Evidence-based medicine: what it is and what it is not.

The evidence-based medicine (EBM) related concepts of hierarchy of evidence, meta-analyses, confidence intervals, study design, etc. are nowadays so widespread, that clinicians willing to use today's medical literature with understanding have no choice but to become familiar with EBM principles and methodologies. Although surgeons may perceive that evidence-based medicine mandates a strict adherence to randomised trials, it more accurately involves informed and effective use of all types of evidence (from meta-analysis of randomised trials to individual case series and case reports. With the ever-increasing amount of available information, surgeons must consider a shift in paradigm from traditional practice to one that involves question formulation, validity assessment of available studies and appropriate application of research evidence to individual patients.