Extended lateral segmentectomy using intraoperative ultrasound to obtain a partial liver graft.

The important features of extended lateral segmentectomy to obtain a partial liver graft comprising the left lateral segment and the left half of the medial segment are described with special reference to anatomical variation of the hepatic venous system. Ramification patterns of the hepatic vein tributaries around the juncture of the major hepatic veins with the inferior vena cava are delineated before starting liver resection, using intraoperative ultrasound. The left medial vein draining the left part of the medial segment is recognized close to the confluence of the middle and left hepatic veins. This tributary flows into the left hepatic vein in the majority of cases, but sometimes into the middle hepatic vein. The liver transection line is established in order to obtain the graft, including the drainage area of the left medial vein. Intraoperative ultrasound is indispensable for identifying the left medial vein in extended lateral segmentectomy.