Anestesia neuroaxial comparada à anestesia geral para procedimentos na metade inferior do corpo: revis？o sistemática de revis？es sistemáticas

background and objectives: systematic reviews organize literature data by combining results from published studies in order to resolve conflicts in the area of medical knowledge describing the interventions. the inadequate reporting of systematic reviews can damage the credibility and interfere in the results' quality. the objective of this study was to determine the frequency of good quality systematic reviews comparing neuraxial anesthesia with general anesthesia for procedures on the lower half of the body. methods: systematic review of systematic reviews. primary variable: the frequency of good quality systematic reviews. the information was analyzed from the following databases: lilacs (january 1982 to december 2010); pubmed (january 1950 to december 2010); the cochrane database of systematic review and database of abstracts of reviews of effects (volume 10, 2010); and scielo (december 2010). the quality of systematic reviews was determined by the overview quality assessment questionnaire. the sample size calculation showed that it was necessary to analyze eight systematic reviews, taking into account that the frequency of good quality systematic reviews was 5%, an absolute precision of 15%, and a significance level of 5%. results: were identified 1,995 articles. the selection process eliminated 1,968 articles. twenty-seven articles of systematic reviews were read in full, 9 were excluded due to incompatibility with the inclusion criteria, and 8 were duplicate publications. ten systematic reviews were assessed for their quality. the frequency of good quality systematic reviews was 40% (4/10; 95% ci 9.6 to 70.4%). conclusion: the frequency of good quality systematic reviews was 40%.