RESUMO
As the leading global search engine with billions of daily queries, Google and its open-source Google Trends (Google, Mountain View, CA) represent an emerging and powerful tool for epidemiological and medical research. Within the field of plastic surgery, Google Trends has yielded insights into online interest for facial feminization surgery, gender-affirmation surgery, cosmetic body procedures, and breast reconstruction, among other common procedures. The existing literature of Google Trends in plastic surgery was systematically reviewed following established Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Google Trends' 4 input variables-keyword, region, period, and category-were assessed. Seventeen plastic surgery studies employing Google Trends were reviewed. There was strong inter-rater reliability (Cohen's kappa = 0.68). Analyzing keyword syntax, only 3 of 17 studies (17.6%) used the "+" function to combine terms, which can significantly improve sensitivity. For the region variable, 12 of 16 studies (75%) conducted worldwide searches; yet, none of the studies used any non-English keywords, introducing significant bias. For the period, 88.2% of studies utilized a timespan of greater than 5 years, resulting in monthly intervals between data points in Google Trends. For the "category" variable, none of the studies appear to have employed the "surgery," "cosmetic surgery" or "health" categories to improve specificity. Google Trends is presented as an emerging methodology in plastic surgery research. The strengths and limitations of Google Trends as a resource for plastic surgeons and medical professionals are discussed, and a recommended step-by-step guide for conducting and interpreting Google Trends research is outlined.