Implantation of the Left Lateral Segment

Techniques of transplantation of the liver grafts obtained from splitting procedures differ according to the type of graft and split. The main technical difference is related to wheter or not the graft includes the inferior vena cava (IVC) and therefore wheter preservation of the IVC is or is not required during the recipient’s hepatectomy.
Basically, 4 types of graft are to be considered:
a)	right graft from standard split liver (including IVC) &
b)	left graft from standard split liver (without IVC) &
c)	right graft from modified “equal size” split liver (without IVC) &
d)	left graft from modified “equal size” split liver (including IVC) &

Patient position and incision
The patient is placed on the table in supine position, with both arms extended, soft pads are carefully placed under the recumbent parts of the body, to prevent pressure sores.
Several incision may be used for pediatric liver transplantation: among them the most commonly used are the bilateral subcostal and the “Mercedes” type. We prefer to use an incision that goes on the midline from the xifoid to right above the umbilicus and then turns at right angle to the right, to a point at midline between the iliac spine and the costal margin. No effort is made to include in the incision the scars of previous operations.
Using the iron intern retractor and the Stieber’s rib retractor, this incision gives an excellent exposure of the surgical field and allows the surgeon to perform a liver transplant, either in adults or in small babies, with the help of a first assistant only &.
A sample of the peritoneal fluid is systematically sent for culture. The entire operation is performed with 3.5X magnification telescopes and headlight.

Mobilization of the liver
In patients with previous operations (such as Kasai procedure), mobilization of the liver may be troublesome, due to the portal hypertension and to the adhesions that develop, particularly between the large and small bowel, the stomach and the lower face of the liver. Careful sharp, rather than blunt dissection is used as much as possible, because it reduces the risk of injury to the bowel and because, if necessary, a sharp cut is easier to repair than a blunt tear. Most of the dissection is performed with the electrocautery to obtain proper haemostasis, by keeping the plane as close as possible to the liver parenchyma.
In patients with no previous surgery this part of the procedure is usually straightforward and is limited to section of the falciform and right and left triangular and coronary ligaments.

Dissection of the hepatic pedicle
The lower face of the liver is retracted upwards to give access to the hepatic pedicle. In patients with a previous Kasai operation, the first step is isolation and section of the jejunal loop as close as possible to the porto-enterostomy, with ligation of the stumps. A swab culture of the lumen of the loop is usually performed. In patients without biliary atresia the common bile duct is ligated and sectioned first.
The right and left branch of the hepatic artery are then dissected, ligated and sectioned. Last, the portal vein is encircled and dissected free, by section of all the surrounding cellular and lymphatic tissue. The dissection of the vessel is pushed distally to include its right and left branches. In case of hypoplasia of the portal vein, with a diameter lower than 5 mm, the dissection may be extended proximally, down to the confluence of the superior mesenteric and the splenic veins, to allow the implantation of a vein graft at this site. In this case, the coronary gastric vein is usually ligated and sectioned.

Dissection of the IVC 
The serosa on the anterior surface of the infrahepatic vena cava is opened and the vessel encircled,if possible above the right adrenal vein which is preserved. The retro hepatic portion of the IVC is then dissected from its posterior connections, with ligation and section of posterior phrenic veins, if present. The manoeuver is performed from below to above, from the right side, with the right lobe of the liver luxated outside the abdomen, until the supra hepatic portion of the vessel is reached &. A  peace of gauze, placed from the left, under the caudate lobe may help in the procedure, by bulking behind the IVC. This part of the dissection is somewhat less extended than in total hepatectomy for a standard whole size transplant and may even be avoided if lateral clamping of the IVC is planned &.
Our preference, however, is for complete crossclamping of the IVC, which is rather well tolerated by children and makes performing the venous outflow anastomosis easier. The dissection is therefore necessary &.
The liver is then freed from the anterior face of the IVC by section of the accessory hepatic veins which are tied or suture ligated. Only the lower two thirds of this dissection are performed at this time, performing the remaining upper third, including the confluence of the hepatic veins with the IVC, after the cross-clamping.

Cross-clamping and hepatectomy
At this time the liver is almost completely free, connected only to the portal vein, the main hepatic veins and few accessory hepatic veins. The portal vein is ligated and sectioned as distally as possible, preferably at its right and left branch, vascular clamps are then placed to completely occlude the infra- and supra-hepatic IVC : and the liver is removed by sectioning the three main hepatic veins and the remaining accessory hepatic veins with scissors, so as to preserve the IVC continuity :. The orifices of the accessory hepatic veins are sutured after the hepatectomy &.

Implantation of the graft
The left graft obtained by standard split liver is substantially different from a whole sized graft and its implantation requires significant deviations from the standard technique of liver transplantation.
Assuring an adequate venous outflow requires a careful technique of anastomosis between the left hepatic vein of the graft and the IVC of the recipient and a proper positioning of the graft itself, which is rotated clockwise 45° on a transversal plane and somewhat on a frontal plane too. The final position of the cut surface of the parenchyma, including the new hilum of the graft, is high and posterior, so that the portal vein and hepatic artery have a course that is curved and longer than the usual. For this reason these two vessels, differently from a standard transplant, need to be kept rather long, in order to take a gentle curve, rather than a sharp kinking. These aspects are absolutely crucial for success of the procedure and make it more difficult than the standard transplant, even for an experienced surgeon.
The outflow anastomosis is end to side between the left hepatic vein of the graft and the IVC of the recipient, with a triangulation technique &. The bridge between the ostia of the right and middle hepatic veins is cut to obtain a single opening. The ostium of the left hepatic vein may be treated in the same fashion, to obtain a further enlargement of the opening, or simply suture-closed. The opening is then enlarged caudahad by cutting   the anterior face of the IVC to obtain a wide reversed triangular orifice. The cuff of the hepatic vein of the graft is trimmed as short as possible, to avoid kinking, so that some amount of parenchyma needs often to be taken by stitches, while performing the suture. Three 5/0 vascular monofilament sutures are placed taking the three corners of the graft and recipient orifices. The graft is then placed in the hepatic fossa of the recipient and the triangular anastomosis performed with three running sutures. Before completing the anastomosis the graft is perfused via a cannula in the portal vein, with 200-500 ml of Ringer lactated solution at 4°C.
The second anastomosis is the portal one :. The cannula is removed from the portal vein of the graft (more properly the left branch of the donor’s portal vein) and a clamp is placed on the recipient’s portal vein which is opened. The two vessels are then connected by an end-to-end anastomosis with running sutures of 6/0 or 7/0 vascular monofilament. Both the length and the section of the vessels are crucial. As already mentioned the length should be sufficient for the vessel to make a gentle curve reaching the hilum of the graft; as for the section, the limiting factor is the size of the graft cuff. In the majority of cases the recipient’s vessel matches this size rather well. If not, it can be cut at its bifurcation, to obtain a branch patch &. In case of a real hypoplasia of the recipient’s portal vein, the confluence of the mesenteric and splenic vein can be clamped, the vessel sectioned at this level and a venous graft from the donor (usually the splenic or the external iliac vein) interposed between the confluence and the portal vein of the new liver &.
After completion of the anastomosis the portal, the infra-hepatic caval and supra-hepatic caval clamps are removed thus reperfusing the graft.
The hemostasis is checked and completed at the sites of the anastomosis and at the cut surface of the liver. Major hemorrhage is uncommon at this site, with grafts obtained by the in situ splitting technique.  
The arterial anastomosis comes next :. The arterial axis of the graft usually includes the proper and common hepatic artery, in continuity with the celiac artery and a patch of the aorta. The level of the anastomosis is chosen at any place along the recipient’s arterial axis, and the two vessels are trimmed to obtain a similar  section and a adequate length according to what has already been said concerning the portal vein. The anastomosis is performed end-to-end with a running suture of 7/0 or 8/0 vascular monofilament. If the recipient’s arterial axis is deemed inadequate, the aorta can be clamped at the origin of the celiac artery or just below the renal arteries and an end-to-side anastomosis can be performed at one of these sites. In the latter case the interposition of an arterial graft from the donor, usually represented by an iliac artery, may be necessary.
Last comes the biliary reconstruction which is in every case an hepatico-jejunostomy with a Roux-en-Y loop. A typical Roux-en-Y loop is realized with a single or double layer end-to-side jejuno-jejunostomy. In patients with a previous Kasai operation the loop already exists and is therefore utilized. The loop stump is closed and a small opening is created close to it, on the anti mesenteric border of the jejunum. The mucosa is everted by means of four stitches of 6/0 slow reabsorbing monofilament. The bile duct is then anastomosed to this opening with a 7/0 or a 8/0 slow reabsorbing monofilament. A running or an interrupted suture : is alternatively used according  to the local situation. The bile duct of the graft may be single or double, in the latter case two different anastomoses are performed.
A final check for bleeding points and for patency of the vascular anastomoses is then performed and the appendix is usually removed. The abdominal cavity is then rinsed with saline and Povidone-Iodine solution and with Amphotericine B and two Jackson-Pratt drains are placed, one between the cut surface of the graft and the diaphragm and one below the graft, in the celiac area. The abdominal wall is closed with running sutures and staples or stitches for the skin.

Technical variations
Implantation of a right graft from a modified “equal size” split liver technique
The hepatectomy is carried out as previously described and the graft is then placed in the right part of the hepatic fossa, where it usually takes its normal position. The right hepatic vein cuff of the graft is anastomosed end to end to the right hepatic vein cuff of the recipient; the remaining parts of the operation are identical to that previously described. The arterial axis of the graft includes only the right branch of the hepatic artery and its reconstruction may require the interposition of an arterial graft taken from the donor; the splenic or the superior mesenteric artery are usually suitable. The bile duct is anastomosed, either to a Roux en Y loop or to the recipient’s right or common hepatic duct.
Reconstruction of the recipient’s inferior vena cava for malignancy
Childhood hepatic malignancies of the have been considered a contraindication to the use of split liver graft graft, since the need for the retention of the recipient’s IVC would potentially preclude the obtaining of a tumor free margin &.
A technical variation, that has allowed us to successfully use left lateral segment grafts to transplant children affected by hepatic malignancies, involves the replacement of the recipient’s IVC using an iliac vein graft from the donor &.
On the back table a wide V-shaped opening on the wall of the common iliac vein graft from the donor is made. The left hepatic vein of the left lateral segment graft is anastomosed end-to-side to the V-shaped opening on the common iliac vein with two 5/0 Prolene running sutures $. On the recipient a total hepatectomy is usually performed using the standard technique removing the liver together with the retro-hepatic IVC. At this point the left lateral segment graft with the iliac vein graft is anastomosed to the supra-hepatic IVC in an end-to-end fashion with a 4/0 Prolene running suture. The inferior edge of the iliac graft is then anastomosed to the infra-hepatic IVC with a 5/0 Prolene running suture. The portal vein, hepatic artery anastomosis and the hepatico-jejunostomy on a Roux-en-Y loop are performed in the usual manner.
Implantation of a right graft from “standard” split liver and of a left graft from modified “equal size” split liver .
These two grafts include the donor’s retro-hepatic vena cava: the hepatectomy includes therefore the removal of the recipient’s vessel. The vessel is clamped above and below the liver, usually after ligation and section of the right adrenal vein, and removed together with the native liver. If the graft to be implanted is a right one from a standard splitting technique, the procedure is carried out as for a common whole-size graft. The supra-hepatic vena cava anastomosis is performed end to end, using a 3/0 or 4/0 polypropilene running suture, then the graft is flushed through the portal vein, with 500 cc of 4°C Lactate Ringer’s solution while the infra hepatic vena cava is anastomosed with a 4 or 5/0 polypropilene. Then the portal anastomosis is performed with a 6/0 or 7/0 Polypropilene suture and the graft is reperfused. Since the arterial supply is represented only by the right branch of the hepatic artery, the interposition of an arterial graft may be required for its reconstruction.
If the graft is a left one from a modified “equal size” splitting technique, the implantation differs from the implantation of a standard whole-size graft only in that a slight, 25°-30°, axial rotation of the graft to the right is required $.