More than one-third of successfully nonoperatively treated patients with complicated appendicitis experienced...

Although nonoperative treatment (non-OPT) for complicated appendicitis is performed widely, the long-term outcomes and merits of interval appendectomy (IA) need to be evaluated.

Between April 2007 and December 2013, all appendicitis patients with well-circumscribed abscess or phlegmon were required to select either laparoscopic surgery (OPT) or non-OPT with optional IA on admission. Optional IA was planned at ≥3months after non-OPT. For non-OPT, intravenous injection of antibiotics was continued until the serum C-reactive protein concentration decreased to <0.5mg/dL, with occasional drainage of abscesses.

Thirty-three patients chose OPT, and 55 chose non-OPT. Among non-OPT patients, 16 selected IA. The success rate of non-OPT was 98.2%. Recurrence occurred in 13 (34.2%) of the 38 non-IA group patients. Although the non-IA group patients frequently had perforated appendicitis at recurrence, they visited the hospital earlier than at the initial appendicitis and had less inflammation. Readmission rate or complications in patients undergoing IA were not different compared with those of the patients in the non-IA group, who had recurrence at ≥3months, or with those of patients in the OPT group.

Although many patients experienced recurrent appendicitis after successful nonoperative treatment, IA may not be necessary after non-OPT.

Prospective comparative study, level II.