Retroaortic Renal Vein Variations and Hematuria: An Anatomical and Clinical Analysis

Background: The retroaortic left renal vein (RV) is an anatomical variant in which the left RV runs between the aorta and the vertebrae and drains into the inferior vena cava. Aims and Objective: This study aims to investigate the potential relationship between retroaortic renal vein (RARV) morphology and hematuria. Materials and Methods: Abdominal computed tomography images of 371 individuals were analyzed. The frequency and types of RARV variations were assessed and compared between patients ages 10–90 years with and without hematuria. Morphometric measurements, angles, and vertebral levels of RARV types were also analyzed. Results: Contrary to previous studies, no clinically significant relationship was found between RARV and hematuria. The most common RARV variation observed was Type 2, differing from the literature, which frequently cites Type 1 as the most prevalent. The Type 2 variation was the most commonly observed in both females and males, typically located at the L2–L3 vertebral level. Despite similar compression observations in individuals with and without hematuria, no direct association with hematuria was identified. The correlation analysis revealed a statistically significant positive correlation between hematuria classification based on urinary erythrocyte ratio and the ratios of diameters of the RARV at the retroaortic level and the middle of the RV. Conclusion: The study underscores the importance of recognizing RARV variations, especially Type 2, during abdominal examinations to prevent complications during retroperitoneal or renal interventions. Although a direct relationship between RARV and hematuria was not established, the findings contribute to understanding the anatomical and clinical significance of RARV variations.