Morphologic evaluation of the renal veins: a study with autopsy material from Colombian subjects

Renal venous drainage presents a large degree of variability. The purpose of this study was to determine the morphological expression of the renal veins. Renal vein formation patterns, their morphometry, and frequency of additional veins were studied in a sample of 156 pairs of kidneys, the vascular beds of which were subjected to an injection-corrosion technique, taken from cadaver specimens autopsied at National Institute of Legal Medicine and Forensics Sciences in Bucaramanga, Colombia. A single renal vein (RV) was found bilaterally in 122 (78.2%) samples, whereas 34 (21.8%) kidneys had additional RVs (left side 33 cases, right side one case). Of the specimens with multiple right renal veins (RRV), 28 (17.9%) had two RVs and five (3.2%) had three RVs. Of the left kidneys, 99.4% had one LRV and 0.6% had two LRVs. The lengths of the left and right renal veins were 56.5±12.7 mm and 23.6±8.21 mm, respectively; the caliber of the left renal vein (LRV) was 12.3±1.41 mm, whereas the caliber of the RRV was 10.9±1.56 mm, a statistically non-significant difference (p=0.262). 82.7% of the LRVs and the 73.1% of the RRVs (p=0.768) originated at the extra-hilum level. Renal vein formation pattern characterized by the confluence of upper and lower tributaries was found in 61.6% of the cases, whereas 16.3% of the specimens had upper, medium, and lower tributaries. Variation patterns found in this study point towards a wide morphological expression of these vessels that needs to be taken into account for both imaging and surgical procedures.