Extra-hepatic Biliary Tract Surgery Flashcards
Where is the gall bladder anatomically in the liver?
It is located in a depression between the quadrate lobe medially and the right medial lobe laterally
Where does bile drain from?
Hepatic ducts
What is different about the anatomy of cat gall bladder?
Bilobed
Where is the cystic duct anatomically located?
Extends from the neck of the gall bladder to the junction of the first branch from the liver
What is the course of the common bile duct
Courses into the lesser omentum and enters the duodenum on the mesenteric border.
Diameter of common bile duct in dogs?
3mm
Diameter of common bile duct in cats?
2-2.5mm
Is the terminal portion of the common bile duct intra and extra mural?
Intra
Where does the common bile duct terminate?
In the duodenum near the opening of the pancreatic duct at the major duodenal papilla.
What is different about the common bile duct in cats compared to dogs?
In cats, the common bile duct fuses with the pancreatic duct before reaching the papilla.
Which is the larger of the 2 pancreatic ducts?
Accessory
Where does the accessory pancreatic duct enter the duodenum?
Minor duodenal papilla (about 2.5 cm aboral to the major papilla)
What % of cats have an accessory pancreatic duct?
20%
Main extra hepatic diseases that require surgery? (3)
Extra-hepatic biliary obstruction (EHBO), traumatic injury and cholecystitis
What regional structure does the following refer to:
Choledoch
Common bile duct
What regional structure does the following refer to:
Cholangi
Any bile duct/vessel
What regional structure does the following refer to:
Cholelith
Stones
What regional structure does the following refer to:
Cholecyst
Gall bladder
What is a mucocele?
Mucous filled sac within the gall bladder due to dysfunctional mucous secreting cells
Common dog breed for mucocele? (3)
Border terrier
Shetland sheepdog
Miniature schnauzer
Prevalence of mucoceles in cats?
Rare
Common signalment in dogs with cholelithasis?
Age, breed, sex
Older, small breed, female
Common signalment in cats with cholelithasis?
Age, sex
Middle age-old, male
The most common causes of biliary tract obstruction in the dog are (2)
Pancreatitis
Neoplasia
Why are inflammatory causes of biliary obstruction most common in cats?
the intimate association between the pancreatic duct and common bile duct
What is triaditis?
Cholangitis
Pancreatitis
IBD
Biliary dx clinical signs? (9)
Jaundice
Vomiting
Abdominal pain (may not be present until bile becomes infected)
Ascites
Lethargy
Weight loss
Fever
Anorexia
Acute abdomen/septic shock
In cats, which tends to come first: Bilirubinuria or bilirubinaemia?
Bilirubinuria
Imaging of choice for biliary dx?
Ultrasound
Why may an ultrasound need to be repeated for biliary dx?
Dynamic nature of obtructive processes
What MAY xrays show with biliary dx? (4)
radiopaque stones in 14 to 50 % of the cases
hepatomegaly
gall bladder distension
loss of visceral detail suggestive of bile peritonitis.
When taking a bile espiration, why should you obtain as much bile as poss?
To prevent leakage
How to determine bile acid sept peritonitis?
When free abdominal fluid is sampled, bilirubin and/or bile acids should be determined in fluid and serum. With bile rupture the values of both parameters are higher in the fluid than in serum.
What other dx process is common with a mucocele?
Endocrinopathy
Possible medical management options for biliary dx?
Ursodeoxycholic acid
ABX
Vitamin K1
IVFT
What are the pharaco properties of Ursodeoxycholic acid? (2)
improve bile flow
help protect hepatocyte membranes
When is Ursodeoxycholic acid NOT advised?
Complete obstruction
Why is aggressive ABx advocated with biliary dx?
ideally based on culture and sensitivity, as EHBO can lead to bile stasis and bacterial growth and potentially septicaemia and enterotoxemia
Pre surgical ABx for Gram negative bacteria (e.coli)
Enrofloxacin
Pre surgical ABx for anaerobes (C.perfringens) (2)
Amoxicillin or metronidazole
Why is vitamin K1 a good option for biliary dx?
Vitamin K deficiency can occur secondarily to chronic biliary obstruction and this can lead to lowered levels of clotting factors II,VII, IX and X.
Dogs with gall bladder mucoceles often present with gall bladder necrosis and biliary obstruction, with significant mortality rates in symptomatic patients.
What treatment is indicated?
Cholecystectomy
Indications for gall bladder sx? (6)
Mucocele
Septic bile peritonitis
Cholelith
Bile flow obstruct - unresponsive to medical tx
Mass
EHBO due to pancreatitis
How to assess common bile duct patency at surgery? (3)
- Manual express
- Normograde catheter
- Retrograde catheter (only if necc!)
Choledochal stenting is mainly indicated for?
Short term stabilisation of bile duct during the course of a reversible disease process e.g., pancreatitis.
How are choledochal stents removed?
Stents should be passed in the faeces in 1-11 months or retrieved endoscopically if necessary.
Why can choledochal stents not be left in place long term?
Risk of ascending infect
Advantages of choledochal stenting? (2)
Less technically demanding than cholecystoenterostomy
The potential to be less time consuming
Placement of a choledochal stent:
Where is the intestinal incision made?
Longitudinal duodenotomy of the anti-mesenteric border of the duodenum opposite the major duodenal papilla.
Placement of a choledochal stent:
How to place after duodenal incision?
Pass 5- 10 cm red rubber catheter up the common bile duct via the major duodenal papilla so that one half is in the bile duct and the other half is in the duodenum.
Placement of a choledochal stent:
How to close?
Suture the stent to the submucosa using absorbable suture material.
Close duodenotomy
Thinking about the anatomy of the cat, why might choledochal stenting have a less favourable outcome in this species?
n cats, the implications of the stent on pancreatic function still need further evaluation as the lack of an accessory pancreatic duct in most cats means that exocrine pancreatic outflow could be obstructed by the presence of the stent.
Cholecystotomy is rarely performed but may be indicated when? (2)
remove some choleliths
when the gall bladder contents are inspissated and cannot be aspirated into a syringe
How to manipulate gall bladder during cholecystotomy?
Pack around gall bladder with large, soaked laparotomy pads and place stay sutures to aid manipulation of the gall bladder.
Cholecystotomy:
How is it entered?
Incise the fundus (rounded end of gall bladder), remove contents and submit for culture.
Following Cholecystotomy; how is it lavaged?
Warm, sterile saline
How to check bile duct patency with Cholecystotomy?
Catheterise the common bile duct via the cystic duct with a 3.5 or 5 Fr catheter to ensure patency.
How to close gall bladder following cholecystotomy?
Close gall bladder with 1 or 2 layer inverting absorbable sutures.
What are the main indications for cholecystectomy?
Cholelithiasis
Gall bladder neoplasia
Gall bladder trauma
Biliary mucocele
During a cholecystectomy; how to expose the gall bladder?
Expose the gall bladder and incise the visceral peritoneum along the junction of the gall bladder and liver with Metzenbaum scissors
Apply gentle traction to the gall bladder and using blunt dissection free it from the liver
During cholecystectomy; what needs to be identified an avoided?
The common bile duct and avoid damaging it during the procedure. If necessary, identify the common bile duct by carrying out a small enterotomy and placing a 3.5 or 5 Fr soft catheter into the duct via the duodenal papilla
What to clamp + ligate in cholecystectomy?
Clamp and double ligate the cystic duct and cystic artery with non-absorbable monofilamentsuture
Cut the duct distal to the ligatures and remove the gall bladder
Submit a portion of the wall plus bile for culture if infection is suspected
Submit the remainder of the gall bladder for histologic analysis if indicated
What is Choledochotomy?
direct incision of the common bile duct.
What must the common bile duct be to perform a choledochotomy?
- Dilated
- Not friable
Steps of a choledochotomy?
- Surround the bile duct with soaked laparotomy pads and place traction sutures in the distended bile duct.
- Make a small incision in the bile duct and remove obstruction.
- Flush the duct with warm saline and ensure patency.
- Close the duct with a single layer of simple interrupted or continuous suture.
- Submit stone for analysis
What is Cholecystoenterostomy?
Biliary diversion
When is Cholecystoenterostomy indicated?
- Trauma
- Inability to demonstrate patency
If a cholecystojejunostomy is performed, which aspect of jejunum should be used? Why?
proximal jejunum should be used to decrease the incidence of postoperative maldigestion of lipids.
What may occur more commonly as a sequela to cholecystojejunostomy than cholecystoduodenostomy?
Duodenal ulcer
Biliary diversion:
Bring the gall bladder and which side of the duodenum into close proximity so they are under no tension.
anti-mesenteric
Biliary diversion; what sutures between the serosa of the gall bladder and the serosa of the duodenum. Leave the ends long to help with manipulating tissues.
Using absorbable suture material, place a 3-4 cm line of continuous
Biliary diversion; what happens after you have drained the bladder?
make a 2.5-4 cm incision parallel to the preplaced suture line
during biliary diversion; what does an assistant occlude? What does the surgeon do?
proximal and distal jejunum make a similar incision in the duodenum.
Biliary diversion:
In dogs, it has been recommended that the stoma between the bowel and the gall bladder be at least how long (if possible) to minimize the potential for obstruction of bile flow or retention of bowel contents in the gall bladder.
3 to 4 cm
During biliary diversion - if a stoma is too small; what is the risk? (2)
stricture
ascending or chronic cholecystitis/hepatitis.
Biliary diversion; Using absorbable suture place a continuous suture line between the gall bladder mucosa and duodenum mucosa.
Where to start and finish?
Start at the edges closest to the original suture line then finish with the mucosa furthest from the suture line.
Why is the prognosis for biliary diversion in dogs guarded? (2)
Bleeding
Ascending infect
Tube cholecystostomy is used for
For temporary biliary decompression when bile duct is obstructed but is expected to remain fully functional once the primary disease process has been efficiently treated.
Peri-operative complications of biliary dx? (6)
Haemorrhage
Dehiscence
Hypotension
Pancreatitis
Pleural effusion
Electrolyte abnormality
When is bleeding likely to happen in biliary surgery? How can it be prevented?
Major bleeding can occur during dissection of the gall bladder form the hepatic fossa.
Pro-coagulation sheets can be placed in the hepatic fossa after dissection.
If haemorrhage becomes a significant issue and only when performing a bile flow diversion, the surgeon can decide not to dissect the gall bladder and do what instead?
apply the loop of jejunum directly to the gall bladder. This can be done only if tension free suturing can be achieved.
What artery is critical to preserve in biliary surgery? What happens if damaged?
It is critical to preserve the cystic artery in case of the bile flow diversion. If damaged, ischemic necrosis usually occurs in 24 to 48 hours.
Why does pancreatitis happen after biliary sx?
Pancreatitis can occur because of excessive traction on the pancreas.
Possible cause of hypotension after biliary surgery?
It is hypothesised that absence of bile salts in the intestinal tract leads to bacterial overgrowth and endotoxin absorption. An impaired clearance of endotoxins by the reticuloendothelial system will result in endotoxemia – a cause of hypotension. The hypotension is most often refractive to vasopressors.
How does pleural effusion occur with biliary dx?
Pleural effusion can occur after biliary tract rupture or cholecystectomy with spillage of gall bladder content in the abdominal cavity and copious lavage. Absorption and circulation of caustic bile products through diaphragmatic lymphatic vessels leading to inflammation and subsequent extravasation of fluid in the pleural space is the advocated mechanism.
Common electrolyte disturbances with biliary dx? (3)
Hypoglycaemia, hypokalaemia and hypoproteinaemia
