[Left-sided inferior vena cava: source of peroperative difficulties in nephrectomy of a horseshoe kidney with pyonephrosis].

A case of left-sided inferior vena cava, discovered intra-operatively, is reported. The authors consider that the operative risk associated with this anomaly could have been avoided by preoperative ultrasonographic localisation of the vessel. They recommend that ultrasonographic localisation of the inferior vena cava should be an integral part of every renal ultrasonography examination.