Perioperative management - Left lateral liver resection, laparoscopic

The indication for laparoscopic liver resection depends less on the tumor entity but rather on the meaningful feasibility of the laparoscopic procedure. In turn, feasibility is governed primarily by the anatomical and functional technical parameters some of which also apply to conventional open liver resections.

Functional technical parameters

• Is R0 resection feasible?
• Will the resection leave a volume large enough for residual liver function?
• Number of previous (hepatic) operations (adhesions)?
• Reoperation after previous open liver surgery?

Anatomical parameters

• Tumor size?
• Number of lesions?
• Segmental location of the lesion(s)?

The so-called “laparoscopic segments II, III, IVB, V, and VI according to Couinaud” are particularly amenable to laparoscopic resection of benign and malignant tumors.

To date, laparoscopic resection of segments II and III can be considered state of the art in centers, since often the parenchymal bridge to segment IV is narrow and the hilar blood supply of the liver is easily accessible. Usually, Pringle’s maneuver is not required.

Because the limited view of the surgeon in laparoscopic liver resections markedly impacts on their feasibility, the line of resection should be linear and course in one plane only. Unlike in open surgery, during minimally invasive procedures it is hardly possible to alter the line of resection: For this reason, the resection strategy must be defined beforehand and may only be modified slightly following intraoperative ultrasonography.

Considering the aspects above, benign lesions such as adenomas, focal nodular, hyperplasia and symptomatic hemangiomas are good indications for laparoscopic liver resections. Malignant tumors primarily comprise liver metastases in colorectal cancer, but also hepatocellular carcinoma and metastases in breast cancer. In terms of technical feasibility this includes wedge resections, segment resections and left lateral resections.

Malignancies must meet the following conditions:

• Peripheral solitary tumor, maximum size 5cm or, in tumors >5cm, located in segment II/II
• Tumor located in segment II, III, IVb, V or VI
• No. of masses ≦3, all located in same lobe
• R0 resection feasible with one line of resection (left lateral resection, left/right hemihepatectomy)
• Large enough distance between lesion and central structures (inferior vena cava, hepatic veins, pedicle = branch from portal vein, hepatic artery and common hepatic duct)
• No previous hepatic surgery
• No concomitant procedures planned, e.g., colon resection, incisional hernia repair etc.

However, laparoscopic liver resection is indicated not just in tumors but is increasingly favored in harvesting hepatic grafts from living donors.

• Marked cirrhosis of the liver (Child C, possibly also stage B)
• Patient generally inoperable because of underlying disease; assessment must include cardiac risks in particular
• Significant adhesions, particularly in the upper quadrants
• Tumor invasion of adjacent tissues
• Large tumors which may be breached by small grasping forceps, thereby allowing possible tumor cell spread
• In advanced hepatic cirrhosis and in hepatocellular cancer with a tumor load of no more than three masses <5cm liver transplantation should also be considered

Lesions in the poster and superior parts of the liver, the so-called “non-laparoscopic segments I, IVa and VIII, are not contraindicated per se for minimally invasive procedures, but pose extreme technical challenges.

In the same way, patients requiring extensive oncological lymph node resection (e.g., in CCC) or where resectability is uncertain from the very beginning, are also poor candidates for this type of surgery.

Apart from the increased risk of hemorrhage in lesions close to vessels or the hilum, there is also the increased risk of air embolism once larger hepatic veins are injured.

Patient history and clinical examination

Lab studies

• Standard preoperative lab study with coagulation panel, blood group and possibly, depending on the underlying disease, other studies as well
• Specific liver parameters: Transaminases, bilirubin, alkaline phosphatase, hepatitis serology (pathologic lab parameters do not contribute significantly to the differential diagnosis of liver lesions)
• Tumor markers: AFP (alpha-1 fetoprotein), TPA (tissue polypeptide antigen), CEA, CA19-9

AFP is the definitive tumor marker in hepatocellular carcinoma (HCC); the presence of HCC may be assumed in 95% of cases with AFP levels >400μL/L. Beware: Chronic hepatitis B and C may also elevate the AFP level without HCC being present.

Contrast- and non-contrast-enhanced ultrasonography (CEUS/NCEUS)

Assessment of focal hepatic lesions with non-contrast-enhanced B-mode ultrasonography and color-coded Doppler ultrasound allows reliable classification of liver lesions in up to 60% of patients (e.g., cysts, typical hemangiomas, focal fatty infiltration/sparing).

The echo texture in HCC may vary. About 75% of HCCs appear as hypoechoic round masses. Demonstration of arterial blood flow in color-coded Doppler ultrasonography is indicative of HCC. CEUS lends itself for further diagnostic work-up of liver lesions with ambiguous findings on non-contrast-enhanced ultrasonography. For CEUS to differentiate between benign and malignant neoplasias and allow differential diagnostic classification, it is necessary to assess vessel geometry and particularly the dynamics of the contrast agent.

• Benign liver lesions are characterized by sustained contrast during the portocaval and sinusoidal perfusion phase.
• CEUS in HCC typically demonstrates hyperperfusion during the early arterial phase, i.e., there is rapid contrast agent wash-in. In well differentiated HCC the contrast agent is only washed out slowly, while in moderately/poorly differentiated hepatic cancer the contrast agent is washed out rapidly.
• Since intrahepatic CCC does not demonstrate characteristic behavior on ultrasonography, this modality cannot differentiate CCC from other intrahepatic masses. Ultrasonography of extrahepatic lesions yields indirect information such as dilation of the biliary tree.
• In many cases Doppler ultrasonography can shed light on tumor induced vascular invasion and compression, especially when it involves the portal venous system.

Contrast-enhanced CT

Today, contrast-enhanced CT studies with non-enhanced, arterial and portocaval phases are regarded standard in the diagnostic work-up of HCC. During the arterial phase HCC demonstrates as a hyperdense mass while it becomes isodense or hypodense during the portocaval phase.

Magnetic resonance imaging

MRI should be performed whenever CT findings are ambiguous, and particularly when HCC is suspected.

On MRI intrahepatic CCC appears as a nonspecific finding. One important diagnostic modality in the work-up of extrahepatic CCC is MR-cholangiopancreatography (MRCP) which allows better assessment of suprahilar tumor spread than ERCP.

Combined positron emission tomography and CT

Combined with CT imaging “18-F-fluorodesoxyglucose positron emissions tomography“, better known as FDG-PET, has seen increasing application in the diagnostic work-up and treatment monitoring of solid malignancies. The principle behind this modality is the increased enhancement of FDG in tumor tissue.

Increased enhancement of HCC is indicative of a low degree of differentiation and thus poorer prognosis. Lack of FDG enhancement denotes a differentiated tumor.

FDG-PET plays an important role in the diagnostic work-up of locoregional lymph nodes in CCC and in the detection of distant metastases; the modality is markedly better in this than computerized tomography alone.

PET-CET may also be considered whenever extrahepatic primaries demand full-scale diagnostic work-up.

Endoscopic retrograde cholangiopancreatography (ERCP)

ERCP plays a secondary role in the HCC diagnostics. Therapeutic indications include ERCP stenting in tumor obstruction of the common bile duct.

ERCP In CCC is employed as both diagnostic and therapeutic modality. Proximal and distal tumor locations are easily identified, and ERCP also allows specimen collection for cytology.

Liver biopsy

Under certain conditions liver biopsy may be indicated in HCC. According to the American Association for the Study of Liver Diseases (AASLD) this should be performed in:

• Intrahepatic masses between 1cm and 2cm in diameter.
• Mass without definitive characteristics on imaging.

Whenever imaging yields findings characteristic for HCC biopsy is not required.

Intrahepatic tumors with a diameter >2cm should be biopsied if the mass does not demonstrate characteristic behavior on imaging and the AFP level is <200ng/mL. In extrahepatic CCC histology of specimens obtained by ERCP will confirm the diagnosis. This includes brush cytology, forceps biopsy and bile aspiration; combining these modalities will improve sensitivity.

• In case of increased cardiovascular risk, work up the risk of surgery by further diagnostic studies (exercise ECG, echocardiography, coronary angiography, pulmonary function testing)
• For patients at risk sufficient bed capacity on the ICU
• Allocate 4-6 PRBCs, possibly FFP and PRP
• Preoperative single-shot 2^ndgeneration cephalosporin + metronidazole half an hour before skin incision

In general, the patient does not require special preparation, although an enema is recommended.

When obtaining informed consent, the standard forms for patient information should be used because these include pertinent anatomical figures where the patient’s findings can be entered. Informed consent must include a discussion of the alternatives and possible additional treatment options; in particular, it should involve explanation of interventional measures including intraoperative radio frequency ablation and the possibility of broadening the original planned procedure.

Obtaining informed consent before a liver resection also must include information on possible cholecystectomy, and in laparoscopic procedure the possibility of conversion to an open procedure.

General risks

• Bleeding
• Secondary bleeding
• Necessity of blood transfusions with corresponding transfusion risks
• Thromboembolism
• Wound infection
• Abscess
• Injury to adjacent organs/structures (stomach, esophagus, spleen, diaphragm)
• Burst abdomen
• Incisional hernia
• Redo procedure
• Death

Special risks

• Hepatic parenchymal necrosis
• Biliary fistula
• Bilioma
• Hemobilia
• Biliary peritonitis
• Bile duct stenosis
• Pleural effusion
• Air embolism (when hepatic veins are opened accidentally/unnoticed)
• Portal vein thrombosis
• Hepatic artery thrombosis
• Chronic liver failure
• Liver failure with hepatic coma
• Tumor recurrence