Supernumerary renal vessels: analysis of frequency and configuration in 996 computed tomography studies

Number, course and division pattern of renal vessels is highly variable. Variant renal vasculature is of high interest in nephrectomy for the renal transplantations, both in deceased and living donors. The purpose of the study was to analyse the frequency of supernumerary renal vessels in a large cohort of patients undergoing the multiphase abdominopelvic computed tomography (CT), as well as analyse the possible patterns of coexisting supernumerary arteries in veins.

A retrospective analysis of abdominopelvic CT studies within 1 year period was performed. In each study, number of renal arteries and veins was recorded. Course of left renal vein was classified into normal, retro- or periaortic. For statistical analysis of normal distribution data, t-Student test was used. Chi-square test was used for frequency of variant vessel distribution. Pearson correlation coefficient was used for the analysis of coexistence of supernumerary vessels.

996 patients were included in the analysis, male to female ratio: 481:515 (48%:52%). Mean age was 57.9 ± 14.7 years. Single renal arteries were observed in 73% of cases, while single renal veins in 95%. Circumaortic or retroaortic courses of left renal veins were observed in 10% of cases. Number of renal vessels has been compared in patients with and without supernumerary vessels. In patients with supernumerary left renal artery, significantly more right renal vessels were observed. In patients with supernumerary right renal vein, mean number of all remaining vessels was significantly higher.

Supernumerary renal vessels are a frequent finding in abdominal CT studies. Finding a supernumerary vessel should increase awareness of possible other supernumerary renal vessels.