Management of Biliary and Pancreatic Ductal Obstruction: Endoprosthesis and Nasobiliary/Nasopancreatic Drain Placement

Nadav Sahar, MD

Richard A. Kozarek, MD, FACG, FASGE, AGAF, FACP

Therapeutic endoscopy has become the mainstay for treatment of biliary and pancreatic ductal obstruction and has acceptable complication rates in comparison to surgical or percutaneous drainage alternatives. Endoscopic placement of prostheses is useful in treating benign and malignant obstructions of the pancreaticobiliary tree, decompression of stone disease, prevention of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis, and closure of leakage and disruptions.

Biliary and pancreatic stents are now available in various designs and sizes and are either plastic or metal. Pancreatic stents generally differ from biliary stents by being of smaller diameter and having unique side holes that permit drainage of side branches.

INDICATIONS

As is the general rule for all ERCP cases, the indication for the procedure must be clear and not merely for diagnostic purposes (see Chapter 25). Of note, ductal drainage is often achieved by sphincterotomy alone, without the need for stenting (see Chapter 26). Common indications for endoscopic stenting include the following.

Biliary Endoprosthesis

1. Treatment of benign strictures (chronic pancreatitis, sclerosing cholangitis, posttransplant, post-sphincterotomy stenosis, etc.)
2. Malignant biliary obstruction (biliary, pancreatic, periampullary, or metastatic tumors)
3. Relief of obstructive jaundice
4. Closure of bile leaks or fistulae
5. Incomplete removal of bile duct stones
6. Trans-cystic duct gallbladder drainage in high-risk surgical patients

Pancreatic Endoprosthesis

1. Prevention of post-ERCP pancreatitis (usually reserved for high-risk patients—difficult cannulation, endoscopic ampullectomy, precut sphincterotomy, inadvertent repeated cannulation, etc.)
2. Treatment of pancreatic duct disruption or fistula
3. Drainage of pseudocysts
4. Pancreatic stones prior to endoscopic removal or extracorporeal shock-wave lithotripsy (ESWL)
5. Treatment of pancreatic strictures (such as seen in chronic pancreatitis)
6. Malignant pancreatic obstruction (more commonly for palliation)

Nasobiliary Drain

1. Palliation of malignant hilar strictures
2. Closure of bile leaks
3. Biliary obstruction secondary to difficult-to-treat bile duct stones
4. Post-ERCP when there is suspicion of incomplete stone removal, thereby enabling repeat cholangiogram

Nasopancreatic Drain

1. Similar to pancreatic endoprostheses when short-term drainage is desired or to aid targeting for ESWL
2. Pancreatic duct irrigation following ESWL

PREPARATION

Please also refer to general preparation before ERCP as detailed in Chapter 25 and the use of prophylactic antibiotics in Chapter 1.

EQUIPMENT, ENDOSCOPES, DEVICES, ACCESSORIES

1. The majority of therapeutic duodenoscopes have a 4.2 mm working channel enabling insertion of large endoprostheses up to 11.5 Fr in diameter. For pediatric patients or patients with high-grade luminal stenosis, smaller working channels may be required (i.e., pediatric colonoscopes, diagnostic
duodenoscopes, balloon enteroscopes, etc.), but these allow placement of stents up to 7 Fr in caliber. 7 mm duodenoscopes for neonates are variably available which allow placement of 5 Fr stents only.
2. Cannulation catheters range from 5 Fr standard-tip single channel to ultra-tapered 5-4-3 Fr and 6-7 Fr steerable ERCP catheters as well as dual-lumen ERCP catheters.
3. Guidewires range from 0.018″ to 0.035″ diameter and include hybrid and hydrophilic, straight, and angle-tips.
4. Sphincterotome (double or triple lumen to allow guidewire and contrast injection)
- a. Standard 6 Fr to 7 Fr diameter traction-type
- b. Small-caliber (5 Fr) wire-guided traction-
- c. Billroth II sphincterotome designed for B-II and Roux anatomy
- d. Needle knife
5. Water-soluble contrast (standard plus nonionic contrast for patients allergic to iodinated contrast)
6. Electrocautery unit
7. Dilating catheter 3 Fr to 10 Fr diameter
8. Dilating balloons 4 mm to 20 mm
9. 5 Fr to 10 Fr screw-type dilators (or stent extractors)
10. Snares, rat-tooth grasping forceps, and stone-retrieval baskets
11. Sclerotherapy needles, thermocoagulation (bipolar or heater probe) probes, and endoscopic clips for hemostasis
12. Wire-guided cytology brush
13. Small biopsy forceps

BILIARY ENDOPROSTHESES

Plastic stents: These are composed of polyethylene, polyurethane, or polytetrafluoroethylene and range in diameter from 5 Fr to 11.5 Fr. Plastic biliary stents are available in lengths from 1 to 18 cm long, are straight (angled, curved) with internal and external flaps to preclude migration, or are pigtail shaped.

Self-expanding metallic stents (SEMS): These were designed in order to overcome early stent occlusion which can occur with plastic stents. They are available as uncovered, partially (PC-SEMS) or fully covered (FC-SEMS). Most SEMS are made of nitinol. They range in lengths from 4 to 12 cm and diameters from 6 to 10 mm.

PANCREATIC ENDOPROSTHESES

Plastic stents: Plastic pancreatic stents are available in diameters ranging from 3 Fr to 11.5 Fr and lengths ranging from 2 to 25 cm. The inner end is always straight with one, two, or no flanges.
In order to prevent inward migration, the outer end is either straight with two flanges or has a single partial pigtail. Most of these stents are deployed over a wire.

Self-expanding metallic stents (SEMS): Currently only one SEMS is specifically designed for drainage of the main pancreatic duct (Niti-S, TaeWoong, Seoul, South Korea). Other fully covered SEMS used off-label have shown promising results, to include the biliary WallFlex stent (Boston Scientific) and the Viabil stent (Gore Medical), although the smallest diameter of these stents is 8 mm. 4, 6, and 8 mm WallFlex stents designed for the pancreas are under study currently but have not been FDA approved.

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