Segment IV Hepatectomy

Isolated laparoscopic anatomical segmentectomy 4 is a technically demanding procedure due to the two transection planes: on the left, along the umbilical ligament, and on the right, along the middle hepatic vein (MHV). The use of intraoperative ultrasound (IOUS) and of the negative staining by indocyanine green (ICG) administration are fundamental tools in order to correctly perform the removal of S4. The two lines of transections may be performed: first, from the periphery to the cranial side by dividing all the portal branches to S4. Then, the transection line moves from the cranial side to the periphery by following the ischemic demarcation line on the surface and the course of the MHV deeply. The cranio-ventral approach to the MHV from its root side may be considered as an effective technique for the second line of transection in order to follow the correct plane of segmentectomy, by decreasing the risk of injury of its venous branches.