Digital Single-operator Cholangioscopy (DSOC) Improves Interobserver Agreement (IOA) and Accuracy for Evaluation of Indeterminate Biliary Strictures: The Monaco Classification.

BACKGROUND: Visual characteristics seen during digital single-operator cholangioscopy (DSOC) have not been validated. The aim of this 2-phase study was to define terminology by consensus for the visual diagnosis of biliary lesions to develop a model for optimization of the diagnostic performance of DSOC. MATERIALS AND METHODS: In phase 1 (criteria identification), video-cholangioscopy clips were reviewed by 12 expert biliary endoscopists, who were blinded to the final diagnosis. Visual criteria were consolidated into the following categories: (1) stricture, (2) lesion, (3) mucosal features, (4) papillary projections, (5) ulceration, (6) abnormal vessels, (7) scarring, (8) pronounced pit pattern.During the second phase (validation), 14 expert endoscopists reviewed DSOC (SpyGlass DS, Boston Scientific) clips using the 8 criteria to assess interobserver agreement (IOA) rate. RESULTS: In phase 1, consensus for visual findings were categorized into 8 criteria titled the "Monaco Classification." The frequency of criteria were: (1) presence of stricture-75%, (2) presence of lesion type-55%, (3) mucosal features-55%, (4) papillary projections-45%, (5) ulceration-42.5%, (6) abnormal vessels-10%, (7) scarring-40%, and (8) pronounced pit pattern-10%. The accuracy on final diagnosis based on visual impression alone was 70%.In phase 2, the IOA rate using Monaco Classification criteria ranged from slight to fair. The presumptive diagnosis IOA was fair (κ=0.31, SE=0.02), and overall diagnostic accuracy was 70%. CONCLUSIONS: The Monaco classification identifies 8 visual criteria for biliary lesions on single-operator digital cholangioscopy. Using the criteria, the IOA and diagnostic accuracy rate of DSOC is improved compared with prior studies.

A newly modified access balloon catheter for direct peroral cholangioscopy by using an ultraslim upper endoscope (with videos).

BACKGROUND AND AIMS: Direct peroral cholangioscopy (POC) by using an ultraslim upper endoscope has been increasingly applied for diagnosis and treatment of diverse biliary diseases. Recently, an intraductal balloon catheter has been used commonly to guide the flexible ultraslim endoscope. However, accessibility into the bile duct remains a limitation of the procedure. The aim of this study was to evaluate the feasibility and success rate of an intraductal balloon-guided direct POC by using an ultraslim endoscope with a newly modified 5F balloon catheter. METHODS: In total, 36 patients with biliary obstruction were included prospectively for a direct POC by using an ultraslim endoscope with a newly modified intraductal 5F balloon catheter. The main outcome measure was technical success, defined as successful advancement of the ultraslim endoscope into the obstructed segment of the biliary tree or the bifurcation. Secondary outcomes were mean time for the total procedure, intubation into the common bile duct and advancement up to the target site after intubation of the ultraslim endoscope, technical success rates of diagnostic and therapeutic interventions, and adverse events. RESULTS: The intraductal balloon-guided direct POC using a newly modified 5F balloon catheter was completed successfully in 35 of 36 patients (97.2%). The mean times for total procedure, intubation into the distal common bile duct, and advancement up to the obstructed bile duct segment were 27.3 ± 7.2, 2.2 ± 0.5, and 0.8 ± 0.4 minutes, respectively. In total, 49 interventions were performed in 35 patients, excluding 1 patient in whom we failed to perform direct POC. Technical success of the interventions was achieved with 44 of 49 procedures (89.8%). No adverse events, including cholangitis, were observed. CONCLUSIONS: A newly modified 5F balloon catheter seemed to facilitate performing intraductal balloon-guided direct POC for direct visual examination of the bile duct in patients with biliary obstruction. Continued development of endoscopes and accessories are expected to further improve the performance of direct POC.

Is mitochondrial DNA copy number associated with clinical characteristics and prognosis in gastric cancer?

Alterations in mitochondrial DNA (mtDNA) have been studied in various cancers. However, the clinical value of mtDNA copy number (mtCN) alterations in gastric cancer (GC) is poorly understood. In the present study, we investigated whether alterations in mtCNs might be associated with clinicopathological parameters in GC cases. mtCN was measured in 109 patients with GC by quantitative real-time PCR. Then, correlations with clinicopathological characteristics were analyzed. mtCN was elevated in 64.2% of GC tissues compared with paired, adjacent, non-cancerous tissue. However, the observed alterations in mtCN were not associated with any clinicopathological characteristics, including age, gender, TN stage, Lauren classification, lymph node metastasis, and depth of invasion. Moreover, Kaplan-Meier survival curves revealed that mtCN was not significantly associated with the survival of GC patients. In this study, we demonstrated that mtCN was not a significant marker for predicting clinical characteristics or prognosis in GC.

Usefulness of endoscopic ultrasound-guided sampling using core biopsy needle as a percutaneous biopsy rescue for diagnosis of solid liver mass: Combined histological-cytological analysis.

BACKGROUND AND STUDY AIMS: Endoscopic ultrasound (EUS)-guided fine needle aspiration (EUS-FNA) is one of the alternative methods for tissue sampling of liver solid mass. However, the diagnostic efficacy using cytology alone was limited. In this study, we evaluate the diagnostic accuracy of EUS-guided fine needle biopsy (EUS-FNB) as a percutaneous biopsy rescue for liver solid mass. PATIENTS AND METHODS: The EUS-FNB using core biopsy needle for liver solid mass was performed prospectively for patients who were failure to acquire a tissue or achieve a diagnosis using percutaneous liver biopsy. The primary outcome was the diagnostic accuracy of EUS-FNB for malignancy and specific tumor type. The secondary outcomes were the median numbers of passes required to establish a diagnosis, the proportions of patients in whom immunohistochemical (IHC) stain was possible and obtained adequate specimen, and safety of EUS-FNB. RESULTS: Twenty-one patients (12 women; mean age, 63 years [range, 37-81]) underwent EUS-FNB for solid liver masses. The median number of needle passes was 2.0 (range, 1-5). On-site cytology and cytology with Papanicolaou stain showed malignancy in 16 patients (76.2%) and 17 patients (81.0%), respectively. In histology with HE stain, 19 patients (90.5%) were diagnosed malignancy and optimal to IHC stain. The overall diagnostic accuracy for malignancy and specific tumor type were 90.5% and 85.7%, respectively. No complications were seen. CONCLUSIONS: EUS-FNB with core biopsy needle for solid liver mass may be helpful in the management of patients who are unable to diagnose using percutaneous liver biopsy.

Predictability of preoperative 18F-FDG PET for histopathological differentiation and early recurrence of primary malignant intrahepatic tumors.

OBJECTIVE: The limited studies with 18F-fluorodeoxyglucose (18F-FDG)-PET reported results and interpretations that differed between hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (IHCC). We investigated the correlation between preoperative PET results and postoperative prognosis, including early (time-to-recurrence<6 months) tumor recurrence, and histopathological tumor differentiation in patients who had undergone surgery for primary malignant intrahepatic tumors, including HCC and IHCC. MATERIALS AND METHODS: We retrospectively reviewed 357 patients who had undergone curative surgery for malignant hepatic tumors, including primary HCC or IHCC, other than Klatskin tumors at a tertiary academic hospital between January 2005 and June 2012. All patients had undergone an 18F-FDG PET/computed tomography scan preoperatively and the maximum standardized uptake value of the tumor (max SUV tumor) and the tumor-to-nontumor SUV ratio (TNR) were calculated from 18F-FDG uptake. Histopathological differentiation grading was confirmed postoperatively. RESULTS: Among the patients, 115 cases with primary malignant intrahepatic tumors fulfilled the inclusion criteria. On univariate analysis, preoperative max SUV tumor and TNR showed a correlation with the overall and early tumor recurrence of HCC, but only max SUV tumor was associated with overall and early recurrence of IHCC (P<0.05). When considering postoperative histopathological differentiation, a correlation between max SUV tumor and TNR with HCC and between max SUV tumor and IHCC was found (P<0.05). However, on multivariate analysis, only early recurrence was associated with TNR in HCC and with max SUV tumor in IHCC. CONCLUSION: A preoperative 18F-FDG PET scan can be considered a useful reference for postoperative tumor recurrence and histopathological differentiation in cases of primary malignant intrahepatic tumors. 18F-FDG PET scan results should be interpreted separately for malignant liver tumors.

Clinical usefulness of intraductal ultrasonography for the management of acute biliary pancreatitis.

BACKGROUND AND AIM: Identifying a bile duct (BD) stone in patients with acute biliary pancreatitis (ABP) is important for the management and prevention of recurrent attack of pancreatitis. However, small BD stones may not be detected on endoscopic retrograde cholangiopancreatography (ERCP). The aim of this study was to prospectively evaluate the usefulness of intraductal ultrasonography (IDUS) in patients suspected to have ABP but with no evidence of choledocholithiasis on ERCP. METHODS: A total 92 patients suspected with ABP without evidence of BD stones on imaging studies including ERCP were enrolled. Wire-guided IDUS was performed during ERCP in all patients. Stones or sludge detected by IDUS were confirmed after endoscopic sphincterotomy (EST) and extraction. If IDUS finding was negative, then we swept the BD with a balloon catheter and/or basket without EST. After endoscopic management, comparison between IDUS and endoscopic finding was carried out to determine the diagnostic accuracy of IDUS. RESULTS: Among the 92 patients, IDUS revealed BD stones in 33 (35.9%). All 33 patients' stones were confirmed by endoscopic visualization after EST and BD exploration. During the mean follow up of 24 months, recurrent pancreatitis did not occur in 90 of 92 patients (97.9%) with ABP after endoscopic treatment according to the IDUS findings. CONCLUSIONS: IDUS improves diagnostic accuracy for the detection of clinically occult BD stones in patients suspicious ABP. IDUS-guided endoscopic management for patients with ABP can avoid unnecessary EST and help prevent recurrent pancreatitis.

Core biopsy needle versus standard aspiration needle for endoscopic ultrasound-guided sampling of solid pancreatic masses: a randomized parallel-group study.

BACKGROUND AND STUDY AIMS: An endoscopic ultrasound (EUS)-guided fine needle biopsy (EUS-FNB) device using a core biopsy needle was developed to improve diagnostic accuracy by simultaneously obtaining cytological aspirates and histological core samples. We prospectively compared the diagnostic accuracy of EUS-FNB with standard EUS-guided fine needle aspiration (EUS-FNA) in patients with solid pancreatic masses. PATIENTS AND METHODS: Between January 2012 and May 2013, consecutive patients with solid pancreatic masses were prospectively enrolled and randomized to undergo EUS-FNB using a core biopsy needle or EUS-FNA using a standard aspiration needle at a single tertiary center. The specimen was analyzed by onsite cytology, Papanicolaou-stain cytology, and histology. The main outcome measure was diagnostic accuracy for malignancy. The secondary outcome measures were: the median number of passes required to establish a diagnosis, the proportion of patients in whom the diagnosis was established with each pass, and complication rates. RESULTS: The overall accuracy of combining onsite cytology with Papanicolaou-stain cytology and histology was not significantly different for the FNB (n = 58) and FNA (n = 58) groups (98.3 % [95 %CI 94.9 % - 100 %] vs. 94.8 % [95 %CI 91.9 % - 100 %]; P = 0.671). Compared with FNA, FNB required a significantly lower median number of needle passes to establish a diagnosis (1.0 vs. 2.0; P < 0.001). On subgroup analysis of 111 patients with malignant lesions, the proportion of patients in whom malignancy was diagnosed on the first pass was significantly greater in the FNB group (72.7 % vs. 37.5 %; P < 0.001). CONCLUSIONS: The overall accuracy of FNB and FNA in patients with solid pancreatic masses was comparable; however, fewer passes were required to establish the diagnosis of malignancy using FNB.This study was registered on the UMIN Clinical Trial Registry (UMIN000014057).

Usefulness of intraductal ultrasonography in icteric patients with highly suspected choledocholithiasis showing normal endoscopic retrograde cholangiopancreatography.

BACKGROUND: Choledocholithiasis is one of the causes of jaundice and may require urgent treatment. Endoscopic retrograde cholangiopancreatography (ERCP) has been the primary management strategy for choledocholithiasis. However, small stones can be overlooked during ERCP. AIM: The aim of this study was to evaluate the accuracy of intraductal ultrasonography (IDUS) for detecting choledocholithiasis in icteric patients with highly suspected common bile duct (CBD) stones without definite stone diagnosis on ERCP. METHODS: Ninety-five icteric (bilirubin ≥ 3 mg/dL) patients who underwent ERCP for highly suspected choledocholithiasis without definite filling defects on cholangiography were prospectively enrolled in the present study. We evaluated the bile duct using IDUS for the presence of stones or sludge. Reference standard for choledocholithiasis was endoscopic extraction of stone or sludge. RESULT: Bile duct stones were detected with IDUS in 31 of 95 patients (32.6%). IDUS findings were confirmed by endoscopic stone extraction in all patients. The mean diameter of CBD stones detected by IDUS was 2.9 mm (range 1-7 mm). IDUS revealed biliary sludge in 24 patients (25.2%) which was confirmed by sludge extraction in 21 patients (87.5%). In dilated CBD, detection rate of bile duct stone/sludge based on IDUS was significantly higher than in non-dilated CBD (p = 0.004). CONCLUSION: IDUS is useful for the detection of occult CBD stone on ERCP in icteric patients with highly suspected CBD stones.

A triple approach for diagnostic assessment of endoscopic ultrasound-guided fine needle aspiration in pancreatic solid masses and lymph nodes.

BACKGROUND AND AIMS: Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) has been becoming the standard tool for acquiring pancreatic lesion tissue. However, a single cytologic or histologic evaluation is not satisfactory for diagnosis. In this study, we evaluated the diagnostic yield of EUS-FNA for pancreatic solid masses and intra-abdominal lymph nodes using a triple approach. METHODS: This study included patients undergoing evaluation for a solid pancreatic mass (n = 59) or intra-abdominal lymph nodes (n = 16) using EUS-FNA with a 22- or 25-gauge (G) needle, respectively. The specimens from each pass were analyzed by on-site cytology using Diff-Quick stain, cytology using Papanicolaou stain, and histology with immunohistochemical (IHC) staining. RESULTS: A total of 75 patients (49 males; mean age; 63.7 years) were included. The median number of needle pass for diagnosis of malignancy was 2.0, and there was no technical failure. The diagnostic accuracies with on-site cytology, cytology using Papanicolaou staining, and histology were 70.7, 80.0, and 80.0 %, respectively. The diagnostic accuracy using a triple approach was significantly greater than cytology using Papanicolaou staining alone (94.7 vs. 80.0 %; p = 0.007). In patients with malignant lesions, cytology identified 12 of 71 (16.9 %) malignant lesions that were not diagnosed by histology using IHC, and histology identified six (8.5 %) malignant lesions that were not diagnosed by cytology. CONCLUSION: On-site cytopathologic evaluation combined with cytologic and histologic analysis with IHC stain for one-pass specimen is considered to be able to increase the overall accuracy of EUS-FNA in pancreatic solid masses and lymph nodes.

A newly designed fully covered metal stent for lumen apposition in EUS-guided drainage and access: a feasibility study (with videos).

BACKGROUND: A lumen-apposing stent can be used effectively under endosonographic guidance. OBJECTIVE: To evaluate a newly designed, fully covered self-expandable metal stent with folding anchoring flanges for lumen apposition assembled on a conventional delivery system. DESIGN: Retrospective case series and animal study. SETTING: Tertiary care academic medical centers. SUBJECTS: Six pigs for animal study and 7 patients, 3 of whom underwent endoscopic drainage for acute cholecystitis (AC) and 4 for pancreatic fluid collection (PFC). INTERVENTION: Stent deployment under EUS guidance after puncturing, passage of an endoscope through the stent into the gallbladder (GB), or PFC with conventional endoscopic procedures. MAIN OUTCOME MEASUREMENTS: Technical and clinical success, adverse events, and removability. RESULTS: In the animal study, the stent was successfully inserted and deployed in the GB via a transgastric approach under EUS guidance without adverse events in all 6 pigs. Contrast injection demonstrated the absence of leakage. Cholecystoscopy with enhanced endoscopy was performed successfully in all animals after stent placement. All stents were intact and were removed successfully at 4 weeks. GB firmly adhered to the stomach with an intact cholecystogastric tract on necropsy and histopathology. The stents were successfully deployed without adverse effects in 7 patients. AC or PFC was resolved after stent placement in all patients. Endoscopic procedures were possible through the stent. Stent migration was not observed. The stent was successfully removed from the 4 patients with PFC after complete resolution. LIMITATIONS: Small sample size, retrospective study. CONCLUSIONS: Transenteric drainage and endoscopic intervention by using a novel fully covered self-expandable metal stent for lumen apposition under EUS guidance is feasible for the management of AC and PFC. Further study is warranted.

Clinicopathological characteristics of PIK3CA and HBx mutations in Korean patients with hepatocellular carcinomas.

Hepatocellular carcinoma (HCC) is the fourth most common form of cancer in the Korean population, caused primarily by infection with either the Hepatitis B or C virus. Progression of this disease is frequently associated with mutations in either phosphoinositide-3-kinase, catalytic, alpha (PIK3CA) or hepatitis B virus X (HBx) gene. Previous studies have examined the frequency of PIK3CA mutations in HCC, although the clinical significance of these mutations has not been studied in a Korean population. In addition, HBx appears to play a key role in modulating a wide range of cellular functions, leading to HCC. In this study, we examined microdissected tumor samples from 50 HCC patients who underwent hepatectomy at Keimyung University Dongsan Medical Center. These patients were screened for mutations in PIK3CA and HBx to identify the clinical outcomes associated with these mutations. Exons 9 and 20 of PIK3CA and the entirety of HBx were screened for mutations by polymerase chain reaction and direct DNA sequencing. PIK3CA mutations were detected in 7 of 50 patients (14%). Among the 42 patients who were seropositive for hepatitis B, 17 (40.5%) had HBx mutations and 4 (9.52%) had mutations in PIK3CA. PIK3CA mutations were strongly correlated with tumor size. Patients harboring HBx mutations exhibited a longer time to recurrence; this difference was statistically significant not only in comparison with the PIK3CA mutation but also compared with those without any mutations. This result suggests a role for PIK3CA and HBx mutations as prognostic markers in HCC.

Delayed endoscopic papillary large balloon dilation after sphincterotomy for removing large bile duct stones in patients with acute cholangitis.

BACKGROUND: Endoscopic papillary large balloon dilation (EPLBD) after an endoscopic sphincterotomy (EST) is an option for endoscopic removal of large common bile duct (CBD) stones. However, risks or fear of severe adverse events remain. AIMS: Our aim was to compare the safety and efficacy of delayed EPLBD after EST with concurrent EST and EPLBD in patients with acute cholangitis by large CBD stones. PATIENTS AND METHODS: A total of sixty-eight patients with acute cholangitis from large CBD stones were enrolled in this prospective observational study. Thirty-five patients underwent concurrent EST and EPLBD at the same session (group A). Thirty-three patients underwent only EST at the first session, and EPLBD with stone removal was performed during a second session (group B). The complete stone removal rate and adverse events rate were analyzed. RESULTS: Both groups resulted in similar outcomes in terms of overall successful stone removal (100% in both groups) and the use of additional lithotripsy (22.9% in group A and 24.2% in group B). Six patients (17.1%) in group A had procedural-related adverse events including one patient with death by perforation, one with significant bleeding, and four with pancreatitis, including one moderate grade. However, there was no procedure-related complication in group B (p < 0.05). CONCLUSIONS: Delayed EPLBD after EST may reduce complications associated with EPLBD and extraction of large bile duct stones in patients with acute cholangitis.

Comparison of endoscopic papillary balloon dilation and sphincterotomy in young patients with CBD stones and gallstones.

BACKGROUND AND AIMS: Endoscopic biliary sphincterotomy (EBS) results in permanent loss of sphincter function and its long-term complications are unknown. Endoscopic papillary balloon dilation (EPBD) is an alternative procedure that preserves sphincter function, although it is associated with a higher risk of pancreatitis than is EBS. The aim of this study was to evaluate the safety and outcomes of EPBD with limited indications for removal of common bile duct (CBD) stones combined with gallstones in patients younger than 40 years. METHODS: Young (age < 40 years) patients who had CBD stones combined with gallstones on imaging studies were enrolled in this study. A total of 132 patients were randomly divided into the EPBD group (n = 62) or the EBS group (n = 70) for extraction of CBD stones. The ballooning size of EPBD ranged from 6 to 10 mm. RESULTS: Complete bile duct clearance was achieved in 98.4 % (61/62) of the EPBD group and 100 % (70/70) of the EBS group. Mechanical lithotripsy was required in 8.1 % (5/62) of the EPBD group and 8.6 % (6/70) of the EBS group. The early complication rates were 8.1 % (5/62) (five pancreatitis) in the EPBD group and 11.4 % (8/70) (five [7.1 %] pancreatitis, two bleeding and one perforation) in the EBS group. The recurrence rates of CBD stones were 1.6 % (1/62) in the EPBD group and 5.7 % (4/70) in the EBS group. CONCLUSIONS: EPBD with limited indications was safe and effective as EBS for removal of CBD stones combined with gallstones in young patients who had a longer life expectancy.

Endoscopic papillary large balloon dilation for the management of recurrent difficult bile duct stones after previous endoscopic sphincterotomy.

BACKGROUND: Endoscopic management of recurrent bile duct stones after endoscopic sphincterotomy (EST) is effective and safe. However, repeat EST for extension of a previous EST for recurrent bile duct stones may involve substantial risk. The aim of the present study was to evaluate the safety and efficacy of endoscopic papillary large balloon dilation (EPLBD) without repeat EST for recurrent difficult bile duct stones after previous EST. PATIENTS AND METHODS: From January 2006 to October 2010, a total of 52 patients were enrolled; all had undergone EPLBD (balloon diameter: 12-20 mm) to remove recurrent difficult bile duct stones after previous EST. In all patients, stone removal had failed with conventional methods using a basket and/or balloon. The size of the balloon for EPLBD was selected to fit the diameter of the common bile duct or the largest stone. RESULTS: The median interval between initial EST and stone recurrence was 2.2 years (range 1-10). Median diameters of thelargest stone and balloon were 20.1 mm (range 12-40) and 14.7 mm (range 12-20), respectively. Complete stone removal was achieved in all patients (100%). The median number of endoscopic retrograde cholangiopancreatography sessions needed for complete stone removal was 1.6 (range 1-3). Additional lithotripsy was required in 16 patients (30.7%). No procedure-related complications were documented, with the exception of four cases of asymptomatic hyperamylasemia. The recurrence rate of CBD stones after bile duct clearance was 17.3% (9/52) during the follow-up period (mean 27.0 ± 14.1 months). CONCLUSIONS: EPLBD without repeat EST is effective and relatively safe for the extraction of recurrent difficult bile duct stones after previous EST.

Usefulness of pancreatic duct wire-guided endoscopic papillectomy for ampullary adenoma for preventing post-procedure pancreatitis.

BACKGROUND AND STUDY AIMS: After endoscopic papillectomy, pancreatic duct stenting is important in preventing pancreatitis, but duct cannulation can be difficult following conventional snare resection. Pancreatic duct wire-guided endoscopic snaring before resection can reduce the post-procedure stenting failure rate. We evaluated the usefulness of this approach. PATIENTS AND METHODS: Pancreatic duct wire-guided endoscopic papillectomy was performed in 72 patients with ampullary adenoma. The snare loop was passed over a guide wire inserted into the pancreatic duct. After resection, a pancreatic stent was immediately placed along or alongside the guide wire. RESULTS: Pancreatic duct stenting was successful in all patients after endoscopic papillectomy. Post-procedure pancreatitis occurred in 6/72 (8 %), but was mild and resolved with conservative treatment. Complete endoscopic resection of ampullary adenoma was achieved in 65/72 (90 %), with en bloc resection in 60/72 (83 %). There was no procedure-associated mortality. Follow-up (mean 23.7 months) showed recurrence in 5/65 (8 %) who had undergone complete resection. CONCLUSIONS: Pancreatic duct wire-guided endoscopic snare papillectomy for ampullary adenoma effectively facilitated pancreatic duct stenting to prevent severe post-procedure pancreatitis.

Papillary balloon dilation is not itself a cause of post-endoscopic retrograde cholangiopancreatography pancreatitis; results of anterograde and retrograde papillary balloon dilation.

OBJECTIVES: The mechanism of pancreatitis development following endoscopic papillary balloon dilation (EPBD) remains unknown. Antegrade dilation with percutaneous transhepatic papillary balloon dilation (PTPBD) allows the removal of bile duct stones or fragments during percutaneous choledochoscopic lithotomy, with less mechanical trauma to the papilla than with EPBD-mediated stone removal. METHODS: A total of 56 patients with bile duct stones underwent antegrade dilation with PTPBD from March 2006 to February 2011. A total of 208 patients with common bile duct stones underwent retrograde dilation with EPBD during the same period. The conditions of papillary balloon dilation were identical in both groups. The frequencies of pancreatitis and hyperamylasemia were compared in both groups. RESULTS: Pancreatitis occurred in 14 (6.7%) of 208 patients in the EPBD group (mild, nine; moderate, four; severe, one). There was no case of pancreatitis among 56 patients in the PTPBD group (P < 0.05). Hyperamylasemia developed in significantly more patients treated in the EPBD group (62, 29.8%) compared with the PTPBD group (4, 7.1%; P < 0.05). Complete bile duct clearance was achieved in 98.2% of PTPBD group and 97.1% of EPBD group. CONCLUSIONS: The rates of post-procedural pancreatitis and hyperamylasemia were significantly higher after retrograde dilation with EPBD than after antegrade dilation with PTPBD for the removal of bile duct stones. Although the mechanism of pancreatitis following papillary balloon dilation remains unclear, post-EPBD pancreatitis may be associated with procedures before and after balloon dilation similar to mechanical lithotripsy rather than balloon dilation itself.