Resumen de Initial experience with endoscopic retrograde cholangiography and endoscopic retrograde biliary stenting for treatment of extrahepatic bile duct obstruction in dogs
Objective—To describe techniques for endoscopic retrograde cholangiography (ERC) and endoscopic retrograde biliary stenting of the common bile duct (CBD) for minimally invasive treatment of extrahepatic bile duct obstruction (EHBDO) in dogs.
Design—Experimental study and clinical report.
Animals—7 healthy research dogs and 2 canine patients.
Procedures—ERC and endoscopic retrograde biliary stenting were performed in healthy purpose-bred research dogs and client-owned dogs with a diagnosis of EHBDO that underwent an attempted biliary stent procedure. Research dogs were euthanized after completion of the procedure and underwent necropsy. With dogs under general anesthesia, the pylorus was cannulated with a side-view duodenoscope, and the duodenum was entered. The major duodenal papilla (MDP) and minor duodenal papilla were then identified, and the MDP was cannulated. Endoscopic retrograde cholangiography and endoscopic retrograde biliary stenting were attempted with the aid of endoscopy and fluoroscopy in all dogs. Procedure time, outcome for duodenal and MDP cannulation, and success of stent placement were recorded.
Results—Endoscopic retrograde cholangiography was successfully performed in 5 of 7 research dogs and in 1 of 2 patients. Biliary stenting was achieved in 4 of 7 research dogs and 1 of 2 patients, with a polyurethane (n = 4) or self-expanding metallic stent (1). One patient had a mass such that visualization of the MDP was impossible and no attempt at biliary cannulation could be made. After placement, stent patency was documented by means of contrast cholangiography and visualization of biliary drainage into the duodenum intra-operatively. No major complications occurred during or after the procedure in any patient. Follow-up information 685 days after stent placement in 1 patient provided evidence of biliary patency on serial repeated ultrasonography and no evidence of complications.
Conclusions and Clinical Relevance—ERC and endoscopic retrograde biliary stenting were successfully performed in a small group of healthy dogs and 1 patient with EHBDO, but were technically challenging procedures. Further investigation of this minimally invasive technique for the treatment of EHBDO in dogs is necessary before this may be considered a viable alternative to current treatment methods.
Endoscopic retrograde cholangiopancreatography, first described in human patients in 1970,1 is a minimally invasive technique that combines endoscopy and fluoroscopy to image and perform various treatments within the biliary system (ERC) and pancreatic ducts (ERP). This technique can detect irregularities in the biliary and pancreatic ducts, enable identification and biopsy of suspicious lesions, allow collection of bile samples for evaluation, and localize gallstones to facilitate removal.2,3 Additionally, with this technique, bile duct obstructions can be definitively diagnosed and treated via therapeutic interventions including sphincterotomy or retrograde endoscopic biliary stenting.2–6 In human patients, ERCP is now considered the optimal minimally invasive treatment modality for diagnosis of many biliary and exocrine pancreatic tract diseases in adults.2,3,6 Diagnostic and therapeutic ERCP has more recently been described in children and has been found to be highly effective when performed with correct equipment and by appropriately trained operators.4–7 The most common cause of biliary obstruction in human patients is cholelithiasis, followed by pancreatitis, pancreatitis-associated biliary strictures, pancreatic or biliary neoplasia, and CBD strictures.2,6–9 Endoscopic retrograde sphincterotomy with biliary stenting is considered the treatment of choice for many of these conditions.2–4,6,8,10–13 Traditional reported treatment for EHBDO in veterinary small animal patients involves laparotomy with surgical manipulation of the CBD and pancreatic duct via choledochotomy, diversion procedures such as cholecystoenterostomy, or surgical stent placement across the MDP.14–19 Surgical biliary diversion techniques in dogs and cats have been associated with a 25% to 73% and 50% to 75% mortality rate, respectively.14–19 When a traditional open surgical approach was used for the placement of biliary stents, the mortality rate has been reported to be 30.7% in dogs16 and 28% in cats,17 respectively. Prolonged anesthesia times (median, 3.5 hours; range, 2.4 to 6.75 hours)16 and manipulation of the pancreatic and biliary system in unstable patients may contribute to the high morbidity and mortality rates reported with traditional rerouting surgery or open surgical stent placement.14–19 In human patients, similar risks and complications of traditional open surgeries in debilitated patients have led to the use of interventional radiology-guided procedures (eg, placement of cholecystostomy tubes and percutaneous biliary stenting) and interventional endoscopy techniques (eg, ERCP and biliary stenting) in an effort to minimize procedure-related complications.3,20–22 Frequently, biliary stenting is recommended as a bridge to more invasive biliary surgery once the patient is stabilized.22 The use of cholecystostomy tubes23 or decompressive cholecystocentesis24 are other minimally invasive options for temporary biliary decompression, although these procedures do not allow drainage of bile salts into the gastrointestinal tract. Endotoxemia and bacterial translocation may occur because the lack of luminal bile salts may promote increased intestinal permeability and intestinal bacterial overgrowth, which can overwhelm the hepatic reticuloendothelial system.25,26 This typically requires enteric bile salt replacement of the drained bile via a feeding tube until patency is reestablished. These procedures often help stabilize the patient, which can facilitate a more definitive permanent decompressive procedure at a later time.23–25 In 1974, Falkenstein et al27 reported performing ERCP in healthy dogs for physician training and research purposes and indicated that success in achieving CBD cannulation improved with experience. In 2005, Spillmann et al28,29 first reported successfully performing diagnostic ERCP in 7 clinically normal research dogs and 30 canine patients with vague gastrointestinal signs. To our knowledge, endoscopic biliary stenting has not been reported in the veterinary literature to date. The objective of the study reported here was to describe our initial experience with ERC and endoscopic retrograde biliary stenting of the CBD for minimally invasive treatment of EHBDO in dogs. The feasibility of the technique was evaluated in healthy research dogs, followed by treatment of 2 patients with EHBDO.
