EUS-guided biliary drainage involves the visualization of dilated extra- and or intrahepatic bile ducts and the puncture of these ducts with a needle or a direct access device (LAMS). Puncture of dilated left intrahepatic bile ducts is usually performed from the upper part of the stomach whereas the common bile duct is best accessed from the bulbar portion of the duodenum. Aspiration of bile confirms the position within the bile duct. If necessary contrast injection provides cholangiography to plan the desired intervention. Subsequently, several procedures can be performed, depending on the clinical scenario and the puncture site.
Rendez-vous technique: This technique is mainly used for benign indications when retrograde cannulation of the bile duct fails. A prerequisite for the technique is an endoscopically accessible ampulla or anastomosis. After puncture of the bile duct, a guidewire is advanced via the needle through the ampullary orifice into the duodenum or the surgical anastomosis. While this might be easy in some cases, several challenges may occur. Firstly, with the trans-bulbar approach, the wire may find its way into the intrahepatic bile ducts rather than the ampulla. This can usually be overcome by moving to a long scope position, by deflecting the endoscope tip towards the ampulla or by using a guidewire with an angled tip. Secondly, the wire may not be able to pass the ampullary orifice (due to a distal stricture, impacted stone, ampullary stenosis, etc.). In that case, it might be necessary to insert a papillotome over the wire into the bile duct to further steer and support the wire. Advancement of a papillotome requires a prior cystogastrotomy using a 6 Fr cystogastrotome (preferred) or 4 mm balloon dilatation. Once transpapillary passage of the wire is achieved, the wire should be introduced deeply in the duodenum. The needle and the endoscope are removed leaving the wire in place. Next, a duodenoscope is introduced to visualize the wire protruding from the ampullary orifice. In most cases it is possible to cannulate the bile duct next to the wire. Occasionally, the wire needs to be retrieved using a snare into the endoscope instrument channel. In this way a papillotome can be introduced over the wire directly in the bile duct.
Choledochoduodenostomy (CDS): This technique (Figure 1A) is mainly used for malignant distal bile duct obstruction when the ampulla is not accessible or when retrograde cannulation fails. It is important to verify duodenal patency beforehand, or to place a duodenal stent or an endoscopic gastrojejunostomy if indicated. The conventional technique involves trans-bulbar puncture of the dilated common bile duct, then a guidewire is advanced upstream into an intrahepatic bile duct and the puncture tract is dilated with a cystogastrotome (6 Fr) or a dilation balloon (4 mm). Thereafter, a fully covered metallic stent can be left in place to achieve biliary drainage. Stent migration can be an issue and can be overcome in different ways: By using a long covered metal stent, a LAMS (AxiosR, Boston Scientific, USA; NagiR stent, Taewoong Medical, South Korea) or by placing a partially covered stent with the uncovered portion within the bile duct. However, no short partially covered biliary stents are available at the current time (minimal length is currently 8cm with an uncovered part of 3 cm or 4 cm).
Figure 1 Schematic and case illustration of the choledochoduodenostomy (A) and the hepaticogastrostomy (B).
Patient A had a distal bile duct obstruction due to a locally advanced pancreatic head carcinoma. Patient B had a large perihilar metastasis of a small cell lung carcinoma with a complete obstruction of the proximal common bile duct but preserved left-right intrahepatic bile duct communication. The choledochoduodenostomy can be combined with a duodenal stent or an endoscopic gastrojejunostomy if indicated. Adapted from Paik et al.
The novel approach involves the use of a LAMS, with direct puncture of the dilated common bile duct using pure cut current, optional placement of a guidewire and delivery of the LAMS without a further dilation step. This technique is now favored in most centers. An 8 mm or 10 mm diameter stent is usually used, and for safe LAMS placement the diameter of the CBD should exceed 10 mm, to avoid misplacement
Hepaticogastrostomy (HGS): This technique (Figure 1B) can be used for proximal (perihilar) bile duct obstruction when the ampulla is not accessible, when retrograde cannulation fails, or when the left lobe cannot be drained by ERCP. It can also be used for malignant distal bile duct obstruction if the common bile duct is not accessible due to surgically altered anatomy (e.g., after Whipple procedure or roux-en-Y gastric bypass). It is the preferred technique by some experts in any distal malignant obstruction. In cases of perihilar bile duct obstruction, this route of drainage can only drain the left hepatic ducts in case of total hilar obstruction, or both liver lobes in case of left-right biliary communication. After puncture, guidewire introduction and dilatation of the puncture tract (using a 6 Fr cystogastrotome or a 4 mm dilatation balloon), a partially covered stent can be placed, with the uncovered part in the bile duct to prevent migration and the covered part bridging the bile duct and the gastric lumen (Giobor stent, Taewoong Medical, South Korea).
In benign diseases, the HGS can be created with a plastic stent to allow for removal, dilation and sequential repeat access to the bile ducts either for stricture dilatation, or stone lithotripsy.
EUS-guided antegrade transpapillary stent placement: This technique involves the same initial steps as described above for the rendez-vous technique but after placement of the guidewire, a metallic stent is advanced through the ampullary orifice in an antegrade fashion. This is technically more challenging than EUS-guided transmural drainage and does not eliminate the risk of pancreatitis. As such, the technique should be reserved for patients with benign distal bile duct strictures (e.g., in the context of chronic pancreatitis) in whom both the retrograde and rendez-vous approaches have failed. HGS and antegrade stent placement may be combined.