Posterior Lumbar Vein Off The Retrohepatic Inferior Vena Cava: A Novel Anatomical Variant With Surgical Implications

Purpose: Resection of tumors involving the inferior vena cava requires vascular control of posteriorly draining lumbar veins to ensure a bloodless field. Surgical texts and atlases assert that lumbar veins do not insert into the inferior vena cava superior to the renal hilum. However, at our institution we have encountered patients undergoing inferior vena cava tumor thrombectomy who have a posterior lumbar vein cephalad to the renal veins. Since this represents an unrecognized source of hemorrhage, we investigated the frequency of a superior lumbar vein in cadaveric dissection.Materials and Methods: Retroperitoneal cadaveric dissection of the inferior vena cava was done to assess the frequency of a lumbar vein draining into the inferior vena cava cephalad to the renal veins.Results: Of the 49 cadaveric dissections performed 19 (38.8%) showed a single posterior lumbar vein between the diaphragm and the renal hilum. Of these 19 cadavers 15 (78.9%) were male. This vein was located an average +/- SD of 7.4 +/- 0.6 cm cephalad to the right renal vein and it was 3.7 +/- 1.6 cm in diameter. In all cadavers this vein inserted within 30 degrees to the left or right of the posterior (also termed dorsal) aspect of the inferior vena cava.Conclusions: The identification of a lumbar vein between the renal hilum and the diaphragm represents an important anatomical variant that occurs in a significant percent of individuals. Surgeons will benefit from the knowledge of this variant of inferior vena cava vasculature and should anticipate the presence of this vein to prevent unnecessary morbidity and mortality secondary to unexpected hemorrhage, particularly in male patients.