Biliary strictures arise from diverse benign and malignant etiologies, and accurate differentiation is pivotal for prognosis and treatment selection. Conventional endoscopic retrograde cholangiopancreatography (ERCP)-based sampling (brush cytology and forceps biopsy) suffers from limited sensitivity despite high specificity, leaving a substantial proportion as indeterminate biliary strictures. Peroral cholangioscopy (POCS) enables direct intraductal visualization and targeted biopsies, thereby enhancing diagnostic yield. This review summarizes technological evolution from fiber-optic mother–baby systems to digital single-operator cholangioscopy and direct POCS, as well as the integration of image-enhanced endoscopy and emerging wide-channel scopes. Visual criteria for malignancy—tumor vessels, irregular granular or papillary/villous patterns, and friability—achieve high sensitivity and interobserver reliability with proposed classifications (Monaco, Mendoza). For cholangiocarcinoma, POCS-guided mapping biopsies precisely assess longitudinal intraepithelial tumor spread, informing R0 surgical planning. Randomized trials indicate higher or at least comparable sensitivity of POCS-guided biopsies relative to ERCP sampling, while novel forceps and larger working channels increase specimen size and reduce the number of biopsies. Artificial intelligence (AI) applied to POCS images shows promise for real-time risk stratification and improved targeting. Therapeutically, POCS guides intraductal lithotripsy with high clearance rates, and facilitates management in surgically altered anatomy in concert with endoscopic ultrasound-guided biliary drainage or transendosonographically/ guided created route procedure. Adverse events, chiefly pancreatitis and cholangitis, warrant attention to intraductal pressure control and CO2 insufflation. POCS has established an essential role in the diagnostic algorithm for biliary strictures; future advances will likely come from enhanced imaging, AI assistance, and next-generation digital cholangioscopes with larger biopsy devices.

Postoperative pancreatic fistulas (POPFs) are common adverse events that occur after pancreatic surgery. Endoscopic ultrasonography (EUS)-guided drainage (EUS-D) is a first-line treatment, similar to that for pancreatic fluid collection (PFCs) after acute pancreatitis. However, some POPFs do not develop fluid collections depending on the presence or location of the surgical drain, whereas others develop fluid collections, such as postoperative fluid collections (POPFCs). Although POPFCs are similar to PFCs, the strategy and modality for POPF management need to be modified according to the presence of fluid collections, surgical drains, and surgical type. As discussed for PFCs, the indications, timing, and selection of interventions or stents for EUS-D have not been fully elucidated for POPFs. In this review, we discuss the management of POPFs and POPFCs in comparison with PFCs due to acute pancreatitis and summarize the topics that should be addressed in future studies.

Postoperative pancreatic fistulas (POPFs) are common adverse events that occur after pancreatic surgery. Endoscopic ultrasonography (EUS)-guided drainage (EUS-D) is a first-line treatment, similar to that for pancreatic fluid collection (PFCs) after acute pancreatitis. However, some POPFs do not develop fluid collections depending on the presence or location of the surgical drain, whereas others develop fluid collections, such as postoperative fluid collections (POPFCs). Although POPFCs are similar to PFCs, the strategy and modality for POPF management need to be modified according to the presence of fluid collections, surgical drains, and surgical type. As discussed for PFCs, the indications, timing, and selection of interventions or stents for EUS-D have not been fully elucidated for POPFs. In this review, we discuss the management of POPFs and POPFCs in comparison with PFCs due to acute pancreatitis and summarize the topics that should be addressed in future studies.

Postoperative pancreatic fistulas (POPFs) are common adverse events that occur after pancreatic surgery. Endoscopic ultrasonography (EUS)-guided drainage (EUS-D) is a first-line treatment, similar to that for pancreatic fluid collection (PFCs) after acute pancreatitis. However, some POPFs do not develop fluid collections depending on the presence or location of the surgical drain, whereas others develop fluid collections, such as postoperative fluid collections (POPFCs). Although POPFCs are similar to PFCs, the strategy and modality for POPF management need to be modified according to the presence of fluid collections, surgical drains, and surgical type. As discussed for PFCs, the indications, timing, and selection of interventions or stents for EUS-D have not been fully elucidated for POPFs. In this review, we discuss the management of POPFs and POPFCs in comparison with PFCs due to acute pancreatitis and summarize the topics that should be addressed in future studies.

Background/Aims: 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. Methods: 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. Results: 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. Conclusions 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/Aims: The aim of this study was to evaluate the safety and efficacy of partially covered self-expandable metallic stents (PCSEMS) in patients undergoing neoadjuvant chemo (radio) therapy (NAC) for pancreatic cancer (PC). Methods: This was a prospective multicenter study to evaluate the safety and efficacy of PCSEMS in patients receiving NAC for resectable and borderline resectable PC. The primary endpoint was the rate of recurrent biliary obstruction (RBO). Results: Twenty-six patients with PC (three with resectable PC and 23 with borderline resectable PC) who underwent NAC at seven Japanese centers were included in the analysis. Both the technical and functional success rates of PCSEMS placement were 100%. Early stent-related complications were observed in three patients (11.5%): mild pancreatitis (n=2) and mild liver abscess (n=1). The median time to surgery or palliation was 4.0 months. Surgical resection was eventually performed in 73.1% of patients, and stent removal during surgery was successful in all patients. RBO was observed in nine patients (34.6%): seven with stent occlusion, one with kinking and one with migration. The RBO rates in resected cases and nonresected cases were 36.8% and 28.6%, respectively. Conclusions Biliary drainage by PCSEMS was safe and feasible in patients undergoing NAC for resectable and borderline resectable PC.

The Japanese Society of Hepato-Biliary-Pancreatic Surgery launched the clinical practice guidelines for the management of biliary tract cancers (cholangiocarcinoma, gallbladder cancer, and ampullary cancer) in 2007, then published the 2nd version in 2014. In this 3rd version, clinical questions (CQs) were proposed on six topics. The recommendation, grade for recommendation, and statement for each CQ were discussed and finalized by an evidence-based approach. Recommendations were graded as grade 1 (strong) or grade 2 (weak) according to the concepts of the grading of recommendations assessment, development, and evaluation system. The 31 CQs covered the six topics: (1) prophylactic treatment, (2) diagnosis, (3) biliary drainage, (4) surgical treatment, (5) chemotherapy, and (6) radiation therapy. In the 31 CQs, 14 recommendations were rated strong and 14 recommendations weak. The remaining three CQs had no recommendation. Each CQ includes a statement of how the recommendations were graded. This latest guideline provides recommendations for important clinical aspects based on evidence. Future collaboration with the cancer registry will be key for assessing the guidelines and establishing new evidence.

Endoscopic management of bile duct stones is now the standard of care, but challenges remain with difficult bile duct stones. There are some known factors associated with technically difficult bile duct stones, such as large size and surgically altered anatomy. Endoscopic mechanical lithotripsy is now the standard technique used to remove large bile duct stones, but the efficacy of endoscopic papillary large balloon dilatation (EPLBD) and cholangioscopy with intraductal lithotripsy has been increasingly reported. In patients with surgically altered anatomy, biliary access before stone removal can be technically difficult. Endotherapy using two new endoscopes is now utilized in clinical practice: enteroscopy-assisted endoscopic retrograde cholangiopancreatography and endoscopic ultrasound-guided antegrade treatment. These new approaches can be combined with EPLBD and/or cholangioscopy to remove large bile duct stones from patients with surgically altered anatomy. Since various endoscopic procedures are now available, endoscopists should learn the indications, advantages and disadvantages of each technique for better management of bile duct stones.

Background/Aims: Recently, a three-plane symmetric nee-dle with Franseen geometry was developed for endoscopic ultrasound-guided fine needle biopsy (EUS-FNB). In this ret-rospective study, tissue acquisition per pass was compared between 22-gauge Franseen FNB and standard fine needle aspiration (FNA) needles in patients with solid pancreatic le-sions. Methods: Consecutive patients who underwent EUSFNA or EUS-FNB for solid pancreatic lesions between Octo-ber 2014 and March 2018 were retrospectively studied. The tissue acquisition rate and the diagnostic performance per session, per pass, and at first pass were compared. Results: A total of 663 passes (300 by the FNB needle and 363 by the standard FNA needle) were performed in 154 patients (71 FNB and 83 FNA). The tissue acquisition rate per session and at first pass in the FNB and FNA groups was 100% and 95% (p=0.13) and 87% and 69% (p=0.007), respectively. The multivariate analysis revealed that among the patients, EUS-FNB (odds ratio, 3.07; p=0.01) was associated with a higher first-pass tissue acquisition rate. While the tissue ac-quisition rate reached a plateau after the 4th pass with FNA, it reached a plateau after the 2nd pass with FNB. Among the 129 malignant cases, the histological tissue acquisition rate per session was similar (100% and 94%), but the sensitivity by histology alone per session was higher for FNB than for FNA (93% and 73%, p<0.01). Conclusions The results of our retrospective analysis indicated that compared with a standard FNA needle, a 22-gauge Franseen FNB needle was associated with a higher first-pass tissue acquisition rate.

Endoscopic transpapillary biliary drainage is the current standard of care for unresectable hilar malignant biliary obstruction (MBO) and bilateral metal stent placement is shown to have longer patency. However, technical and clinical failure is possible and percutaneous transhepatic biliary drainage (PTBD) is sometimes necessary. Endoscopic ultrasound-guided biliary drainage (EUS-BD) is increasingly being reported as an alternative rescue procedure to PTBD. EUS-BD has a potential advantage of not traversing the biliary stricture and internal drainage can be completed in a single session. Some approaches to bilateral biliary drainage for hilar MBO under EUS-guidance include a bridging method, hepaticoduodenostomy, and a combination of EUS-BD and transpapillary biliary drainage. The aim of this review is to summarize data on EUS-BD for hilar MBO and to clarify its advantages over the conventional approaches such as endoscopic transpapillary biliary drainage and PTBD.
Constriction, Pathologic ; Drainage ; Endosonography ; Methods ; Standard of Care ; Stents