1. Introduction

INTRODUCTION

Evidence Based Medicine for the Surgeon

What is Evidence Based Medicine ?

Clinical Decision making

The purpose of this review is to update surgeons on finding and applying best evidence in clinical surgery.  Large amounts of evidence exist to support clinical decisions, yet it can be difficult to find and apply the best answers to clinical questions.  We often start with pubmed, although in 2010 there are better ways of going about searching.  A pubmed search tends to produce a feast or a famine of results, with no straightforward way of sorting useful from distracting papers.  Articles disagree with one another, yet not everyone can be correct.  Advances in surgical research take a long time to influence clinical practice. 
Newer tools such as clinical practice guidelines and evidence based reviews are meant to provide clinicians with quick access to high quality, clinically relevant research.  Search strategies specifically designed to answer clinical questions can be used when credible practice guidelines or evidence based reviews do not exist.  Understanding and applying the tools of evidence based medicine makes it easier to find the best information to support clinical decisions.
Surgeons need to make clinical decisions all the time, and if you count the decisions you make during a single consultation, you will find that there are many of them - what is the diagnosis? does the diagnosis need confirmatory tests? what is the prognosis? does the prognosis apply to this patient?     The most important decision we make is how to treat the patient - whether to operate or not, which operation to do, how to do it, when, what else to do in the after care.  In order to make the best decisions, we want to use the best information - but what is the best information?  Usually, the best information is an unbiased summary of real outcomes experienced by real patients as a result of the decision.

The Evidence Based Medicine movement contends that the best way to make decisions about patients is to explicitly and conscientiously apply the results of well designed clinical studies - that is, properly designed and controlled studies looking at the outcomes of real clinical decisions on real clinical patients.  Evidence Based Medicine is a widespread movement that had its origins in the 1980’s at McMaster University in Ontario, Canada under David Sackett and his colleagues.  Training in clinical epidemiology and applying its tools to different fields in medicine and surgery has become a very common career path for doctors in North America and Europe.  There are many unanswered questions, and clinical science is advancing all the time.  Many questions or decisions we make in daily practice have newer and better answers than we may be aware of or than we may apply.

The evidence based medicine movement began with considerations of biases in clinical studies, showed us how to critically appraise individual studies, and developed ways of combining studies using systematic reviews, meta-analyses, decision support tools, and practice guidelines.  This review will go backwards through time - starting with practice guidelines and decision support tools, then looking at systematic reviews and meta analyses, then looking at critical appraisal of individual studies, sources of bias, and considerations in research design.  Searching for best evidence should be efficient, and we should use the work of others (practice guidelines and decision support tools) if it is applicable and of high quality.