Stent migration and sludge formation remain significant problems associated with covered self-expandable metal stents (CSEMSs). The EGIS biliary stent fully covered flare type (EGIS biliary stent), a new type of polytetrafluoroethylene-coated self-expandable metal stent with low axial force and an anti-migration system, was developed to overcome these disadvantages. We conducted this study to evaluate the efficacy and safety of this stent in comparison with conventional CSEMS (c-CSEMS).

We retrospectively analyzed consecutive patients with unresectable pancreatic cancer who received initial CSEMS for distal malignant biliary obstruction. The primary outcome was time to recurrent biliary obstruction (RBO). Secondary outcomes included technical success rate, functional success rate, stent-related adverse events, causes of RBO, and re-intervention.

A total of 40 patients were included (EGIS group: 20; c-CSEMS group: 20). The technical and functional success rates were similar between the two groups. Stent-related adverse event rates (20% vs. 15%, p > 0.99) and overall RBO rates (56% vs. 50%, p > 0.99) were not significantly different between the two groups. Stent migration was the most common cause of RBO in the EGIS group, while stent occlusion was in the c-CSEMS group. The median time to RBO (102 vs. 434 days, p = 0.10) was not significantly different between the two groups. Endoscopic transpapillary re-intervention was successful in most patients in both groups.

The EGIS biliary stent was not associated with a longer time to RBO compared to c-CSEMS. Further improvements, especially against stent migration, are needed to improve its efficacy.

No prospective studies have verified the incidence of cholecystitis in patients using the covered self-expandable metallic stent. In this study, we aimed to investigate the incidence of cholecystitis and its risk factors after low axial force covered self-expandable metallic stent placement for malignant distal biliary obstruction.

This multicenter prospective study included patients diagnosed with unresectable distal biliary obstruction between November 2019 and October 2022 who underwent low axial force covered self-expandable metallic stent placement.

The technical success in the 93 analyzed patients was 100% and clinical success was 98.9%. The 70-mm covered self-expandable metallic stent was the most used in 53 patients (57.0%), followed by the 80-mm type in 27 patients (29.0%), 60-mm type in 12 patients (12.9%), and 50-mm type in 1 patient (1.1%). Cholecystitis after covered self-expandable metallic stent placement occurred in six patients (6.5%). The median time to onset was 46 days (range, 16-315 days), with 1 case in the early stage and five cases in the late stage. There was one mild case, one moderate case, and four severe cases. The presence of tumor involvement at the orifice of the cystic duct was identified as an independent risk factor (odds ratio, 17.0; 95% confidence interval, 1.5-195.1; p = 0.023).

The presence of tumor involvement at the orifice of the cystic duct was an independent risk factor for the development of cholecystitis after low axial covered self-expandable metallic stent placement.

University Hospital Medical Information Network (UMIN) (http://www.umin.ac.jp, registration number: UMIN 000038209).

For preoperative biliary drainage of pancreatic cancer (PC), a 10-mm diameter metal stent (MS) is commonly used; however, the rate of pancreatitis is high. It is hypothesized that smaller-diameter MS may reduce the rate of pancreatitis. Therefore, we conducted a multicenter prospective study to evaluate the efficacy and safety of 7-mm MS.

Patients requiring initial biliary drainage for obstructive jaundice caused by PC and scheduled for surgery from six facilities were included. After endoscopic retrograde cholangiography, a 7-mm MS was placed at the site of biliary obstruction. The primary endpoint was the rate of pancreatitis, and the secondary endpoints included early and late adverse events (AEs). The pancreatitis rate was assumed to be 18% and 5% with 10- and 7-mm MS, respectively; with a power of 80% and one-sided significance level of 10%, the planned enrollment was 38 patients. If pancreatitis occurred in no more than three patients, this indicates that the 7-mm MS effectively reduced incidence of pancreatitis.

Overall, 38 patients were enrolled, and 35 patients in whom a 7-mm MS was successfully placed were analyzed. All MS were placed after sphincterotomy. Pancreatitis occurred in four patients (11.4%) and no early AEs were observed. Surgery was performed in 24 patients and late AEs included stent occlusion in eight patients (23%) and cholecystitis in four patients (11%).

The 7-mm MS did not reduce incidence of pancreatitis among surgical candidates for PC.

Approximately 60% of pancreatic cancers occur in the pancreatic head and may present as obstructive jaundice due to bile duct invasion. Obstructive jaundice often leads to poor general conditions and acute cholangitis, interfering with surgery and chemotherapy and requiring biliary drainage. The first choice of treatment for biliary drainage is the endoscopic transpapillary approach. In unresectable tumors, self-expandable metal stents (SEMSs) are most commonly used and are classified into uncovered and covered SEMSs. Recently, antireflux metal stents and large- or small-diameter SEMSs have become commercially available, and their usefulness has been reported. Plastic stents are infrequently used in patients with resectable biliary obstruction; however, owing to the recent trend in preoperative chemotherapy, SEMSs are frequently used because of the long time to recurrent biliary obstruction. Endoscopic ultrasound-guided biliary drainage (EUS-BD) is often performed in patients who are not eligible for the transpapillary approach, and favorable outcomes have been reported. Different EUS-BD techniques and specialized stents have been developed and can be safely used in high-volume centers. The indications for EUS-BD are expected to further expand in the future.

To date, only thinner-diameter metal stents have been evaluated for unresectable malignant distal biliary obstruction (UR-MDBO). This study investigated the outcomes and optimal cohorts for a 6-mm-diameter fully covered self-expandable metal stent (FCSEMS) compared with those for a 10-mm-diameter FCSEMS.

This single-center retrospective cohort study included patients who underwent initial transpapillary metal stenting for UR-MDBO. Propensity score matching (1:1) analysis was performed.

Of 133/68 patients who underwent 6-mm/10-mm-diameter FCSEMS deployment, 59 in each group were selected. The median time to recurrent biliary obstruction was not significantly different between the groups (p=0.46). In contrast, use of the 6-mm-diameter FCSEMS resulted in a significantly reduced incidence of stent-related adverse events (AEs) (p=0.016), especially cholecystitis (p=0.032), and patients aged <70 years were particularly affected by this significant reduction. Among the patients in the end-stage cohort who were unable to continue chemotherapy after FCSEMS deployment, the free rate of stent-related events, including recurrent biliary obstruction and stent-related AEs, was significantly higher in the 6-mm group (p=0.027).

For UR-MDBO, a 6-mm-diameter FCSEMS can be an optimal and safe option in the younger cohort with a relatively high risk of AEs and in the end-stage cohort requiring safer drainage without interference from stent-related events during times of poor prognosis.

A 70-year-old woman presented with stage III pancreatic head cancer. After endoscopic sphincterotomy, a fully covered self-expandable metallic stent (FCSEMS) was placed in the common bile duct to manage jaundice. The patient developed a fever and abdominal pain 40 days after stent placement, with a suspected diagnosis of infected pancreatic pseudocyst. Purulent discharge from the papilla was observed during FCSEMS removal, and pancreatography revealed a pseudocyst connected to the main pancreatic duct. The pancreatic pseudocyst resolved after transpapillary drainage. Pancreatic pseudocysts should be suspected after biliary FCSEMS placement, and prompt removal and endoscopic drainage of the FCSEMS should be considered.

Endoscopic ultrasound-guided biliary drainage (EUS-BD) is an alternative to endoscopic retrograde cholangiopancreatography (ERCP)-guided transpapillary drainage in malignant distal biliary obstruction (MDBO). This meta-analysis of randomized controlled trials (RCTs) aims to compare the outcomes of these 2 approaches.

Electronic databases from January 2005 through December 2023 were searched for RCTs comparing outcomes of EUS-BD and ERCP for treating MDBO. Pooled proportions, risk ratio (RR), and odds ratio were calculated using random-effects models.

Five RCTs comprising 519 patients were included in the final analysis. The pooled RR for overall technical success with EUS-BD compared with ERCP was 1.05 (95% confidence interval [CI] = 0.96-1.16, P = 0.246, I2 = 61%) and for clinical success was 0.99 (95% CI = 0.95-1.04, P = 0.850, I2 = 0%). The pooled rate of procedure-related pancreatitis was 7.20% (95% CI = 3.60-13.80, I2 = 34%) in the ERCP group compared with zero in the EUS-BD group. The pooled RR for stent dysfunction with EUS-BD compared with ERCP was 0.48 (95% CI = 0.28-0.83, P = 0.008, I2 = 7%). The weighted mean procedure time was 13.43 (SD = 10.12) minutes for EUS-BD compared with 21.06 (SD = 6.64) minutes for ERCP. The mean stent patency was 194.11 (SD = 52.12) days in the EUS-BD group and 187 (SD = 60.70) days in the ERCP group.

EUS-BD is an efficient and safe alternative to ERCP in MDBO. An almost nonexistent risk of procedure-related pancreatitis, lower procedure time, and ease of use make this an attractive primary approach to biliary decompression in centers with expertise.

Endoscopic retrograde cholangiopancreatography-guided transpapillary gallbladder drainage has emerged as an effective alternative for management of acute cholecystitis in nonoperable candidates. Delayed acute pancreatitis has not been previously described as an adverse event with this procedure. In this article, we describe 3 patients who developed acute pancreatitis between 2 and 6 weeks after stent insertion with no alternative inciting cause. Delayed acute pancreatitis may represent a rare and previously uncharacterized adverse event related to transpapillary gallbladder drainage.

The 10-mm self-expandable metal stent (SEMS) is the standard for endoscopic transpapillary biliary drainage before pancreatic cancer surgery. However, the efficacy of stents thinner than 10 mm has not been adequately validated. Therefore, we aimed to evaluate the safety of a 6-mm fully covered SEMS (FCSEMS) for distal malignant biliary obstruction (DMBO) during preoperative chemotherapy for pancreatic cancer.

This was a single-arm, multicenter, prospective phase II study of endoscopic transpapillary initial biliary drainage for DMBO before pancreatic cancer surgery. The primary endpoint was stent-related adverse events, and the key secondary endpoint was the non-recurrent biliary obstruction (non-RBO) rate during the observation period for both resectable (R) and borderline resectable (BR) pancreatic cancers.

The study enrolled 33 patients, among whom 32 received the study treatment. There were 23 and 9 cases of R and BR pancreatic cancers, respectively. The technical and clinical success rates were 97.0% and 90.1%, respectively. The stent-related adverse event rate was 3.1% (n = 1, acute pancreatitis) (95% confidential interval, 0.00-16.2), which met the criteria to be considered safe. The overall non-RBO rate during the observation period (median 96 days) was 78.1% (82.6% and 66.7% for R and BR pancreatic cancer cases, respectively).

The 6-mm FCSEMS is an extremely safe metallic stent with a low stent-related adverse event rate of 3.1% for preoperative biliary drainage in pancreatic cancer. It is considered the optimal stent for preoperative biliary drainage in terms of the non-RBO rate. UMIN Clinical Trial Registry (UMIN-CTR 000041704).

Background and study aims Pancreatitis is a potentially lethal adverse event of endoscopic transpapillary placement of a self-expandable metal stent (SEMS) for malignant biliary obstruction (MBO). Deep learning-based image recognition has not been investigated in predicting pancreatitis in this setting. Patients and methods We included 70 patients who underwent endoscopic placement of a SEMS for nonresectable distal MBO. We constructed a convolutional neural network (CNN) model for pancreatitis prediction using a series of pre-procedure computed tomography images covering the whole pancreas (≥ 120,960 augmented images in total). We examined the additional effects of the CNN-based probabilities on the following machine learning models based on clinical parameters: logistic regression, support vector machine with a linear or RBF kernel, random forest classifier, and gradient boosting classifier. Model performance was assessed based on the area under the curve (AUC) in the receiver operating characteristic analysis, positive predictive value (PPV), accuracy, and specificity. Results The CNN model was associated with moderate levels of performance metrics: AUC, 0.67; PPV, 0.45; accuracy, 0.66; and specificity, 0.63. When added to the machine learning models, the CNN-based probabilities increased the performance metrics. The logistic regression model with the CNN-based probabilities had an AUC of 0.74, PPV of 0.85, accuracy of 0.83, and specificity of 0.96, compared with 0.72, 0.78, 0.77, and 0.96, respectively, without the probabilities. Conclusions The CNN-based model may increase predictability for pancreatitis following endoscopic placement of a biliary SEMS. Our findings support the potential of deep learning technology to improve prognostic models in pancreatobiliary therapeutic endoscopy.

Unresectable ampullary cancer (AC) is a rare disease entity. The risk factors for recurrent biliary obstruction (RBO) following endoscopic biliary stenting (EBS) for unresectable AC remain unknown. In this study we aimed to evaluate the cumulative RBO rate and to identify risk factors for RBO following palliative EBS in patients with unresectable AC.

This multicenter retrospective observational study enrolled consecutive patients with unresectable AC who had undergone palliative EBS between April 2011 and December 2021. The cumulative rate of and risk factors for RBO following palliative EBS were evaluated via multivariate analysis.

The study analysis comprised 107 patients with a median age of 84 years (interquartile range 79-88 years). Plastic stents (PSs) and self-expandable metal stents (SEMSs) were placed in 53 and 54 patients, respectively. Functional success was accomplished in 104 (97.2%) patients. Of these, RBO occurred in 62 (59.6%) patients, with obstruction and complete/partial migration occurring in 47 and 15 patients, respectively. The median time to RBO was 190 days. Multivariate analysis showed that PS was associated with a higher rate of RBO compared to SEMS (hazard ratio [HR] 2.48; P < 0.01) and that the presence of common bile duct stones/sludge immediately after EBS was an independent risk factor for RBO (HR 1.99; P = 0.04).

The use of SEMS compared to PS during EBS reduced the time to RBO in patients with unresectable AC. Common bile duct stones/sludge immediately after EBS was a risk factor for RBO.

10-mm self-expandable metal stents (SEMSs) are commonly used for preoperative biliary drainage in pancreatic cancer. However, smaller diameter SEMSs have attracted attention with the attempt to reduce stent-related adverse events (AEs).

We retrospectively analyzed consecutive borderline resectable pancreatic cancer patients who underwent neoadjuvant therapy and fully covered SEMS (FCSEMS) placement from April 2015 to May 2023. The primary outcome was stent-related non-event rate (NER), which was defined as the rate of completion of surgery without developing any preoperative events (recurrent biliary obstruction [RBO] or stent-related AEs). Secondary outcomes included stent-related AEs, causes of RBO, and cumulative incidence of RBO. Risk factors for pancreatitis, RBO, and stent migration were also examined.

A total of 76 patients were included (6-mm group: 23; 10-mm group: 53). Stent-related NER (57% vs. 64%, p = 0.610), stent-related AEs (4% vs. 15%, p = 0.263), overall RBO rates (39% vs. 23%, p = 0.168), cumulative incidence of RBO (hazard ratio, 2.24; 95% confidence interval, 0.95-5.25; p = 0.065) were not significantly different between the two groups. Tumor involvement of the pancreatic duct was identified as a risk-reducing factor for pancreatitis, while an FCSEMS diameter of 6 mm was not identified as a risk factor for RBO and stent migration.

Stent-related NER was not significantly affected by FCSEMS diameter. Further studies are needed to confirm the usefulness of 6-mm diameter FCSEMS for preoperative biliary drainage in patients with borderline resectable pancreatic cancer.

Self-expandable metal stent (SEMS) insertion is the standard palliative treatment for unresectable malignant extrahepatic biliary obstruction (MBO). Drawbacks of conventional fully covered SEMS (FCSEMS) and uncovered SEMS (USEMS) include stent migration and tumor ingrowth, respectively. This study aimed to compare stent patency in MBO with the newly design multi-hole SEMS (MHSEMS), which has multiple small side holes in the stent membrane, with conventional FCSEMS and UCSEMS.

This retrospective study using a propensity score matching design and stent patency times of 40 patients with MHSEMS was compared to 40 and 34 patients with FCSEMS and UCSEMS during the same period, respectively. Secondary outcomes were procedure-related adverse events, clinical success rate, time to recurrent biliary obstruction (RBO), and etiology of RBO. RBO was compared using Kaplan-Meier analysis.

Baseline characteristics after matching were comparable among the 3 groups. RBO rates were 21%, 37%, and 55% for MHSEMS, FCSEMS, and UCSEMS, respectively (p = 0.014), at a mean time of 479, 353, and 306 days, respectively (MHSEMS vs UCSEMS, p = 0.002). Rate of tumor ingrowth was highest in the UCSEMS group (42.4% vs 13.2% in MHSEMS; p = 0.005 and vs 0% in FCSEMS; p < 0.001). Stent migration rate was highest in the FCSEMS group at 15.8% vs 2.6% in MHSEMS (p = 0.047) and 0% in UCSEMS (p = 0.005).

MHSEMS provided the longest stent patency time with lowest RBO rate compared to conventional SEMS by showing a lower stent migration rate than FCSEMS and a lower tumor ingrowth rate than UCSEMS.

Endoscopic placement of self-expandable metal stents (SEMSs) for malignant distal biliary obstruction (MDBO) may be accompanied by several types of adverse events. The present study analyzed the adverse events occurring after SEMS placement for MDBO.

The present study retrospectively investigated the incidence and types of adverse events in patients who underwent SEMS placement for MDBO between April 2018 and March 2021 at 26 hospitals. Risk factors for acute pancreatitis, cholecystitis, and recurrent biliary obstruction (RBO) were evaluated by univariate and multivariate analyses.

Of the 1425 patients implanted with SEMSs for MDBO, 228 (16.0%) and 393 (27.6%) experienced early adverse events and RBO, respectively. Pancreatic duct without tumor involvement (P = .023), intact papilla (P = .025), and SEMS placement across the papilla (P = .037) were independent risk factors for acute pancreatitis. Tumor involvement in the orifice of the cystic duct was an independent risk factor for cholecystitis (P < .001). Use of fully and partially covered SEMSs was an independent risk factor for food impaction and/or sludge. Use of fully covered SEMSs was an independent risk factor for stent migration. Use of uncovered SEMSs and laser-cut SEMSs was an independent risk factor for tumor ingrowth.

Pancreatic duct without tumor involvement, intact papilla, and SEMS placement across the papilla were independent risk factors for acute pancreatitis, and tumor involvement in the orifice of the cystic duct was an independent risk factor for cholecystitis. The risk factors for food impaction and/or sludge, stent migration, and tumor ingrowth differed among types of SEMSs.

Background and aims: In the treatment of post-cholecystectomy bile leaks, endoscopic naso-biliary drainage (ENBD) or biliary stenting using plastic stents is the standard of care. Fully covered self-expandable metal stent (FCSEMS) placement across the sphincter of Oddi is considered a salvage therapy for refractory cases, but pancreatitis and migration are the major concerns. Intraductal placement of a dumbbell-shaped FCSEMS (D-SEMS) could avoid these drawbacks of FCMSESs. In this retrospective study, we investigated the usefulness of intraductal placement of the D-SEMS for post-cholecystectomy bile leaks. Methods: Six patients who underwent intraductal placement of the D-SEMS for post-cholecystectomy bile leaks were enrolled. This method was performed as initial treatment in three patients and as salvage treatment in three ENBD refractory cases. Results: Technical and clinical successes were obtained in 6 (100%) patients and 5 (83%) patients, respectively. One clinically unsuccessful patient required laparoscopic peritoneal lavage. The early adverse event was one case of mild pancreatitis (17%). The median duration of the D-SEMS indwelling was 61 days (42-606 days) with no migration cases, all of which were successfully removed. The median follow-up after index ERCP was 761 (range: 161-1392) days with no cases of recurrent bile leaks. Conclusions: Intraductal placement of the D-SEMS for post-cholecystectomy bile leaks might be safe and effective even in refractory cases.

Although numerous retrieval baskets are currently available for the extraction of bile duct stones, their mechanical properties have not been evaluated. This study aimed to ascertain the characteristics of retrieval baskets for bile duct stones by examining their mechanical properties.

This experimental study tested the mechanical properties of seven retrieval baskets for bile duct stones. The radial force (RF) was measured using a dedicated measurement device and the axial force (AF) was measured using the conventional manual method.

The mean RF differed significantly among the baskets (p < 0.001) and was the strongest for VorticCatch (1.62 N ± 0.02) and COAXIS (1.62 N ± 0.04), followed by RASEN (1.27 N ± 0.02), Memory Basket (0.95 N ± 0.01), 8-wire Nitinol Basket (0.93 N ± 0.01), StoneHunter (0.78 N ± 0.01) and Flower Basket (0.37 N ± 0.01), respectively. The mean AF differed significantly among the baskets (p < 0.001) and was the highest for VorticCatch (0.668 N ± 0.032), followed by COAXIS (0.629 N ± 0.041), StoneHunter (0.574 N ± 0.037), 8-wire Nitinol Basket (0.546 N ± 0.010), Memory Basket (0.542 N ± 0.024), RASEN (0.435 N ± 0.008) and Flower Basket (0.297 N ± 0.011), respectively. The baskets were categorized into four groups with comparable mechanical properties based on the RF and AF: group 1, low RF and low AF; group 2, moderate RF and moderate AF; group 3, high RF and moderate AF; and group 4, high RF and high AF.

This study revealed distinct mechanical properties of various retrieval baskets used for extracting bile duct stones, which may enhance the understanding of their action. Our results could also aid the development of retrieval baskets in future.

Mechanical properties (MPs) and axial and radial force (AF and RF) may influence the efficacy and complications of self-expandable metallic stent (SEMS) placement. We measured the MPs of various SEMSs and examined their influence on the SEMS clinical ability.

We evaluated the MPs of 29 types of 10-mm SEMSs. RF was measured using a conventional measurement device. AF was measured using the conventional and new methods, and the correlation between the methods was evaluated.

A high correlation in AFs was observed, as measured by the new and conventional manual methods. AF and RF scatterplots divided the SEMSs into three subgroups according to structure: hook-and-cross-type (low AF and RF), cross-type (high AF and low RF), and laser-cut-type (intermediate AF and high RF). The hook-and-cross-type had the largest axial force zero border (>20°), followed by the laser-cut and cross types.

MPs were related to stent structure. Hook-and-cross-type SEMSs had a low AF and high axial force zero border and were considered safest because they caused minimal stress on the biliary wall. However, the increase in RF must be overcome.

Background and study aims  We developed a self-expandable metallic stent (SEMS) with a distal tapered end to reproduce the physiological bile flow with a pressure gradient due to the difference in the diameter. We aimed to evaluate the safety and efficacy of the newly developed distal tapered covered metal stent (TMS) for distal malignant biliary obstruction (DMBO). Patients and methods  This single-center, prospective, single-arm study was conducted in patients with DMBO. The primary endpoint was time to recurrent biliary obstruction (TRBO), and the secondary endpoints were the survival time and incidence of adverse events (AEs). Results  Thirty-five patients (15 men, 20 women; median age, 81 years [range: 53-92]) were enrolled between December 2017 and December 2019. The primary diseases were pancreatic head cancer in 25 cases, bile duct cancer in eight cases, and ampullary cancer in two cases. TMS was successfully placed in all cases. Acute cholecystitis occurred as an early AE (within 30 days) in two cases (5.7 %). The median TRBO was 503 days, median survival time was 239 days. RBO was observed in 10 cases (28.6 %), and the causes were distal migration in six cases, proximal migration in two cases, biliary sludge in one case, and tumor overgrowth in one case. Conclusions  Endoscopic placement of the newly developed TMS in patients with DMBO is technically feasible and safe, and the TRBO was remarkably long. The anti-reflux mechanism based on the difference in diameter may be effective, and a randomized controlled trial with a conventional SEMS is required.

Pancreatitis is the most common complication of post-endoscopic retrograde cholangiopancreatography (ERCP). There are currently no prediction models, particularly for post-ERCP pancreatitis (PEP) after biliary stent placement due to malignant biliary obstruction (MBO). To that end, we aim to develop and validate a predictive model for PEP.

We retrospectively analyzed the data of patients who underwent ERCP for biliary stent placement due to MBO at the Second Affiliated Hospital of Harbin Medical University from January 1, 2014 to August 31, 2021. The eligible patients were randomly allocated to the development and validation cohorts. A prediction model was built using the development cohort, and the model's effect was validated using a validation cohort.

A total of 1524 patients were enrolled, including 1016 in the development cohort and 508 in the validation cohort, with an overall PEP rate of 7.1%. The model's predictors included acute pancreatitis history, the absence of pancreatic duct dilation, nonpancreatic cancer, difficult cannulation, and pancreatic injection. The area under the curve (AUC) in the development cohort was 0.810, and the incidence of PEP in the low-risk, medium-risk, and high-risk groups was 1.53%, 9.12%, and 36.36%, respectively. Meanwhile, the AUC of the validation cohort was 0.781, and the incidence of PEP in the low-risk, medium-risk, and high-risk groups was 4.17%, 8.75%, and 41.67%, respectively.

This study was the first to build and validate a risk prediction model, especially for PEP after biliary stent placement due to MBO. Moreover, this model might assist clinicians in identifying high-risk patients and help implement preventive measures in a more timely manner.

Although covered self-expandable metal stents (CSEMSs) are associated with the risk of postendoscopic retrograde cholangiopancreatography (ERCP) pancreatitis due to pancreatic duct (PD) orifice obstruction, they are often used for biliary drainage treatment in malignant biliary obstruction (MBO). This study aimed to investigate the efficacy of PD stenting in preventing post-ERCP pancreatitis after CSEMS implantation.

This retrospective cohort study analyzed 554 patients with transpapillary CSEMS for MBO. Patients with noninitial deployment, benign disease, CSEMS deployment above the papilla, surgically altered anatomy, uncovered self-expandable metal stents, multiple thin self-expandable metal stents, and unavailable procedure videos were excluded. Logistic regression analysis estimated the association between PD stenting and post-ERCP pancreatitis incidence. We adjusted for age, sex, pancreatitis history, prophylactic rectal nonsteroidal anti-inflammatory drug use, naïve papilla, MBO etiology, and prolonged biliary cannulation time.

Among 554 patients, 67 (12.1%) experienced post-ERCP pancreatitis. Post-ERCP pancreatitis was recorded in 13.7% of patients in the non-PD stenting and 4.3% in the PD stenting groups. Pancreatic duct stenting was associated with lower risks of post-ERCP pancreatitis (odds ratio [OR] 0.28; 95% confidence interval [CI] 0.099-0.79; P = 0.028). In multivariable analysis, the association between PD stenting and lower post-ERCP pancreatitis incidence was consistent (OR 0.19; 95% CI 0.062-0.58; P = 0.0034).

Pancreatic duct stenting could reduce the risk of post-ERCP pancreatitis after CSEMSs.

A 69-year-old man was referred to our hospital with obstructive jaundice. A tumor with poor contrast enhancement was found in the pancreatic head, but there was no evidence of pancreatic atrophy, irregular stenosis, or dilation of the main pancreatic duct. He was diagnosed with borderline resectable pancreatic cancer with distal malignant biliary obstruction. After plastic stent placement, serum bilirubin levels improved, and chemotherapy was started. However, he developed cholangitis; thus, the plastic stent was replaced with a covered self-expandable metallic stent. He subsequently developed a delayed pancreatic fistula due to main pancreatic duct disruption. An endoscopic nasopancreatic duct drainage tube was placed to bridge the main pancreatic duct disruption after removing the covered self-expandable metallic stent. In addition, endoscopic ultrasound-guided transmural drainage was performed for the infected fluid collection caused by the pancreatic fistula, and the clinical symptoms quickly improved. This case presents the possibility of a delayed pancreatic fistula due to self-expandable metallic stent deployment. The need for considering such delayed complications when placing self-expanding metallic stents is highlighted.

Percutaneous transhepatic cholangiodrainage (PTCD) and percutaneous transhepatic biliary stenting (PTBS) may be used as a palliative treatment for inoperable patients with malignant biliary obstruction (MBO) to improve the prognosis and their quality of life. However, acute pancreatitis is a common and severe complication that cannot be ignored after PTCD and PTBS in patients with MBO. A few cases may develop severe pancreatitis with a higher mortality rate. In this study, we summarize the known risk factors for acute pancreatitis after percutaneous biliary interventional procedures and investigate possible risk factors to reduce its occurrence by early identifying high-risk patients and taking appropriate measures.

In a recent randomized controlled trial, a double bare metal stent (DBS) showed better stent patency than single-layer metal stents. However, clear evidence comparing the efficacy of uncovered (UCDBS) and partially covered (PCDBS) DBSs for distal malignant biliary obstruction (MBO) is lacking. Therefore, we compared the clinical outcomes including stent patency of UCDBSs versus PCDBSs.

A multicenter, randomized study was performed in patients with distal MBO. The primary endpoint was stent patency. Secondary endpoints were the proportion of patients with patent stents at 6 months, risk factors for stent dysfunction, overall survival, technical and clinical success rates of stent placement, and other adverse events (AEs).

Among 258 included patients, 130 were randomly assigned to the PCDBS group and 128 to the UCDBS group. The mean duration of stent patency of the PCDBS (421.2 days; 95% confidence interval [CI], 346.7-495.7) was longer than that of the UCDBS (377.4 days; 95% CI, 299.7-455.0), although total stent dysfunction and stent dysfunction within 6 months were not different between groups. Multivariate analysis indicated that chemotherapy after stent placement was a significant factor for overall survival (hazard ratio, .570; 95% CI, .408-.796) and had a marginal impact on stent patency (hazard ratio, 1.569; 95% CI, .923-2.667). There were no remarkable differences in AEs, including pancreatitis, cholecystitis, and stent migration, between the 2 groups.

The use of PCDBSs compared with UCDBSs in patients with distal MBO has unclear benefits regarding stent patency and overall survival, although PCDBSs have a lower rate of tumor ingrowth. (Clinical trial registration number: NCT02937246.).

This study aimed to evaluate the efficacy of a novel fully covered self-expandable metal stent (SEMS) with dumbbell-shaped flare ends for the palliation of distal biliary obstruction (DBO) due to unresectable pancreatic cancer (UPC). Patients with DBO due to UPC who received the novel HILZO fully covered stent (HFS), the WALLFLEX partially covered stent (WPS) or fully covered stent (WFS) were analyzed. The incidence of recurrent biliary obstruction (RBO), time to RBO (TRBO), and the incidence of complications were compared among the three SEMS groups. Eighty-four patients (HFS, n = 36; WPS, n = 20; WFS, n = 28) were included. The incidence of RBO was low in the HFS group (versus the WPS and WFS group, p = 0.033 and 0.023, respectively). TRBO in the HFS group was longer than that in the WFS group (p = 0.049). Placement of the HFS was an independent factor for long TRBO in multivariable analysis (p = 0.040). The incidence of pancreatitis and cholecystitis in the HFS group was low (one for each). It is recommended to use the HFS for the palliation of DBO due to UPC from the viewpoint of the low incidence of RBO and complications.

In the case of an unresectable malignant hilar biliary obstruction (MHBO), the optimal drainage method has not yet been established. Recently, an 8 mm, fully covered, self-expandable metal stent (FCSEMS) with an ultra-slim introducer has become available. In this article, the results of whole-liver drainage tests using this novel FCSEMS for MHBO are reported.

Unresectable MHBOs up to Bismuth IIIa with strictures limited to the secondary branches were eligible. The proximal end of the stent was placed in such a way as to avoid blocking the side branches, and the distal end was placed above the papilla when possible. Consecutive patients treated between April 2017 and January 2021 were retrospectively analyzed. The technical and functional success rates, rates and causes of recurrent biliary obstruction (RBO), time to RBO (TRBO), revision for RBO, and adverse events (AEs) were evaluated.

Eleven patients (Bismuth I/II/IIIa: 1/7/3) were enrolled. Two stents were placed in nine patients and three were placed in two patients. Both the technical and functional success rates were 100%. RBO occurred in four (36%) patients due to sludge formation. Revision was performed for three patients, with the successful removal of all stents. The median TRBO was 187 days, and no late AEs other than the RBO occurred. Regarding the distal position of the stent, the RBO rate was significantly lower (14.3% vs. 75%, p = 0.041) and the cumulative TRBO was significantly longer (median TRBO: not reached vs. 80 days, p = 0.031) in the case of the placement above the papilla than the placement across the papilla.

For unresectable MHBOs of Bismuth I, II, and IIIa, whole-liver drainage with a novel 8 mm FCSEMS possessing an ultra-slim introducer was feasible and potentially safe, with favorable stent patency. Placement above the papilla might be preferrable to placement across the papilla.

To summarize the current status and future perspectives of the endoscopic management of biliary strictures.

In addition to conventional diagnostic modalities, such as cross-sectional imaging and endoscopic ultrasonography (EUS), per-oral cholangioscopy is helpful for indeterminate biliary strictures. It allows direct visualization of the biliary tract and targeted biopsy. For distal malignant biliary obstruction (MBO), a self-expandable metal stent (SEMS) via endoscopic retrograde cholangiopancreatography (ERCP) is a standard of care. EUS-guided biliary drainage (EUS-BD) is an emerging alternative to percutaneous transhepatic biliary drainage in cases with failed ERCP. EUS-BD is also an effective salvage option for perihilar MBO, which can not be managed via ERCP or percutaneous transhepatic biliary drainage. Preoperative drainage is necessary for most jaundiced patients as neoadjuvant chemotherapy is widely administered for resectable and borderline resectable pancreatic cancer, and a SEMS is preferred in this setting, too. For benign biliary strictures, a covered SEMS can improve stricture resolution and reduce the number of endoscopic sessions as compared to plastic stents.

ERCP and EUS play a central role in the diagnosis and drainage for both malignant and benign biliary strictures.

Biliary stent placement remains a palliative treatment for patients with unresectable distal malignant biliary strictures (DMBS). The incidence of post-ERCP-pancreatitis (PEP) significantly increases in patients receiving fully covered self-expandable metal stents (FCSEMS) who undergo endoscopic retrograde cholangiopancreatography (ERCP).

This review provides an overview of prevention of PEP after stent implantation for DMBSs. The following operational variables were evaluated: (1) stent type (plastic or metal stent); (2) stent location (above or across the sphincter of Oddi); (3) prophylactic pancreatic duct stent placement; (4) endoscopic sphincterotomy (EST). PubMed, EMBASE, and Cochrane database were searched to identify eligible studies up to October 2021. The odds ratio (OR) with 95% confidence intervals (CI) were pooled using fixed- or random- effects models.

1. PEP occurs more frequently in DMBS patients with self-expandable metal stents (SEMS) compared to that plastic stent (PS). 2. The PEP incidence is higher in covered stents than that in uncovered self-expandable metal stents (USEMS), but not significantly. 3. PEP incidence increases in patients receiving transpapillary FCSEMS placement, particularly when there is an absence of pancreatic duct dilation, and prophylactic pancreatic stenting is recommended for these patients. 4. Limited studies with small sample indicate that there is no significant difference in PEP incidence between transpapillary and suprapapillary stents placement for DMBS. 5. Limited studies indicate that EST does not significantly affect the incidence of pancreatitis in DMBS patients.

Two methods of transpapillary covered self-expandable metal stent (SEMS) placement are used for distal malignant biliary obstruction (MBO): after initial drainage by plastic stent (two-step method) and without previous drainage (one-step method).

In total, 90 patients with unresectable pancreatic cancer and distal MBO were enrolled in this prospective multicenter randomized study and allocated to one-step (n = 45) and two-step (n = 45) groups. The main outcome was the time to recurrent biliary obstruction (TRBO). Secondary outcomes were the rates of early and late adverse events, survival time, the time required for bilirubin level reduction, and cost-effectiveness.

The median TRBO did not differ significantly between the one-step and two-step groups (not available vs 314 days, P = 0.134). SEMS migration occurred significantly more frequently in the two-step group (14.3% vs 0%, P = 0.026). No significant difference was observed between groups in early (7.3% vs 14.3%, P = 0.483) or late (12.2% and 11.9%, P = 1) adverse events other than RBO, survival time (P = 0.104), or the median number of days required to reach a bilirubin level considered to be acceptable for chemotherapy administration (<3 mg/dL; P = 0.881). The total costs of stent placement and reintervention were significantly lower in the one-step SEMS group (3347 vs 5465 US dollars, P < 0.001).

The superiority of TRBO with two-step SEMS placement was not demonstrated. One-step SEMS placement might be a promising method from the viewpoints of cost-effectiveness and less invasiveness (UMIN-CTR clinical trial registration number: UMIN000016010).

Post-ERCP pancreatitis (PEP) after self-expandable metallic stent (SEMS) insertion across the papilla of Vater is an important adverse event that affects the patient's quality of life (QOL). We examined the predictive factors of PEP after SEMS insertion to treat obstructive jaundice due to malignancy.

Ninety patients who underwent biliary SEMS insertion for biliary obstruction due to malignancy at Iwata City Hospital between 2010 and 2018 were reviewed. We evaluated the relationship between the incidence of PEP after biliary SEMS insertion and clinical factors. We measured the thickness of the pancreatic parenchyma and diameter of the main pancreatic duct (MPD) at the left side of the corpus vertebrae.

Mild and severe PEP were diagnosed in 10 (11.1%) and 1 (1.1%) patients, respectively. Only the thickness of the pancreatic parenchyma and diameter of MPD significantly differed between the PEP and non-PEP groups. The incidence of PEP among patients whose thickness of the pancreatic parenchyma at the left side of the corpus vertebrae was less than 9.5 mm (0%) on computed tomography was lower than that in patients whose thickness was 9.5 mm or greater (34.4%). Similarly, a wider (5 mm or more) diameter of MPD (4.3%) reduced the incidence of PEP compared with a narrower diameter (40.0%). Logistic regression analysis revealed that the probability of PEP decreases 3.91 times for every 1-mm increase in MPD diameter (95% CI 1.23-12.4, p = .02).

Based on our study, a dilated MPD is a negative predictive factor of pancreatitis related to biliary SEMS insertion.

Background and study aims  There are conflicting data regarding the risk of post-ERCP pancreatitis (PEP) with self-expandable metallic stents (SEMS) compared to polyethylene stents (PS) in malignant biliary obstructions and limited data related to benign obstructions. Patients and methods  A retrospective cohort study was performed of 1136 patients who underwent ERCP for biliary obstruction and received SEMS or PS at a tertiary-care medical center between January 2011 and October 2016. We evaluated the association between stent type (SEMS vs PS) and PEP in malignant and benign biliary obstructions. Results  Among the 1136 patients included in our study, 399 had SEMS placed and 737 had PS placed. Patients with PS were more likely to have pancreatic duct cannulation, pancreatic duct stent placement, double guidewire technique, sphincterotomy and sphincteroplasty as compared to the SEMS group. On multivariate analysis, PEP rates were higher in the SEMS group (8.0 %) versus the PS group (4.8 %) (OR 2.27 [CI, 1.22, 4.24]) for all obstructions. For malignant obstructions, PEP rates were 7.8 % and 6.6 % for SEMS and plastic stents, respectively (OR 1.54 [CI, 0.72, 3.30]). For benign obstructions the PEP rate was higher in the SEMS group (8.8 %) compared to the PS group (4.2 %) (OR 3.67 [CI, 1.50, 8.97]). No significant differences between PEP severity were identified based on stent type when stratified based on benign and malignant. Conclusions  PEP rates were higher when SEMS were used for benign obstruction as compared to PS. For malignant obstruction, no difference was identified in PEP rates with use of SEMS vs PS.

Two types of self-expandable metal stents (SEMS) are available for malignant distal biliary obstruction: fully covered SEMS (FCSEMS) and uncovered SEMS. FCSEMS can prevent stent ingrowth, but a major concern is spontaneous migration. This study aimed to determine whether the additional insertion of a double-pigtail plastic stent to anchor the FCSEMS can prevent migration.

68 patients with unresectable, malignant, distal, biliary obstruction were included in this multicenter, randomized, superiority trial. The patients were randomly assigned to receive either the FCSEMS plus an anchoring plastic stent (n = 33) or an FCSEMS alone (n = 35). After placement of the FCSEMS, the anchoring stent was inserted inside the FCSEMS. The primary outcome was the rate of stent migration during the 6-month follow-up. The secondary outcomes were stent-related adverse events, stent patency, and survival rates.

The baseline characteristics were similar between the two groups. The rate of stent migration at 6 months was significantly lower in patients with the FCSEMS plus anchoring stent (15 % vs. 40 %; P = 0.02). The mean stent patency was significantly longer in the FCSEMS plus anchoring group (237 days [95 % confidence interval [CI] 199 to 275] vs. 173 days [95 %CI 130 to 217]; P = 0.048). There were no significant differences in stent-related adverse events and overall survival rates at 6 months between the two groups.

Our data suggest that the additional double-pigtail plastic stent anchored the FCSEMS to prevent migration and prolonged patency without any serious adverse events.