Systematic review of transanal total mesorectal excision literature according to the ideal framework: The evolution never ends

Background: Designing studies to assess critically novel procedures can be challenging; thus, the process to achieve robust evidence is frequently problematic. The aim of this systematic review was to evaluate if literature on transanal total mesorectal excision is evolving according to the Idea, Development, Exploration, Assessment, and Long-term results framework. Methods: Literature on transanal total mesorectal excision was searched according to the preferred reporting items for systematic reviews and meta-analyses statement, and these variables were recorded: bibliometric data, design, corresponding author's nationality, number of patients enrolled, and Idea, Development, Exploration, Assessment, and Long-term results stages (stage 0, stage 1, stage 2, stage 3, and stage 4). Results: Out of 447 articles retrieved, 247 were selected (76.5% single center and 23.5% multicenter collaborations), including 35 reviews, 15 meta-analyses, 24 other publications, and 173 articles classified according to Idea, Development, Exploration, Assessment, and Long-term results stages (19 stage 0, 27 stage 1, 111 stage 2, 7 stage 3, and 9 stage 4). Overall, impact factor produced was 634.10. Reviewing corresponding authors’ nationalities, 32 countries were identified, with the United States, China, and the United Kingdom the most reported; nearly all were from the Northern Hemisphere. Publication of stage 3 and 4 articles started in 2014, whereas stage 0 and 1 articles were stably published over time. The number of patients increased in correspondence with the Idea, Development, Exploration, Assessment, and Long-term results stages (case series with >51 patients, respectively, 100.0% stage 3, 77.8% stage 4, and 33.3% stage 2, P =.005). Conclusion: The number of stage 3 and 4 articles is still low; however, the technical innovation of transanal total mesorectal excision is a non-stop process with preclinical studies stably published over time.