The presented work is only a minor contribution to the extensively elaborated method of surgical treatment of subrenal aneurysms of the abdominal aorta, informing on the unusual pattern of important anatomical structures in the surgical field involving the retroaortal localization of the left renal artery which runs closely dorsally behind the proximal neck of the aneurysm. The incidence of major venous anomalies which are associated with the aortal section and which include in particular the circumaortal left renal vein (circumaortal annulus) left-sided transposition of the lower vena cava or its duplicity and preaortal conncection of iliac veins amounts according to data in the literature to 5.6% [1], a left renal vein 2% [18] and the incidence of these anomalies in surgery of the abdominal aorta is 0.8% [3]. The presence of the anomaly we encountered was detected already before surgery due to the careful evaluation of the spiral CT and called for a change of the usual surgical technique because of the risk of injury of the renal vein during construction of the proximal anastomosis by the usual inclusion technique from the inside of the aneurysm. A more extensive release of the proximal cervix of the aneurysm was necessary with isolation of the adjacent ventral portion of the left renal vein, complete transverse severing of the aorta at the level of the proximal cervix and direct end to end suture of the proximal anastomosis. This case-history draws attention to the possibility of venous malformations whichmaymake the course of surgery on the abdominal aorta difficult and draws attention to the importance of CT examination during elective operations of aneurysms of the abdominal aorta.

        Key words: aneurysm of the abdominal aorta – major venous anomalies – renal vein – retroartal position