Anatomical Variants of the Renal Veins and Their Relationship with Morphofunctional Alterations of the Kidney: A Systematic Review and Meta-Analysis of Prevalence.

Background: Variations in renal veins are quite common, and most people do not experience issues due to them. However, these variations are important for healthcare professionals, especially in surgical procedures and imaging studies, as precise knowledge of vascular anatomy is essential to avoid complications during medical interventions. The purpose of this study was to expose the frequency of anatomical variations in the renal vein (RV) and detail their relationship with the retroperitoneal and renal regions. Methods: A systematic search was conducted in the Medline, Scopus, Web of Science, Google Scholar, CINAHL, and LILACS databases from their inception until January 2024. Two authors independently carried out the search, study selection, and data extraction and assessed methodological quality using a quality assurance tool for anatomical studies (AQUA). Ultimately, consolidated prevalence was estimated using a random effects model. Results: In total, 91 studies meeting the eligibility criteria were identified. This study included 91 investigations with a total of 46,664 subjects; the meta-analysis encompassed 64 studies. The overall prevalence of multiple renal veins was 5%, with a confidence interval (CI) of 4% to 5%. The prevalence of the renal vein trajectory was 5%, with a CI of 4% to 5%. The prevalence of renal vein branching was 3%, with a CI of 0% to 6%. Lastly, the prevalence of unusual renal vein origin was 2%, with a CI of 1% to 4%. Conclusions: The analysis of these variants is crucial for both surgical clinical management and the treatment of patients with renal transplant and hemodialysis.

Association between types of abdominopelvic cancer in patients with situs inversus total: Systematic review.

BACKGROUND: Situs inversus is a rare congenital anatomical variant that involves a group of anomalies regarding the arrangement of intrathoracic and intraabdominal organs. Being able to find in the abdominal region the liver, gallbladder, inferior vena cava, and head of the pancreas and ascending colon on the left side of the abdomen, while on the right side there is the spleen, the stomach, the body of the pancreas, the ligament of Treitz, descending colon among others. In this same way, the thoracic organs, lungs and heart, are changed in their position in a mirror translocation. METHODS: We systematically searched MEDLINE, Web of Science, Google Scholar, CINAHL, Scopus, and LILACS; the search strategy included a combination of the following terms: "Situs inversus," "Situs inversus totalis," "Cancer," "Neoplasm," "Abdominopelvic regions," and "clinical anatomy." RESULTS: Within the 41 included studies, 46 patients with situs inversus who had cancer, in addition to being found in this organ and in these regions, we also found as a result that the majority of the studies in the research were in stage II; finally, no one study could assert the direct relationship between the situs inversus totalis and the cancer. CONCLUSION: If our hallmarks could make us think that more exhaustive follow-up of the stomach and other organs should be carried out in these patients, there could also be other predisposing factors for cancer, which is why more studies are suggested to give future diagnostic and treatment guidelines treatment.