In Table 25.3, different measures that need to be taken into account to prevent the risk of post-HR liver insufficiency are described.

One important factor is the pre-existence of liver parenchyma diseases, which could limit the extension of HRs and the patient’s possibility to tolerate an HR. The presence of cirrhosis, fibrosis, steatosis and/or chemotherapy associated hepatic toxicity are factors that the surgeon has to assess prior to surgery. These different conditions determine an impaired hepatic functional reserve and a minor hepatic regeneration rate; with an increased morbidity, mortality and post-HR liver insufficiency rate.

In cirrhotic patients, the Child Pugh’s classification is important to determine liver function and to select and categorize patients. In Child Pugh A patients, HR can be performed and a 50% of the total liver parenchyma can be resected; in Child B patients up to a 25% and in Child C HR is contraindicated and other procedures should be considered (Transarterial chemoembolization [TACE], portal vein embolization [PVE], radiofrequency ablation [RFA]) [6].

The Model for End-stage Liver Disease (MELD) score is a mathematical model described initially to evaluate the short-term results of the Transjugular Intrahepatic Portal Shunt (TIPS) placement. Posteriorly, the MELD score was used to determine priority for patients on the waiting list for liver transplantation. Most recently, the MELD is also used as a prognostic factor to develop post-HR liver insufficiency. Different series showed that, in the preoperative assessment of cirrhotic patient undergoing an HR, a high MELD score presented higher risk to develop liver insufficiency (using a cut off of nine points: liver insufficiency 0% vs. 29%, and using 11 points: 0% vs. 37.5%). It has also been showed that and initial MELD >11 points prior to HR, with an increasing value between the 3rd and 5th postoperative day, is an independent factor for the development of post-HR liver insufficiency.

There are different tests to globally assess the liver function (indocyanine green clearance test, Limax test, MEGX, etc.) that allow stratifying patient’s risk for liver insufficiency. However, they are not available worldwide; in this case patient’s clinical history, symptoms, laboratory tests and imaging should be carefully evaluated prior to HR.

In all patients undergoing HRs, a volumetry of the Future Liver Remnant (FLR) should be carried out. The FLR volume has to be assessed according to patient’s weight or body surface area and the Total Liver Volume (TLV). CT-scan and MR can be used to precisely determine the FLR volume. The total liver volume can be also calculated with the same studies or using any of the available formula, such as:

The most important ratio is between the FLR and the TLV (FLR/TLV) and patient’s weight (FLR/weight). It is recommended to preserve a 25% of the TLV in patients with normal livers, >30% in patients with diseased livers (steatosis, chemotoxicity, etc.) and >40% in cirrhotic patients.

The accepted ratio between FLR/weight is 0.8. This ratio is widely used in living related donor liver transplantation. The advantage of this ratio is that is independent from the resected volume. It is also useful to preoperatively determine, in those patients who will undergo an extended HR, who will need a procedure to increase or to preserve the FLR.

In those cases in which the pre- or intraoperative assessment determines an insufficient FLR, portal vein occlusion (either by ligation or PVE) should be indicated. With these techniques, a degree of hypertrophy of 10–40% in 4–8 weeks is achieved and HR can be safely performed afterwards. However, a group of patients cannot be resected using these strategies due to an insufficient hypertrophy or due to an accelerated tumor growth. For this reason, it is important to rule out (before PVE) the presence of tumor in the FLR.

There is a new surgical strategy to increase the FLR volume (reducing the post HR liver insufficiency) denominated Associated Liver Partition and Portal vein occlusion for Staged hepatectomy (ALPPS). This two-staged surgery consists in a first procedure where the tumors from the FLR are removed, the hepatic transection is performed and the portal vein is occluded; and a second procedure where the HR is performed, usually 7–10 days after the first one. With this new strategy, a faster and greater FLR hypertrophy is achieved (up to a 200% in 7–10 days). When the ALPPS procedure is carried out, the number of R0 patients is higher than simple portal occlusion (in an intention to treat analysis). Another advantage is that in ALPPS, due to the possibility to resect the nodules in the FLR, patients with bilobar and multiple tumors are amenable to undergo surgery. However, as ALPPS is a new procedure, further studies on oncological long-term outcomes are needed.

When a HR is performed, the surgeon should try to do non-anatomical resections and to spare as much parenchyma as possible (local and multiple resections vs. extended resections). During resection, Pringle’s maneuver and low central venous pressure (<5 cm H₂O) are necessary to decrease the blood loss.

There is no consensus on the algorithm to treat patients with obstructive jaundice in proximal biliary tumors that will need a HR. There is no evidence whether the patient should be percutaneously drained or not (prior to surgery). Patients with cholangitis, coagulopathy, malnutrition, or patients who will undergo PVE, percutaneous transhepatic biliary drainage (PTBD) is mandatory. However, there is no evidence to routinely perform a PTBD based only in bilirubin levels [5].