Hepatobiliary surgery - Liver surgery EIRIN VESTENG

Transcription

1 Hepatobiliary surgery - Liver surgery EIRIN VESTENG

2 Outline I. Surgical anatomy of the liver II. III. IV. Physiology of the liver Diagnostic options in liver diseases Benigns lesions V. Liver cysts VI. Liver absesses VII. Primary malignant neoplasms VIII. Secondary malignant neoplasms IX. Liver transplantation

3 1. Surgical anatomy of the liver THE LIVER IS ONE OF THE LARGEST VISCERAL ORGANS IN OUR BODY, COVERING 2% OF TOTAL BODY WEIGHT. IT DEVELOPS AS AN EMBRYOLOGIC OUTPOUCHING FROM THE DUODENUM.

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5 1. Surgical anatomy of the liver - Sectors & segments The liver has a complex segmental anatomy, often simplified by characterized as having 4 lobes right, left, caudate (R) and quadrate (R), or just right & left lobes.

6 1. Surgical anatomy of the liver - Sectors & segments The anatomical right & left lobes are separated by an imaginary line called major lobar fissure (Cantlie line or principal plane) running from the medial aspect of the gallbladder fossa to the IVC, running parallel with the fissure of the round ligament. This division marks the course of the middle hepatic vein. The right hepatic vein further subdivides the right liver into anterior (segments V and VIII) and posterior (segments VI and VII) sectors, while the umbilical fissure subdivides the left liver into the medial (segment IV) and left lateral sector (segments II and III).

7 1. Surgical anatomy of the liver - Sectors & segments The liver is divided into 4 sectors & 8 segments based on the branching of the portal triads and hepatic veins. The three main hepatic veins (left, right & middle) divide the liver into four sectors (portal sectors): Right posterior sector (segments VI & VII) Right anterior sector (segments V & VIII) Left medial sector (segment IV) Left lateral sector (segments II & III) The caudate lobe (segment I) is an exception because its venous drainage is directly into the vena cava and is therefore independent of the major hepatic veins.

8 1. Surgical anatomy of the liver - Sectors & segments The portal sectors are supplied by independent portal pedicles arising from the right or left main pedicles. The divisions separating the sectors are called portal scissurae, within each of which runs a hepatic vein. Further branching of the pedicles subdivides the sectors into segments. Segments I-IV comprise the left liver Segments V-VIII comprise the right liver Each segment is supplied by an independent portal pedicle, which forms the basis of sublobar segmental resections.

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10 1. Surgical anatomy of the liver - Portal circulation The portal vein is formed by the confluence of the splenic and superior mesenteric veins at the level of the 2 nd lumbar vertebra behind the head of the pancreas. It runs for approximately 6 9 cm to the hilum of the liver, where it divides into the main right and left branches.

11 1. Surgical anatomy of the liver - Venous blood supply Both the portal and hepatic venous systems are valveless. The main portal vein terminates in the porta hepatis by dividing into right and left branches. The right branch divide into anterior and posterior sectoral divisions. The left branch gives branches to segments II, III, and IV; a large branch to the caudate lobe The hepatic veins (left, right & middle) represent the final common pathway for the central veins of the lobules of the liver IVC

12 1. Surgical anatomy of the liver - Arterial blood supply The common hepatic artery arises from the celiac trunk, ascends in the hepatoduodenal ligament, and gives rise to the right gastric, gastroduodenal, and proper hepatic arteries; The proper hepatic artery then divides into the right and left hepatic arterial branches in the liver hilum. The hepatic artery supplies approximately 25% of the 1500 ml of blood that enters the liver each minute; the remaining 75% is supplied by the portal vein. Within the liver, the hepatic arterial branches travel with segmental bile ducts and portal vein branches.

13 1. Surgical anatomy of the liver - Biliary drainage The biliary tree arises within the liver from bile canaliculi, formed from specialized segments of the hepatocyte membrane. Bile canaliculi join to form progressively larger channels, resulting in segmental bile ducts that drain each segment. The right anterior and right posterior sectoral ducts unite to form the main right hepatic duct, while the union of ducts draining segments II, III, and IV forms the left hepatic duct. Drainage of segment I (caudate lobe) is principally into the left hepatic duct

14 1. Surgical anatomy of the liver - Lymphatics Lymphatics draining superficial lobules of the liver follow a subcapsular course to the diaphragm, to the suspensory ligaments of the liver, or to the posterior mediastinum, while others enter the porta hepatis. Lymphatics arising from lobules deep within the liver travel either with the hepatic veins along the vena cava or with the portal veins into the porta hepatis. Most of the lymphatic drainage of the liver is to the hepatoduodenal ligament.

15 1. Surgical anatomy of the liver - Nerves The liver and biliary tree are innervated by sympathetic fibers arising from T7 to T10 and by parasympathetic fibers from the right and left vagus nerves. The postganglionic sympathetic nerves arise from the celiac ganglia. Fibers derived from the celiac ganglia and vagus nerves form a plexus of nerves that run along the anterior and posterior aspects of the hepatic artery.

16 2. Physiology of the liver

17 2. Physiology of the liver Total hepatic blood flow (about 1500 ml/min; 30 ml/min per kg body weight) constitutes 25% of the cardiac output, though the liver accounts for only 2.5% of body weight. About 30% of the hepatic volume is blood (12% of total blood volume). 2/3 of the flow enters through the portal vein and 1/3 through the hepatic artery. Pressure in the portal vein is normally low (10 15 cm H 2 O [7 11 mm Hg]). The liver derives half of its oxygen from hepatic arterial blood and half from portal venous blood.

18 2. Physiology of the liver Blood flow within the liver is uniform. Hepatic blood flow to the liver is regulated by a number of factors. Muscular sphincters at the inlet and outlet of sinusoids The cells lining the hepatic sinusoids Portal venous and hepatic arterial blood becomes pooled after entering the periphery of the hepatic sinusoid. Hepatic arterial flow increases or decreases reciprocally with changes in portal flow (arterial compensatory response); however, portal venous flow does not increase with reductions in arterial flow.

19 2. Physiology of the liver Occlusion of the right or left portal venous branches result in ipsilateral hepatic atrophy and contralateral hypertrophy. Intentional occlusion of a major portal vein branch (usually the right) is a procedure being used with greater frequency prior to major hepatic resection, primarily when the regenerative capacity of the future liver remnant is questionable (size concerns or underlying parenchymal disease). By causing atrophy of the liver to be resected and hypertrophy of the future liver remnant, the risk of postop hepatic failure may be reduced!

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21 3. Diagnostic options in liver diseases

22 3. Diagnostic options in liver diseases Blood tests: Liver function tests ASAT, ALAT, ALP, GGT, bilirubin, albumin and prothrombin time other bloodtests for specific liver problems or genetic conditions. Imaging tests: CT, MRI, USG Tissue analysis: Biopsy

23 4. Benign lesions HEPATIC HEMANGIOMA HEPATOCELLULAR ADENOMA FOCAL NODULAR HYPERPLASIA (FNH) INFANTILE HEPATIC HEMANGIOENDOTHELIOMA (IHH)

24 4. Benign lesions - Hemangioma Hemangioma is the most common benign hepatic tumor. No malignant potential known. Women > men (4-6:1) Sx: Hemangiomas are usually Asx and discovered incidentally. They may cause RUQ pain or fullness. May present ruptures (sx: severe abd pain, hemodynamic instability) Dx: Suspicion after USG, Doppler. CT or MRI should be performed after suspicion. Do not biopsy. TX: ASx hemangiomas should be documented but left alone. Irrespective of their size, the only reasons to resect hemangiomas are for Sx or diagnostic uncertainty. Symptomatic hemangiomas should be excised by lobectomy or enucleation. Even large lesions can be safely removed. Ruptured hemangiomas should be treated with hemodynamic stabilization followed by surgical resection or arterial embolization.

25 4. Benign lesions - Hemangioma

26 4. Benign lesions - Hepatic adenoma Strongly ass w/the use of OCPs, anabolic steroids, pregnancy and certain fertility drugs. Women > men (9:1). There is malignant potential (HCC) Sx: usually Asx and discovered incidentally. RUQ pain or fullness, palpable abd mass. May present ruptured. Dx: Suspicion is on USG. Besides biopsy, the most accurate dx test is MRI w / gadolinium enhancement. Workup may include α-fp. Tx: Asx hepatic adenomas should be documented but left alone and monitored. Pt should d/c any OCP.s, anabolic steroids and avoid pregnancy. Surgical resections should be undertaken if the adenomas is symptomatic, large or if the woman anticipates pregnancy. Monitor with sonography and annual α-fp BUT, the general recommendation is that adenomas should be resected because of the risks of malignant change and spontaneous hemorrhage. Small peripheral lesions may be removed with wedge excisions, but larger tumors require more extensive resections.

27 4. Benign lesions - Hepatic adenoma

28 4. Benign lesions - Focal nodular hyperplasia FNH is the 2 nd most common benign solid tumor of the liver with no malignant potential. Female > Male, average 40 y.o, 85% are solitary tumors Unlike hepatic adenoma - the use of OCP s does not appear to predispose to the development of FNH, but may stimulate growth. Sx: usually Asx. Suspicion is on USG. Dx: can be made radiologically via CT, with its characteristic central scar (80%). Tc-99m sulfur colloid scan may helpful to differentiate it from hepatic adenoma & HCC). Rupture is likely non-existant Tx: D/c OCPs (?), routine monitoring w / USG

29 4. Benign lesions - Focal nodular hyperplasia

30 4. Benign lesions - Focal nodular hyperplasia Tc-99m sulfur colloid scan FNH «hot spot» Tc-99m sulfur colloid scan Not an FNH «cold spot»

31 5. Liver cysts

32 5. Liver cysts A number of different cystic lesions may affect the liver. Simple hepatic cysts, the most common, are unilocular fluid-filled lesions, generally no sx. Many patients have multiple simple cysts, which should not be confused with polycystic liver disease, a progressive condition characterized by cystic replacement of virtually the entire liver. The occasional large cyst may present as an upper abdominal mass or discomfort. Solitary cysts lined with cuboidal epithelium are classified as cystadenomas and should be resected, since they are premalignant. Dx: MRI, USG, CT Complex, multilocular (septated) cysts (if not echinococcal) are often neoplastic and should be resected.

33 5. Liver cysts

34 5. Liver cysts There are few indications for aspirating hepatic cysts simple cysts reaccumulate fluid quickly, neoplastic cysts must be excised, and parasitic cysts might rupture and the parasite thus be allowed to spread. It is possible to eliminate small cysts by aspiration of the contents followed by an injection into the lumen of ml of absolute alcohol; however, small cysts almost never cause symptoms and generally require no treatment. Large symptomatic cysts are difficult to eradicate with alcohol injections, and serious superinfection of the cyst cavity may occur. The simplest method of treatment consists of laparoscopic cyst fenestration (wide excision of the cyst wall). A tongue of omentum is fixed so it lies in the residual cyst cavity as an ancillary measure to prevent the edges from coapting. The operation is curative in nearly all patients.

35 5. Liver cysts

36 6. Liver abscesses

37 6. Liver abscesses Hepatic abscesses may be bacterial, parasitic, or fungal in origin. (US: bacterial > parasitic > fungal) Cases are about evenly divided between those with a single abscess and those with multiple abscesses. About 90% of right lobe abscesses are solitary, while only 10% of left lobe abscesses are solitary. In most cases, the dev. of a hepatic abscess follows a suppurative process elsewhere in the body. About 40% of patients have an underlying malignancy. Other cases develop after generalized sepsis from bacterial endocarditis, renal infection, or pneumonitis. In 25% of cases, no antecedent infection can be documented ("cryptogenic" abscesses). In most cases, the organism is of enteric origin. Escherichia coli, Klebsiella pneumoniae, bacteroides, enterococci (eg, Streptococcus faecalis), anaerobic streptococci (eg, Peptostreptococcus), and microaerophilic streptococci are most common.

38 6. Liver abscesses

39 6. Liver abscesses Sx: Asx, fever, jaundice, RUQ pain, chills, malaise, fatigue Dx: USG, CT, MRI Tx: Antibiotics should be started promptly (aminoglycoside, clindamycin or metronidazole & ampicillin). Modified after culture results. About 80% adequately treated by drainage catheters inserted percutaneously under ultrasound or CT guidance. Whether the patient has a single abscess or multiple abscesses, this is usually the most appropriate initial therapy. The catheters can be removed in 1 2 weeks after output becomes nonpurulent and scant. Surgical intervention is more often necessary in cases of multiple, loculated collections or when the abscess cavity contains a large amount of necrotic debris. In such cases, open debridement should be considered early.

40 7. Primary malignant neoplasms HEPATOCELLULAR CARCINOMA (HCC) INTRAHEPATIC CHOLANGIOCARCINOMA HEPATOBLASTOMA (CHILDREN) HEPATIC ANGIOSARCOMA

41 7. Primary malignant neoplasms Liver malignancy may arise from hepatocytes (hepatocellular carcinoma [HCC], the most common) or biliary epithelial cells (intrahepatic cholangiocarcinoma). A mixture of both have also been described. Neonates may also develop a variant of HCC called hepatoblastoma. Angiosarcoma of the liver, a rare fatal tumor, has been seen in workers intensively exposed to vinyl chloride for prolonged periods in polymerization plants. Most pts w / malignancy of the liver will have RUQ pain, as well as high liver enzymes and anemia. RUQ pain is often first followed by RUQ USG (to r/o biliary tract obstruction), but in suspicion of malignancy, CT w/contrast should always be performed. In differentiating the type of malignancy, the pt s history is of the utmost importance. Achieving a cure for malignancies involving the liver & biliary tract will require resection of some sort.

42 7. Primary malignant neoplasms - Hepatocellular carcinoma HCC is the most common primary hepatic malignancy (85-90%) Male > female (2:1) average 50 y.o Risk factors include: Cirrhosis, chronic HBV/HCV infection, hemochromatosis, schistosomiasis, environmental and occupational toxins (aflatoxin (Aspergillus spp), PVC, organochloride pestacides), thorotrast Sx: dull, achy RUQ pain; malaise, jaundice, hepatomegaly, tender abd mass, fever, weight loss, acute hemorrhage/shock Dx: May be suspected on USG, the best initial dx test on suspicion of HCC is CT w/contrast. Liver enzymes & a-fp (tumor marker) will be elevated. The most accurate test is biopsy. Tx: Ideally resection; if non-resectable, transplantation is only hope of cure. There is no effective chemotherapy for HCC. 5-year survival rate for pts with HCC - <16% HCC supplied primarily by the hepatic artery

43 7. Primary malignant neoplasms - Hepatocellular carcinoma

44 7. Primary malignant neoplasms - Intrahepatic cholangiocarcinoma Cholangiocarcinoma makes up a small fraction of primary liver cancers. Unlike HCC, intrahepatic cholangiocarcinoma is less frequently associated with cirrhosis. Risk factors: primary sclerosing cholangitis, liver fluke infection (Clonorchis sinensis) or sporadic. Emerging evidence also suggests chronic HCV, obesity, diabetes mellitus, chronic liver disease and smoking. Intrahepatic cholangiocarcinoma generally presents as a large mass within the liver and is therefore clinically distinct from cholangiocarcinoma arising from the extrahepatic biliary tree. Intrahepatic or extrahepatic spread of disease is not uncommon by the time the tumor is detected. These tumors infrequently cause symptoms at early stages and therefore often grow to a large size before they become apparent, frequently because of pain.

45 7. Primary malignant neoplasms - Treatment Liver Transplantation HCC is the only solid neoplasm for which transplantation plays a significant role. Is the optimal curative treatment for HCC Milan criteria 5-year survival 70% Partial Hepatectomy Is the next best option The minimal criteria of resectability that must be met are (1) disease confined to the liver and (2) disease amenable to a complete resection. Anatomical segmentectomies are preferred to nonanatomical resections.

46 7. Primary malignant neoplasms - Treatment Ethanol injection (percutaneous ablative technique) In pts with small, unresectable tumors. USG or CT guidance 95% ethanol (5-20mL) Can approach complete necrosis in % of tumors < 2 cm Ø Radiofrequency Ablation (RFA) (percutaneous ablative technique of choice) In pts with small, unresectable tumors. USG or CT needle + radiofrequency generator that generates thermal energy to bring about tumor destruction. RFA can be used percutaneously, laparoscopically, or at laparotomy. The goal of RFA is the same at that of ethanol injection: to achieve complete tumor necrosis.

47 7. Primary malignant neoplasms - Treatment Arterial Embolization (ablative technique) This approach takes advantage of the fact that primary liver cancers derive disproportionately greater blood supply from the hepatic arterial circulation compared to the surrounding liver. The strategy is to combine selective hepatic arterial injection of cancer chemotherapeutic agents with arterial embolization, the latter to produce tumor necrosis and slow the washout of the drugs. Liver-directed therapy (under investigation) Systemic therapy (under investigation)

48 7. Primary malignant neoplasms - Treatment

49 8. Secondary malignant neoplasms METASTATIC NEOPLASMS OF THE LIVER

50 8. Secondary malignant neoplasms By far the most common malignancy of the liver In many instances pts are Asx until mets to the liver, after which liver failure ensues. Pt may also have the typical malignant hx of unintended weight loss, malaise and fatigue. Nearly all solid tumors can potentially give rise to liver metastases. Colon cancer is most likely to spread to the liver Breast and lung are also common, pancreas, esophagus, stomach The cirrhotic liver, which often gives rise to primary hepatic tumors, seems to be less susceptible than normal liver to implantation of metastases. Dx: on CT or MRI: colonoscopy CXR often help to find the underlying cancer if it is in question. You may also consider CEA (colon cancer) titers. TX: is targeted on the underlying primary malignancy. Unilobar malignancy may often be treated with partial hepatectomy. Malignancy in both lobes is not amenable for resection.

51 8. Secondary malignant neoplasms

52 9. Liver transplantation

53 9. Liver transplantation First successful human liver transplant, 1967 Dr. Thomas Starzl Most common indication: adults cirrhosis due to chronic hepatitis C infection, children biliary atresia. Current contraindication are few & are primarily related to evidence of cardiopulmonary disease that probibits safe liver transplantation & active substance abuse.

54 9. Liver transplantation - Donor selection It is important that the liver is a rough size match for the donor. Blood type compatibility is preferred but not an absolute requirement. Matching of tissue antigens does not appear to be relevant Donor organ Blood is flushed from the organ (prevent vascular occlusion) Decrease metabolic requirement (cold 4 C) + preservation solution (eg. Viaspan) transplanted within 10-24hours

55 9. Liver transplantation - Operative technique The operation is performed in three phases: 1. the dissection phase, during which the attachments of the diseased liver are dissected and the vascular structures are prepared for resection 2. the anhepatic phase, which extends from the time the host liver is removed until the time the donor liver is revascularized 3. the reperfusion phase, during which blood is circulating through the new organ and the biliary tree is reconstructed. Several techniques are available for handling the retrohepatic vena cava The mainstay of immunosuppression for liver transplant recipients is a calcineurin inhibitor.

56 9. Liver transplantation - Living Donor Liver Transplantation & Split Liver Transplantation The shortage of organs for small children in the late 1980s prompted the development of techniques to reduce the size of an adult liver graft by performing an anatomic resection of one or more lobes and transplanting the reduced graft. The success of living donor liver transplantation from adult donors into children, together with the shortage of suitable adult donors, led to the development by Marcos and Tanaka of techniques to utilize the right lobe from a living donor to transplant into another adult. Nevertheless, living donor liver transplants have become a standard option when timely deceased donor liver transplantation is not possible. By applying the living donor technique to deceased donors, two transplants can be obtained from a single adult liver from a deceased donor. This has been termed a split liver transplant. Typically, the lateral segment of the left lobe is used for a child or very small adult, while the remainder of the liver consisting of the right lobe plus the medial segment of the left lobe is used for an adult..

57 9. Liver transplantation - Complications Complications following liver transplantation are common, but most can be treated effectively. Coagulopathy ( bleeding), primary nonfunctioning of the liver (5-10%) most devastating complication Vascular complication (5-10%) Bile duct complication (20%) Rejection (20-50%) increase immonsuppressive therapy or corticosteroid pulse therapy Fungal infections esp. Candida Albicans ( thrush )

58 Sources: Current diagnosis & treatment, 14th edt (G. doherty) Step up to surgery, 2nd edt Youtube Paul Bohlin Google