Perioperative management - Liver resection, left lateral

Resecting procedures in liver surgery are performed for very different diseases. Primarily, liver malignancies, followed by benign tumors, some non-tumorous benign diseases, and living liver donation.

Common indications for liver resection

1. Malignancies

1.1 Primary

• Hepatocellular carcinoma (HCC)
• Cholangiocellular carcinoma (CCC)
• Cystadenocarcinoma

1.2 Metastases

• Colorectal carcinoma
• Non-colorectal non-endocrine malignancies
• Endocrine malignancies

1.3 Direct tumor invasion

• Gallbladder carcinoma
• Colon carcinoma
• Hilar cholangiocarcinoma
• Gastric carcinoma
• Renal carcinoma
• Adrenal carcinoma
• Retroperitoneal/V. cava sarcomas

2. Benign diseases

2.1 Liver tumors

• Adenoma
• Focal nodular hyperplasia
• Hemangioma
• Cystadenoma

2.2 Non-tumorous conditions

• Liver cysts/polycystic liver degeneration (with rapid progression and clinical symptoms such as pressure sensation, pain, dyspnea or infection)
• Parasitic liver cysts (Echinococcus)
• Intrahepatic stones
• Caroli syndrome
• Recurrent liver abscesses
• Liver trauma
• Living liver donation

When determining the indication for liver resection, functional, surgical-technical, and in the case of malignancies, oncological aspects must be considered.

Oncological aspects

The goal of surgical therapy for liver malignancies is R0 resection, i.e., the macro- and microscopically complete tumor resection. Only in symptomatic neuroendocrine liver metastases can an R2 resection also be indicated, as debulking of over 90% of the tumor mass leads to symptom relief ("cytoreductive surgery").

Functional aspects

The most important cause of perioperative mortality after liver resection is liver failure. Risk evaluation is therefore of crucial importance, as therapeutic options for postoperative liver insufficiency are very limited. The occurrence of postoperative liver failure correlates with:

• Size and quality of the remaining liver tissue (cirrhosis, steatosis, fibrosis)
• Presence of cholestasis or cholangitis
• Extent of operative trauma (size of the resection surface, blood loss, duration of any hilar occlusion)
• Postoperative complications (bile leaks, infections, etc.)

If the liver is not pre-damaged and exhibits normal synthesis and excretion function, approximately 25-30% of the functional liver volume is to be regarded as a guideline for the liver parenchyma that must at least be left behind in a resection. However, a prerequisite for this is impeccable arterial and portal venous blood supply as well as unobstructed hepatic venous and biliary drainage of the remaining liver tissue. Routine laboratory parameters (bilirubin, albumin, cholinesterase, and coagulation) provide a rough orientation about the synthesis and excretion function of the liver, but they are of rather subordinate importance for assessing the liver function reserve after extensive resections.

Assessing the functional reserve of a cirrhotic liver is correspondingly more difficult. In addition to the physical general condition and the Child-Pugh score, the severity of portal hypertension is of decisive importance. The most important parameters for sufficient postoperative liver function are normal bilirubin and a hepatic venous pressure gradient of < 10 mmHg. Indicators for the extent of portal hypertension are spleen size, the presence of esophageal varices, and platelet count (Cave: < 100.000/μl). In liver cirrhosis, the extent of resection is therefore limited (wedge excisions, mono- or bisegmentectomies). Only in Child A stage without portal hypertension can a hemihepatectomy be possible in individual cases. Child C cirrhosis represents a contraindication to liver resection. 

Surgical-technical aspects

From functional and surgical-technical aspects, liver resection should always be considered if indicated when at least two sufficiently large liver segments with adequate vascular and biliary supply or drainage can be left behind.

Surgical therapy of benign liver tumors requires a high degree of critical indication determination and results in descending frequency from:

• diagnostic uncertainty despite extensive diagnostics
• clinical symptomatology, e.g., upper abdominal pain, nausea or cholestasis due to tumor size, compression phenomena or significant size growth
• the risk of rupture and bleeding in adenoma with size > 5 cm
• the risk of degeneration

• Advanced liver cirrhosis (Child stage C, possibly also stage B)
• General inoperability of the patient due to underlying diseases; in particular, cardiac risks must be considered
• In advanced liver cirrhosis and a tumor burden in hepatocellular carcinoma with no more than three lesions < 5 cm, liver transplantation should also be considered

History and clinical examination

Laboratory diagnostics

• Preoperative routine laboratory including coagulation and blood group, possibly supplemented depending on the underlying disease
• Liver-specific: Transaminases, bilirubin, alkaline phosphatase, hepatitis serology (abnormal laboratory values do not fundamentally contribute to the differentiation of liver lesions)
• Tumor markers: AFP (Alpha-1-Fetoprotein), TPA (tissue polypeptide antigen), CEA, CA19-9

The AFP is the decisive tumor marker for hepatocellular carcinoma (HCC), in the case of an AFP increase of > 400 μl/l, the presence of an HCC can be assumed in 95% of cases. Caution: an AFP increase can also occur in chronic hepatitis B or C without HCC.

Ultrasound with and without contrast medium (CM)

The assessment of focal liver lesions with native B-mode ultrasound and color-coded duplex ultrasound enables reliable classification in up to 60% of cases (e.g., cysts, typical hemangiomas, focal fat distribution disorders).

HCCs can exhibit various echo patterns. Approximately 75% of HCCs < 2 cm appear as hypoechoic, round structures. The detection of arterial perfusion in color-coded duplex ultrasound is indicative of an HCC. The CM ultrasound is suitable for further diagnostics of unclear liver lesions. To enable differentiation of malignant from benign findings and to make a differential diagnostic classification, the assessment of the vascular architecture and especially the contrast medium dynamics in the tissue is required:

• Benign liver lesions are characterized by persistent contrast enhancement in the portal venous and sinusoidal perfusion phase.

• The HCC typically appears contrast-sonographically as early arterial hyperperfused, i.e., it shows rapid CM influx. Well-differentiated HCCs wash out the CM only slowly, moderately to poorly differentiated ones wash it out quickly

• The intrahepatic CCC shows no characteristic behavior in ultrasound and is thus hardly clearly distinguishable sonographically from other intrahepatic space-occupying lesions. In extrahepatic location, ultrasound provides indirect clues, for example, dilatation of the bile ducts

Contrast-enhanced CT

The performance of a contrast-enhanced CT with a native, arterial, and portal venous phase is considered the standard today in the diagnostics of HCC. In the arterial phase, the HCC appears as a hyperdense space-occupying lesion, whereas it presents as iso- or hypodense in the portal venous phase.

Magnetic resonance imaging

An MRI should be performed in cases of unclear CT findings and especially in suspected HCC.

The intrahepatic CCC presents nonspecifically in MRI. An important diagnostic tool for extrahepatic CCCs is MR cholangiopancreatography (MRCP), which allows better assessment of suprahilar tumor extension than ERCP.

Positron emission tomography in combination with CT

The “18-F-fluorodeoxyglucose positron emission tomography”, abbreviated FDG-PET, is increasingly used in combination with CT in diagnostics and therapy monitoring of solid malignancies. The method is based on increased accumulation of FDG in tumor tissues.

• In HCC, increased accumulation indicates a low degree of differentiation, which is associated with a poorer prognosis. The absence of FDG accumulation indicates a differentiated tumor.

• In the diagnostics of CCC, FDG-PET plays an important role in the detection of locoregional lymph nodes as well as in the detection of distant metastases, where the method is clearly superior to CT alone.

• A PET-CT is also considered when complete staging for extrahepatic primary tumors is required.

Endoscopic retrograde cholangiopancreatography

• The ERCP plays a rather subordinate role in the diagnostics of an HCC. Therapeutically, stent insertion using ERCP is used in tumor obstruction of the common hepatic duct.
• In CCC, ERCP is used both diagnostically and therapeutically. In extrahepatic CCCs, the tumor can be very well localized and histological confirmation can be obtained. Brush cytology, forceps biopsy, and bile aspiration are available for this, whereby sensitivity can be increased by combining the mentioned methods.

Liver biopsy

In suspected HCC, there is an indication for biopsy under certain conditions. This should be performed according to the guidelines of the American Association for the Study of Liver Diseases (AASLD) in:

• Intrahepatic space-occupying lesions between 1 and 2 cm in diameter
• Absence of clear characteristics of the space-occupying lesion in imaging procedures

An intrahepatic tumor with a diameter > 2 cm should be biopsied if the space-occupying lesion does not present typically in imaging procedures and the AFP is < 200 ng/ml.

• In case of increased cardiopulmonary risk, clarification of the surgical risk through further diagnostics (stress ECG, heart echo, coronary angiography, spirometry)
• Sufficient intensive care capacity for high-risk patients
• Provide 4-6 RBCs, if necessary FFP or PCs
• Perioperative antibiotic administration as single-shot, e.g. 2nd generation cephalosporin + metronidazole 30 minutes before skin incision

A special preparation of the patient is generally not required, enema recommended.

For the patient's informed consent, standardized informed consent forms should be used; these also include corresponding anatomical drawings in which the findings can be entered. Alternatives and additional treatment options should be explained, in particular, interventional measures including intraoperative radiofrequency ablation or extensions of the primary procedure should always be discussed.

Before every planned liver resection, the patient should also be informed about a cholecystectomy.

General Risks

• Bleeding
• Postoperative bleeding
• Hematoma
• Necessity of transfusions with corresponding transfusion risks
• Thromboembolism
• Wound infection
• Abscess
• Injury to adjacent organs/structures (stomach, esophagus, spleen, diaphragm)
• Burst abdomen
• Incisional hernia
• Subsequent intervention
• Mortality

Specific Risks

• Liver parenchyma necrosis
• Bile fistula
• Bilioma
• Hemobilia
• Biliary peritonitis
• Bile duct stenosis
• Pleural effusion
• Air embolism (due to unintended or unnoticed opening of hepatic veins)
• Portal vein thrombosis
• Hepatic artery thrombosis
• Chronic liver insufficiency
• Liver insufficiency with hepatic coma
• Tumor recurrence