Systematic review of experimental studies on intestinal anastomosis

The 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.

Animal 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.

A total of 1342 studies were identified, with a rising publication rate. The objectives of most studies were therapeutic interventions (64·8 per cent) and identification of risk factors (27·5 per cent). Of 350 articles studying experimental therapies, 298 (85·1 per cent) reported a positive effect on anastomotic healing. On average, 44·7 per cent of relevant study characteristics were not reported, in particular details on anastomotic complications (31·6 per cent), use of antibiotics (75·7 per cent), sterile surgery (83·4 per cent) and postoperative analgesia (91·4 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 62·4, 4·9 and 8·5 per cent of publications respectively. Animal models varied widely in terms of species, method to compromise healing, intestinal segment and outcome measures used.

Animal 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.