Non-Surgical Treatment of Appendiceal Abscess or Phlegmon: A Systematic Review and Meta-Analysis

The authors conducted a systematic review of the surgical literature assessing the non-surgical treatment of patients with appendiceal abscess or phlegmon after searching the Medline database from 1964 through 2005. They identified a total of 61 relevant articles, of which the majority were retrospective case studies, with only three prospective randomized studies. The authors looked at various subsets of this group of articles to make predictions about the non-surgical management of appendiceal abscesses or phlegmon, which they termed enclosed appendiceal inflammation. The overall rate of enclosed appendiceal inflammation in 59,448 patients diagnosed with appendicitis was 3.8% (confidence interval 2.6–4.9%). The non-surgical treatment of enclosed appendiceal inflammation is successful in 93% of patients, regardless of age, with up to 20% needing percutaneous drainage of the abscess during their initial hospitalization. Authors reported a threefold increase (odds ratio of 3.3) in morbidity with immediate surgical treatment of appendiceal abscesses (36%) compared to non-surgical management (13%) and an additional 11% morbidity for those patients undergoing an elective interval appendectomy. Non-surgical management had risks associated with missing an underlying cancer (1.2%) or important benign disease, mainly Crohn's disease (0.7%), with most cancer cases occurring in patients older than 40 years of age. The risk of recurrence of appendiceal inflammation or abscess for those patients not undergoing interval appendectomy was 8.9%. Based on these results, the authors conclude that patients presenting with enclosed appendiceal inflammation should be managed non-operatively with percutaneous drainage of abscesses as needed. After successful non-surgical treatment, no interval appendectomy is indicated, but close follow-up should be arranged due to the possibility of recurrence and the risk of missing another underlying condition.