The Circumaortic Left Renal Venous Collar- a Report of Two Cases

The knowledge of morphological variations of renal vein is of extreme importance for the anatomist and clinicians. The highly complex embryological development of left renal vein compared to its right counterpart, results in greater variations that are clinically significant. During the study of 60 renal vascular pedicles in adult human cadaver, two cases of the circumaorticrenal venous collar were observed. It has been reported in the range of 3.5 % to 16.8 % of cases by different authors as compared to present study finding of 6.6 %. Circumaortic veins are the result of persistence of the dorsal arch of the renal collar. The left kidney is usually preferred for transplant surgery since the left renal vein is longer. With a circumaortic venous ring, this advantage is lost due to fixation of the vein at the aortic margin. Thus, the presence of this anomaly is of vital importance to the vascular surgeon and urologist.