A systematic literature study of anatomical variations in human lung fissures and hilar structures

This study aimed to examine the anatomical features and variation prevalence of human lung fissures and hilar structures. Anatomical variations can be seen in these structures and morphometrical data are not consistent. Studies in the literature were reviewed using the PubMed, Scopus, and Google Scholar databases. The method of the study was prepared in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis [PRISMA] protocol. Data on the complete, incomplete, absent and accessory fissures, accessory fissure types, number of arteries, veins and bronchi were extracted and included in the analysis. The Anatomical Quality Assessment (AQUA) tool was used in order to examine potential risks of bias within the included studies. Out of 302 studies initially evaluated, 68 were included in the analysis. It was determined that the prevalence of completion of horizontal fissure of the right lung (56,5%) was lower than oblique fissures, while the prevalence of incomplete and absent fissure (43,4%) were higher than oblique fissures. The prevalence of the left horizontal accessory fissure (9,9%) in the left lung and the inferior accessory fissure type (8,9%) in the right lung were found to be the highest. It has been found that the number of arteries and bronchi in the hilum of the right lung are different from the general anatomy. Although studies on lung fissure variations are more common, studies examining accessory fissures and hilar structures are rare. We think that this study will be useful for clinicians in interpreting radiological images, diagnosing lung pathologies, and applying surgical procedures.