Hepatobilliary Surgery Flashcards
Where is the gallbladder located? What artery supplies it?
between RM and quadrate lobes of the liver
cystic artery
What are the 2 major blood supplies to the liver? Efferent vessel?
- PORTAL VEIN (80%) - low pressure
- HEPATIC ARTERY (20%) - high pressure
hepatic vein enters the caudal vena cava
How do partial and complete lobectomies compare?
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
What is the ideal sample taken from liver biopsies?
multiple samples from multiple lobes
What 3 aspects of liver anatomy makes it difficult to perform surgery on?
- very friable tissue lacking a strong capsule
- difficult hemostasis
- biliary leaks possible
What are 6 major functions of the liver?
- synthesis of plasma proteins
- bile acid production
- produces coagulation factors
- maintains carbohydrate and lipid metabolism —> glucose concentration
- clearance organ (drugs and toxins)
- storage of vitamins, fat, glycogen, and minerals
What 3 things can ultrasonography be used for with the liver?
- rules out biliary obstruction and assesses the organ
- FNA/biopsy
- doppler enhanced = assess blood flow
How does hematocrit affect preoperative considerations?
if it is below 20%, patient should receive preoperative blood transfusions
When does clinical hypoalbuminemia occur? What is its significance?
70-80% of hepatic mass lost
- delayed healing
- decreased bound drugs = more free in plasma and more profound affects with normal dosages
What 6 drugs should be avoided with severe liver disease?
- Acepromazine
- alpha-2 agonists - Xylazine, Dexmedetomidine
- neuromuscular blocker - Pancuronium/Vecuronium
- Telazol
- Diazepam
- NSAIDs
How does liver disease affect coagulation?
causes coagulopathies due to decreased production of clotting factors or consumption
What 2 important aspects of a biochemistry panel are affected by liver disease?
- hypokalemia
- hypoglycemia
What important effect does biliary obstruction have?
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
What 3 factors can reduce hepatic oxygenation? How can venous return be improved?
- hypotension
- excessive sympathetic stimulation (inadequate pain control)
- high airway pressures
remove ascites (sudden removal intra-operatively can cause hypotension)
How is hypotension treated to improve hepatic oxygenation?
vasopressors/inotropes
- Dobutamine
- Dopamine
- Ephedrine
- Epinephrine
- Norepinephrine
- Phenylephrine
What 3 antibiotics are recommended to improve hepatic oxygenation? What 3 should be avoided?
- Penicillin derivatives
- Metronidazole (high doses can cause severe neurological signs)
- Clindamycin
- Doxycycline
- Chlortetracycline
- Erythromycin
What 5 procedures are used for liver biopsies?
- percutaneous core biopsies with ultrasound-guided Trucut (12-18 g needle with a notch for tissue)
- FNA
- laparoscopic - double spoon forceps, guillotine with pre-formed loop suture
- surgical biopsy or lobectomies
- punch biopsy
How is liver trauma initially treated? How does the location of trauma affect this?
conservative - transfusions, fluids
closer to hilus = greater likelihood surgery is necessart (ligation, hepatectomy)
What are the 2 major types of hepatic neoplasia? Where are they more likely to metastasize?
- epithelial - hepatocellular carcinoma/adenoma, cholangiocellular carcinoma/adenoma, carcinoids; regional LNs and lungs
- mesenchymal - HSA (poor prognosis), fibrosarcoma, extraskeletal osteosarcoma, leiomyosarcoma; spleen
1% are primary
What primary hepatic neoplasms are most common in dogs and cats?
DOGS = hepatocellular* and cholangiocellular carcinomas
CATS = cholangiocellular
What are hepatic carcinoids? Biliary cystadenomas?
rare tumors arising from neuroectodermal cells in the liver
benign liver tumors in older cats
What are the 3 types of hepatocellular carcinomas? What are their prognoses like?
- diffuse - on all lobes, poor prognosis
- nodular - poor prognosis
- massive - 1 lobe, better prognosis
Where are most massive adenocarcinomas found?
left lobes
(massive = better prognosis; diffuse = poor)
What are the most common types of cholangiocellular tumors in cats?
adenomas - cystadenoma —> cholecystadenoma
(carcinomas —> carcinomatosis)
Why is metastatic neoplasia common in the liver? What are the most common ones seen?
acts as a filter between abdominal organs and systemic circulation
- lymphosarcoma*
- pancreatic adenocarcinomas
- HSA
- insulinomas
- alimentary and urinary tract tumors
What is the most common treatment of neoplasia? Why?
total lobectomy
rarely responds to chemo or radiotherapy, but does delay progression
How are punch biopsies used to obtain liver biopsies?
- opened abdomen and used normally on the liver
- usually packed with Surgicel, a methylcellulose absorbable sponge, since the tissue is incredibly friable
What liver biopsy samples does the guillotine technique work best for?
peripheral samples that are representative of the lobe
How does a total lobectomy compare to a partial one? How do the different lobes compare?
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
What are te 7 most common complications associated with total lobectomies?
- HEMORRHAGE
- biliary peritonitis
- bacterial proliferation
- sepsis
- coagulopathy
- portal hypertension
- ascites
What are the 2 most common cavitary lesions associated with the liver? What clinical signs are seen?
- abscesses - anorexia, lethargy, weight loss, intermittent abdominal pain
- cysts - typically asymptomatic, abdominal distention, secondary infections behave like abscesses
In what 3 ways are cavitary lesions treated?
- drainage and omentalization
- lobectomy or partial hepatectomy
- antibiotics for 7-10 days (careful with peritonitis)
What are diaphragmatic hernias?
the liver passes through a hole in the diaphragm, causing it to become strangulated
What are the 5 major indications for partial lobectomies?
- biopsies
- trauma
- abscesses
- cysts
- neoplasia
How are partial lobectomies performed? Why are they so dangerous?
- 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
What is a common complication associated with cholecystitis/cholangiohepatitis?
peritonitis due to rupture of the gall bladder, especially when bacteria makes it emphysematous
The etiopathogenesis of biliary mucoceles is unclear. What are 3 possible causes?
- hyperplasia of mucus-secreting cells and excessive mucus production
- alterations in gallbladder motility
- accumulation of inspissated (thickened, congealed) bile
What is the most common signalment for biliary mucoceles? What are some clinical signs?
older small to medium breeds, especially Shelties and Cocker Spaniels
- vomiting
- anorexia
- lethargy
- PU/PD
- diarrhea
- none!
What are the most common PE findings in patients with biliary mucoceles?
- abdominal pain
- icterus
- fever
What are the 4 most common biochemical abnormalities seen with biliary mucoceles?
- elevated alkaline phosphatase (GB-specific)
- elevated alanine aminotransferase
- elevated g-glutamyl transferase
- increased total bilirubin
What is the best diagnostic imaging for biliary mucocele? What is characteristic?
ultrasonography
enlarged GB with immobile echogenic bile in a striated or stellate (kiwi) pattern
What medical management has been recommended for biliary mucoceles? Why is it not commonly used?
choleretic
contraction of the GB can cause rupture
What are the 6 indications for cholecystectomies?
- necrotizing cholecystitis
- chronic cholecystitis
- biliary mucoceles
- cholelithiasis
- neoplasia
- trauma
How can patency of the bile duct be confirmed?
catheterize the bile duct and flushing
- this confirms that the gall bladder can be removed
What pathology of the biliary tree is commonly seen?
- pancreatitis
- trauma (blunt, penetrating wounds)
- neoplasia
What 3 antibiotics are excreting in active form in bile? When are they recommended?
- Amoxicillin
- Cephazolin
- Enrofloxacin
when the patency of the common bile duct cannot be demonstrated
When are temporary solutions for biliary mucoceles recommended? What should be avoided in dogs?
reversible situations (trauma) when patency is demonstrated by catheterization but there is a functional obstruction
biliary diversion
What are cholecystotomy, cholecystectomy, and choledochotomy?
opening a hole in the GB and closing when done
removal of the GB
make a hole in the common bile duct and closing
What is the difference between cholecystoduodenostomy and cholecystojejunostomy?
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)
What must be ligated when performing a cholecystectomy? How should the common bile duct be maintained?
cystic artery
double ligate or hemoclip
(anything that comes out of the body should be submitted to histopath!)
What are 2 extraluminal causes of biliary obstruction?
- pancreatic disease
- duodenal disease
What is a choledochotomy? In what 2 cases is it recommended?
incision into dilated common bile duct
- choledocholithiasis
- biliary sludge
When is bile duct stenting most commonly done? What is the point? How is it done?
relieve obstruction due to extraluminal compression
temporarily divert bile after suturing the bile duct
suture a catheter into the intestinal wall with absorbably suture
When is biliary diversion recommended? What 3 procedures do this?
irreparable obstruction or trauma to the common bile duct
- cholecystoduodenostomy
- cholecystojejunostomy
- Roux-en-Y: jejunal conduit between gallbladder and duodenum or proximal jejunum
How large should the stoma for cholecystoduodenostomies be? Why?
2.5-3 cm
reduces the risk of gallbladder becoming impacted with ingesta causing cholecystitis or cholangiohepatitis
What is the most common complication with biliary diversions? What is seen in cats and dogs?
leakage
CATS = high morbidity and mortality usually linked to underlying disease or chronic vomiting
DOGS = ascending infections and bleeding at stoma site
What are the most common causes of bile peritonitis following biliary diversions?
- 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
What is the most common cause of bleeding following biliary diversions?
failure to ligate the cystic artery
What is the most common sign of bile peritonitis in the abdominal cavity?
green, greenish-brown discoloration
How are abdominal effusions used to diagnose bile peritonitis?
four-quadrant, ultrasound-guided, or diagnostic peritoneal lavage taps are compared to serum bilirubin
- if positive, fluid is > 2x serum
What is the prognosis of sterile and infected bile peritonitis?
STERILE = chemical, well-tolerated and better prognosis
INFECTED = septic, guarded to poor prognosis
What is the main cause of extrahepatic biliary obstructions in cats?
pancreatitis ascending infection causing necrotizing colecystitis peritonitis —> sepsis
+/- duodenal or pancreatic carcinomas
How are drains placed for abdominal effusions?
open belly drainage with suturing of the caudal 1/3
What are the 2 major complications of abdominal effusion drainage?
- bile peritonitis due to failure of adequately ligating the cystic duct and small hepatic ducts entering the cystic duct
- bleeding from hepatic parenchyma and cystic arteries
