Systematic review of experimental studies on intestinal anastomosis

BackgroundThe contribution of animal research to a reduction in clinical intestinal anastomotic leakage is unknown, despite numerous experimental studies. In view of the current societal call to replace, reduce and refine animal experiments, this study examined the quality of animal research related to anastomotic healing and leakage. MethodsAnimal studies on intestinal anastomotic healing were retrieved systematically from PubMed and Embase. Study objective, conclusion and animal model were recorded. Reporting quality and internal validity (reporting of randomization and blinding) were assessed. ResultsA total of 1342 studies were identified, with a rising publication rate. The objectives of most studies were therapeutic interventions (648 per cent) and identification of risk factors (275 per cent). Of 350 articles studying experimental therapies, 298 (851 per cent) reported a positive effect on anastomotic healing. On average, 447 per cent of relevant study characteristics were not reported, in particular details on anastomotic complications (316 per cent), use of antibiotics (757 per cent), sterile surgery (834 per cent) and postoperative analgesia (914 per cent). The proportion of studies with randomization, blinding of surgery and blinding of primary outcome assessment has increased in the past two decades but remains insufficient, being included in only 624, 49 and 85 per cent of publications respectively. Animal models varied widely in terms of species, method to compromise healing, intestinal segment and outcome measures used. ConclusionAnimal research on anastomotic leakage is of poor quality and still increasing, contrary to societal aims. Reporting and study quality must improve if results are to impact on patients. Too many poor-quality, repetitious studies