Endoscopic Ultrasound–Guided Access and Drainage of the Pancreaticobiliary Ductal Systems

Technical Considerations

Anatomically, the EUS-BD approach can be classified into two types: extrahepatic bile duct (EHBD) drainage and intrahepatic bile duct (IHBD) drainage. EUS-guided hepaticogas­trostomy (EUS-HGS) and EUS-guided choledochoduodenostomy (EUS-CDS) are typical transmural EUS-BD techniques. Other options, such as EUS-guided rendezvous (EUS-RV) and EUS-guided antegrade stenting (EUS-AS), have also been reported.

EUS-Guided Extrahepatic Bile Duct Drainage

Puncture of the EHBD via the duodenum (EUS-CDS) ( Fig. 52.1 and Video 52.1 ) is a common approach in EUS-guided EHBD drainage. The EHBD is visualized from the duodenal bulb using EUS in a long scope position. The direction of the needle in the long scope position is toward the hilar bile duct. A 19-guage needle that has been prefilled with contrast medium is used to puncture the EHBD. After injection of contrast medium to delineate the IHBD, a 0.025-inch or 0.035-inch guidewire is placed. Tract dilation is performed using a standard ERCP catheter, a 6-Fr cautery dilator (Cyst-Gastro set, Mediglobe, Germany), and/or a 3- to 4-mm dilating balloon. Using a needle knife may increase the risk of adverse events. With regard to current, a high-frequency electrocautery setting such as AutoCut mode (100 W, effect 4, ICC200, ERBE Elektromedizin GmbH, Tübingen, Germany) is used. It is very important to keep the endoscope pressed against the duodenal wall (endoscopically, the so-called red spot) while taking ultrasonography images of the long axis of the bile duct and guidewire. It is also important to maintain the optimal scope position during radiography. In addition, it is critical to arrange the equipment that will be needed in advance to complete the procedure appropriately and in a short time. Finally, the type of stent used, such as a plastic stent (PS) or a self-expandable metal stent (SEMS) (including fully covered and partially covered SEMS), depends on the preference of the endosonographer, although SEMS appears to be more suitable for avoiding bile leakage and postprocedure bleeding.

Thus far, conventional tubular biliary stents have been used for EUS-CDS. Recently, dedicated stents for EUS-BD have also been developed. The new, commercially available biflanged lumen-apposing metal stent AXIOS (Boston Scientific Corp., Natick, MA) ( Fig. 52.2 ) is a safe and useful SEMS for EUS-CDS. Furthermore, the Hot AXIOS stent (Boston Scientific Corp.), a cautery-enhanced delivery system for single-step EUS-guided puncture and delivery of a lumen-apposing stent for EUS-CDS, has also been developed ( Fig. 52.3 ). When we use this one-step delivery system, freehand EUS-CDS can be performed without any needle puncture or tract dilation, although the bile duct must be dilated to a diameter great than 2 cm for safe stent deployment.

EUS-Guided Intrahepatic Bile Duct Drainage

Puncture of the IHBD via the stomach (EUS-HGS) ( Fig. 52.4 and Video 52.2 ) is a common approach to EUS-guided IHBD drainage. Although rare, transjejunal IHBD drainage is possible in patients with altered anatomy such as total gastrectomy and Roux-en-Y reconstruction. The IHBD is small compared with the EHBD. If the IHBD is not dilated adequately, the use of a 22-guage needle is also an option. However, in such cases, guidewire manipulation following puncture is not easy to perform. After needle puncture, it is important to insert the guidewire into the bile duct as far as possible. Tract dilation of the fistula is achieved by basically the same procedure as is EUS-guided EHBD drainage. Finally, a PS or SEMS is placed in the IHBD. Similar to EUS-CDS, dedicated PSs and SEMSs (including partially or fully covered SEMSs ) have been developed for EUS-HGS ( Fig. 52.5 ).

When selecting the IHBD to puncture, is it better to puncture intrahepatic bile duct 2 (B2) or bile duct 3 (B3)? Although this depends on the patient's anatomy, B2 puncture may provide easier guidewire manipulation and stent delivery system insertion because the puncture is performed smoothly in a downstream direction toward the EHBD compared with B3 puncture. However, the B2 puncture site tends to be close to the esophagogastric junction, and stent deployment or re-intervention may be difficult. Moreover, there is a possibility of transesophageal puncture, leading to mediastinitis.