a tertiary free-standing university children's hospital. Surgical findings were classified into one of four grades of perforation: I. localized or contained perforation, II. Contained abscess with no generalized peritonitis, III. Generalized peritonitis with no dominant abscess, IV. Generalized peritonitis with one or more dominant abscesses. All patients were treated on a clinical pathway that involved all points of care from admission to final follow-up. Outcomes and resource utilization measures were analyzed using Fisher's exact test, Kruskal-Wallis test, One-way ANOVA, and logistic regression.

RESULTS: During the study period, 122 patients completed treatment, and 100% had documented follow-up at a median of 25days after operation. Grades of perforation were: I, 20.5%; II, 37.7%; III, 10.7%; IV, 31.1%. Postoperative abscesses occurred in 12 (9.8%) of patients, almost exclusively in Grade IV perforations. Hospital stay, duration of antibiotics, TPN utilization, and the incidence of postoperative imaging significantly increased with increasing grade of perforation.

CONCLUSION: Outcomes and resource utilization strongly correlate with increasing grade of perforated appendicitis. Postoperative abscesses, additional imaging, and additional invasive procedures occur disproportionately in patients who present with diffuse peritonitis and abscess formation. The current stratification allows risk-adjusted outcome reporting and appropriate assignment of resource burden.

LEVEL OF EVIDENCE: I (Prognosis Study).