[Evidence-based surgery]

Authority-based surgery is slowly being replaced by evidence-based surgery. New and existing interventions are increasingly being studied in randomised controlled trials (RCTs). RCTs allow not only for comparison of different types of surgical interventions but also for comparison with non-surgical interventions and adjuvant therapies. Surgical RCTs have many methodological limitations, such as inherent difficulties with randomisation and blinding, and ethical limitations in using placebo controls. Choosing appropriate intervention groups, providing adequate training for participating surgeons and ensuring a high volume per surgeon reduces the risk of complications due to inexperience. Unplanned cross-over is a potential source of bias in explanatory RCTs comparing surgical interventions. Conducting a surgical RCT requires good collaboration between large and small hospitals due to organisational complexity, ethical limitations, funding and long term follow-up. Acceptance and implementation of the results from surgical RCTs through evidence-based guidelines depends heavily on local opinion leaders and the training of surgical residents.