Four major variations of the venous system in the retroperitoneal space are the retroaortic left renal vein, left renal vein collar, left-sided inferior vena cava, and caval duplication. During surgery, especially, injury in veins is responsible for the most unexpected intraoperative bleeding. Therefore, above-mentioned anomalies pose potential hazards to surgeons during treatment of abdominal aortic aneurysm. Preoperative diagnosis is highly desirable but is not always available so, during abdominal surgery, familiarity with the anatomy of the most common types of venous variations is the first step toward preventing vascular injury. The chapter includes information describing the demographic, clinical, and morphological characteristics of the presence of the aforementioned main vein anomalies including: gender distribution, frequency in population, the most commonly reported symptoms, and associate complications. Massive intraoperative bleeding may be dangerous during aortic dissection; however, venous bleeding is more complicated than arterial hemorrhage. Significant venous bleeding, in particular, can occur if major retroperitoneal venous anomalies are present. The anomalous veins are typically thin-walled, dilated, and tortuous. As a result, manipulation of these veins during abdominal aortic surgery places the patient at high risk of long-term massive hemorrhage.
Part of the book: Aortic Aneurysm