Functional Self-Expandable Metal Stents in Biliary Obstruction

Abstract

Biliary stents are widely used not only for palliative treatment of malignant biliary obstruction but also for benign biliary diseases. Each plastic stent or self-expandable metal stent (SEMS) has its own advantages, and a proper stent should be selected carefully for individual condition. To compensate and overcome several drawbacks of SEMS, functional self-expandable metal stent (FSEMS) has been developed with much progress so far. This article looks into the outcomes and defects of each stent type for benign biliary stricture and describes newly introduced FSEMSs according to their functional categories.

Initial experience with endoscopic retrograde cholangiography and endoscopic retrograde biliary stenting for treatment of extrahepatic bile duct obstruction in dogs

“…41 Because of the high mortality rates reported for surgical treatment of EHBDO (up to 75%) in veterinary patients, [14][15][16][17][18][19] these data further support the need for this type of preliminary investigation in an effort to find new treatment modalities that may decrease overall morbidity and mortality rates. 3,[42][43][44] These stents have been found to maintain patency for between 3 and 6 months typically, which is the time needed for resolution of the underlying disease in human patients. Traditional open surgery may require excessive pancreatic manipulation and prolonged anesthesia times in very debilitated patients and may have a high risk of dehiscence and abdominal contamination associated with the enterotomy incision.…”

“…The cause for such high mortality rates with traditional surgery is not clear but is postulated to be associated with the systemic disease process, resulting in sepsis, impaired reticuloendothelial function, and surgical risks in such patients. [42][43][44] Stent size is usually selected on the basis of the diameter of the CBD, which is estimated from the cholangiogram. [14][15][16][17][18][19] With endoscopic biliary stents, some of these risks may be averted because of minimal pancreatic manipulation endoscopically, lack of the need for laparotomy and intestinal surgery, and the relative speed of the procedure when performed by trained personnel.…”

“…Traditional open surgery may require excessive pancreatic manipulation and prolonged anesthesia times in very debilitated patients and may have a high risk of dehiscence and abdominal contamination associated with the enterotomy incision. 3,9,[44][45][46][47] These stents should be sized to fit the lumen of the CBD and should not be undersized like a plastic biliary stent. Additionally, data from human patients suggest that urgent endoscopic decompression, prior to considering more aggressive surgical revisions, in the case of obstructive biliary jaundice may provide a means for stabilization and reduced morbidity and mortality rates.…”

“…Endoscopic treatment is preferred over surgical intervention in such patients, 3,9,44 with the most common treatment involving biliary stent placement (1 or multiple plastic stents, covered or partially covered SEMSs, or uncovered SEMSs). Benign strictures are commonly reported in human patients associated with chronic pancreatitis, anastomotic lesions after liver transplantation, inflammatory diseases, and biliary stone disease.…”

Resolution of pneumobilia as a predictor of biliary stent occlusion

“…Selfexpandable metal stents provide a larger lumen, providing longer biliary patency and are used for palliation in malignant biliary obstruction [3]. Plastic biliary stents have a median patency of 4-5 months and metallic stents have a median patency of 8-10 months [4].…”