Laparoscopic approach to the hepatic veins
Extrahepatic dissection of the right hepatic vein
The extraparenchymal approach to the right hepatocaval confluent requires the section of the falciform ligament with the complete exposure of the bare area until the diaphragm. The exposure continues with the transection of the right coronaric ligament. The right inferior phrenic vein indicating the right hepatic vein confluence into the inferior vena cava. During the manoeuvres of cranial dissection the surgeon must be careful not to damage the early dorsal branches for the eighth and seventh segments in order to avoid bleeding of difficult management.
The complete mobilization of the right liver continues with the dissection of the triangular ligament and the coronaric ligament in order to expose the inferior vena cava and the right hepatocaval confluence.
The mobilization time in laparoscopy is often difficult to perform due to the parenchymal size of the right liver that hind the operator’s movements, so the tilting of the bed allows to take advantage of the force of gravity in the mobilization manoeuvres.
A special care should be taken not to damage the right confluence not recognizing its position. During the dissection of the hepatic parenchyma from the vena cava, some accessories hepatic veins are identified and sectioned between clips. During this time a low central venous pressure allows to isolate vascular structures more easily and safely.
At the end of the mobilization, the hepatocaval ligament that connects anatomically the seventh with the first segment is isolated and then dissected. Often this connective structure contains an accessory vein; so it is advisable that its section be carried by stapler or clips depending on the size. Once the ligament has been dissected, the origin of the right hepatic vein is exposed. The right hepatic vein is encircled and suspended on a vessel loop and the isolation of the right hepatic vein is completed.
Extrahepatic dissection of the left hepatic vein
The middle and left hepatic veins converges into the antero lateral portion of the vena cava with a common trunk in the 95% of cases; only the 5% of the patients present a separate confluence of the two veins into the vena cava. It should be remembered that dissection and isolation maneuvers of the confluent are often not so easy in laparoscopy and the risks of any damage during the dissection can also be difficult to manage in laparoscopy.
For this reason it is not advisable to insist with isolation after some unsuccessful attempts, leaving as the last part of the intervention the vascular section of the vein. The extra parenchymal isolation of the left hepatic vein, begins similarly to what is described for the right, with the mobilization of the left liver. After dissecting the falciform ligament and the initial part of the left coronaric ligament, the left triangular ligament and the last portion of the left coronaric ligament are dissected distally until the complete mobilization.
The left side of the upper part of the vena cava and the lateral wall of the left hepatic vein are covered by the venous ligament of Aranzio. It’s possible to expose the Aranzio’s ligament after the mobilization and the dislocation of the left hepatic lobe and the dissection of the lesser omentum. The section of the Arantio’s ligament allows the exposure of the end of the left hepatic vein and the vena cava.
At this point it is possible to complete the isolation of the left hepatic vein from the median, paying close attention to the presence of early branches for the second segment that may be injured in traction or isolation manoeuvres. Then with the aid of a right angle forceps is possible to complete the blunt dissection and isolation of the left hepatic vein. At the end the vein is encircled with a vessel loop and the dissection is completed.
Extrahepatic dissection of the common trunk
The first manoeuvre for the isolation of the common trunk requires the dissection of the falciform ligament until the bare area is completely exposed. With the dissection of the bare area the hepato caval confluence is completely exposed. The surgeon proceed with the complete mobilization of the left liver by dissecting the triangular and the coronaric ligaments. In order to reach a complete mobilization of the left lobe is often necessary the section of the Arantio’s ligament. After the mobilization and the dislocation of the left lobe is necessary to expose the hepato caval plan, it’s now possible the dissection of the common trunk from the right hepatic vein paying attention not to injure if there are some dorsal accessories retro hepatic veins for the second and fourth segments. By using a blind dissection is possible to underpass and to encircle the common trunk and then to position a vessel loop to suspend it. The isolation is now completed.