Extreme Variability of the Kidney Hilar Architecture: A Radioanatomical Map to Guide Surgical Approaches

Background: Retroperitoneal surgical corridors, particularly in robotic-assisted partial nephrectomy and donor surgery, require precise knowledge of hilar vascular orientation. The typically described Vein–Artery–Pelvis (VAP) anatomy is often assumed, yet its reliability is poorly quantified. Therefore, the purpose of the present study is to provide a comprehensive radioanatomical map of hilar architecture to enhance surgical safety and predictability. Methods: Contrast-enhanced computed tomography (CT) scans of the abdomen from 200 patients (104 males and 96 females) were evaluated. The anterior-to-posterior sequence of hilar structures, the frequency of early vascular branching, and the presence of accessory vessels were documented and stratified by sex and laterality. Results: The conventional VAP sequence was observed in a minority of cases, occurring in only 32.6% (131 sides). The map identified 37 distinct sequence variants. The most common variants included VAPA (9.0%), AVAP (7.8%), and VAAP (7.0%). Adherence to typical VAP anatomy was significantly lower in males (27.9%) than in females (37.7%). Arterial complexity, characterized by early branching or accessory vessels, was present in 43.2% of sides, with a significantly higher occurrence in males and on the right side. Venous mapping revealed a marked lateral disparity; accessory veins were predominantly right-sided (12.5%), whereas early venous branching was predominantly a left-sided feature (30.0%). Conclusions: Renal hilar architecture demonstrates substantial variability, with the classical VAP configuration representing a minority arrangement. These findings highlight the importance of individualized preoperative imaging assessment and may help anticipate anatomical complexity in retroperitoneal surgery