Clinical significance of peri-appendiceal abscess and phlegmon in acute complicated appendicitis patients undergoing emergency appendectomy.

Background: Although antibiotic therapy has become the primary treatment for acute uncomplicated appendicitis, the management of acute complicated appendicitis necessitates careful consideration of various treatment options.

Aim: To analyze the clinical data of patients who underwent emergency appendectomy for acute complicated appendicitis with peri-appendiceal abscess or phlegmon, identify factors influencing the postoperative length of hospital stay (LOS), and improve treatment strategies.

Methods: The clinical data of acute complicated appendicitis patients with peri-appendiceal abscess or phlegmon who underwent emergency appendectomy at The Department of Emergency Surgery, Zhongshan Hospital, Fudan University from January 2016 to March 2023 were retrospectively analyzed.

Results: A total of 234 patients were included in our study. The duration of symptoms and the presence of an appendicolith were significantly correlated with the occurrence of peri-appendiceal abscess in patients with acute complicated appendicitis (P < 0.001 and P = 0.015, respectively). Patients with symptoms lasting longer than 72 h had a significantly longer postoperative LOS compared to those with symptoms lasting 72 h or less [hazard ratio (HR), 1.208; 95%CI: 1.107-1.319; P < 0.001]. Additionally, patients with peri-appendiceal abscesses had a significantly longer postoperative LOS compared to those with phlegmon (HR, 1.217; 95%CI: 1.095-1.352; P < 0.001). The patients with peri-appendiceal abscesses were divided into two groups based on the median size of the abscess: Those with abscesses smaller than 5.0 cm (n = 69) and those with abscesses 5.0 cm or larger (n = 82). Patients with peri-appendiceal abscesses measuring 5.0 cm or larger had a significantly longer postoperative LOS than those with abscesses smaller than 5.0 cm (P = 0.038).

Conclusion: The duration of symptoms and the presence of an appendicolith are significant risk factors for the formation of peri-appendiceal abscesses in patients with acute complicated appendicitis. Patients with peri-appendiceal abscesses experience a significantly longer postoperative LOS compared to those with peri-appendiceal phlegmon.