Endoscopic biliary stenting is an essential treatment for malignant biliary obstruction (MBO). However, the optimal location for the placement of metal stents (MS) or plastic stents (PS) during the management of MBO, whether above (suprapapillary) or across (transpapillary) the sphincter of Oddi (SO), has not been thoroughly evaluated. This meta-analysis aims to compare the clinical outcomes associated with endoscopic retrograde cholangiopancreatography (ERCP)-guided biliary stents placed above and across the SO in patients with MBO.
A comprehensive search of electronic databases was carried out to identify studies published from inception to April 2022. The clinical outcomes examined including stent patency, stent occlusion, and overall adverse events (AEs) such as cholangitis, post-ERCP pancreatitis (PEP), cholecystitis, stent migration, and bleeding. The selection of a random-effects model or fixed-effects model was based on the presence of heterogeneity.
A total of 12 articles involving 751 patients were analyzed. The findings showed that the suprapapillary approach had longer stent patency compared to the transpapillary approach (mean difference: 38.58; 95% confidence interval 16.02-61.14, P < 0.0001). Additionally, the suprapapillary approach was associated with a lower risk of stent occlusion and overall AEs (P = 0.04, P = 0.002, respectively), particularly in the incidence of PEP (P = 0.009). The incidence of cholangitis, cholecystitis, stent migration, and bleeding were similar between the suprapapillary and transpapillary approaches. The subgroup analyses indicated that suprapillary PS had a significant decrease in the incidence of stent occlusion and longer stent patency, while suprapillary MS had a significant decrease in the incidence of overall AEs and PEP than the transpapillary approach.
Compared with the transpapillary approach, the suprapapillary stent had superiority in longer stent patency, lower rates of stent occlusion and overall AEs, and notably, a lower incidence of PEP. The incidence of cholangitis, cholecystitis, stent migration, and bleeding were similar between the suprapapillary and transpapillary approaches. Further large-scale randomized controlled studies are needed to confirm our findings.
CRD42022336435.

OBJECTIVE: Pancreatobiliary tumours are challenging to diagnose exclusively by imaging methods. Although the optimum moment for carrying out the EUS is not well defined, it has been suggested that the presence of biliary stents may interfere with the proper staging of tumours and the acquisition of samples. We performed a meta-analysis to evaluate the impact of biliary stents on EUS-guided tissue acquisition yield.
METHODS: We conducted a systematic review in different databases, such as PubMed, Cochrane, Medline, and OVID Database. A search was made of all studies published up to February 2022.
RESULTS: Eight studies were analyzed. A total of 3185 patients were included. The mean age was 66.9±2.7 years; 55.4% were male gender. Overall, 1761 patients (55.3%) underwent EUS guided tissue acquisition (EUS-TA) with stents in situ, whereas 1424 patients (44.7%) underwent EUS-TA without stents. The technical success was similar in both groups (EUS-TA with stents: 88% vs EUS-TA without stents: 88%, OR=0.92 [95% CI 0.55-1.56]). The type of stent, the needle size and the number of the passes were similar in both groups.
CONCLUSIONS: EUS-TA has similar diagnostic performance and technical success in patients with or without stents. The type of stent (SEMS or plastic) does not seem to influence the diagnostic performance of EUS-TA. Future prospectives and RCT studies are needed to strengthen these conclusions.

Self-expandable metal stents (SEMSs) are widely used for palliation of distal malignant biliary obstruction (dMBO). However, previous studies comparing the outcomes between uncovered SEMSs (UCSEMSs) and fully covered SEMSs (FCSEMSs) report conflicting results. This large cohort study aimed to compare the clinical outcomes between UCSEMSs and FCSEMSs for dMBO.
A retrospective cohort study was performed in patients with dMBO who underwent either UCSEMS or FCSEMS placement between May 2017 and May 2021. Primary outcomes were rates of clinical success, adverse events (AEs), and unplanned endoscopic reintervention. Secondary outcomes were types of AEs, intervention-free stent patency, and management and outcomes of stent occlusion.
The cohort included 454 patients (364 in the UCSEMS group and 90 in the FCSEMS group). Median follow-up duration was 9.6 months and was similar between the 2 groups. Use of UCSEMSs and FCSEMSs had comparable clinical success (P = .250). However, use of UCSEMSs had significantly higher rates of AEs (33.5% vs 21.1%; P = .023) and unplanned endoscopic reintervention (27.0% vs 11.1%; P = .002). UCSEMSs had a higher rate of stent occlusion (26.9% vs 8.9%; P < .001) and shorter median time to stent occlusion (4.4 months vs 10.7 months; P = .002). Stent reintervention-free survival was higher in the FCSEMS group. FCSEMSs had a significantly higher rate of stent migration (7.8% vs 1.1%; P < .001), but patients in the FCSEMS group had similar rates of cholecystitis (.3% vs 1.1%; P = .872) and post-ERCP pancreatitis (6.3% vs 6.6%; P = .90). When UCSEMSs did occlude, placement of a coaxial plastic stent had a higher rate of stent reocclusion compared with coaxial SEMS placement (46.7% vs 19.7%; P = .007).
FCSEMSs should be considered for the palliation of dMBO because of lower rates of AEs, longer patency rates, and lower rates of unplanned endoscopic intervention.

Cholestasis of the indwelling biliary stents usually leads to stone recurrence after endoscopic retrograde cholangio pancreatoraphy (ERCP). Biliary stents, including metallic and none-degradable plastic stents are widely used in clinical settings due to their many excellent properties. However, conventional biliary stents still suffer from poor antibacterial activity and anti-bile-adhesion, which lead to injured, local fibroblasts proliferating. Currently, various coatings for biliary stents have been prepared to meet the clinical demands. In this review, we start by summarizing and discussing classifications of biliary stents and antibacterial/antibiofilm mechanism. Then, the latest advances about developing antibacterial and antibiofilm coatings for improving the properties of biliary stents are reviewed and discussed in detail. Lastly, we list several possible directions for future development of biliary stents coatings and biliary stent, such as anti-bile-adhesion coating, multifunctional coating, drug-eluting biodegradable biliary stents and 3D printed biliary stents.

OBJECTIVE: The current drain tubes for preventing surgically biliary anastomotic stricture are not naturally and easily removed. If a drain tube using biodegradable material is easily available and the degradation time of the tube is well controlled, surgical anastomotic stricture and fibrosis could be prevented. The aim of this animal study was to evaluate the preventive effect of novel biodegradable stents (BS) on biliary stricture and fibrosis after duct-to-duct (DD) biliary anastomosis.
METHODS: Ten mini-pigs were allocated to the control group (n = 5) and or the stent group (n = 5). The common bile duct was exposed through surgical laparotomy and then resected transversely. In the stent group, a 4-mm or 6-mm polydioxanone/magnesium sheath-core BS was inserted according to the width of the bile duct, followed by DD biliary anastomosis. In the control group, DD biliary anastomosis was performed without BS insertion.
RESULTS: In the stent group, stents were observed without deformity for up to 4 weeks in all animals. Eight weeks later, histopathologic examination revealed that the common bile duct of the anastomosis site was relatively narrower in circumference in the control group compared to the stent group. The degree of fibrosis in the control group was more marked than in the stent group (3.84 mm vs. 0.68 mm, respectively; P < 0.05).
CONCLUSIONS: Our study showed that novel BS maintained their original shape and radial force for an adequate time and then disappeared without adverse events. The BS could prevent postoperative complications and strictures after DD biliary anastomosis.

BACKGROUND: The outcome of percutaneous cholecystostomy (PC) in malignant patients with acute cholecystitis (AC) after biliary stent insertion has not been investigated in a large group.
OBJECTIVE: To evaluate the clinical outcomes of PC for AC after stent insertion in patients with malignant biliary obstruction.
METHODS: From April 2007 to February 2019, 107 patients (57 men, 52 women; mean age = 67.5 years; age range = 27-93 years) who had undergone PC for AC after biliary stent insertion were retrospectively evaluated. Of the 107 patients, 86 underwent biliary stent insertion by the endoscopic approach and the remaining 21 patients by the percutaneous approach. All patients were classified into three groups: those with stent-induced AC; those with cancer-induced AC; and those with AC without mechanical cause (biliary stent, GB stone, or cancer invasion). The mean survival time, recurrence rate, symptom improvement, and cystic duct patency in each patient group were analyzed.
RESULTS: Stent-induced AC (n = 40, 37.4%) developed with a mean onset time of six days (range = 0-14 days), AC without mechanical cause (n = 27, 25.2%), 87 days (range = 15-273 days), and cancer-induced AC (n = 40, 37.4%), 137 days (range = 15-447 days) after stent insertion. Symptom resolution and significant improvement in laboratory test values were achieved in 95 patients (88.8%) within four days after PC.
CONCLUSIONS: PC is a technically safe and effective method for the treatment of AC after biliary stent insertion in patients with malignant biliary obstruction.

Plastic biliary stents that remain in situ for more than 12 months, called forgotten biliary stents (FBSs), can cause complications such as cholangitis, stent migration, stent occlusion, and perforation.
The medical records of patients who underwent ERCP procedures from December 2016 to December 2020 were analysed retrospectively. Data on patient characteristics, indications for ERCP and stenting, stent types, stenting duration, complications, and causes of FBSs were obtained from the hospital’s database.
A total of 48 cases with FBSs were analysed. The mean age (SD) of the patients was 71.23 years (±12.165), the male-to-female ratio was 23/25 (0.92), and the mean stenting duration was 27.12 months (range: 12–84 months). The most common indication for biliary stenting was irretrievable choledochal stones (40/48). Stone formation (79%) and proximal stent migration (26.4%) were the most frequent complications. The patients in the FBS group were significantly older than those from whom stents were removed in a timely manner (71.23 vs. 62.43 years, p < 0.001). Endoscopic treatment was possible in all cases; surgery was not required in any case. The most common cause of FBSs cited by patients was not having been informed about the need for long-term management of their stents (n = 14, 29.2%)
FBSs are potentially problematic particularly in elderly patients. Communication with the patient to remind them of the need for stent management is important for preventing FBSs.

OBJECTIVE: The clinical outcomes and prevalence of adverse events associated with biliary biodegradable stents (BS) can differ according to degradation process and time. The aim of this study was to observe the degradation process and time of different BS prototypes, and to evaluate sequential changes in their mechanical properties.
METHODS: Using an in vitro bile flow phantom model, we compared degradation time, radial force changes, and morphologic changes among four different BS prototypes: polydioxanone (PDO) BS, polyglycolide (PGA) BS, polydioxanone/poly-l-lactic acid (PDO/PLLA) sheath-core BS, and polydioxaone/magnesium (PDO/Mg) sheath-core BS. Using an in vivo swine bile duct dilation model, we performed a direct peroral cholangioscopy (DPOC) examination to observe the biodegradation process and related adverse events at regular intervals.
RESULTS: In the bile flow phantom model, the PGA BS and PDO/Mg BS prototypes showed rapid radial force reduction and morphological changes and complete degradation within six weeks. PDO/PLLA BS maintained high radial force and kept their original shape for longer than the PDO BS, up to 16 weeks. A total of 24 BS were inserted into the dilated bile ducts of 12 swine. In this animal model, DPOC examination revealed that PDO BS and PDO/PLLA BS maintained their original shapes for approximately 12 weeks, but PDO BS showed a greater degree of fragmentation and induced biliary stones and bile duct obstruction.
CONCLUSIONS: Our results showed that PDO/PLLA BS maintained their original shape and radial force for a relatively long time and minimized adverse events.

Several inflammatory conditions of the bile ducts cause strictures that prevent the drainage of bile into the gastrointestinal tract. Non-pharmacological treatments to re-establish bile flow include plastic or self-expanding metal stents (SEMs) that are inserted in the bile ducts during endoscopic retrograde cholangiopancreatography (ERCP) procedures. The focus of this study was to 3D print an anatomically accurate model of the extrahepatic bile ducts (EHBDs) with tissue-like mechanical properties to improve in vitro testing of stent prototypes. Following generation of an EHBD model via computer aided design (CAD), we tested the ability of Formlabs SLA 3D printers to precisely print the model with polymers selected based on the desired mechanical properties. We found the printers were reliable in printing the dimensionally accurate EHBD model with candidate polymers. Next, we evaluated the mechanical properties of Formlabs Elastic (FE), Flexible (FF), and Durable (FD) resins pre- and post-exposure to water, saline, or bile acid solution at 37 °C for up to one week. FE possessed the most bile duct-like mechanical properties based on its elastic moduli, percent elongations at break, and changes in mass under all liquid exposure conditions. EHBD models printed in FE sustained no functional damage during biliary stent deployment or when tube connectors were inserted, and provided a high level of visualization of deployed stents. These results demonstrate that our 3D printed EHBD model facilitates more realistic pre-clinical in vitro testing of biliary stent prototypes.

BACKGROUND: The present study aimed to determine the optimal timing of pancreaticoduodenectomy (PD) following preoperative biliary drainage (PBD) with consideration of postoperative morbidity and survival.
METHODS: Between January 2007 and December 2015, consecutive 1,568 patients underwent PD at a single institution. Their data were reviewed retrospectively.
RESULTS: Of all, 831 patients underwent PBD. The mean duration between drainage and surgery was 16.9 days. Regarding postoperative outcomes, length of hospital stay was longer in the drainage group (P = 0.028). Postoperative pancreatic fistula was not significantly different between the non-drainage and drainage groups (P = 0.162), but major complications occurred more frequently in the drainage group (P = 0.002). Multivariable analysis showed major complications occurred significantly at third and fourth weeks (odds ratios 1.863 and 2.523) after PBD, whereas early surgery performed in the first 2 weeks did not noticeably increase postoperative complications. In multivariable survival comparison, weekly interval beyond 6 weeks was associated with poor survival in those with pancreatic cancer, while patients with bile duct cancer operated on at the fourth week showed worse prognosis.
CONCLUSIONS: Early surgery that reduces the operative delay after PBD may improve both short- and long-term postoperative outcomes in cancer patients undergoing PBD.