Procurement of the Left Lateral Segment

This procedure allows the harvesting of two separate grafts of different size and is indicated when an adult and a pediatric recipient are to be transplanted $. It may be considered an anatomic left lateral sectionectomy. 
Section of the liver is made along the falciform ligament and divides the left lateral section from the medial left section. The left graft $, composed of segments II and III, includes the left hepatic vein, the left branch of the portal vein, and the left branch of the hepatic artery along with the common hepatic artery and the celiac tripod. The right graft, composed of segments I and IV to VIII, includes the vena cava, the right branch of the hepatic artery, and the portal vein along with the origin of the mesenteric and splenic veins :.
The section of the parenchyma can be performed according to one of the several described techniques of parenchymal transection. We recently introduced the use of the UltraCision instrument.

The procedure step by step
The donor is placed in a supine position with both arms extended. Monitoring should include a central venous line and an arterial line. Other lines for rapid infusion are advisable as during the section of the parenchyma bleeding may occur requiring adequate replacement.
The chest and the abdomen of the donor are entered by means of a median incision from the sternal notch to the pubis. 
Once the presence of undiagnosed malignancies is excluded, the caecum, the ascending colon with the hepatic flexure and the whole small bowel are mobilized to allow exposure of the retroperitoneum.  The anterior surface of the aorta is exposed and the inferior mesenteric artery is ligated and divided. The aorta is isolated $ at the level of its bifurcation and of the diaphragm and is encircled with bands. This allows the procedure to be converted to a standard rapid operation in case of instability of the donor.
The intestines are replaced in the abdomen and the round ligament is divided between ligatures. The falciform ligament is sectioned by cauterization up to the sovrahepatic vena cava. Even the left triangular ligament is sectioned by cauterization.
The hepato-gastric ligament is carefully inspected to detect an accessory left hepatic artery originating from the left gastric artery which must be preserved. When this vessel is not detected the ligament is sectioned by cauterization from the hepatic hilum up to the left side of the left hepatic vein :.
The common hepatic artery $ is then identified and dissected from the origin of the gastro-duodenal artery up to its division in right and left hepatic arteries. Once these two branches are clearly identified, the left hepatic artery is encircled with a vessel loop and traced towards the parenchyma : :. If present, branches for the fourth segment should be identified and divided between sutures.
To expose the base of the round ligament, the small bridge of parenchyma connecting the lower portion of segment IV to the left lateral section of the liver is encircled with a clamp and divided :.
The liver is gently separated allowing access to the round ligament which is tractioned upwards. The superficial peritoneal layer of the round ligament is dissected to reveal the venous connections to the forth segment. All these veins must be carefully isolated, ligated with 5-0 monofilament stitches and divided :. The dissection must free all the lateral attachments of the round ligament until it is completely mobilized.
Once the round ligament is dissected, the extrahepatic portion of the left branch of the portal vein $ can be identified just below the left hepatic artery. This vein must be carefully dissected and encircled with a vessel loop : :. Care must be taken to preserve the small branches of the caudate lobe, in proximity to the level where the vessel will be divided. Only the branch to the caudate lobe originating close to the left lateral section should be ligated with 5-0 monofilament stitches and divided.
The left lateral section is gently rotated laterally on the right side and its posterior surface exposed. The ligamentum venosum is completely dissected up to left lateral hepatic vein. With the complete mobilization of the left lateral segments by dissection of their posterior surface, the left hepatic vein can be isolated :. This step is performed by means of a blunt right-angle clamp passed from above between the median and left hepatic veins. A cotton tape must be slung around the vein :.
The bile ducts of the left lateral section of the liver are included in the fibrous tissue of the porta hepatis and should not be dissected. On the contrary, all this fibrous tissue  must be encircled with a thin clamp passed bluntly into the parenchyma from the lateral side of the round ligament to the posterior surface of the section at the beginning of the ligamentum venosum.  Care must be taken to avoid lesions of the posterior wall of the left portal vein and little branch to the caudate lobe. All this tissue must be encircled with a cotton tape and divided sharply with a scalpel : :. This allows the identification of the bile duct of the left lateral segment, which can be single or multiple. During this manoeuvre some bleeding may occur from small arteries, and hemostasis should be achieved by means of 5-0 stitches avoiding cauterization to preserve the vascularization of the biliary ducts. On the side of the fourth segment the biliary ducts must be suture-ligated with absorbable 5-0 monofilament.
The section of the parenchyma can now be performed along the falciform ligament. A small branch in the hepatic edge is sometimes present and can be used as a mark for starting the section.  In favorable cases parenchyma section is performed almost on an avascular plane without legatures. 
It is helpful when identifying the plane of the dissection to pass the cotton tape which encircled the left hepatic vein on the posterior surface of the liver in the fossa of the ductus venosus, laterally to the left branch of the hepatic artery and of the portal vein. Pulling up on this tape, the dissection of the parenchyma is usually easy : :. Some larger vessels must be suture-ligated with 4-0 monofilament.
Once the section of the parenchyma $ is completed, haemostasis is verified.
At this point the procedure continues as a standard donor operation with i.v. administration of Heparin (300 UI/Kg), incannulation and cross-clamp of the aorta, perfusion with preservation solution, venting of the vena cava, and cooling of the abdominal cavity with ice-cold solution.
The left hepatic vein is sectioned close to the vena cava :. Care must be taken to identify a distal bifurcation of this vein. A double left hepatic vein significantly increases the technical difficulty of the implantation of the graft. In this case the vessel should be removed with a cuff of vena cava to allow a single vascular anastomosis with the recipient vena cava.
The left branch of the portal vein is sectioned close to the parenchyma allowing an adequate margin for anastomosis, but preserving the small veins to the caudate lobe as much as possible :. 
The right hepatic artery is sectioned close to its origin :, and the hepatic artery is dissected up to the celiac trunk which is removed along with an aortic cuff.
The left graft $ is now removed and placed in the plastic bag at approximately 4°C. A silastic cannula is inserted into the left portal vein and ligated with a vessel loop. A further perfusion of 1lt of UW solution  is now performed.
The right graft $ is then removed, and cool-perfused like the left graft.