Beware the Anomalous Portal Vein

Abstract

Portal vein thrombosis is an unusual potential complication of liver resection. In our case it was due to ligation of the right branch of the portal vein during right hepatectomy in a patient without portal vein bifurcation. Hepatic angiography can delineate this abnormality and influence the choice of surgical management.

Right Hepatectomy In Patient with Absent Portal Vein Bifurcation

“…Normal portal vein anatomy is observed in 65-86% of all cases [1,2]. In this scenario, main portal vein bifurcates extrahepatically into right main and left main veins which are then subsequently divided into right anterior (inflow to segments V and VIII) and right posterior (inflow to segments VI and VII) as well as left portal branches to segment IV, segment II and III and caudate lobe 3 . Portal vein trifurcation (division of main portal vein into right anterior, right posterior and left main portal veins instead of bifurcation) is most common variation with incidence of about 10%.…”

“…In this variation, first described by Couinaud in 1957, single right portal vein enters the liver hilum with variable intrahepatic portal vein branches supplying left hemiliver [2]. If not recognized, severe complications in form of postoperative remnant liver ischemia, portal vein thrombosis and death can be expected [1,3]. With careful preoperative imaging and planning, successful hepatectomy and liver transplantation can be carried out without difficulty [4,5].…”

Comments on Sato et al.: The anomalous left portal vein

“…The right hepatic vein may also be used for shunting to the anomalous vein as is the usual procedure. The venous anomaly is very important in liver surgery since resection of the right or left liver with ligation of the vein causes necrosis of the remaining liver with death unless liver transplant is immediately available [7]. In living-donor-related liver transplantation removal of the left liver following ligation of the vein causes death of the donor [8,9].…”

Reply to McNulty and Khosa: The anomalous left portal vein — Agenesis of the horizontal segment of the left portal vein

“…In liver surgery, it is easy to understand the lethal consequence of a right hepatic lobectomy or a right hepatectomy [3], since portal branches of the remaining liver are in these cases not connected anymore with the portal trunk. However, the anatomic anomaly described in our paper does not seem to be a contraindication of left hepatectomy or left hepatic lobectomy [4] if the surgeon is aware of the anomaly and is able to prevent a hemorrhagic complication by performing a correct ligation of the proximal or the distal portion of the aberrant vessel.…”