Composite Criteria for Non-Operative Management of Acute Non-Complicated Appendicitis Result in Low Failure Rates

Background The aim of this study is to investigate the outcomes of conservative management of non-complicated acute appendicitis (AA) using our unique institutional protocol, and to compare between these and the outcomes of operative management. Methods Patients admitted to our institution between March 2016 and October 2019 with non-complicated AA were grouped according to their initial management: non-operative versus surgical. Our unique protocol for non-operative management includes: pain < 3 days; afebrile upon admission; non-gravid; WBC <15,000 (x 10(9)/L); CRP < 5 mg/dl; appendix diameter < 1 cm; no appendicolith on imaging; no prior episode of AA; no history of Inflammatory Bowel Disease; no evidence of peritonitis on physical examination. The primary outcome measured was failure of non-surgical management during the index admission. Secondary outcomes included recurrence rate, readmissions, complications, length of antibiotic treatment and length of stay (LOS). Results A total of 695 patients were included, 436 in the operative group and 259 in the non-surgical treatment group. The mean follow-up time was 1004.9 +/- 205.7 days. Patients initially treated conservatively rarely required surgery during their index admission (6.9%). Recurrence rate was 19.1% after a mean follow up of 33.4 months. The overall failure rate of conservative management was documented in 20.8% of the patients. The complication rate was higher in those treated with upfront surgery (1.6% vs. 0.4%, p < 0.001). The overall LOS was not statistically different between the groups. Conclusions Our composite protocol for non-surgical management of non-complicated AA results in a low failure rate. A well calculated patient treatment allocation in non-complicated AA can advocate for wide-spread use of the conservative approach.