Obstructive jaundice can result from benign or malignant etiologies. The common benign conditions include primary sclerosing cholangitis, chronic pancreatitis, and gallstones. Malignant biliary obstruction can be caused by direct tumor infiltration, extrinsic compression by enlarged lymph nodes or malignant lesions, adjacent inflammation, desmoplastic reaction from a tumor, or a combination of these factors. Malignant diseases causing biliary obstruction include pancreatic cancer, ampullary cancer, cholangiocarcinoma, and metastatic diseases. This article focuses on malignant distal biliary obstruction and its management.
Obstructive jaundice can result from benign or malignant etiologies. This article focuses on malignant distal biliary obstruction and its management.
Should drainage of malignant distal biliary obstruction be performed?
The most common cause of malignant distal biliary obstruction is pancreatic cancer and 70% to 90% of patients develop jaundice during the course of their disease. Pancreatic cancer is usually advanced at presentation, and curative resection is possible in less than 15% of patients.
Biliary drainage before surgical resection is controversial; two investigators have reported it to be beneficial but one has reported deleterious effects. In patients with symptomatic malignant obstruction, biliary drainage relieves jaundice and improves symptoms, such as nausea, loss of appetite, and pruritus. In addition, if patients are scheduled to undergo chemotherapy, biliary drainage is essential to avoid the potential hepatotoxicity of chemotherapeutic agents. However, if a patient is asymptomatic and will undergo surgical resection within 1 to 2 weeks, drainage is usually not advisable. By refraining from trying to drain the bile duct in this setting, one can avoid unwanted complications, such as cholangitis, pancreatitis, and perforation that would delay surgery. However, when surgical intervention is planned for more than 3 weeks into the future or is not possible because of the advanced stage of malignancy and the patient is symptomatic, biliary drainage should be considered.
How should biliary obstruction be relieved?
Malignant distal biliary obstruction can be managed by surgical bypass (choledochojejunostomy), by percutaneous transhepatic biliary drainage (PTBD), or by way of an endoscopic approach. Although biliary drainage was predominantly performed surgically before the 1980s, PTBD and then endoscopic drainage have since supplanted surgery for palliation of biliary obstruction. PTBD and surgical drainage are associated with considerable morbidity, patient discomfort, the need for repeated interventions, and occasionally death.
Multiple randomized controlled, prospective nonrandomized, and retrospective studies have compared surgical drainage with endoscopic drainage for malignant biliary obstruction and shown improved outcomes with the latter. A metaanalysis of 24 studies showed that endoscopic placement of plastic stents has the same technical and therapeutic success as surgical drainage procedures, similar quality of life and overall survival, a reduced risk of complications, and shorter hospital stay, albeit with an increased risk of recurrent biliary obstruction. Plastic stents with their small lumen diameters are susceptible to loss of patency within an average of 3 to 4 months because of the formation of adherent bacterial biofilm and accumulation of biliary sludge. However, self-expandable metal stents (SEMS), in their fully expanded state, have a lumen diameter three to four times that of plastic stents. The outcomes with SEMS have been shown to be superior to both surgical drainage and plastic stenting because of the increased SEMS patency from the larger lumens. Today, endoscopic biliary drainage is the standard of care for the treatment of malignant biliary obstruction. PTBD is most often used when endoscopic retrograde cholangiopancreatography (ERCP) has failed. Surgical choledochojejunostomy is usually reserved for relief of dual obstructions of the bile duct and duodenum.
How should biliary obstruction be relieved?
Malignant distal biliary obstruction can be managed by surgical bypass (choledochojejunostomy), by percutaneous transhepatic biliary drainage (PTBD), or by way of an endoscopic approach. Although biliary drainage was predominantly performed surgically before the 1980s, PTBD and then endoscopic drainage have since supplanted surgery for palliation of biliary obstruction. PTBD and surgical drainage are associated with considerable morbidity, patient discomfort, the need for repeated interventions, and occasionally death.
Multiple randomized controlled, prospective nonrandomized, and retrospective studies have compared surgical drainage with endoscopic drainage for malignant biliary obstruction and shown improved outcomes with the latter. A metaanalysis of 24 studies showed that endoscopic placement of plastic stents has the same technical and therapeutic success as surgical drainage procedures, similar quality of life and overall survival, a reduced risk of complications, and shorter hospital stay, albeit with an increased risk of recurrent biliary obstruction. Plastic stents with their small lumen diameters are susceptible to loss of patency within an average of 3 to 4 months because of the formation of adherent bacterial biofilm and accumulation of biliary sludge. However, self-expandable metal stents (SEMS), in their fully expanded state, have a lumen diameter three to four times that of plastic stents. The outcomes with SEMS have been shown to be superior to both surgical drainage and plastic stenting because of the increased SEMS patency from the larger lumens. Today, endoscopic biliary drainage is the standard of care for the treatment of malignant biliary obstruction. PTBD is most often used when endoscopic retrograde cholangiopancreatography (ERCP) has failed. Surgical choledochojejunostomy is usually reserved for relief of dual obstructions of the bile duct and duodenum.
SEMS
Since the first description of the endoscopic placement of SEMS to relieve biliary strictures in patients in 1989, the use of SEMS has been on the rise in the treatment of malignant distal biliary obstruction because of their relatively easy deployment and long duration of patency. By design, SEMS have a minimal surface area on which bacterial biofilm can form. The median patency durations for SEMS have been reported to be 9 to 12 months when used for malignant distal obstruction. In parallel with the advances in the design and material of SEMS, the application of SEMS has also expanded from their initial exclusive use for malignant strictures to their use to treat benign strictures. Many questions remain unanswered about SEMS. This article reviews the issues pertaining to SEMS in the setting of malignant distal biliary strictures.
The commonly used commercially available SEMS are listed in ( Figs. 1–5 ) Table 1 . The first widely used SEMS were made of stainless steel, whereas today most SEMS are made of the nickel alloy nitinol.
| Stent | Manufacturer | Metal, Design, Coating | Covering Options | Length (mm) | Diameter (mm) Options | Radiopacity/No. Markers | Reconstrainability | Delivery Catheter (Fr) | Shortening (%) | Cell Size | Axial Force AF | Radial Force RF | Ends |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Flexxus | ConMed | Nitinol | UC only | 40, 60, 80, 100 | 8, 10 | ++ (tantalum)/4 | No | 7.5 | <1 | +++ | ++ | ++ | Flared |
| a Niti-S | Taewoong Medical | Nitinol, hand-woven | FC, UC | 40, 50, 60, 70, 80, 90, 100, 110, 120 | 8, 10 | ++/10 | Yes (30%–40%) | 8.5 | No | ++ | + | ++ | Looped, flared |
| X-Suit NIR | Olympus Med | Nitinol | UC | 40, 60, 80 | 8, 10 | ++/4 | No | 7.5 | No | ++ | N/A | N/A | Rounded |
| Viabil | Gore Medical | Nitinol, laser cut, ePTFE | FC | 40, 60, 80, 100 | 8, 10 | ++/2 | No | 10 | No | N/A | + | ++ | Flared |
| WallFlex RX | Boston Scientific | Platinol, braided, silicone | UC, PC, FC | 40, 60, 80, 100 | 8, 10 | +++/4 | Yes (80%) | 7.5 | 40 | + | +++ | + | Looped, flared |
| Wallstent RX | Boston Scientific | Elgiloy, braided | UC, FC, PC | 40, 60, 80, 100 | 8, 10 | +++/4 | Yes (80%) | 7.5 | 40 | + | +++ | + | Open, flared |
| Zilver | Cook Medical Endoscopy | Nitinol | UC | 40, 60, 80 | 6, 8, 10 | ++/4 | No | 7 | No | +++ | + | + | Flared |
Recently, Weston and colleagues reported a comparison of the clinical outcomes of nitinol and stainless steel uncovered metal stents for malignant distal biliary stricture. In this study, a total of 81 nitinol and 96 stainless steel stents were placed to relieve malignant biliary strictures. The most common cancer diagnosis was pancreatic (80.2% of nitinol stents and 62.5% of stainless steel stents; P = .06), and the most frequent site of stricture was the common bile duct (85.2% nitinol and 86.5% stainless steel; P = .31). Biliary decompression was achieved in 93.8% of the nitinol group and 86.4% of the stainless steel group ( P = .22). Immediate stent manipulation was required in four patients in each group, and subsequent intervention for poor drainage was performed in 17 patients with nitinol stents (21%) and 26 patients with stainless steel stents (27%) at mean times of 142.1 days (range, 5–541 days; median, 77 days) and 148.1 days (range, 14–375 days; median, 158.5 days), respectively ( P = .17). The overall duration of stent patency in the nitinol and stainless steel groups were similar (median, 129 and 137 days, respectively; P = .61), including in a subgroup analysis performed on patients with pancreatic cancer ( P = .60) and common bile duct strictures ( P = .77). Complication rates were low in both groups (early, 3.7% nitinol and 6.3% stainless steel; late, 2.5% nitinol and 3.1% stainless steel). Of note, 90% of patients underwent chemotherapy and 38% underwent radiation therapy in each group. At the present time, it seems there is no clear clinical advantage in one type of SEMS over the other.
Techniques in cannulating and deploying SEMS in malignant distal biliary stricture
Traditional ERCP and SEMS Deployment
The available imaging studies, such as computed tomography, magnetic resonance imaging, or magnetic resonance cholangiopancreatography, should be thoroughly reviewed. Particular attention should be paid to identifying biliary ductal dilation, foci of strictures, intrahepatic ductal involvement, volume of the liver affected, duodenal stricture, and gastric outlet obstruction. Because the biliary system is sterile until ERCP is performed, the benefits and risks of performing ERCP should be carefully assessed.
The bile duct is usually cannulated with a sphincterotome and a guidewire. Gentle, nontraumatic movements increase the odds of successful cannulation. Often, the mucosa in the setting of malignancy is quite friable and bleeds easily. Therefore, a traumatic approach can result in blurring of the anatomy from mucosal swelling and bleeding, decreasing the chance of successful cannulation. Once biliary cannulation is successful, aspiration of bile should be done before injection to avoid dispersing bacteria that can cause sepsis. The minimal amount of contrast material needed to define the stricture and biliary anatomy should be used because of the difficulty of draining all the contrast material in cases of complex biliary strictures.
Once the stricture is identified, the length, location, and complexity of the stricture are assessed. The length of the stricture is often defined by using the sphincterotome under fluoroscopy. The proximal tip of the sphincterotome is placed at the proximal end of the stricture, and the sphincterotome is grasped at the biopsy port. The sphincterotome is then pulled back down to the ampulla under fluoroscopic visualization. Next, the distance of the sphincterotome that was pulled back from the biopsy port is measured and corresponds to the length of the stricture.
The predeployed metal stent is advanced over the guidewire into the bile duct. Most SEMS have radiopaque markers in their proximal and distal ends (some also have markers in the middle). For stents that foreshorten, the proximal marker should be placed well above the proximal end of the stricture. Once the stent is in the proper place, the outer sheath of the SEMS is slowly withdrawn by an assistant as the endoscopist is applying gentle pulling tension on the stent to compensate for the force of the stent propelling forward. Some stents can be reconstrained when partially deployed up to a certain point if the stent position is not optimal. Most stents that are reconstrainable have a mark on the stent beyond which the stent cannot be reconstrained.
Soon after a SEMS is deployed (see Figs. 1 and 2 ), flow of bile should occur. If a SEMS fails to expand and poor drainage is observed, balloon dilation of the stricture within the stent can be performed to facilitate immediate drainage. The size of the balloon should not be larger than the stent diameter.
Precut Needle-Knife Sphincterotomy
In many patients with pancreatic cancer, the regional anatomy is distorted because of the size of the tumor in the head of the pancreas or peritumoral inflammatory response. This distortion makes placement of the endoscope under the ampulla difficult. In this circumstance, achieving the proper angle for cannulation becomes difficult. One way to cannulate the bile duct is first to place a pancreatic ductal stent and then to perform a precut needle-knife sphincterotomy upward from the pancreatic duct stent in the direction of the bile duct (11–12 o’clock). However, if the tumor extends down to the ampulla, a precut with a needle knife may not help because the bile duct is markedly strictured at the supraampullary segment. Furthermore, collateral vessels from portal vein thrombosis caused by the tumor may increase the risk of bleeding.
Endoscopic Ultrasound-Guided SEMS Placement
The role of endoscopic ultrasound (EUS) has been expanding from a diagnostic to an interventional one, and EUS is now increasingly used to guide biliary drainage. EUS-guided cannulation of the bile duct can facilitate obtaining biliary access when attempts at conventional ERCP-cannulation are not successful. There are three approaches to EUS-guided biliary drainage.
EUS-ERCP rendezvous technique
In this technique, using a 19- or 22-gauge needle, the obstructed bile duct is accessed under EUS guidance through the duodenum at a point proximal to the papilla. A guidewire is passed through the needle into the bile duct and antegrade through the papilla. The echoendoscope is removed and a standard duodenoscope is inserted. The guidewire is then grasped by a forceps and conventional ERCP is performed. Using this approach Kim and colleagues reported that successful bile duct puncture and wire passage was achieved in 15 (100%) of 15 patients and successful drainage was completed in 12 (80%) of 15 patients. Although there were two complications, no bile leak or perforation was seen in this series.
In a variation on this technique, the left hepatic duct can be found by EUS with the scope placed in the stomach. The left hepatic duct is punctured with a 19-gauge needle under EUS guidance, and the guidewire is advanced down to the duodenum through the needle, stricture, and ampulla under fluoroscopic guidance. The echoendoscope is then replaced by a side-viewing endoscope, and the guidewire is grabbed and conventional ERCP can be performed.
EUS-guided transhepatic SEMS placement
Some have described placing SEMS over a guidewire through the stomach wall, liver, and then papilla. In this technique, once the fine needle is removed, the tract is dilated over the wire to 7 Fr or 8.5 Fr catheter using an ERCP catheter (Soehendra Biliary Dilation Catheter; Cook Medical, Winston-Salem, NC, USA). Subsequently, a SEMS is advanced over the guidewire through the therapeutic echoendoscope and deployed across the stricture via the papilla. Nguyen-Tang and colleagues reported five successful placements of SEMS without any complications using this technique. The technique seems to be somewhat more invasive than others and requires expertise in therapeutic endoscopy. Clipping the gastric site of puncture should be considered to prevent leakage of gastric juice through the puncture site.
EUS-guided transluminal SEMS placement
In this technique, the bile duct is visualized by EUS and punctured with a 19- or 22-gauge needle under EUS guidance. The stylet of the needle is then removed and bile is aspirated. Next, a guidewire (0.018–0.025) is introduced into the needle and advanced further into the bile duct. The fine needle is removed, and after balloon dilation of the tract, a SEMS is placed over the guidewire through this tract. The entry point of the bile duct should be near the ampulla and at least within the head of the pancreas (not at the common hepatic duct where bile leaks can occur). In a study involving eight patients who had covered SEMS placed using this technique the technical success rate was 100%, although one duodenal perforation occurred following stent migration.
Specific issues
Covered Versus Uncovered SEMS
Covered SEMS were introduced in the 1990s to improve the patency of SEMS by preventing tissue ingrowth, which occurs in up to 20% of patients who have SEMS placement. However, unlike uncovered SEMS, which are integrated into the tumor or duct wall as a result of pressure necrosis, covered SEMS do not embed and have an increased risk of migration. Although many retrospective studies comparing endoscopic placement of covered SEMS and uncovered SEMS for malignant biliary obstruction have shown prolongation of patency, with covered SEMS, prospective randomized trials have not shown a definitive advantage in one over the other ( Table 2 ). However, covered SEMS were found to have a higher rate of stent migration.
| Authors | Year | Study Design | Number of Patients | SEMS Used | Patency | Complications |
|---|---|---|---|---|---|---|
| Isayama et al | 2004 | Prospective | 115 C: 57 U: 55 | Ultraflex Diamond | C: 225 (11–1155) U: 193 (12–810) | C: Cholecystitis in 2 a Pancreatitis in 5 (8.7%) U: Pancreatitis in 1 (1.8%) Hemorrhage in 2 (3.6%) |
| Yoon et al | 2006 | Retrospective | 77 C: 36 U: 41 | Wallstent | C: 245 U: 202 | C: Migration in 2 (5.5%) Cholecystitis in 1 (2.7%) U: Migration in 1 (2.4%) |
| Park et al | 2006 | Retrospective | 206 C: 98 U: 108 | Wallstent | C: 148.9 U: 143.5 | C: Pancreatitis in 6 (6.1%) Migration in 6 (6.1%) Cholecystitis in 5 (5.6%) U: Pancreatitis in 2 (1.8%) Cholecystitis in 1 (1%) |
| Gonzalez-Huix et al (abstract) | 2008 | Retrospective | 114 C: 61 U: 53 | Wallstent | N/A N/A | C: Migration in 7 (11.5%) Cholecystitis in 2 a Pancreatitis in 1 (1.6%) U: No complication |
| Cho et al (Abstract) | 2009 | Retrospective | 77 C: 39 U: 38 | C: Wallstent U: Bonastent, Hanarostent | C: 227 U: 195 | N/A N/A |
| Gwon et al | 2010 | Prospective and retrospective b | 116 C: 58 U: 58 | C: Hercules U: Silver, Sentinol | C: c 98% 98% 91% 76% U: c 98% 83% 72% 57% | C: Migration in 2 (3.4%) Cholecystitis in 1 (1.7%) U: No complication |
| Kullman et al | 2010 | Prospective | 400 C: 200 U: 200 | Nitinella | C: c 95% 83% 74% 50% U: c 97% 87% 78% 56% | C: Cholangitis in 8 (4%) Pancreatitis in 3 (1.5%) Cholecystitis in 2 (1.1%) U: Cholangitis in 12 (6%) Pancreatitis in 4 (2%) Cholecystitis in 2 (1.1%) |
| Krokidis et al | 2010 | Prospective | 60 C: 30 U: 30 | C: Viabil U: Wallstent | C: 166 ± 87.7 U: 227.3 ± 139.7 | C: Peritoneal irritation in 2 Biloma formation in 1 U: Peritoneal irritation in 3 |
| Telford et al | 2010 | Prospective | 129 C: 68 U: 61 | Wallstent | C: 205 (82–311) U: 159 (75–301) | C: Migration in 8 (12%) Cholecystitis in 3 (7%) U: Cholecystitis in 3 (7%) Pancreatitis in 1 (2%) |
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Expandable Metal Stents: Principles and Tissue Responses
Expandable Stents for Benign Esophageal Disease
Plastic Biliary Stents for Malignant Biliary Diseases
Expandable Metal Stents for Benign Biliary Disease
Expandable Metal Stents for Malignant Hilar Biliary Obstruction
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