Left Lateral Segment Splitting ex situ

After a standard backtable procedure is performed, the left hepatic artery is dissected out, from its origin to the umbilical fissure. The left portal vein as well

Figure 10.9. Anatomical lines for hepatic division in split-liver transplantation,

is freed up from its bifurcation to the level of umbilical fissure. After this is completed, the left hepatic vein is isolated and divided. The left hepatic vein orifice on the cava is closed vertically using 5/0 prolene running suture. The parenchymal transsection line is to the right side of the falciform ligament; parenchymal transsection is performed using scissor dissection. The vascular and bile duct branches are tied and divided. During the parenchymal transection, the portal vein branches supplying the left medial segment (segment 4) must be transected, sometimes causing necrosis of segment 4. When liver splitting is performed ex situ, the viability of segment 4 should be evaluated after the liver is reperfused, and segment 4 should be resected if it becomes dusky following reperfusion.

In situ splitting has many advantages over ex situ splitting. Because no backtable liver division is needed with in situ procurement, so-called cool ischemia is avoided. The vascular supply of segment 4 can be evaluated. Because bleeding and bile leakage from the cut edge are controlled during parenchymal dissection, bleeding from the raw surface on reperfusion is minimal. One part of the liver can be shipped to another center directly from the donor hospital, avoiding extended cold-ischemia time and facilitating intercenter sharing.

In both in situ and ex situ splitting, vessels can be shared based on both recipients' needs. For example, because the hepatic artery is small in pediatric patients, especially those below 1 year of age, it would be ideal to leave the whole celiac axis with the left lateral segment graft, so that the donor celiac axis can be anastomosed to the infrarenal aorta without an extension graft. On the other hand, in adults, the right hepatic artery of the donor can easily be anastomosed to the recipient's right or proper hepatic artery without using operating microscope, since the diameter of the right hepatic artery is generally > 3 mm. In terms of portal vein sharing, the donor's left portal vein is usually long enough to reach the bifurcation of the recipient's portal vein without an extension graft; thus, the main portal vein usually remains with the right graft.

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