Malignant tumors involving a large part of the right lobe with extension into the medial segment of the left lobe are a possible indication for extended right hepatectomy (or trisegmentectomy). Lesions straddling midway between the right and left lobes will require trisegmentectomy. This is a major surgical procedure that requires a highly skilled team trained in this field.
Antibiotics are given and any blood deficiency is corrected. Imaging scans (CT, MRI, or PET-CT) localize the metastases in the liver. Hepatic angiography is not routinely necessary. The lungs must be free of metastases, and studies should not have demonstrated any gross abdominal or colorectal recurrence. The patient must be made aware that a major portion of the liver may need to be excised. Survival of the patient can be anticipated if 20% or more of normal liver tissue remains in the left lobe. If the volume of the remaining live is estimated by three-dimensional reconstruction to be less than 20%, then right portal vein embolization may be performed in order to enhance the residual liver volume through post-embolization hypertrophy of the left lateral segment. If pretreated with greater six cycles of chemotherapy at least 30% of the liver should be retained as the remnant.
A general anesthetic is required. Bilateral large bore IVs are mandatory in anticipation of substantial blood loss. Central venous catheters should be considered standard for major liver surgery and intraoperative monitoring of central venous pressure is helpful. Resistance to large volume resuscitation so as to maintain a CVP <6 greatly reduces blood loss. Once parenchymal transection is complete and large bleeding points addressed, aggressive fluid resuscitation should be undertaken. Continuous arterial pressure monitoring is mandatory.
The patient is placed supine on the operating table with arms extended for access as needed by the anesthesiologist.
The skin of the thorax and abdomen is prepared, since the incision may extend from over the lower sternum to below the umbilicus.
A long right subcostal incision that extends across the left subcostal region provides excellent exposure. Alternatively, a long midline incision starting above the xiphoid and extending below the umbilicus may be used. This procedure requires liberal exposure.
The extent of tumor involvement of both the right lobe and the medial portion of the left lobe is verified by inspection, bimanual palpation, and ultrasonic imaging (figure 1).
The scans are reviewed to reconfirm the location of the lesion and review the vascular supply to the liver. 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. Multiple seeding would cancel the procedure, although some prefer to excise an occasional very small metastasis and proceed with the liver resection.