Risk factors for post-appendicectomy intra-abdominal abscess

Background: Appendicectomy is a common emergency operation, after which maj or 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 i ncidence and risk factors for post-appendicectomy intra-abdominal abscess f ormation. Method: A retrospective review was undertaken of all appendicectomies under taken in Christchurch Hospital between 1 January and 31 December 1995. Appe ndicectomies were identified from a database of histology. The patients' no tes were reviewed and the surgical approach, histological diagnosis and pos toperative complications identified. Results: A total of 417 appendicectomies was identified of which 331 were o pen, 66 laparoscopic, and 20 undertaken at laparotomy. Mean day stays for e ach group were 4.4, 4.2 and 11.5 days, respectively. The percentages of pat ients with acute appendicitis in each group were 87, 58 and 35%. Histologic ally the appendix was inflamed in 80% (334) of patients (acute 232, chronic 15, perforated 56 and gangrenous 24). There were six postoperative intra-a bdominal abscesses (1.4%), all occurring in the open appendicectomy group w hen the histology was either perforated or gangrenous appendicitis (P < 0.0 01). There were no cases of postoperative abscess formation following lapar oscopic 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 foll owing laparoscopic appendicectomy. Conclusion: The incidence of intra-abdominal abscess is 1.4% of all appendi cectomies. The only identified risk factor for development of post-appendic ectomy intra-abdominal abscess was the underlying pathology of gangrenous o r perforated appendicitis.