Figure 1.

Study selection. A total of 1682 articles were identified after PubMed-based literature search using the terms ‘biliary sludge or microlithiasis’ in the published period between 1981 and 2021 and PRISMA guideline-based systemic evaluation. In order to further stratify the 151 articles on screening and matching level, 2 of the 5 predefined inclusion criteria had to be fulfilled for the final inclusion of the articles (inclusion criteria: (1) Definition of microlithiasis and/or biliary sludge is given in the publication; (2) Endoscopic, imaging and/or biochemical procedures used for microlithiasis and/or biliary sludge diagnosis is defined; (3) Specific ultrasonographic features of microlithiasis and/or biliary sludge were defined; (4) A cut-off size value for the diagnosis of microlithiasis was used and (5) Paper dealt explicitly with treatment methods of microlithiasis and/or biliary sludge). In order to take into account the scientific visibility of review papers, these were also included in the literature search. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.