The 100 top-cited studies on postoperative hyperalgesia in the last 30 years: a bibliometric analysis

In recent years, the issue of postoperative pain has raised wide concern in the medical community. Postoperative hyperalgesia (POH), as the primary etiology of pain, has been extensively studied and numerous articles have been published on this topic; however, no comprehensive bibliometric review of POH publications has been conducted. Thus, we aimed to examine the 100 top-cited reports on POH and summarize their key characteristics.

Published studies on POH were retrieved from the Web of Science Core Collection (WoSCC) using the search terms "postoperative hyperalgesia". All papers published since 1980 were searched. The search results were sorted by the frequency of the total citations, and 2 reviewers independently skimmed the abstracts and full texts to identify the 100 top-cited reports. After the 100 top-cited papers were identified, the following data were extracted by the two reviewers: the title, surname(s) of the author(s), name of the first author, publication year, country of origin, article type, institutional affiliations, keywords, source journal, and impact factor (IF) of the journal.

The initial search returned 1,747 papers, published in 466 journals that originated from 1,679 institutions in 48 countries. The 100 top-cited reports received 21,454 citations. The USA was the most cited and most productive country, contributing nearly half of the 100 top-cited papers. The numbers of studies on POH have trended upward and continue to increase each year.

An analysis of the 100 top-cited studies on POH provided a better guidance for ongoing researches. The prominent keywords "opioid-induced hyperalgesia", especially "remifentanil", is still on top of POH research area. Nevertheless, the mechanism of POH is intricate and unclear, which is crucial to conduct further studies and find some new interventions.