The abdominal cavity is carefully inspected for evidence of pinpoint or large metastases in the pouch of Douglas, colon, mesentery, small bowel, omentum, or peritoneum. Any suspicious areas are excised for frozen section examination. The liver surface is inspected for evidence of metastases, followed by bimanual palpation to verify the diagnostic procedures suggesting metastasis in the left lobe of the liver. Metastases deep within the left lobe rather than superficially are best evaluated with a hand-held ultrasound probe. Metastases readily seen on the surface of the left lobe can be locally excised with a 1-cm margin. Metastases near the inferior liver margin can be removed by wedge incision.
The line of transection is outlined extending into the bed of the gallbladder. The left hepatic vein is the major vessel in the dome of the left lobe (figure 1). When the tumor is located deep in the left lobe, the left lobe is mobilized by division of the falciform and coronary ligaments (figure 2).
Since the median margin of the left lobe extends into the gallbladder bed, a cholecystectomy is performed after ligation and division of the cystic artery and cystic duct. Removal of the gallbladder improves the exposure for the identification of the major hepatic ducts and vessels to be divided and ligated (figure 3).
The hilar plate is incised and the bridge of liver parenchyma overlying the umbilical fissure, if present, is divided to enhance the exposure of the structures entering the left lobe. The left hepatic duct is freed up for the sufficient distance to allow passage of a right-angle clamp. This is done carefully so as to not injure any aberrant ducts which may be inserting from the right lobe of the liver. The duct is doubly ligated and then divided (figure 4). The division of the left hepatic duct exposes the underlying left hepatic artery, which usually arises from the proper hepatic artery. The surgeon should seek out the presence of aberrant arterial anatomy. The most common variation is the abnormal origin of the left hepatic artery from the left gastric artery. In this case, the left hepatic artery will run through the cranial portion of the hepatogastric ligament (pars densa) in the lesser omentum.
The left hepatic artery is gently freed up a short distance from its point of origin and doubly tied with 2-0 nonabsorbable sutures proximally (figure 5). The area of the arterial bifurcation is inspected to be certain the blood supply to the right lobe is intact and then the artery is divided between the ligatures.
The left branch of the portal vein is now exposed. The area of the bifurcation of the portal vein is carefully freed up and the left branch mobilized for a sufficient distance to permit the application of a pair of curved Cooley vascular clamps without compromising the bifurcation of the portal vein. The left branch of the portal vein is divided a short distance beyond the clamps to permit closure of the proximal end of the branch of the portal vein with a continuous horizontal mattress suture of 4-0 synthetic nonabsorbable suture that is then run back as an over-and-over suture after the method of Cameron (figure 6). If the caudate (Segment 1) is to be preserved, the surgeon must take care to divide the left portal vein distal to the caudate branch at the base of the umbilical fissure. Alternatively, the portal vein can be divided using a vascular stapler. A final inspection determines that the blood supply to the right lobe is functioning normally.
The blood loss should be lessened if the left hepatic vein is ligated before the liver tissue is divided. The left hepatic vein is freed of liver substance until a sufficient distance is gained to permit the application of a pair of long curved Cooley vascular clamps. The left lateral segment (Segments 2 and 3) can be lifted to expose the ligamentum venosum. When this is divided at its most cranial extent, a window is opened along the inferior border of the left hepatic vein as well as the middle hepatic vein depending upon their point of convergence. The path of the middle hepatic vein must be visualized as separate from the left hepatic vein. The end of the vein projecting beyond the clamps is closed first with a continuous mattress suture and then back with an over-and-over suture (figure 7). The clamps are removed and a final check is made that the proximal caval end of the divided left hepatic vein is secure. A vascular stapler may be utilized to control the left hepatic vein.
A line of demarcation between the right and left lobes develops after the portal structures have been divided. This line tends to curve in a concave manner to the left until the dome of the liver is reached. Ultrasonic dissecting instruments are available for dividing (figure 8) and aspirating the liver tissue with easier exposure for ligation of the larger ducts and vessels, especially the venous branches of the median hepatic vein. Alternatively, an electrocautery or other energy device may be used to divide the liver parenchyma or an endoscopic GIA stapler can be used once the internal vascular anatomy is clearly definedsonographically.
Some have used deeply placed absorbable mattress sutures, starting at the anterior lower liver edge and progressing upward along the line of demarcation. The liver tissue should be compressed with the capsule intact and not crushed. The liver may be divided in a variety of ways but ligatures or clips must be applied to the larger vessels or bile ducts on the cut surface of the right lobe. Clips are usually adequate on the left lobe side, which is to be resected. The deeply placed interrupted sutures near the dome of the liver do not go completely through all the liver tissue in the region of the dome.
The raw surface of the right lobe is carefully inspected for bleeding points as well as for bile leakage, which may require a suture ligature (figure 9). Surface coagulation may be obtained with an argon beam electrocautery system. This may lessen the need for application of various hemostatic materials to the cut surface of the residual liver. The omentum can be mobilized and anchored over the divided surface of the right lobe. Closed-system Silastic suction drains can be considered if there is concern for bile leakage.
Resuscitation should be initiated by the anesthesiologist until normal liver turgor has returned while the abdomen is still open as small bleeding points may develop.