AIM: To evaluate the technical feasibility of a modified tapered metal tip and low profile introducer for one-step endoscopic ultrasound (EUS)-guided biliary drainage (EUS-BD) in a new experimental biliary dilatation porcine model.
METHODS: A novel dedicated device for one-step EUS-guided biliary drainage system (DEUS) introducer has size 3F tapered catheter with size 4F metal tip for simple puncture of the intestinal wall and liver parenchyma without graded dilation. A self-expandable metal stent, consisting of both uncovered and nitinol-covered portions, was preloaded into DEUS introducer. After establishment of a biliary dilatation model using endoscopic hemoclips or band ligation with argon plasma coagulation in 9 mini-pigs, EUS-BD using a DEUS was performed following 19-G needle puncture without the use of fistula dilation devices.
RESULTS: One-step EUS-BD was technically successful in seven pigs [7/9 (77.8%) as intention to treat] without the aid of devices for fistula dilation from the high body of stomach or far distal esophagus to the intrahepatic (n = 2) or common hepatic (n = 5) duct. Primary technical failure occurred in two cases that did not show adequate biliary dilatation. In seven pigs with a successful bile duct dilatation, the technical success rate was 100% (7/7 as per protocol). Median procedure time from confirmation of the dilated bile duct to successful placement of a metallic stent was 10 min (IQR; 8.9-18.1). There were no immediate procedure-related complications.
CONCLUSION: Modified tapered metal tip and low profile introducer may be technically feasible for one-step EUS-BD in experimental porcine model.
Endoscopic ultrasound; Biliary drainage; Biliary dilation; Feasibility; Complications
The rendezvous procedure combines an endoscopic technique with percutaneous transhepatic biliary drainage (PTBD). When a selective common bile duct cannulation fails, PTBD allows successful drainage and retrograde access for subsequent rendezvous techniques. Traditionally, rendezvous procedures such as the PTBD-assisted over-the-wire cannulation method, or the parallel cannulation technique, may be available when a bile duct cannot be selectively cannulated. When selective intrahepatic bile duct (IHD) cannulation fails, this modified rendezvous technique may be a feasible alternative. We report the case of a modified rendezvous technique, in which the guidewire was retrogradely passed into the IHD through the C2 catheter after end-to-end contact between the tips of the sphincterotome and the C2 catheter at the ampulla’s orifice, in a 39-year-old man who had been diagnosed with gallbladder carcinoma with a metastatic right IHD obstruction. Clinically this procedure may be a feasible and timesaving technique.
Endoscopic retrograde cholangiopancreatography; Intrahepatic bile duct; Rendezvous technique
Duodenal perforation during endoscopic retrograde cholangiopancreatography (ERCP) is a rare complication, but it has a relatively high mortality risk. Early diagnosis and prompt management are key factors for the successful treatment of ERCP-related perforation. The management of perforation can initially be conservative in cases resulting from sphincterotomy or guide wire trauma. However, the current standard treatment for duodenal free wall perforation is surgical repair. Recently, several case reports of endoscopic closure techniques using endoclips, endoloops, or fully covered metal stents have been described. We describe four cases of iatrogenic duodenal bulb or lateral wall perforation caused by the scope tip that occurred during ERCP in tertiary referral centers. All the cases were simply managed by endoclips under transparent cap-assisted endoscopy. Based on the available evidence and our experience, endoscopic closure was a safe and feasible method even for duodenoscope-induced perforations. Our results suggest that endoscopists may be more willing to use this treatment.
Duodenal perforation; Endoscopic retrograde cholangiopancreatography; Endoscopic therapy; Endoclip
The aim of this study was to evaluate whether the mucosa-tracking technique is effective for improving precutting-related pancreatitis and the sustained failure of bile duct cannulation in precut papillotomy (PP) with the Iso-Tome (MTW Endoskopie).
From September 2004 to June 2006, PP was performed with the Iso-Tome if biliary cannulation failed by conventional methods for approximately 5 minutes. The pink intrapapillary mucosa (PIPM) exposed by PP was tracked and classified into four groups: fully exposed and oriented to the direction of the bile duct (group A) or the pancreatic duct (group B), partially exposed (group C), or unexposed (group D). The success rate of bile duct cannulation (SRBC), the procedure time required for successful bile duct cannulation (PTBC), and the complications in the first session were compared between the mucosa-exposed groups (MEGs; group A, B, and C) and the mucosa-unexposed group (MUEG; group D).
A total of 59 patients (25 females, 34 males) with a mean age of 65.2 years were enrolled. The MEGs and MUEG comprised 52 (88.1%) and 7 (11.9%) patients, respectively. SRBC in the first session was 86.4% (51/59) in total and 92.3% (48/52) in the MEGs, compared to only 42.9% (3/7) in the MUEG (p=0.005). The mean PTBC in the MEGs and MUEG was 8.7 minutes and 16.3 minutes, respectively (p=0.23). Complications occurred in 6.8% of the patients (4/59; all pancreatitis); there were no differences between the MEGs (5.8%, 3/52) and MUEG (14.3%, 1/7; p=0.41). All four patients with pancreatitis were managed medically.
The mucosa-tracking technique in PP with the Iso-Tome is a feasible and useful method of enhancing SRBC. PIPM is an important endoscopic landmark for successful PP.
Precut papillotomy; Iso-Tome; Mucosatracking technique; Pink intrapapillary mucosa
Biliary stent-related enteric perforations are very rare complications that are caused by the sharp end of a metallic stent, stent migration, or tumor invasion. Moreover, the choledochoduodenal fistula resulting from metallic biliary stent-induced perforation is extremely rare. Here, we report a case in which a spontaneous choledochoduodenal fistula occurred after biliary metallic stent placement in a patient with an Ampulla of Vater carcinoma but was successfully managed by supportive treatments, including nasobiliary drainage. This case might have occurred as the result of a rupture of the bile duct following pressure necrosis and inflammation caused by impacted calculi and food materials over the tumor ingrowth in the uncovered biliary stent.
Choledochoduodenal fistula; Stents; Ampulla of Vater
AIM: To compare small sphincterotomy combined with endoscopic papillary large balloon dilation (SES + ELBD) and endoscopic sphincterotomy (EST) for large bile duct stones.
METHODS: We compared prospectively SES + ELBD (group A, n = 27) with conventional EST (group B, n = 28) for the treatment of large bile duct stones (≥ 15 mm). When the stone could not be removed with a normal basket, mechanical lithotripsy was performed. We compared the rates of complete stone removal with one session and application of mechanical lithotripsy.
RESULTS: No significant differences were observed in the mean largest stone size (A: 20.8 mm, B: 21.3 mm), bile duct diameter (A: 21.4 mm, B: 20.5 mm), number of stones (A: 2.2, B: 2.3), or procedure time (A: 18 min, B: 19 min) between the two groups. The rates of complete stone removal with one session was 85% in group A and 86% in group B (P = 0.473). Mechanical lithotripsy was required for stone removal in nine of 27 patients (33%) in group A and nine of 28 patients (32%, P = 0.527) in group B.
CONCLUSION: SES + ELBD did not show significant benefits compared to conventional EST, especially for the removal of large (≥ 15 mm) bile duct stones.
Sphincterotomy; Endoscopic; Balloon dilatation; Cholelithiasis; Lithotripsy
Gallbladder diverticula have the appearance of hernia-like protrusions of the gallbladder wall. This disorder may not be diagnosed until surgically resected because it has no clinical significance unless there are associated diseases. Gallbladder pseudodiverticula have an acquired cause, multiple fundal lesions, an association with gallstones, internal saccular lesions without external hernia-like protrusions, and little to no smooth muscle in the gallbladder wall. We report a unique anomaly of multiple pseudodiverticula presenting with calculous cholecystitis, which was pathologically different from true diverticula and had a unique shape similar to a bunch of grapes and a septation infilling pattern on endoscopic retrograde cholangiography.
Chemical ablation of the gallbladder is effective in patients at high risk of complications after surgery. Percutaneous gallbladder drainage is an effective treatment for cholecystitis; however, when the drain tube cannot be removed because of recurrent symptoms, retaining it can cause problems. An 82-year-old woman presented with cholecystitis and cholangitis caused by biliary stent occlusion and suspected tumor invasion of the cystic duct. We present successful chemical ablation of the gallbladder using pure alcohol, through a percutaneous gallbladder drainage tube, in a patient who developed intractable cholecystitis with obstruction of the cystic duct after receiving a biliary stent. Our results suggest that chemical ablation therapy is an effective alternative to surgical therapy for intractable cholecystitis.
Percutaneous cholecystostomy; Cholecystitis; Biliary stenting; Alcohol; Chemical therapy
AIM: To investigate the relationship between post-endoscopic resection (ER) scars on magnifying endoscopy (ME) and the pathological diagnosis in order to validate the clinical significance of ME.
METHODS: From January, 2007 to June, 2008, 124 patients with 129 post-ER scar lesions were enrolled. Mucosal pit patterns on ME were compared with conventional endoscopy (CE) findings and histological results obtained from targeted biopsies.
RESULTS: CE findings showed nodular scars (53/129), erythematous scars (85/129), and ulcerative scars (4/129). The post-ER scars were classified into four pit patterns of sulci and ridges on ME: (I) 47 round; (II) 54 short rod or tubular; (III) 19 branched or gyrus-like; and (IV) 9 destroyed pits. Sensitivity and specificity were 88.9% and 62.5%, respectively, by the presence of nodularity on CE. Erythematous lesions were high sensitivity (100%), but specificity was as low as 36.7%. The range of the positive predictive value (PPV) on CE was as low as 10.6%-25%. Nine type IV pit patterns were diagnosed as tumor lesions, and 120 cases of type I-III pit patterns revealed non-neoplastic lesions. Thus, the sensitivity, specificity, and the PPV of ME were 100%.
CONCLUSION: ME findings can detect the presence of tumor in post-ER scar lesions, and make evident the biopsy target site in short-term follow-up. Further large-scale and long-term studies are needed to determine whether ME can replace endoscopic biopsy.
Endoscopic mucosal resection; Endoscopic submucosal dissection; Magnifying endoscopy; Pit pattern; Scar
A Killian-Jamieson diverticulum (KJD) is an unfamiliar and rare cervical esophageal diverticulum. This diverticulum originates on the anterolateral wall of the proximal cervical esophagus through a muscular gap (the Killian-Jamieson space) below the cricopharyngeal muscle and lateral to the longitudinal muscle of the esophagus. To date, only surgical treatment has been recommended for a symptomatic KJD due to its close proximity to the recurrent laryngeal nerve and the concern of possible nerve injury. Recently, traditional open surgery for a symptomatic KJD is being challenged by the development of new endoscopic techniques and devices. We present here a case of a symptomatic KJD that was successfully treated with the flexible endoscopic diverticulotomy using two new devices. An isolated-tip needle-knife papillotome (Iso-Tome) was used for the dissection of the tissue bridge of the diverticulum. And a flexible overtube with a modified distal end (a fitted overtube) was used for adequate visualization of the tissue bridge of the diverticulum and protection of the surrounding tissue during dissection of the tissue bridge. Our successful experience suggests that the flexible endoscopic diverticulotomy with the use of appropriate endoscopic devices can be a safe and effective method for the treatment of a symptomatic KJD.
Esophagus; Diverticulum; Killian-Jamieson diverticulum; Endoscopy; Diverticulotomy
Duodenal perforations caused by biliary prostheses are not uncommon, and they are potentially life threatening and require immediate treatment. We describe an unusual case of aortic aneurysm and rupture which occurred after retroperitoneal aortoduodenal fistula formation as a rare complication caused by biliary metallic stent-related duodenal perforation. To our knowledge, this is the first report describing a lethal complication of a bleeding, aortoduodenal fistula and caused by biliary metallic stent-induced perforation.
Stents; Retroperitoneal perforation; Aortic aneurysm; Fistula
Perforation of the gallbladder with cholecystohepatic communication is a rare cause of liver abscess. Because it is a rare entity, the treatment modality has not been fully established. We report for the first time a patient with an intrahepatic abscess due to gallbladder perforation successfully treated by endoscopic stent placement into the gallbladder who had a poor response to continuous percutaneous drainage.
Liver abscess; Gallbladder perforation; Endoscopic stent placement; Cholecystohepatic communication
Endoscopic palliative biliary drainage is considered as a gold standard treatment in advanced or inoperable hilar cholangiocarcinoma. Also, metal stents are preferred over plastic stents in patients with >3 months life expectancy. However, the endoscopic intervention of advanced hilar obstruction is often more challenging and complex than that of distal malignant biliary obstructions. In this literature review, we describe the issues commonly encountered during endoscopic unilateral (single) versus bilateral (multiple) biliary stenting for malignant hilar obstruction. Also, we provide technical guidance to improve the technical success rates and patient outcomes, focusing on bilateral metallic stenting techniques such as stent-in-stent or side-by-side deployment.
Hilar cholangiocarcinoma; Metal stents; Bilateral drainage
Endoscopic retrograde cholangiopancreatography (ERCP) is an essential technique for the diagnosis and treatment of pancreatobiliary diseases. However, ERCP-related complications such as pancreatitis, cholangitis, hemorrhage, and perforation may be problematic. For a successful and safe ERCP, preprocedural evaluations of the patients and intervention-related risk factors are needed. Furthermore, in light of the recent population aging and increase in chronic cardiopulmonary diseases in Korea, precautions including endoscopic sedation and prevention of cardiopulmonary complications should be considered. In this literature review, we describe these risk factors and the use of endoscopic sedation. In addition, we reviewed the commonly available guidewires, including their materials and options, used as a basic accessory for ERCP procedures.
Cholangiopancreatography, endoscopic retrograde; Complications; Guidewire
Afferent loop syndrome caused by an impacted enterolith is very rare, and endoscopic removal of the enterolith may be difficult if a stricture is present or the normal anatomy has been altered. Electrohydraulic lithotripsy is commonly used for endoscopic fragmentation of biliary and pancreatic duct stones. A 64-year-old man who had undergone subtotal gastrectomy and gastrojejunostomy presented with acute, severe abdominal pain for a duration of 2 hours. Initially, he was diagnosed with acute pancreatitis because of an elevated amylase level and pain, but was finally diagnosed with acute afferent loop syndrome when an impacted enterolith was identified by computed tomography. We successfully removed the enterolith using direct electrohydraulic lithotripsy conducted using a transparent cap-fitted endoscope without complications. We found that this procedure was therapeutically beneficial.
Afferent loop syndrome; Enterolith; Electrohydraulic lithotripsy
Numerous clinical trials to improve the success rate of biliary access in difficult biliary cannulation (DBC) during ERCP have been reported. However, standard guidelines or sequential protocol analysis according to different methods are limited in place. We planned to investigate a sequential protocol to facilitate selective biliary access for DBC during ERCP.
This prospective clinical study enrolled 711 patients with naïve papillae at a tertiary referral center. If wire-guided cannulation was deemed to have failed due to the DBC criteria, then according to the cannulation algorithm early precut fistulotomy (EPF; cannulation time > 5 min, papillary contacts > 5 times, or hook-nose-shaped papilla), double-guidewire cannulation (DGC; unintentional pancreatic duct cannulation ≥ 3 times), and precut after placement of a pancreatic stent (PPS; if DGC was difficult or failed) were performed sequentially. The main outcome measurements were the technical success, procedure outcomes, and complications.
Initially, a total of 140 (19.7%) patients with DBC underwent EPF (n = 71) and DGC (n = 69). Then, in DGC group 36 patients switched to PPS due to difficulty criteria. The successful biliary cannulation rate was 97.1% (136/140; 94.4% [67/71] with EPF, 47.8% [33/69] with DGC, and 100% [36/36] with PPS; P < 0.001). The mean successful cannulation time (standard deviation) was 559.4 (412.8) seconds in EPF, 314.8 (65.2) seconds in DGC, and 706.0 (469.4) seconds in PPS (P < 0.05). The DGC group had a relatively low successful cannulation rate (47.8%) but had a shorter cannulation time compared to the other groups due to early switching to the PPS method in difficult or failed DGC. Post-ERCP pancreatitis developed in 14 (10%) patients (9 mild, 1 moderate), which did not differ significantly among the groups (P = 0.870) or compared with the conventional group (P = 0.125).
Based on the sequential protocol analysis, EPF, DGC, and PPS may be safe and feasible for DBC. The use of EPF in selected DBC criteria, DGC in unintentional pancreatic duct cannulations, and PPS in failed or difficult DGC may facilitate successful biliary cannulation.
Difficult biliary cannulation; Precut; Double guidewire cannulation; Pancreatic stent
Epithelial-mesenchymal transition (EMT)-related proteins may exhibit differential expression in intestinal type or pancreatobiliary type ampulla of Vater carcinomas (AVCs). We evaluated the expression of E-cadherin, β-catenin, and S100A4 in intestinal and nonintestinal type AVCs and analyzed their relationships with clinicopathological variables and survival.
A clinicopathological review of 105 patients with AVCs and immunohistochemical staining for E-cadherin, β-catenin, and S100A4 were performed. The association between clinicopathological parameters, histological type, and expression of EMT proteins and their effects on survival were analyzed.
Sixty-five intestinal type, 35 pancreatobiliary type, and five other types of AVCs were identified. The severity of EMT changes differed between the AVC types; membranous loss of E-cadherin and β-catenin was observed in nonintestinal type tumors, whereas aberrant nonmembranous β-catenin expression was observed in intestinal type tumors. EMT-related changes were more pronounced in the invasive tumor margin than in the tumor center, and these EMT-related changes were related to tumor aggressiveness. Among the clinicopathological parameters, a desmoplastic reaction was related to overall survival, and the reaction was more severe in nonintestinal type than in intestinal type AVCs.
Dysregulation of E-cadherin, β-cadherin, and S100A4 expression may play a role in the carcinogenesis and tumor progression of AVCs.
Ampullary adenocarcinoma; Intestinal type; Pancreatobiliary type; Epithelial-mesenchymal transition
Iatrogenic duodenal perforation associated with endoscopic retrograde cholangiopancreatography (ERCP) is a very uncommon complication that is often lethal. Perforations during ERCP are caused by endoscopic sphincterotomy, placement of biliary or duodenal stents, guidewire-related causes, and endoscopy itself. In particular, perforation of the medial or lateral duodenal wall usually requires prompt diagnosis and surgical management. Perforation can follow various clinical courses, and management depends on the cause of the perforation. Cases resulting from sphincterotomy or guidewire-induced perforation can be managed by conservative treatment and biliary diversion. The current standard treatment for perforation of the duodenal free wall is early surgical repair. However, several reports of primary endoscopic closure techniques using endoclip, endoloop, or newly developed endoscopic devices have recently been described, even for use in direct perforation of the duodenal wall.
Cholangiopancreatography, endoscopic retrograde; Perforation; Duodenum; Therapeutics
Brunner's gland hamartoma is a rare benign small bowel neoplasm and most lesions are small and asymptomatic. However, large hamartoma-related obstructive symptoms and hemorrhage related to tumor ulceration manifest as hematemesis or melena. The exact pathogenesis if these lesions is not well known, but they are thought to be frequently associated with Helicobacter pylori infections and chronic pancreatitis. We report the case of a 45-year-old man who presented with melena due to a large pedunculated Brunner's gland hamartoma arising from the pylorus. It was successfully removed by endoscopic mucosal resection with piecemeal technique because of too large tumor size for application of a conventional snare.
Brunner's gland hamartoma; Hematemesis; Melena; Endoscopic mucosal resection
Placement of a self-expanding metal stent (SEMS) is an effective method for palliation of a malignant biliary obstruction. However, metal stents can cause various complications, including stent migration. Distally migrated metal stents, particularly covered SEMS, can be removed successfully in most cases. Stent trimming using argon plasma coagulation may be helpful in difficult cases despite conventional methods. However, no serious complications related to the trimming or remnant stent removal method have been reported due to the limited number of cases. In particular, proximal migration of a remnant fragmented metal stent after stent trimming followed by balloon sweeping has not been reported. We report an unusual case of proximal migration of a remnant metal stent during balloon sweeping following stent trimming by argon plasma coagulation. The remnant metal stent was successfully removed with rotation technique using a basket and revised endoscopically.
Pancreatic neoplasms; Stents; Cholangiopancreatography, endoscopic retrograde; Argon plasma coagulation
Choledochal cysts are congenital anomalies of the biliary tract manifested by cystic dilatation of the extrahepatic and intrahepatic bile ducts. Choledochal cyst is not rare in far-East Asian countries. Type II choledochal cysts account for 2% of all such cysts. They are true diverticula of the extrahepatic bile duct and communicate with the bile duct through a narrow stalk. This condition is associated with significant complications, such as ductal strictures, stone formation, cholangitis, rupture and secondary biliary cirrhosis. We describe a case of a huge impacted stone in a diverticular choledochal cyst which masqueraded as an unusual cystic duct stone causing Mirizzi's syndrome.
Choledochal cyst; Mirizzi's syndrome; Cholangitis
During endoscopic retrograde cholangiopancreatography (ERCP), all efforts should be made to be aware of radiation hazards and to reduce radiation exposure. The aim of this study was to investigate the status of radiation protective equipment and the awareness of radiation exposure in health care providers performing ERCP in Korean hospitals.
A survey with a total of 42 questions was sent to each respondent via mail or e-mail between October 2010 and March 2011. The survey targeted nurses and radiation technicians who participated in ERCP in secondary or tertiary referral centers.
A total of 78 providers from 38 hospitals responded to the surveys (response rate, 52%). The preparation and actual utilization rates of protective equipment were 55.3% and 61.9% for lead shields, 100% and 98.7% for lead aprons, 47.4% and 37.8% for lead glasses, 97.4% and 94.7% for thyroid shields, and 57.7% and 68.9% for radiation dosimeters, respectively. The common reason for not wearing protective equipment was that the equipment was bothersome, according to 45.7% of the respondents.
More protective equipment, such as lead shields and lead glasses, should be provided to health care providers involved in ERCP. In particular, the actual utilization rate for lead glasses was very low.
Endoscopic retrograde cholangiopancreatography; Radiation exposure; Protective equipment
In this study, we examined the efficacy and toxicity of S-1 with cisplatin as a second-line palliative chemotherapy for gemcitabine-refractory pancreatic cancer patients. Patients who had been previously treated with gemcitabine-based chemotherapy as palliative first-line chemotherapy received S-1/cisplatin [body surface area (BSA) <1.25 m2, S-1 40 mg/day; BSA ≤1.25 to <1.5 m2, 50 mg/day; BSA ≥1.5 m2 60 mg/day, orally, bid, daily on days 1–14 followed by a 7-day washout and cisplatin 60 mg/m2/day intravenously on day 1] every three weeks. The enrollment of 32 patients was planned, but the study was terminated early, prior to the first stage, following the enrollment of 11 patients. The median age of the patients was 56 (range, 42–74) years. Nine patients had a performance status (PS) of one. In total, there were 21 chemotherapy cycles and the median treatment duration was 21 (range, 7–96) days. Of the 11 patients, five could not be evaluated due to discontinuation prior to the response evaluation. One of the six evaluable patients achieved stable disease (9.1% in intention to treat analysis and 16.7% in per-protocol analysis), while five had progressive disease. Grade 3–4 hematological toxicities were anemia in one, neutropenia in one and thrombocytopenia in one cycle. Grade 3–4 nonhematological toxicities were fatigue in three, nausea in four, anorexia in two, diarrhea in one and peripheral neuropathy in two cycles. With a median follow-up period of 8.9 (range, 3.2–11.3) months, the median time to progression was 44 days [95% confidence interval (CI) 25.4–62.6] and the median overall survival was 81 days (95% CI 9.3–152.7). Combination chemotherapy with S-1 and cisplatin as applied in this study did not result in promising antitumor activity, a high degree of toxicity and poor compliance.
pancreatic cancer; S-1; cisplatin; gemcitabine-refractory
The placement of self expandable metal stent (SEMS) is one of the palliative therapeutic options for patients with unresectable malignant biliary obstruction. The aim of this study was to compare the effectiveness of a covered SEMS versus the conventional plastic stent.
We retrospectively evaluated 44 patients with unresectable malignant biliary obstruction who were treated with a covered SEMS (21 patients) or a plastic stent (10 Fr, 23 patients). We analyzed the technical success rate, functional success rate, early complications, late complications, stent patency and survival rate.
There was one case in the covered SEMS group that had failed technically, but was corrected successfully using lasso. Functional success rates were 90.5% in the covered SEMS group and 91.3% in the plastic stent group. There was no difference in early complications between the two groups. Median patency of the stent was significantly prolonged in patients who had a covered SEMS (233.6 days) compared with those who had a plastic stent (94.6 days) (p=0.006). During the follow-up period, stent occlusion occurred in 11 patients of the covered SEMS group. Mean survival showed no significant difference between the two groups (covered SEMS group, 236.9 days; plastic stent group, 222.3 days; p=0.182).
The patency of the covered SEMS was longer than that of the plastic stent and the lasso of the covered SEMS was available for repositioning of the stent.
Malignant biliary obstruction; Self-expandable metal stent; Plastic stent