Liver surgeryDr.Muayad Abass Fadhel

Surgery department Medical college –Baghdad

university

Al-Madena copy

The liver is the largest organ in the body, weighing 1.5 kg in the average 70-kg man.

The liver parenchyma is entirely covered bya thin capsule and by visceral peritoneum on all

but the posterior surface of the liver, termed the ‘bare area’.

The liver is divided into a large right lobe, which constitutes three-quarters of the

liver parenchyma, and a smaller left lobe. Surgical resection of these lobes would be termed a right or left lobectomy.

Anatomy

left triangular ligament The right triangular ligament falciform ligament (remnant of the umbilical vein), which runs from the umbilicus to the

liver between them right and left lobes, passing into the interlobar fissure.

Ligaments and peritoneal reflections

The blood supply to the liver is unique, 80% being derived from the portal vein and 20% from the hepatic artery.

The arterial blood supply in most individuals is derived from the coeliac trunk of the aorta, where the hepatic artery arises along with the splenic artery. After supplying the gastroduodenal artery, it branches at a very variable level to produce the right and left hepatic arteries.

The blood supply to the right lobe of the liver may be partly or completely supplied by a right hepatic artery arising from the superior mesenteric artery

Similarly, the arterial blood supply to the left lobe of the liver may be derived from the coeliac trunk via its left gastric branch.

Liver blood supply

The hepatic artery, portal vein and bile duct are present within the free edge of the lesser omentum or the ‘hepatoduodenal ligament’.

The usual anatomical relationship of these structures is for the bile duct to be within the free edge, the hepatic artery to be above and medial, and the portal vein to lie posteriorly.

Within this ligament, the common hepatic duct is joined by the cystic duct at a varying level to form the common bile duct.

The common hepatic artery branches at a variable level within the ligament to form two, or often three, main arterial branches to the liver. The right hepatic artery often crosses the bile duct either anteriorly or posteriorly before giving rise to the cystic artery.

Multiple small hepatic arterial branches provide blood to the bile duct, principally from the right hepatic artery.

The portal vein arises from the confluence of the splenic vein and the superior mesenteric vein behind the neck of thepancreas. It has some important tributaries, including the left gastric vein which joins just above the pancreas.

The venous drainage of the liver is via the hepatic veins into the IVC.

Venous drainage of the liver

The inferior hepatic veins are short vessels that pass directly between the liver parenchyma and the anterior wall of the IVC.

The major venous drainage is through three large veins that join the IVC immediately below the diaphragm. .

The right hepatic vein can be exposed fully outside the liver

, but the middle and left veins usually join within the liver parenchyma.

■ Maintaining core body temperature ■ pH balance and correction of lactic acidosis ■ Synthesis of clotting factors ■ Glucose metabolism, glycolysis and

gluconeogenesis ■ Urea formation from protein catabolism ■ Bilirubin formation from haemoglobin

degradation ■ Drug and hormone metabolism ■ Removal of gut endotoxins and foreign

antigens

Main functions of the liver

USED TO Detect presence of liver disease Distinguish among different types of liver

diseases Gauge the extent of known liver damage Follow the response of treatment

Liver function test

Tests based on detoxification & excretory functions Serum bilirubin Urine bilirubin Blood ammonia Serum enzymes : AST, ALT, GGT,

5’Nucleotidase,ALP

Tests that measure Biosynthetic function of liver Serum Albumin Serum Globulins PT ,INR

Bilirubin is synthesised in the liver and excreted in the bile. Increased levels may be associated with: 1-increased haemoglobin breakdown

2- hepatocellular dysfunction resulting in impaired bilirubin transport and excretion, or

3- biliary obstruction.

Liver function test

Serum Bilirubin A break down product of porphyrin ring of

heme – containing proteins , found in blood in 2 fractions – conj/unconj Conjugated : water soluble , so excreted by

kidneys Unconjugated : insoluble in water , bound to

albumin in blood About 300 mg of bilirubin is formed per day

Serum Bilirubin Normal total serum bilirubin: 0.3 – 1.3 mg/dl Direct/conjugated bilirubin: 0.1 – 0.4 mg/dl Indirect/unconjugated bilirubin: 0.2 –

0.9mg/dl

Urine Bilirubin Unconj bilirubin – binds to albumin in serum

& not filtered by kidneys Any bilirubin in urine is conj.bilirubin, the

presence of bilirubinuria – liver ds. In acute viral hepatitis – bilirubin appears in

urine before urobilinogen and jaundice. Undiagnosed febrile illness with

bilirubinuria - hepatitis

Blood Ammonia Produced by normal protein metabolism by

intestinal bacteria in colon Liver – detoxification – converting into urea

which is excreted by kidneys. Pts with advanced liver diseases contributes

to hyperammonemia. .

The transaminase levels [aspartate transaminase (AST) and alanine transaminase (ALT)] reflect acute hepatocellular damage, as does the gamma-glutamyl transpeptidase (GGT) level, which may be used to detect the liver injury associated with acute alcohol ingestion.

The synthetic functions of the liver are reflected in the ability to synthesise proteins (albumin level) and clotting factors (prothrombin time).

The standard method of monitoring liver function in patients with chronic liver disease is serial measurement of bilirubin, albumin and prothrombin time.

Alanine transaminase(SGPT) Normal : 7 – 41 U/L ALT found primarily in liver.

Aspartate transaminase (SGOT) Normal – 12 – 38U/L AST – liver , cardiac muscles, skeletal muscle,

kidneys, brain, pancreas, lungs, leucocytes, RBC in decreasing order.

Serum Enzymes – that reflect cholestasis 2 enzymes Alkaline Phosphatase 5’Nucleotidase

Alkaline Phosphatase

< 3 fold rise can be seen in many types of liver ds ( infective, alcoholic hepatitis, HCC )

>4 times – cholestatic liver ds, infiltrative liver ds, bone ds with rapid bone turnover .

In absence of jaundice/elevated aminotransferases – elevated ALP of liver – often early cholestasis and less often infiltrative hepatic ds.

Isolated rise of ALP – hodgkins lymphoma, diabetes hyperthyroidism CHF amyloidosis inf.bowel ds Not helpful in diff b/w intrahep & extrahep

cholestasis

5’Nucleotidase Normal :2 – 10 U/L Moderate elevated – hepatitis Highly elevated – biliary obs Unlike ALP , the level is unrelated with

osteoblastic activity ie.. Unaffected by bone ds.

Test Normal range Bilirubin 5–17 μmol l–1 Alkaline phosphatase (ALP) 35–130 IU l–1 Aspartate transaminase (AST) 5–40 IU l–1 Alanine transaminase (ALT) 5–40 IU l–1 Gamma-glutamyl transpeptidase (GGT) 10–

48 IU l–1 Albumin 35–50 g l–1 Prothrombin time (PT) 12–16 s

Imaging of the liver

This is the first-line test owing to its safety and availability.

It is entirely operator dependent. It is useful for determining bile duct dilatation, the

presence of gallstones and the presence of liver tumours.

Doppler ultrasound allows flow in the hepatic artery, portal vein and hepatic veins to be assessed. In some countries, it is used as a screening test for the

development of primary liver cancers in a high-risk population.

Ultrasound is useful in guiding the percutaneous biopsy of a liver lesion

Ultrasound

The current ‘gold standard’ for liver imaging is triple-phase, multislice, spiral computerised tomography (CT).

This provides fine detail of liver lesions down to less than 1 cm in diameter and gives information on their nature .

Oral contrast enhancement allows visualisation of the stomach and duodenum in relation to the liver hilum.

The early arterial phase of the intravenous contrast vascular enhancement is particularly useful for detecting small liver cancers, owing to their preferential arterial blood supply.

Computerised tomography

The venous phase maps the branches of the portal vein within the liver and the drainage via the hepatic veins.

Inflammatory liver lesions often exhibit rim enhancement with intravenous contrast, whereas the common haemangioma characteristically shows late venous enhancement.

The density of any liver lesion can be measured, which can be useful in establishing the presence of a cystic lesion.

Magnetic resonance imaging (MRI) would appear to be as effective an imaging modality as CT in the majority of patients with liver disease.

It does, however, offer several advantages. First, the use of iodine-containing intravenous

contrast agents is precluded in many patients because of a history of allergy.Those patients should be offered MRI rather than contrast CT.

Second, magnetic resonance cholangiopancreatography (MRCP) provides excellent quality, non-invasive imaging of the biliary tract.

Magnetic resonance imaging

It is useful for diagnostic questions when ERCP has failed or is impossible due to previous surgery.

Magnetic resonance angiography (MRA) similarly provides high-quality images of the hepatic artery and portal vein, without the need for arterial cannulation.

It is used as an alternative to selective hepatic angiography for diagnosis.

It is particularly useful in patients with chronic liver disease and a coagulopathy in whom the patency of the portal vein and its branches is in question.

ERCP is required in patients with obstructive jaundice who cannot undergo MRCP because of claustrophobia

or where an endoscopic intervention is anticipated based on previous imaging [endoscopic removal of common bile duct (CBD) stones or insertion of a palliative biliary tract stent].

Endoscopic retrogradecholangiopancreatography

A preoperative check of coagulation is essential, along with prophylactic antibiotics and an explanation of the main complications, which include pancreatitis, cholangitis and bleeding or perforation of the duodenum related to sphincterotomy.

PTC is indicated where endoscopic cholangiography has failed or is impossible, e.g. in patients with previous pancreatoduodenectomy or Pólya gastrectomy.

It is often required in patients with hilar bile duct tumours to guide external drainage of the bile ducts to relieve jaundice and to direct stent insertion.

Percutaneous transhepatic cholangiography

Selective visceral angiography may be required for diagnostic purposes but, with improving cross-sectional imaging (CT and MR angiography), is usually employed for therapeutic intervention.

Prior to liver resection, it may be used to visualise the anatomy of the hepatic artery to the right and left sides of the liver and to confirm patency or tumour involvement of the portal vein.

Angiography

It can also provide additional information on the nature of a liver nodule, as primary liver tumours have a well developed arterial blood supply.

Therapeutic interventions include the occlusion of arteriovenous malformations, the embolisation of bleeding sites in the liver and the treatment of liver tumours (transarterial embolisation, TAE).

Radioisotope scanning can provide diagnostic information that cannot be obtained by other imaging modalities.

Iodoida is a technetium-99m (99mTc)-labelled radionuclide that is administered

intravenously, removed from the circulation by the liver,

processed by hepatocytes and excreted in the bile.

Imaging under a gamma camera allows its uptake and excretion to be monitored in real time.

Nuclear medicine scanning

These data are particularly useful when a bile leak or biliary obstruction is suspected and a non-invasive screening test is required.

A sulphur colloid liver scan allows Kupffer cell activity in the liver to be determined.

This may be particularly useful to confirm the nature of a liver lesion;

adenomas and haemangiomas lack Kupffer cells and hence show no uptake of sulphur colloid.

Laparoscopy is useful for the staging of hepatopancreatobiliary cancers.

Lesions overlooked by conventional imaging are mainly peritoneal metastases and superficial liver tumours.

Laparoscopic ultrasound provides

additional information for liver tumours on their proximity to the major vessels and bile duct branches.

Laparoscopy and laparoscopic ultrasound

Ultrasound :Standard first-line investigation Spiral CT :Anatomical planning for liver surgery MRI :Alternative to spiral CT MRCP: First-line, non-invasive cholangiography ERCP :Imaging the biliary tract when endoscopicintervention is anticipated (e.g. ductalstones) PTC :Biliary tract imaging when ERCP impossible or failed Angiography :To detect vascular involvement by tumour Nuclear medicine :To quantify biliary excretion and tumourspread Laparoscopy/Laparoscopic US: To detect peritoneal

tumour spread and superficial liver metastases

Imaging modality Principal indication

Liver trauma can be divided into blunt and penetrating injuries.

Blunt injury produces contusion, laceration and avulsion injuries to the liver, often in association with splenic, mesenteric or renal injury.

Penetrating injuries, such as stab and gunshot wounds, are often associated

with chest or pericardial involvement .

LIVER TRAUMA

Clinical diagnosis suspicion of a possible liver injury is essential. All lower chest and upper abdominal stab

wounds should be suspect, especially if considerable blood volume replacement has been required.

Similarly, severe crushing injuries to the lower chest or upper abdomen often combine rib fractures, haemothorax and damage to the spleen and/or liver.

Diagnosis of liver injury

Patients who are haemodynamically stable should have an oral and intravenous contrast-enhanced CT scan of the chest and abdomen.

This will demonstrate evidence of parenchymal damage to the liver or spleen as well as associated traumatic injuries to their

feeding vessels.

Additional investigations that may be of value include peritoneal lavage, which can confirm the presence of haemoperitoneum, and laparoscopy, which can demonstrate an associated diaphragmatic rupture.

Penetrating The initial management of a patient with an upper

abdominal penetrating injury is the basis of resuscitation.

The initial survey assesses the patient’s airway patency, breathing pattern and circulation.

Peripheral venous access is gained with two large-bore cannulae and blood sent for cross-match of 10 units of blood,

Full blood count, urea and electrolytes, liver function tests, clotting screen, glucose and amylase.

Initial management of liver injuries

Initial volume replacement should be with colloid or O-negative blood if necessary.

Arterial blood gases should be obtained and the patient intubated and ventilated if the gas exchange is inadequate.

Intercostal chest drains should be inserted if associated pneumothorax or haemothorax is suspected

. Once initial resuscitation has commenced, the patient should be transferred to the operating theatre, with further resuscitation performed on the operating table.

The necessity for fresh frozen plasma and cryoprecipitate should be discussed with the blood transfusion service immediately the patient arrives, as these patients rapidly develop irreversible coagulopathies due to a lack of fibrinogen and clotting factors.

Blunt trauma With severe blunt injuries, the plan for resuscitation

and management is as outlined above for penetrating injuries.

For the patient who is haemodynamically stable, imaging by CT should be performed to further evaluate the nature of the injury.

The basic surgical management differs between penetrating and blunt injuries thought to involve the liver;

penetrating injuries should be explored, whereas blunt injuries can be treated conservatively.

The indication for discontinuing conservative treatment for blunt trauma would be evidence of on-going blood loss despite correction of any underlying coagulopathy and the development of signs of generalised peritonitis.

A rooftop incision gives excellent visualisation

of the liver and spleen and, if necessary, can be extended upwards for a median sternotomy.

A stab incision in the liver can be sutured with a fine absorbable monofilament suture.

If necessary, this may be facilitated by producing vascular inflow occlusion by placing an atraumatic clamp across the foramen of Winslow (the Pringle manoeuvre).

The surgical approach to liver trauma

Lacerations to the hepatic artery should be identified by placing an atraumatic bulldog clamp on the proximal vessel prior to repair with 5/0 or 6/0 Prolene suture.

If unavoidable, the hepatic artery may be ligated, although parenchymal necrosis and abscess formation will result in some individuals.

Portal vein injuries should be repaired with 5/0 Prolene, again with exposure of the vessel being facilitated by the placement of an atraumatic vascular clamp.

Diffuse parenchymal injuries should be treated by packing the liver to produce haemostasis.

This is effective for the majority of liver injuries if the liver is packed against the

natural contour of the diaphragm by packing from below.

Large abdominal packs should be used to ease their removal, and the

abdomen closed to facilitate compression of the parenchyma.

Necrotic tissue should be removed, but poorly perfused, though viable, liver left in situ.

If packing is necessary, the patient should have the packs removed after 48 hours, and usually no further surgical intervention is required. Antibiotic cover is advisable, and full reversal of any coagulopathy is essential.

A subcapsular or intrahepatic haematoma requires no specific intervention and should be allowed to resolve spontaneously.

Abscesses may form as a result of secondary infection of an area of parenchymal ischaemia, especially after penetrating trauma.

Treatment is with systemic antibiotics and aspiration under ultrasound guidance once the necrotic tissue has liquefied.

Bile collections require aspiration under ultrasound guidance or percutaneous insertion of a pigtail drain. The site of origin of a biliary fistula should be determined by

endoscopic or percutaneous cholangiography, and biliary decompression achieved by nasobiliary or percutaneous transhepatic drainage or stent

insertion.

Other complications of liver trauma

Late vascular complications include hepatic artery aneurysm and arteriovenous or arteriobiliary fistulae

. These are best treated nonsurgically by a specialist hepatobiliary interventional radiologist.

The feeding vessel can be embolised transarterially. Hepatic failure may occur following extensive liver

trauma. This will usually reverse with conservative supportive

treatment if the blood supply and biliary drainage of the liver are intact

■ Remember associated injuries ■ At-risk groups Stabbing/gunshot in lower chest or upper abdomen Crush injury with multiple rib fractures ■ Resuscitate Airway Breathing Circulation ■ Assessment of injury Spiral CT with contrast Laparotomy if haemodynamically unstable ■ Treatment Correct coagulopathy Suture lacerations Resect if major vascular injury Packing if diffuse parenchymal injury

Management of liver trauma

Other complications of liver trauma ■ Intrahepatic haematoma ■ Liver abscess ■ Bile collection ■ Biliary fistula ■ Hepatic artery aneurysm ■ Arteriovenous fistula ■ Arteriobiliary fistula ■ Liver failure

Other complications of liver trauma

The aetiology of a pyogenic liver abscess is unexplained in the majority of patients.

It has an increased incidence in the elderly, diabetics and the immunosuppressed, who usually present with anorexia, fevers and malaise, accompanied by right upper quadrant discomfort.

The diagnosis is suggested by the finding of a multiloculated cystic mass on ultrasound or CT scan.

And is confirmed by aspiration for culture and sensitivity.

Pyogenic liver abscess