Risk factors for post-appendicectomy intra-abdominal abscess

Appendicectomy is a common emergency operation, after which major complications are uncommon, however when they do occur they are a major cause of concern to patient and surgeon. This study aims to determine the incidence and risk factors for post-appendicectomy intra-abdominal abscess formation.

A retrospective review was undertaken of all appendicectomies undertaken in Christchurch Hospital between 1 January and 31 December 1995. Appendicectomies were identified from a database of histology. The patients' notes were reviewed and the surgical approach, histological diagnosis and postoperative complications identified.

A total of 417 appendicectomies was identified of which 331 were open, 66 laparoscopic, and 20 undertaken at laparotomy. Mean day stays for each group were 4.4, 4.2 and 11.5 days, respectively. The percentages of patients with acute appendicitis in each group were 87, 58 and 35%. Histologically the appendix was inflamed in 80% (334) of patients (acute 232, chronic 15, perforated 56 and gangrenous 24). There were six postoperative intra-abdominal abscesses (1.4%), all occurring in the open appendicectomy group when the histology was either perforated or gangrenous appendicitis (P < 0.001). There were no cases of postoperative abscess formation following laparoscopic appendicectomy. All cases of postoperative intra-abdominal abscess were associated with perforated and/or gangrenous appendicitis (P < 0.001). The incidence of intra-abdominal abscesses was 7.5% with a perforated and/or gangrenous appendix. There were two cases of iatrogenic perforation following laparoscopic appendicectomy.

The incidence of intra-abdominal abscess is 1.4% of all appendicectomies. The only identified risk factor for development of post-appendicectomy intra-abdominal abscess was the underlying pathology of gangrenous or perforated appendicitis.