A randomized, controlled multicenter feasibility pilot trial on imaging confirmed uncomplicated acute appendicitis: Appendectomy vs. symptomatic treatment in pediatric patients (the APPSYPP) trial study protocol.

Introduction: Imaging-confirmed uncomplicated acute appendicitis can be effectively and safely treated with antibiotics in most adults and children. Symptomatic treatment may have similar efficacy and safety.

Methods And Analysis: The APPSYPP trial is a randomized national multicenter feasibility superiority pilot study comparing appendectomy with symptomatic treatment in children with imaging-confirmed uncomplicated acute appendicitis.

Inclusion Criteria: 1) age ≥ 7 and < 16 years, 2) imaging-confirmed uncomplicated acute appendicitis and 3) CRP ≤ 65 mg/l. Patients are randomized to receive emergency laparoscopic appendectomy or symptomatic treatment. To ensure patient safety, symptomatically treated patients are hospitalized for at least 24 h receiving standard practice intravenous fluids and analgesics according to standard clinical practice. Primary outcome is 30-day treatment success defined by the absence of any treatment failure criteria. In appendectomy, treatment failure is defined as normal appendiceal histopathology or any postintervention complication requiring general anesthesia. In symptomatic treatment, treatment failure is defined as 1) inability for hospital discharge without appendectomy within 48 h after randomization with a finding of histopathologically inflamed appendix, 2) appendectomy during the initial hospital stay due to clinical progression of appendicitis with complicated acute appendicitis both histopathologically and surgically, 3) appendectomy with a histopathological finding of acute appendicitis after hospital discharge, or 4) any complication of appendicitis requiring general anesthesia. Detailed predefined secondary outcomes will be analyzed.

Ethics And Dissemination: Study was approved by Ethics Committee of Helsinki University Hospital (ID:HUS/1993/2021), conducted in compliance with the declaration of Helsinki with results disseminated in peer-reviewed scientific journals.

Trial Registration: ClinicalTrials.gov (NCT05289713).