The successful local excision of benign liver tumors has fostered a more aggressive surgical approach to the excision of hepatic metastases of colorectal malignancies. During the first 2 or more years after the removal of a colorectal tumor, carcinoembryonic antigen (CEA) levels are measured every 3 months. When the CEA level begins to rise, recurrence must be considered. In the absence of proof of metastasis or recurrence in the rectum, colon, lung, or peritoneal cavity, a search is made for hepatic metastases. Imaging by CT, MRI, or PET scans is performed. Hepatic angiography is usually not necessary and has been replaced by CT or MRI with coronal reconstruction to define regional anatomy. Any evidence of liver metastases requires an evaluation of the number, size, and location of the metastases. It is hoped that none or only one or two solitary metastases will be verified in locations easily accessible to the surgeon. The age and general condition of the patient, as well as the size, number, and locations of metastases, are considered in making a decision to attempt curative resection. Given the sensitivity of modern imaging, “blind” abdominal exploration for rising CEA in the absence of radiographic abnormalities is discouraged. The patient should be fully informed and should participate in making a decision to reoperate. The patient should be made aware that a major portion of the liver may need to be excised. A residual of 20 percent or more of normal liver tissue remaining in the left lobe is essential for survival.
Perioperative antibiotics are given, and any blood deficiency is corrected. Studies should have ruled out metastases to the lungs and general peritoneal cavity insofar as possible.
A general anesthetic that has minimal potential to harm the liver is required.
The patient is placed flat on the table in a modest reverse Trendelenburg position.
The skin of the thorax and abdomen is prepared, since the incision may extend from over the lower sternum to below the umbilicus. Appropriate catheters are placed to provide ready access for the administration of blood, fluids, and medications and central venous pressures should be monitored.
A long right subcostal incision that extends across the midline as a bilateral subcostal incision with a midline extension to the xiphoid provides excellent exposure. Alternatively, a liberal midline incision extending from well above the xiphoid to or below the umbilicus may be used.
The extent of tumor involvement in the right lobe is verified by inspection of a bimanual palpation (Figure 1). The angiograms and imaging scans available in the operative room are reviewed to reconfirm the location of the lesion. In patients with colorectal metastases, it is essential to palpate and visualize the pouch of Douglas for metastases as well as the entire colon, small bowel, mesentery, omentum, and peritoneum. If there is suspicion of intraperitoneal spread, many surgeons will first view the peritoneal space with a diagnostic laparoscopy. Multiple seeding would cancel the procedure, although some prefer to excise or cauterize an occasional small metastasis and proceed with the liver section. The extent and location of all hepatic metastases is noted using ultrasound directly on the liver surface. Understanding the relationship of lesions in question with major vascular structures is essential to minimizing blood loss.
The liver is mobilized by dividing the falciform and right triangular ligaments as well as freeing the liver posteriorly from the diaphragm (Figure 2). Some surgeons prefer not to cut the triangular ligament, as it provides stabilization and support for the left lobe. The cystic artery and cystic duct are ligated, and the gallbladder removed, since the gallbladder bed is the dividing line between the left and right lobes of the liver. The right hepatic duct is easier to visualize after removal of the gallbladder. A clear exposure of the right hepatic duct is essential to avoid interference with the area of bifurcation supplying the left hepatic duct.
The right hepatic duct is divided under clear vision and double-sutured with one or more transfixing sutures (Figure 3). After the right duct is divided, the variable arterial supply is exposed. The surgeon should at this time review imaging, alert to the possibility that the right hepatic artery may arise from the superior mesenteric artery. The right hepatic artery is ligated and divided (Figure 4). The left hepatic artery must be visualized to be certain it has not been obstructed or compromised in any way. Variations in the arterial blood supply between the right and left lobes of the liver should be remembered by the surgeon during the dissection in this area.
The right and left branches of the portal vein are clearly exposed before the right branch of the portal vein is doubly clamped with straight Cooley vascular clamps. Both ends of the portal vein are oversewn with a continuous 4-0 nonabsorbable suture. For additional security, the end of the proximal vein may be doubly closed with horizontal mattress sutures (Figure 5A). Alternatively, the right portal vein may be divided using a vascular stapler Figure 5B).
Special attention must be given to taking down the hilar plate, followed by freeing up the left hepatic duct, the left hepatic artery, and the left branch of the portal vein from the undersurface of the overlying liver. These vessels enter the liver near the falciform ligament. After the vessels and other structures are gently dissected away from the liver, a logical area is exposed for the division between the right lobe and the medial segment of the left lobe of the liver.