Abdominal drainage to prevent intra-peritoneal abscess after open appendectomy for complicated appendicitis

Appendectomy, the surgical removal of the appendix, is performed primarily for acute appendicitis. Patients who undergo appendectomy for complicated appendicitis, defined as gangrenous or perforated appendicitis, are more likely to suffer from postoperative complications. The routine use of abdominal drainage to reduce postoperative complications after appendectomy for complicated appendicitis is controversial.

To assess the safety and efficacy of abdominal drainage to prevent intra-peritoneal abscess after open appendectomy for complicated appendicitis.

We searched The Cochrane Library (Issue 1, 2014), MEDLINE (1950 to February 2014), EMBASE (1974 to February 2014), Science Citation Index Expanded (1900 to February 2014), and Chinese Biomedical Literature Database (CBM) (1978 to February 2014).

We included all randomised controlled trials (RCTs) that compared abdominal drainage and no drainage in patients undergoing emergency open appendectomy for complicated appendicitis.

Two review authors identified the trials for inclusion, collected the data, and assessed the risk of bias independently. We performed the meta-analyses using Review Manager 5. We calculated the risk ratio (RR) for dichotomous outcomes (or a Peto odds ratio for very rare outcomes), and the mean difference (MD) for continuous outcomes with 95% confidence intervals (CI).

We included five trials involving 453 patients with complicated appendicitis who were randomised to the drainage group (n = 228) and the no drainage group (n = 225) after emergency open appendectomies. All of the trials were at a high risk of bias. There were no significant differences between the two groups in the rates of intra-peritoneal abscess or wound infection. The hospital stay was longer in the drainage group than in the no drainage group (MD 2.04 days; 95% CI 1.46 to 2.62) (34.4% increase of an 'average' hospital stay).

The quality of the current evidence is very low. It is not clear whether routine abdominal drainage has any effect on the prevention of intra-peritoneal abscess after open appendectomy for complicated appendicitis. Abdominal drainage after an emergency open appendectomy may be associated with delayed hospital discharge for patients with complicated appendicitis.