Surgery of the gall bladder and bile duct is indicated for bile duct laceration, bile duct obstruction and gallbladder mucocele. It rarely requires surgery unless the patient cannot be stabilized with appropriate fluid-therapy and blood transfusion. Cholelithiasis has to be considered when obstructive icterus is present Stones could be solitary, numerous or sand-like. Most canine and feline stones are calcium salts of bilirubinate. Bile stasis and inflammation might be cause for the formation of bile stones. Cholecystitis has been reported in dogs. It could be acute or chronic and a necrotizing or emphysematous form has been described. Extrahepatic biliary obstruction occurs when disease processes interfere with normal flow of bile from the liver and the gallbladder into the intestine.
The liver has 6 lobes: left medial and lateral, right medial and lateral, quadrate lobe and the caudate lobe with two processes. The liver lobes are attached to the diaphragm by the triangular ligaments. There are also the hepato-gastric ligament, the duodeno-hepatic ligament with the bile duct and the hepato-renal ligament stabilizing the liver. The liver receives 70% of its blood supply from the portal vein and 30% from the hepatic artery. The blood from the hepatic artery and the portal vein mixes in the hepatic sinusoids and is released in the caudal vena cava through the hepatic vein. There is one hepatic vein per liver lobe.
Intrahepatic bile ducts in each liver lobes collect extrahepatic bile ducts. There is one bile duct per liver lobe collecting into the common bile duct. The cystic bile duct connects the gallbladder to the common bile duct. The gallbladder receives it blood supply from the cystic artery that is a branch of the hepatic artery.
Portal venous blood is an important source of bacteria for the liver. Infections of the liver and biliary tract commonly involve gram-negative aerobic bacteria (E. coli, Enterococcus faecalis, Proteus, Klebsiella). Anaerobic bacteria can also colonize the liver in dogs (Clostridium).
Antibiotics are routinely administered when hepatobiliary surgery is performed. Cephalosporins provide broad spectrum coverage. When anaerobic bacteria are suspected, metronidazole or enrofloxacin should be used.
Cholecystotomy is indicated to remove inspissated bile or biliary sludge, gelatinous bile or gallstones and bile duct stones. It is also performed to cannulate the bile duct to evaluate its patency.
Two stay sutures of 3-0 monofilament are placed in the gall bladder. A small incision is made between the two stay sutures and suction is used to aspirate the bile overflow before it contaminates the abdominal cavity. The incision is then enlarged with Metzenbaum scissors. The incision should be long enough to perform the procedure. The bile duct needs to be catheterized before closure. It could be difficult to achieve good catheterization because of the angle of the cystic duct with the common bile duct.
A biopsy of the wall of the gallbladder is taken for histology and culture before closure. The gallbladder is then closed with a simple suture pattern with 4-0 monofilament absorbable suture. A one-layer closure is sufficient.
A cholecystectomy is required when the gallbladder is the primary cause of the pathological process or if the damage to the gall bladder is too severe and might contribute to the recurrence of the disease. Cholecystitis and gallbladder mucocele are best treated by cholecystectomy.
Cholecystectomy requires the dissection of the gallbladder from the quadrate lobe. The gallbladder is lodged in the hepatic fossa and it is covered by visceral peritoneum. Dissection starts at the fundus of the gall bladder by an incision through the visceral peritoneum. The dissection should not be in the liver parenchyma because severe bleeding will occur. The dissection is then carried with cautery toward the infundibulum of the gall bladder. The cystic duct and the cystic artery are isolated, clamped and ligated. The cystic duct is ligated at a sufficient distance from the common bile duct to prevent kinking of the common bile duct. If the liver parenchyma is bleeding, cautery could be used to control the bleeding or gentle pressure could be applied for 5 minutes. Gelfoam could also be applied on the bleeding surface of the liver.
Cholecystoduodenostomy is the procedure of choice for bile diversion in dogs and cats when the gall bladder is not directly involved in the disease process that is causing the bile duct obstruction. It could be a palliative procedure for bile duct obstruction due to neoplasia.
The gall bladder is detached for the hepatic fossa as described for the cholecystectomy. Then the gall bladder is brought into contact with the duodenum with two stay sutures. Special attention should be placed on the cystic duct to avoid twisting and occlusion. The stoma between the gall bladder and the duodenum should be between 2 and 4 cm. A first layer of sutures is applied between serosal layers on the back side of the duodenum. The gall bladder and the duodenum are then incised. A simple continuous suture is placed between the mucosal layers of the gall bladder and the duodenum. Finally, another layer of simple continuous suture is placed between the serosa of the duodenum and the serosa of the gall bladder. A 4-0 monofilament absorbable suture material is used for the procedure.
After cholecystoduodenostomy, patients are at risk of ascending cholangiohepatitis and need to be maintained on enrofloxacin long term.
Choledochoduodenostomy can be performed if a benign obstruction occurs at the distal end of the bile duct. Significant dilation of the proximal part of the common bile has to be present to be able to perform this procedure.
The distal part of the common bile duct is separated from the pancreas and the duodenum. It is then implanted more proximal into the wall of the duodenum with two simple interrupted sutures.