To drain or not to drain: a cumulative meta-analysis of the use of routine abdominal drains after pancreatic resection

BACKGROUND: To warrant the adoption or rejection of health care interventions in daily practice, it is important to establish the point at which the available evidence is considered sufficiently conclusive. This process must avoid bias resulting from multiple testing and take account of heterogeneity across studies. The present paper addresses the issue of whether the available evidence may be considered sufficiently conclusive to continue or discontinue the current practice of postoperative abdominal drainage after pancreatic resection. METHODS: A systematic review was conducted of randomized and non-randomized studies comparing outcomes after routine intra-abdominal drainage with those after no drainage after pancreatic resection. Studies were retrieved from the PubMed, Cochrane Central Trial Register and EMBASE databases and meta-analysed cumulatively, adjusting for multiple testing and heterogeneity using the iterated logarithm method. RESULTS: Three reports, describing, respectively, one randomized and two non-randomized studies with a comparative design, met the inclusion criteria predefined for primary studies reporting on drain management and complications after pancreatic resection. These studies included 89, 179 and 226 patients, respectively. The absolute differences in rates of postoperative complications in these studies were -6.4%, -9.5% and -6.3%, respectively, in favour of the no-drain groups. The cumulative risk difference in major complications, adjusted for multiple testing and heterogeneity, was -7.8%, with a 95% confidence interval of -20.2% to 4.7% (P = 0.214). CONCLUSIONS: The routine use of abdominal drains after pancreatic resection may result in a higher risk for major complications, but the evidence is inconclusive