Palliation of malignant extrahepatic biliary obstruction with plastic versus expandable metal stents: an evidence-based approach

Abstract

Malignant extrahepatic (nonhilar) biliary obstruction is associated most commonly with pancreatic adenocarcinoma, but also may result from other pancreatic tumors, ampullary cancer, cholangiocarcinoma, gallbladder cancer, and malignant lymphadenopathy. The incidence of pancreatic adenocarcinoma is increasing, and it is estimated that >28,000 new cases will be diagnosed in the United States this year.1Jemal A. Murray T. Samuels A. Ghafoor A. Ward E. Thun M.J. Cancer statistics, 2003.CA Cancer J Clin. 2003; 53: 5-26Crossref PubMed Scopus (3363) Google Scholar Although it is the 10th most common malignancy, it is the 4th leading cause of cancer-related mortality and 2nd most common cause of cancer deaths for all gastrointestinal-related carcinomas.2Greenlee R.T. Murray T. Bolden S. Wingo P.A. Cancer statistics, 2000.CA Cancer J Clin. 2000; 50: 7-33Crossref PubMed Scopus (3963) Google Scholar Most patients with pancreatic cancer present late in their course, have either locally extensive or metastatic disease, and have a median survival of only 4–6 months.3Moossa A.R. Gamagami R.A. Diagnosis and staging of pancreatic neoplasms.Surg Clin North Am. 1995; 75: 871-890PubMed Scopus (55) Google Scholar, 4Warshaw A.L. Fernandez-del Castillo C. Pancreatic carcinoma.N Engl J Med. 1992; 326: 455-465Crossref PubMed Scopus (1544) Google Scholar At the time of diagnosis, only 10%–20% of patients are candidates for curative resection.5Barkin J.S. Goldstein J.A. Diagnostic approach to pancreatic cancer.Gastroenterol Clin North Am. 1999; 28: 709-722Abstract Full Text Full Text PDF PubMed Scopus (48) Google Scholar, 6Kozarek R.A. Endoscopy in the management of malignant obstructive jaundice.Gastrointest Endosc Clin North Am. 1996; 6: 153-176PubMed Google Scholar Late presentation, aggressive nature, and lack of effective therapies all contribute to the poor prognosis. Biliary obstruction develops in 70%–90% of patients and may lead to secondary complications, including jaundice, pruritus, hepatocellular dysfunction, cholangitis, malabsorption, and coagulopathy.4Warshaw A.L. Fernandez-del Castillo C. Pancreatic carcinoma.N Engl J Med. 1992; 326: 455-465Crossref PubMed Scopus (1544) Google Scholar, 7Smith A.C. Dowsett J.F. Russell R.C. Hatfield A.R. Cotton P.B. Randomised trial of endoscopic stenting versus surgical bypass in malignant low bileduct obstruction.Lancet. 1994; 344: 1655-1660Abstract PubMed Scopus (794) Google Scholar, 8Lichtenstein D.R. Carr-Locke D.L. Endoscopic palliation for unresectable pancreatic carcinoma.Surg Clin North Am. 1995; 75: 969-988PubMed Scopus (69) Google Scholar As a result, in most patients, the primary goal is to relieve biliary obstruction, which can be performed by surgical, radiological, or endoscopic means. These techniques are equally effective at relieving obstructive jaundice, with no difference in overall survival.7Smith A.C. Dowsett J.F. Russell R.C. Hatfield A.R. Cotton P.B. Randomised trial of endoscopic stenting versus surgical bypass in malignant low bileduct obstruction.Lancet. 1994; 344: 1655-1660Abstract PubMed Scopus (794) Google Scholar, 8Lichtenstein D.R. Carr-Locke D.L. Endoscopic palliation for unresectable pancreatic carcinoma.Surg Clin North Am. 1995; 75: 969-988PubMed Scopus (69) Google Scholar, 9Leung J.W. Emery R. Cotton P.B. Russell R.C. Vallon A.G. Mason R.R. Management of malignant obstructive jaundice at The Middlesex Hospital.Br J Surg. 1983; 70: 584-586Crossref PubMed Scopus (68) Google Scholar, 10Speer A.G. Cotton P.B. Russell R.C. Mason R.R. Hatfield A.R. Leung J.W. MacRae K.D. Houghton J. Lennon C.A. Randomised trial of endoscopic versus percutaneous stent insertion in malignant obstructive jaundice.Lancet. 1987; 2: 57-62Abstract PubMed Scopus (592) Google Scholar, 11Brandabur J.J. Kozarek R.A. Ball T.J. Hofer B.O. Ryan Jr, J.A. Traverso L.W. Freeny P.C. Lewis G.P. Nonoperative versus operative treatment of obstructive jaundice in pancreatic cancer cost and survival analysis.Am J Gastroenterol. 1988; 83: 1132-1139PubMed Google Scholar, 12Shepherd H.A. Royle G. Ross A.P. Diba A. Arthur M. Colin-Jones D. Endoscopic biliary endoprosthesis in the palliation of malignant obstruction of the distal common bile duct a randomized trial.Br J Surg. 1988; 75: 1166-1168Crossref PubMed Scopus (499) Google Scholar, 13Andersen J.R. Sorensen S.M. Kruse A. Rokkjaer M. Matzen P. Randomised trial of endoscopic endoprosthesis versus operative bypass in malignant obstructive jaundice.Gut. 1989; 30: 1132-1135Crossref PubMed Scopus (561) Google Scholar, 14van den Bosch R.P. van der Schelling G.P. Klinkenbijl J.H. Mulder P.G. van Blankenstein M. Jeekel J. Guidelines for the application of surgery and endoprostheses in the palliation of obstructive jaundice in advanced cancer of the pancreas.Ann Surg. 1994; 219: 18-24Crossref PubMed Scopus (143) Google Scholar, 15Mitty R. Cave D.R. Randomized trial of endoscopic stenting versus surgical bypass in malignant low bile duct obstruction.Gastrointest Endosc. 1995; 42: 281-282PubMed Google Scholar, 16Raikar G.V. Melin M.M. Ress A. Lettieri S.Z. Poterucha J.J. Nagorney D.M. Donohue J.H. Cost-effective analysis of surgical palliation versus endoscopic stenting in the management of unresectable pancreatic cancer.Ann Surg Oncol. 1996; 3: 470-475Crossref PubMed Google Scholar Endoscopic stent insertion safely and effectively reestablishes bile flow, alleviates jaundice and pruritus, and may improve quality of life (QOL).17Ballinger A.B. McHugh M. Catnach S.M. Alstead E.M. Clark M.L. Symptom relief and quality of life after stenting for malignant bile duct obstruction.Gut. 1994; 35: 467-470Crossref PubMed Scopus (243) Google Scholar, 18Luman W. Cull A. Palmer K.R. Quality of life in patients stented for malignant biliary obstructions.Eur J Gastroenterol Hepatol. 1997; 9: 481-484Crossref PubMed Scopus (114) Google Scholar, 19Abraham N.S. Barkun J.S. Barkun A.N. Palliation of malignant biliary obstruction a prospective trial examining impact on quality of life.Gastrointest Endosc. 2002; 56: 835-841Abstract Full Text Full Text PDF PubMed Scopus (175) Google Scholar In addition, endoscopic therapy with stent placement may offer lower morbidity and mortality, shorter hospitalization, and diminished overall cost compared with surgical or radiological approaches.7Smith A.C. Dowsett J.F. Russell R.C. Hatfield A.R. Cotton P.B. Randomised trial of endoscopic stenting versus surgical bypass in malignant low bileduct obstruction.Lancet. 1994; 344: 1655-1660Abstract PubMed Scopus (794) Google Scholar, 10Speer A.G. Cotton P.B. Russell R.C. Mason R.R. Hatfield A.R. Leung J.W. MacRae K.D. Houghton J. Lennon C.A. Randomised trial of endoscopic versus percutaneous stent insertion in malignant obstructive jaundice.Lancet. 1987; 2: 57-62Abstract PubMed Scopus (592) Google Scholar, 11Brandabur J.J. Kozarek R.A. Ball T.J. Hofer B.O. Ryan Jr, J.A. Traverso L.W. Freeny P.C. Lewis G.P. Nonoperative versus operative treatment of obstructive jaundice in pancreatic cancer cost and survival analysis.Am J Gastroenterol. 1988; 83: 1132-1139PubMed Google Scholar, 12Shepherd H.A. Royle G. Ross A.P. Diba A. Arthur M. Colin-Jones D. Endoscopic biliary endoprosthesis in the palliation of malignant obstruction of the distal common bile duct a randomized trial.Br J Surg. 1988; 75: 1166-1168Crossref PubMed Scopus (499) Google Scholar, 15Mitty R. Cave D.R. Randomized trial of endoscopic stenting versus surgical bypass in malignant low bile duct obstruction.Gastrointest Endosc. 1995; 42: 281-282PubMed Google Scholar, 16Raikar G.V. Melin M.M. Ress A. Lettieri S.Z. Poterucha J.J. Nagorney D.M. Donohue J.H. Cost-effective analysis of surgical palliation versus endoscopic stenting in the management of unresectable pancreatic cancer.Ann Surg Oncol. 1996; 3: 470-475Crossref PubMed Google Scholar Therefore, in most centers, endoscopic stent placement is favored for palliation of malignant extrahepatic biliary obstruction in patients who are poor surgical candidates and those with unresectable disease caused by extensive locoregional spread or distant metastases. Endoscopic insertion of a plastic or metal stent is technically successful in ∼90%–95% of patients with malignant extrahepatic biliary obstruction.20Davids P.H. Groen A.K. Rauws E.A. Tytgat G.N. Huibregtse K. Randomised trial of self-expanding metal stents versus polyethylene stents for distal malignant biliary obstruction.Lancet. 1992; 340: 1488-1492Abstract PubMed Scopus (968) Google Scholar, 21Carr-Locke D.L. Ball T.J. Connors P.J. Cotton P.B. Geenen J.E. Hawes R.H. Jowell P.S. Kozarek R.A. Lehman G.A. Meier P.B. Ostroff J.W. Multicenter, randomized, controlled trial of metal stents for malignant obstruction of the common bile duct.Gastrointest Endosc. 1993; 39 ([abstr]): 310AGoogle Scholar, 22Knyrim K. Wagner H.J. Pausch J. Vakil N. A prospective, randomized, controlled trial of metal stents for malignant obstruction of the common bile duct.Endoscopy. 1993; 25: 207-212Crossref PubMed Scopus (503) Google Scholar, 23Prat F. Chapat O. Ducot B. Ponchon T. Pelletier G. Fritsch J. Choury A.D. Buffet C. A randomized trial of endoscopic drainage methods for inoperable malignant strictures of the common bile duct.Gastrointest Endosc. 1998; 47: 1-7Abstract Full Text Full Text PDF PubMed Scopus (426) Google Scholar, 24Kaassis M. Boyer J. Dumas R. Ponchon T. Coumaros D. Delcenserie R. Canard J.M. Fritsch J. Rey J.F. Burtin P. Plastic or metal stents for malignant stricture of the common bile duct? Results of a randomized prospective study.Gastrointest Endosc. 2003; 57: 178-182Abstract Full Text PDF PubMed Scopus (395) Google Scholar Plastic stents commonly are used because of their efficacy and low cost. These stents are exchanged easily as long as duodenal narrowing does not prohibit passage of the endoscope. The major drawback of plastic stents is the formation of a bacterial biofilm, leading to stent obstruction, recurrent jaundice, and occasional cholangitis. As a result, a repeated endoscopic retrograde cholangiogram (ERC) and stent exchange are necessary in 30%–60% of patients with malignant extrahepatic biliary obstruction.7Smith A.C. Dowsett J.F. Russell R.C. Hatfield A.R. Cotton P.B. Randomised trial of endoscopic stenting versus surgical bypass in malignant low bileduct obstruction.Lancet. 1994; 344: 1655-1660Abstract PubMed Scopus (794) Google Scholar, 20Davids P.H. Groen A.K. Rauws E.A. Tytgat G.N. Huibregtse K. Randomised trial of self-expanding metal stents versus polyethylene stents for distal malignant biliary obstruction.Lancet. 1992; 340: 1488-1492Abstract PubMed Scopus (968) Google Scholar, 22Knyrim K. Wagner H.J. Pausch J. Vakil N. A prospective, randomized, controlled trial of metal stents for malignant obstruction of the common bile duct.Endoscopy. 1993; 25: 207-212Crossref PubMed Scopus (503) Google Scholar, 24Kaassis M. Boyer J. Dumas R. Ponchon T. Coumaros D. Delcenserie R. Canard J.M. Fritsch J. Rey J.F. Burtin P. Plastic or metal stents for malignant stricture of the common bile duct? Results of a randomized prospective study.Gastrointest Endosc. 2003; 57: 178-182Abstract Full Text PDF PubMed Scopus (395) Google Scholar, 25Schmassmann A. von Gunten E. Knuchel J. Scheurer U. Fehr H.F. Halter F. Wallstents versus plastic stents in malignant biliary obstruction effects of stent patency of the first and second stent on patient compliance and survival.Am J Gastroenterol. 1996; 91: 654-659PubMed Google Scholar Efforts to prolong the patency of plastic stents have included alterations in stent design and administration of ursodeoxycholic acid, antibiotics, aspirin, or other agents.26England R.E. Martin D.F. Morris J. Sheridan M.B. Frost R. Freeman A. Lawrie B. Deakin M. Fraser I. Smith K. A prospective randomised multicentre trial comparing 10 Fr Teflon Tannenbaum stents with 10 Fr polyethylene Cotton-Leung stents in patients with malignant common duct strictures.Gut. 2000; 46: 395-400Crossref PubMed Scopus (73) Google Scholar, 27Libby E.D. Leung J.W. Ultrasmooth plastic to prevent stent clogging.Gastrointest Endosc. 1994; 40: 386-387Abstract Full Text Full Text PDF PubMed Scopus (10) Google Scholar, 28Sung J.Y. Shaffer E.A. Costerton J.W. Antibacterial activity of bile salts against common biliary pathogens. Effects of hydrophobicity of the molecule and in the presence of phospholipids.Dig Dis Sci. 1993; 38: 2104-2112Crossref PubMed Scopus (73) Google Scholar, 29Ghosh S. Palmer K.R. Prevention of biliary stent occlusion using cyclical antibiotics and ursodeoxycholic acid.Gut. 1994; 35: 1757-1759Crossref PubMed Scopus (73) Google Scholar Unfortunately, these therapies have had minimal impact on stent patency and clinical outcomes. More recently, self-expanding metal stents (SEMS), which achieve a larger luminal diameter, have been used with the goal of prolonging stent patency. Comparative trials showed greater patency and overall cost-effectiveness for SEMS relative to plastic stents because of the need for fewer repeated interventions.20Davids P.H. Groen A.K. Rauws E.A. Tytgat G.N. Huibregtse K. Randomised trial of self-expanding metal stents versus polyethylene stents for distal malignant biliary obstruction.Lancet. 1992; 340: 1488-1492Abstract PubMed Scopus (968) Google Scholar, 21Carr-Locke D.L. Ball T.J. Connors P.J. Cotton P.B. Geenen J.E. Hawes R.H. Jowell P.S. Kozarek R.A. Lehman G.A. Meier P.B. Ostroff J.W. Multicenter, randomized, controlled trial of metal stents for malignant obstruction of the common bile duct.Gastrointest Endosc. 1993; 39 ([abstr]): 310AGoogle Scholar, 22Knyrim K. Wagner H.J. Pausch J. Vakil N. A prospective, randomized, controlled trial of metal stents for malignant obstruction of the common bile duct.Endoscopy. 1993; 25: 207-212Crossref PubMed Scopus (503) Google Scholar, 23Prat F. Chapat O. Ducot B. Ponchon T. Pelletier G. Fritsch J. Choury A.D. Buffet C. A randomized trial of endoscopic drainage methods for inoperable malignant strictures of the common bile duct.Gastrointest Endosc. 1998; 47: 1-7Abstract Full Text Full Text PDF PubMed Scopus (426) Google Scholar, 24Kaassis M. Boyer J. Dumas R. Ponchon T. Coumaros D. Delcenserie R. Canard J.M. Fritsch J. Rey J.F. Burtin P. Plastic or metal stents for malignant stricture of the common bile duct? Results of a randomized prospective study.Gastrointest Endosc. 2003; 57: 178-182Abstract Full Text PDF PubMed Scopus (395) Google Scholar However, they offer no survival advantage compared with plastic stents and have an uncertain influence on QOL.20Davids P.H. Groen A.K. Rauws E.A. Tytgat G.N. Huibregtse K. Randomised trial of self-expanding metal stents versus polyethylene stents for distal malignant biliary obstruction.Lancet. 1992; 340: 1488-1492Abstract PubMed Scopus (968) Google Scholar, 21Carr-Locke D.L. Ball T.J. Connors P.J. Cotton P.B. Geenen J.E. Hawes R.H. Jowell P.S. Kozarek R.A. Lehman G.A. Meier P.B. Ostroff J.W. Multicenter, randomized, controlled trial of metal stents for malignant obstruction of the common bile duct.Gastrointest Endosc. 1993; 39 ([abstr]): 310AGoogle Scholar, 22Knyrim K. Wagner H.J. Pausch J. Vakil N. A prospective, randomized, controlled trial of metal stents for malignant obstruction of the common bile duct.Endoscopy. 1993; 25: 207-212Crossref PubMed Scopus (503) Google Scholar, 23Prat F. Chapat O. Ducot B. Ponchon T. Pelletier G. Fritsch J. Choury A.D. Buffet C. A randomized trial of endoscopic drainage methods for inoperable malignant strictures of the common bile duct.Gastrointest Endosc. 1998; 47: 1-7Abstract Full Text Full Text PDF PubMed Scopus (426) Google Scholar, 24Kaassis M. Boyer J. Dumas R. Ponchon T. Coumaros D. Delcenserie R. Canard J.M. Fritsch J. Rey J.F. Burtin P. Plastic or metal stents for malignant stricture of the common bile duct? Results of a randomized prospective study.Gastrointest Endosc. 2003; 57: 178-182Abstract Full Text PDF PubMed Scopus (395) Google Scholar Therefore, selection of plastic stents versus SEMS for the relief of malignant extrahepatic biliary obstruction currently is debated. This review summarizes the endoscopic method for plastic stent and SEMS insertion for relief of extrahepatic malignant biliary obstruction. Publications specific to this topic are reviewed, and evidence-based guidelines regarding the indications, role, and outcomes of plastic versus metal endoscopic stent therapy are developed. Potential future areas of investigation are proposed when evidence is incomplete to base a firm recommendation. A comprehensive literature review was undertaken using Ovid (http://www.ovid.com) and the “explode” version of each of the following key words: plastic stent, metal stent, biliary obstruction, bile duct obstruction, and obstructive jaundice. These terms were used to search MEDLINE from 1960 through 2003. Only studies published in English were included. Results of the search were augmented by a review of the references from each of these reports, with inclusion of additional articles considered germane to the topic. Plastic stents were introduced in 1979 as a means to endoscopically relieve benign and malignant extrahepatic biliary obstruction.30Soehendra N. Reynders-Frederix V. [Palliative biliary duct drainage. A new method for endoscopic introduction of a new drain].Dtsch Med Wochenschr. 1979; 104: 206-207Crossref PubMed Scopus (77) Google Scholar Plastic stents are inserted over a guide wire into a position that traverses the stricture, thereby restoring bile flow. They are available in a variety of shapes, lengths, and sizes. Most endoscopists typically use a 10 Fr straight polyethylene stent with side flaps at both ends that inhibit stent migration. A multifactorial process that is influenced by bacteria, proteins, bile viscosity, and stent properties limits the duration of stent patency.31Sung J.Y. Leung J.W. Shaffer E.A. Lam K. Costerton J.W. Bacterial biofilm, brown pigment stone and blockage of biliary stents.J Gastroenterol Hepatol. 1993; 8: 28-34Crossref PubMed Scopus (78) Google Scholar, 32Leung J.W. Liu Y. Chan R.C. Tang Y. Mina Y. Cheng A.F. Silva Jr, J. Early attachment of anaerobic bacteria may play an important role in biliary stent blockage.Gastrointest Endosc. 2000; 52: 725-729Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar, 33Leung J.W. Liu Y. Cheung S. Chan R.C. Inciardi J.F. Cheng A.F. Effect of antibiotic-loaded hydrophilic stent in the prevention of bacterial adherence a study of the charge, discharge, and recharge concept using ciprofloxacin.Gastrointest Endosc. 2001; 53: 431-437Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar, 34Leung J.W. Liu Y.L. Chan R.C. Ling T.K. Cheng A.F. Effects of adherence factors and human bile on bacterial attachment and biliary stent blockage an in vitro study.Gastrointest Endosc. 2002; 56: 72-77Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar, 35Leung J.W. Liu Y.L. Desta T. Libby E. Inciardi J.F. Lam K. Is there a synergistic effect between mixed bacterial infection in biofilm formation on biliary stents?.Gastrointest Endosc. 1998; 48: 250-257Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar, 36Leung J.W. Liu Y.L. Desta T.D. Libby E.D. Inciardi J.F. Lam K. In vitro evaluation of antibiotic prophylaxis in the prevention of biliary stent blockage.Gastrointest Endosc. 2000; 51: 296-303Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar, 37Speer A.G. Cotton P.B. Rode J. Seddon A.M. Neal C.R. Holton J. Costerton J.W. Biliary stent blockage with bacterial biofilm. A light and electron microscopy study.Ann Intern Med. 1988; 108: 546-553Crossref PubMed Scopus (183) Google Scholar, 38Coene P.P. Groen A.K. Cheng J. Out M.M. Tytgat G.N. Huibregtse K. Clogging of biliary endoprostheses a new perspective.Gut. 1990; 31: 913-917Crossref PubMed Scopus (120) Google Scholar, 39Dowidar N. Kolmos H.J. Matzen P. Experimental clogging of biliary endoprostheses. Role of bacteria, endoprosthesis material, and design.Scand J Gastroenterol. 1992; 27: 77-80Crossref PubMed Scopus (56) Google Scholar This process results in the deposition of sludge, which contains a bacterial biofilm and calcium bilirubinate and calcium palmitate crystals.31Sung J.Y. Leung J.W. Shaffer E.A. Lam K. Costerton J.W. Bacterial biofilm, brown pigment stone and blockage of biliary stents.J Gastroenterol Hepatol. 1993; 8: 28-34Crossref PubMed Scopus (78) Google Scholar, 32Leung J.W. Liu Y. Chan R.C. Tang Y. Mina Y. Cheng A.F. Silva Jr, J. Early attachment of anaerobic bacteria may play an important role in biliary stent blockage.Gastrointest Endosc. 2000; 52: 725-729Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar, 33Leung J.W. Liu Y. Cheung S. Chan R.C. Inciardi J.F. Cheng A.F. Effect of antibiotic-loaded hydrophilic stent in the prevention of bacterial adherence a study of the charge, discharge, and recharge concept using ciprofloxacin.Gastrointest Endosc. 2001; 53: 431-437Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar, 34Leung J.W. Liu Y.L. Chan R.C. Ling T.K. Cheng A.F. Effects of adherence factors and human bile on bacterial attachment and biliary stent blockage an in vitro study.Gastrointest Endosc. 2002; 56: 72-77Abstract Full Text Full Text PDF PubMed Scopus (22) Google Scholar, 35Leung J.W. Liu Y.L. Desta T. Libby E. Inciardi J.F. Lam K. Is there a synergistic effect between mixed bacterial infection in biofilm formation on biliary stents?.Gastrointest Endosc. 1998; 48: 250-257Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar, 36Leung J.W. Liu Y.L. Desta T.D. Libby E.D. Inciardi J.F. Lam K. In vitro evaluation of antibiotic prophylaxis in the prevention of biliary stent blockage.Gastrointest Endosc. 2000; 51: 296-303Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar, 37Speer A.G. Cotton P.B. Rode J. Seddon A.M. Neal C.R. Holton J. Costerton J.W. Biliary stent blockage with bacterial biofilm. A light and electron microscopy study.Ann Intern Med. 1988; 108: 546-553Crossref PubMed Scopus (183) Google Scholar, 38Coene P.P. Groen A.K. Cheng J. Out M.M. Tytgat G.N. Huibregtse K. Clogging of biliary endoprostheses a new perspective.Gut. 1990; 31: 913-917Crossref PubMed Scopus (120) Google Scholar, 39Dowidar N. Kolmos H.J. Matzen P. Experimental clogging of biliary endoprostheses. Role of bacteria, endoprosthesis material, and design.Scand J Gastroenterol. 1992; 27: 77-80Crossref PubMed Scopus (56) Google Scholar Stent occlusion typically develops after 3–5 months and predisposes to biliary obstruction and occasionally results in cholangitis, thereby requiring a repeated ERC and stent exchange.20Davids P.H. Groen A.K. Rauws E.A. Tytgat G.N. Huibregtse K. Randomised trial of self-expanding metal stents versus polyethylene stents for distal malignant biliary obstruction.Lancet. 1992; 340: 1488-1492Abstract PubMed Scopus (968) Google Scholar, 21Carr-Locke D.L. Ball T.J. Connors P.J. Cotton P.B. Geenen J.E. Hawes R.H. Jowell P.S. Kozarek R.A. Lehman G.A. Meier P.B. Ostroff J.W. Multicenter, randomized, controlled trial of metal stents for malignant obstruction of the common bile duct.Gastrointest Endosc. 1993; 39 ([abstr]): 310AGoogle Scholar, 22Knyrim K. Wagner H.J. Pausch J. Vakil N. A prospective, randomized, controlled trial of metal stents for malignant obstruction of the common bile duct.Endoscopy. 1993; 25: 207-212Crossref PubMed Scopus (503) Google Scholar, 23Prat F. Chapat O. Ducot B. Ponchon T. Pelletier G. Fritsch J. Choury A.D. Buffet C. A randomized trial of endoscopic drainage methods for inoperable malignant strictures of the common bile duct.Gastrointest Endosc. 1998; 47: 1-7Abstract Full Text Full Text PDF PubMed Scopus (426) Google Scholar, 24Kaassis M. Boyer J. Dumas R. Ponchon T. Coumaros D. Delcenserie R. Canard J.M. Fritsch J. Rey J.F. Burtin P. Plastic or metal stents for malignant stricture of the common bile duct? Results of a randomized prospective study.Gastrointest Endosc. 2003; 57: 178-182Abstract Full Text PDF PubMed Scopus (395) Google Scholar, 25Schmassmann A. von Gunten E. Knuchel J. Scheurer U. Fehr H.F. Halter F. Wallstents versus plastic stents in malignant biliary obstruction effects of stent patency of the first and second stent on patient compliance and survival.Am J Gastroenterol. 1996; 91: 654-659PubMed Google Scholar The optimal strategy for plastic stent exchange has yet to be determined.40Mokhashi M.S. Rawls E. Tarnasky P.R. Patel R.S. Tang H. Yeoh K.G. Scheduled versus as required stent exchanges for malignant biliary obstruction. a prospective randomized study.Gastrointest Endosc. 2000; 51 ([abstr]): 142AGoogle Scholar Whereas some endoscopists recommend stent exchange at the earliest sign of obstruction, others advocate prophylactic exchange on a scheduled basis to avoid potential complications of stent occlusion.41Frakes J.T. Johanson J.F. Stake J.J. Optimal timing for stent replacement in malignant biliary tract obstruction.Gastrointest Endosc. 1993; 39: 164-167Abstract Full Text PDF PubMed Scopus (37) Google Scholar, 42Hoffman B.J. Marsh W.H. Cunningham J.T. Periodic exchange of biliary stents.Gastrointest Endosc. 1995; 41: 267-268Abstract Full Text Full Text PDF PubMed Scopus (6) Google Scholar Acceptance of prophylactic stent exchange is limited by the lack of data showing clinical or financial benefit of this approach and uncertainty regarding the optimal frequency of exchange. Furthermore, studies have shown that an ERC and stent exchange, when performed after the development of stent occlusion, seldom are associated with severe cholangitis.20Davids P.H. Groen A.K. Rauws E.A. Tytgat G.N. Huibregtse K. Randomised trial of self-expanding metal stents versus polyethylene stents for distal malignant biliary obstruction.Lancet. 1992; 340: 1488-1492Abstract PubMed Scopus (968) Google Scholar, 22Knyrim K. Wagner H.J. Pausch J. Vakil N. A prospective, randomized, controlled trial of metal stents for malignant obstruction of the common bile duct.Endoscopy. 1993; 25: 207-212Crossref PubMed Scopus (503) Google Scholar, 24Kaassis M. Boyer J. Dumas R. Ponchon T. Coumaros D. Delcenserie R. Canard J.M. Fritsch J. Rey J.F. Burtin P. Plastic or metal stents for malignant stricture of the common bile duct? Results of a randomized prospective study.Gastrointest Endosc. 2003; 57: 178-182Abstract Full Text PDF PubMed Scopus (395) Google Scholar, 43Gilbert D.A. DiMarino Jr, A.J. Jensen D.M. Katon R.M. Kimmey M.B. Laine L.A. MacFaydyen B.V. Michaletz-Onody P.A. Zuckerman G. Status evaluation: biliary stents. American Society for Gastrointestinal Endoscopy Technology Assessment Committee.Gastrointest Endosc. 1992; 38: 750-752Abstract Full Text PDF PubMed Scopus (41) Google Scholar The absence of prospective comparative data limits the strength of either recommendation. The literature documents a number of measures to attempt to prolong the patency of plastic stents. They include the following measures: 1.Use of larger caliber stents. Comparative trials have shown that stent patency is significantly prolonged by the use of larger caliber stents (10 and 11.5 Fr) versus smaller caliber stents (5, 7, and 8.5 Fr).44Maillot N. Aucher P. Robert S. Richer J.P. Bon D. Moesch C. Grollier G. Irani J. Carretier M. Beauchant M. Polyethylene stent blockage a porcine model.Gastrointest Endosc. 2000; 51: 12-18Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar, 45Speer A.G. Cotton P.B. MacRae K.D. Endoscopic management of malignant biliary obstruction stents of 10 French gauge are preferable to stents of 8 French gauge.Gastrointest Endosc. 1988; 34: 412-417Abstract Full Text PDF PubMed Scopus (194) Google Scholar, 46Pedersen F.M. Endoscopic management of malignant biliary obstruction. Is stent size of 10 French gauge better than 7 French gauge?.Scand J Gastroenterol. 1993; 28: 185-189Crossref PubMed Scopus (40) Google Scholar However, there is no apparent advantage in regard to the use of 11.5 Fr stents compared with 10 Fr stents.47Kadakia S.C. Starnes E. Comparison of 10 French gauge stent with 11.5 French gauge stent in patients with biliary tract diseases.Gastrointest Endosc. 1992; 38: 454-459Abstract Full Text PDF PubMed Scopus (79) Google Scholar, 48Pereira-Lima J.C. Jakobs R. Maier M. Benz C. Kohler B. Riemann J.F. Endoscopic biliary stenting for the palliation of pancreatic cancer results, survival predictive factors, and comparison of 10-French with 11.5-French gauge stents.Am J Gastroenterol. 1996; 91: 2179-2184PubMed Google Scholar2.Use of stents without side holes. The Tannenbaum stent (Wilson-Cook, Winston-Salem, NC) was designed without side holes, with the goal of reducing turbulence and optimizing bile flow. Although some reported prolonged patency with this stent,24Kaassis M. Boyer J. Dumas R. Ponchon T. Coumaros D. Delcenserie R. Canard J.M. Fritsch J. Rey J.F. Burtin P. Plastic or metal stents for malignant stricture of the common bile duct? Results of a randomized prospective study.Gastrointest Endosc. 2003; 57: 178-182Abstract Full Text PDF PubMed Scopus (395) Google Scholar others found that neither the lack of side holes nor the use of Teflon itself prolongs stent patency or improves clinical outcome.26England R.E. Martin D.F. Morris J. Sheridan M.B. Frost R. Freeman A. Lawrie B. Deakin M. Fraser I. Smith K. A prospective randomised multicentre trial comparing 10 Fr Teflon Tannenbaum stents with 10 Fr polyethylene Cotton-Leung stents in patients with malignant common duct strictures.Gut. 2000; 46: 395-400Crossref PubMed Scopus (73) Google Scholar, 49Catalano M.F. Geenen J.E. Lehman G.A. Siegel J.H. Jacob L. McKinley M.J. Raijman I. Meier P. Jacobson I. Kozarek R. Al-Kawas F.H. Lo S.K. Dua K.S. Baille J. Ginsberg G.G. Parsons W. Meyerson S.M. Cohen S. Nelson D.B. McHattie J.D. Carr-Locke D.L. “Tannenbaum” Teflon stents versus traditional polyethylene stents for treatment of