Living Donor Liver Procurement

Living donor liver transplantation (LDLT) has the advantage of availability of donor organs and may produce better long-term results than any other source of organs for pediatric or adult liver transplantation. This is a resource-intensive procedure, requiring the simultaneous use of a donor room and a recipient room, as well as two surgical teams.

In the pediatric population, most of the time, this involves donation of a left lateral segment (Couinaud's segments 2 and 3) from a relative. The resection starts with a careful dissection of the left hepatic artery within the hepatoduodenal ligament, with identification of the vital supply to the left median segment IV and the right lobe of the liver. Branches to the caudate lobe are sacrificed whenever necessary. The left lateral branch of the portal vein is isolated to obtain a single portal venous inflow to the graft. Dissection continues anteriorly along the round ligament separating the left lateral segment from the left median segment, along the medial edge of the round ligament.

The continuation of the round ligament between the posterior surface of the left lateral segment and the anterior surface of the caudate lobe is dissected to approach the left hepatic vein posteriorly. The left lateral segment is mobilized by the severing of the falciform ligament and the left triangular ligament, and the left hepatic vein is freed anteriorly. In the majority of cases, the left hepatic vein can be controlled extraparenchymatously. Finally, the bile duct is dissected and, after clear identification, encircled to be severed with scalpel at a late time. If necessary, the orifices of the median segment and the caudate lobe are sutured-ligated safely. The parenchymal dissection continues without vascular occlusion of either right or left lateral liver portions to avoid warm ischemia. The use of sharp and blunt dissection during the parenchymal dissection, with hemoclip application to larger vascular structures, is employed. Once full anatomical isolation is achieved, the hepatic artery, portal vein, and hepatic vein are clamped, severed, and taken to the backtable, where they are immediately flushed with UW solution through the portal vein and hepatic artery, and the bile duct is rinsed. If necessary, arterial and venous lengthening can be achieved using vascular interposition grafts from the donor-using saphenous vein.

Major limitations to adult-to-adult LRLT lie in the amount that can be safely removed from the living donor, which may be too small to function as a graft. Techniques using full right lobes (Couinaud's segments 5, 6, 7, and 8) appear very promising, though. The minimal need for donor tissue must be at least 1% of recipient weight. Ratios of < 0.7% are at high risk for the "small for size" phenomena leading to graft dysfunction. Intraoperatively, either the Cavitron Ultrasonic Aspirator (CUSA) and/or the Harmonic Scalpel is used almost exclusively in the donor procurements. The surgeon proceeds with the hilar dissection first, isolating the right branches of the portal vein and hepatic artery with vessel loops. Dissection and division between silk ties of the short hepatic veins draining the right hemicaudate are fundamental to identify clearly and isolate the right hepatic vein. Short hepatic veins larger than 5 mm in diameter are divided with the idea of reanastomosing them later in the recipient. The parenchymal dissection then proceeds along Cantlie's line till the bile duct is reached. Then it turns medially at a 30° angle to allow for proper procurement of the right hemicaudate and vessels to the right lobe. If the decision is made to heparinize the patient, heparin is used at doses of 3,000 to 5,000 units just prior to clamping the vessels, with minimal to no intraoperative bleeding. Once the parenchymal resection is complete, the portal vein is cut and bleeding from the specimen is allowed, and the hepatic artery follows suit. The dissection then proceeds to divide the right hepatic vein and the lobe is removed. Once removed, the lobe is weighed on the backtable and flushed with either UW or chilled lactated Ringer's solution, then taken to the recipient's room for implantation, which proceeds using the piggyback technique. Biliary reconstruction is done with either and end-to-end anastomosis over an internal stent if a single duct drains the donor right lobe. More commonly, however, two or more ducts necessitate that a Roux-en-Y anastomosis be fashioned.

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