Evidence-based surgery: Where and how to find and evaluate the correct evidence

Physicians obtain their professional knowledge from many sources, including textbooks, colleagues, articles, reviews, and electronic databases. The amount of new knowledge is enormous, and it is impossible for the individual doctor to read it all. In the search for the best evidence to practice evidence-based medicine, there are many pitfalls. Randomized controlled trials and systematic reviews are considered the strongest evidence for assessing treatment effectiveness. In many situations, especially with surgical problems, randomized controlled trials do not exist and will never be performed. Results from observational studies may be the best evidence available and might be as good as that from randomized trials, but results should be read with care, especially when different studies are compiled. There are many possibilities for bias both within individual trials and when systematic reviews with meta-analyses are performed. Systematic reviews produced by the Cochrane Collaboration tend to be performed more rigorously and have a higher methodologic standard than do traditional reviews. In conclusion, it is important to understand both the advantages and pitfalls of the various trial designs that exist and be able to use this knowledge to evaluate trials. In many areas of surgery, knowledge is sparse and many more rigorous studies are required.