Renal vein anatomy and its implications for retroperitoneal surgery.

Because of its complicated embryological development, the anatomy of the renal veins shows extensive variability. A full understanding of the potential anatomical variations is imperative for retroperitoneal operations. Based on 4,520 retroperitoneal computerized tomography scans, anatomical studies of autopsy material of 354 unselected cases and intraoperative observations made during 215 major retroperitoneal procedures, an attempt was made to define the most common renal vein variants and retrace their development during embryogenesis. Awareness of rare anomalies in urological and general surgery is crucial to prevent severe damage to the venous drainage of the left kidney, and because troublesome bleeding may occur during vascular and retroperitoneal oncological procedures in patients with unknown venous anomalies. We found the incidence of these variants to be 0.8 versus 1.7 versus 3.7%, respectively.