Hepatobilliary Surgery Flashcards

1
Q

Where is the gallbladder located? What artery supplies it?

A

between RM and quadrate lobes of the liver

cystic artery

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2
Q

What are the 2 major blood supplies to the liver? Efferent vessel?

A
  1. PORTAL VEIN (80%) - low pressure
  2. HEPATIC ARTERY (20%) - high pressure

hepatic vein enters the caudal vena cava

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3
Q

How do partial and complete lobectomies compare?

A

PARTIAL - only taking off a portion, very dangerous since there is no strong capsule to the liver

COMPLETE - removal of the entire lobe at the level of the hilus, safer because the vessel can be easily ligated

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4
Q

What is the ideal sample taken from liver biopsies?

A

multiple samples from multiple lobes

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5
Q

What 3 aspects of liver anatomy makes it difficult to perform surgery on?

A
  1. very friable tissue lacking a strong capsule
  2. difficult hemostasis
  3. biliary leaks possible
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6
Q

What are 6 major functions of the liver?

A
  1. synthesis of plasma proteins
  2. bile acid production
  3. produces coagulation factors
  4. maintains carbohydrate and lipid metabolism —> glucose concentration
  5. clearance organ (drugs and toxins)
  6. storage of vitamins, fat, glycogen, and minerals
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7
Q

What 3 things can ultrasonography be used for with the liver?

A
  1. rules out biliary obstruction and assesses the organ
  2. FNA/biopsy
  3. doppler enhanced = assess blood flow
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8
Q

How does hematocrit affect preoperative considerations?

A

if it is below 20%, patient should receive preoperative blood transfusions

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9
Q

When does clinical hypoalbuminemia occur? What is its significance?

A

70-80% of hepatic mass lost

  • delayed healing
  • decreased bound drugs = more free in plasma and more profound affects with normal dosages
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10
Q

What 6 drugs should be avoided with severe liver disease?

A
  1. Acepromazine
  2. alpha-2 agonists - Xylazine, Dexmedetomidine
  3. neuromuscular blocker - Pancuronium/Vecuronium
  4. Telazol
  5. Diazepam
  6. NSAIDs
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11
Q

How does liver disease affect coagulation?

A

causes coagulopathies due to decreased production of clotting factors or consumption

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12
Q

What 2 important aspects of a biochemistry panel are affected by liver disease?

A
  1. hypokalemia
  2. hypoglycemia
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13
Q

What important effect does biliary obstruction have?

A

alters enteric absorption of vitamin K and other fat-soluble vitamins (D, E, A)

  • decreased synthesisi of plasma clotting proteins, factors II, VII, IX, and X
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14
Q

What 3 factors can reduce hepatic oxygenation? How can venous return be improved?

A
  1. hypotension
  2. excessive sympathetic stimulation (inadequate pain control)
  3. high airway pressures

remove ascites (sudden removal intra-operatively can cause hypotension)

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15
Q

How is hypotension treated to improve hepatic oxygenation?

A

vasopressors/inotropes

  • Dobutamine
  • Dopamine
  • Ephedrine
  • Epinephrine
  • Norepinephrine
  • Phenylephrine
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16
Q

What 3 antibiotics are recommended to improve hepatic oxygenation? What 3 should be avoided?

A
  1. Penicillin derivatives
  2. Metronidazole (high doses can cause severe neurological signs)
  3. Clindamycin
  • Doxycycline
  • Chlortetracycline
  • Erythromycin
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17
Q

What 5 procedures are used for liver biopsies?

A
  1. percutaneous core biopsies with ultrasound-guided Trucut (12-18 g needle with a notch for tissue)
  2. FNA
  3. laparoscopic - double spoon forceps, guillotine with pre-formed loop suture
  4. surgical biopsy or lobectomies
  5. punch biopsy
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18
Q

How is liver trauma initially treated? How does the location of trauma affect this?

A

conservative - transfusions, fluids

closer to hilus = greater likelihood surgery is necessart (ligation, hepatectomy)

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19
Q

What are the 2 major types of hepatic neoplasia? Where are they more likely to metastasize?

A
  1. epithelial - hepatocellular carcinoma/adenoma, cholangiocellular carcinoma/adenoma, carcinoids; regional LNs and lungs
  2. mesenchymal - HSA (poor prognosis), fibrosarcoma, extraskeletal osteosarcoma, leiomyosarcoma; spleen

1% are primary

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20
Q

What primary hepatic neoplasms are most common in dogs and cats?

A

DOGS = hepatocellular* and cholangiocellular carcinomas

CATS = cholangiocellular

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21
Q

What are hepatic carcinoids? Biliary cystadenomas?

A

rare tumors arising from neuroectodermal cells in the liver

benign liver tumors in older cats

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22
Q

What are the 3 types of hepatocellular carcinomas? What are their prognoses like?

A
  1. diffuse - on all lobes, poor prognosis
  2. nodular - poor prognosis
  3. massive - 1 lobe, better prognosis
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23
Q

Where are most massive adenocarcinomas found?

A

left lobes

(massive = better prognosis; diffuse = poor)

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24
Q

What are the most common types of cholangiocellular tumors in cats?

A

adenomas - cystadenoma —> cholecystadenoma

(carcinomas —> carcinomatosis)

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25
Q

Why is metastatic neoplasia common in the liver? What are the most common ones seen?

A

acts as a filter between abdominal organs and systemic circulation

  • lymphosarcoma*
  • pancreatic adenocarcinomas
  • HSA
  • insulinomas
  • alimentary and urinary tract tumors
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26
Q

What is the most common treatment of neoplasia? Why?

A

total lobectomy

rarely responds to chemo or radiotherapy, but does delay progression

27
Q

How are punch biopsies used to obtain liver biopsies?

A
  • opened abdomen and used normally on the liver
  • usually packed with Surgicel, a methylcellulose absorbable sponge, since the tissue is incredibly friable
28
Q

What liver biopsy samples does the guillotine technique work best for?

A

peripheral samples that are representative of the lobe

29
Q

How does a total lobectomy compare to a partial one? How do the different lobes compare?

A

less technically demanding and safer —> uses Rummel tourniquet and stapler

  • left lobes are more detached
  • right lateral and caudate lobes require dissection around vena cava
30
Q

What are te 7 most common complications associated with total lobectomies?

A
  1. HEMORRHAGE
  2. biliary peritonitis
  3. bacterial proliferation
  4. sepsis
  5. coagulopathy
  6. portal hypertension
  7. ascites
31
Q

What are the 2 most common cavitary lesions associated with the liver? What clinical signs are seen?

A
  1. abscesses - anorexia, lethargy, weight loss, intermittent abdominal pain
  2. cysts - typically asymptomatic, abdominal distention, secondary infections behave like abscesses
32
Q

In what 3 ways are cavitary lesions treated?

A
  1. drainage and omentalization
  2. lobectomy or partial hepatectomy
  3. antibiotics for 7-10 days (careful with peritonitis)
33
Q

What are diaphragmatic hernias?

A

the liver passes through a hole in the diaphragm, causing it to become strangulated

34
Q

What are the 5 major indications for partial lobectomies?

A
  1. biopsies
  2. trauma
  3. abscesses
  4. cysts
  5. neoplasia
34
Q

How are partial lobectomies performed? Why are they so dangerous?

A
  • sharply incise the liver capsule
  • fracture parenchyma with fingers gently
  • locate and ligate large blood vessels and bile duct
  • electrocauterize small vessels

finger fracturing through hepatocytes leads to high blood loss

34
Q

What is a common complication associated with cholecystitis/cholangiohepatitis?

A

peritonitis due to rupture of the gall bladder, especially when bacteria makes it emphysematous

35
Q

The etiopathogenesis of biliary mucoceles is unclear. What are 3 possible causes?

A
  1. hyperplasia of mucus-secreting cells and excessive mucus production
  2. alterations in gallbladder motility
  3. accumulation of inspissated (thickened, congealed) bile
36
Q

What is the most common signalment for biliary mucoceles? What are some clinical signs?

A

older small to medium breeds, especially Shelties and Cocker Spaniels

  • vomiting
  • anorexia
  • lethargy
  • PU/PD
  • diarrhea
  • none!
37
Q

What are the most common PE findings in patients with biliary mucoceles?

A
  • abdominal pain
  • icterus
  • fever
38
Q

What are the 4 most common biochemical abnormalities seen with biliary mucoceles?

A
  1. elevated alkaline phosphatase (GB-specific)
  2. elevated alanine aminotransferase
  3. elevated g-glutamyl transferase
  4. increased total bilirubin
39
Q

What is the best diagnostic imaging for biliary mucocele? What is characteristic?

A

ultrasonography

enlarged GB with immobile echogenic bile in a striated or stellate (kiwi) pattern

40
Q

What medical management has been recommended for biliary mucoceles? Why is it not commonly used?

A

choleretic

contraction of the GB can cause rupture

40
Q

What are the 6 indications for cholecystectomies?

A
  1. necrotizing cholecystitis
  2. chronic cholecystitis
  3. biliary mucoceles
  4. cholelithiasis
  5. neoplasia
  6. trauma
41
Q

How can patency of the bile duct be confirmed?

A

catheterize the bile duct and flushing

  • this confirms that the gall bladder can be removed
42
Q

What pathology of the biliary tree is commonly seen?

A
  • pancreatitis
  • trauma (blunt, penetrating wounds)
  • neoplasia
43
Q

What 3 antibiotics are excreting in active form in bile? When are they recommended?

A
  1. Amoxicillin
  2. Cephazolin
  3. Enrofloxacin

when the patency of the common bile duct cannot be demonstrated

44
Q

When are temporary solutions for biliary mucoceles recommended? What should be avoided in dogs?

A

reversible situations (trauma) when patency is demonstrated by catheterization but there is a functional obstruction

biliary diversion

45
Q

What are cholecystotomy, cholecystectomy, and choledochotomy?

A

opening a hole in the GB and closing when done

removal of the GB

make a hole in the common bile duct and closing

46
Q

What is the difference between cholecystoduodenostomy and cholecystojejunostomy?

A

attaching the gallbladder to the duodenum (has a lot of complications)

attaching the gallbladder to the jejunum (stoma no smaller than 2.5-3 cm)

47
Q

What must be ligated when performing a cholecystectomy? How should the common bile duct be maintained?

A

cystic artery

double ligate or hemoclip

(anything that comes out of the body should be submitted to histopath!)

48
Q

What are 2 extraluminal causes of biliary obstruction?

A
  1. pancreatic disease
  2. duodenal disease
49
Q

What is a choledochotomy? In what 2 cases is it recommended?

A

incision into dilated common bile duct

  1. choledocholithiasis
  2. biliary sludge
50
Q

When is bile duct stenting most commonly done? What is the point? How is it done?

A

relieve obstruction due to extraluminal compression

temporarily divert bile after suturing the bile duct

suture a catheter into the intestinal wall with absorbably suture

51
Q

When is biliary diversion recommended? What 3 procedures do this?

A

irreparable obstruction or trauma to the common bile duct

  1. cholecystoduodenostomy
  2. cholecystojejunostomy
  3. Roux-en-Y: jejunal conduit between gallbladder and duodenum or proximal jejunum
52
Q

How large should the stoma for cholecystoduodenostomies be? Why?

A

2.5-3 cm

reduces the risk of gallbladder becoming impacted with ingesta causing cholecystitis or cholangiohepatitis

53
Q

What is the most common complication with biliary diversions? What is seen in cats and dogs?

A

leakage

CATS = high morbidity and mortality usually linked to underlying disease or chronic vomiting

DOGS = ascending infections and bleeding at stoma site

54
Q

What are the most common causes of bile peritonitis following biliary diversions?

A
  • failure to adequately ligate the bile duct
  • failure to recognize and ligate small ducts entering the cystic duct
  • trauma of the bile duct (+ iatrogenic)
  • spontaneous rupture of the gallbladder
55
Q

What is the most common cause of bleeding following biliary diversions?

A

failure to ligate the cystic artery

56
Q

What is the most common sign of bile peritonitis in the abdominal cavity?

A

green, greenish-brown discoloration

57
Q

How are abdominal effusions used to diagnose bile peritonitis?

A

four-quadrant, ultrasound-guided, or diagnostic peritoneal lavage taps are compared to serum bilirubin

  • if positive, fluid is > 2x serum
58
Q

What is the prognosis of sterile and infected bile peritonitis?

A

STERILE = chemical, well-tolerated and better prognosis

INFECTED = septic, guarded to poor prognosis

59
Q

What is the main cause of extrahepatic biliary obstructions in cats?

A

pancreatitis ascending infection causing necrotizing colecystitis peritonitis —> sepsis

+/- duodenal or pancreatic carcinomas

60
Q

How are drains placed for abdominal effusions?

A

open belly drainage with suturing of the caudal 1/3

61
Q

What are the 2 major complications of abdominal effusion drainage?

A
  1. bile peritonitis due to failure of adequately ligating the cystic duct and small hepatic ducts entering the cystic duct
  2. bleeding from hepatic parenchyma and cystic arteries