[Systematic reviews and meta-analyses in surgery].

The enormous number of medical publications available online and in print media makes it difficult for surgeons to keep abreast of new scientific developments. In addition to information overload and lack of time, studies of questionable quality and expertise when performing systematic literature searches jeopardize proper surgical decision making. The concept of systematic reviews (SR) and meta-analyses (MA) is based on a critically appraised synthesis of individual trials addressing comparable medical problems. This qualitative evaluation and quantitative aggregation of research findings offer valid decision making tools for the clinician, scientist, and health care authorities. Systematic reviews employ comprehensive methods to control for potential bias when synthesizing individual trials. Thus the clinical question and methodological aspects should be defined a priori in a protocol. In the following step the relevant literature must be identified through systematic searches in databases. After critical assessment of the methodological quality and heterogeneity of individual studies, the results can be presented qualitatively. They also can be quantitatively summarized in MA if appropriate. Compared to single trials, properly conducted SR and MA facilitate more precise estimation of the treatment effect of surgical interventions. Hence they represent an ideal basis for future research endeavors. In conclusion, SR and MA implemented in clinical guidelines, evidence-based consumer information, or health technology assessment, enable the necessary bridging between research and clinical practice.