Hepatocellular carcinoma treated with radical resection after endoscopic diagnosis of the extent of bile duct invasion: A case report

Hepatocellular carcinoma invasion of the bile duct is rare and has a poor prognosis. A 77-year-old man presented at the emergency department with persistent pain in the right hypochondrium. Blood tests and imaging studies revealed a 70-mm occupying lesion in the right lobe of the liver and dilated intrahepatic bile ducts. He was diagnosed with obstructive jaundice and cholangitis. Imaging studies showed an internal mass with poor contrast effects. A liver biopsy was performed to confirm the diagnosis and hepatocellular carcinoma was suspected. Endoscopic retrograde cholangiopancreatography, endoscopic ultrasound, and peroral cholangioscopy were performed to determine the treatment strategy. The bile duct invasion did not extend to the porta hepatis; therefore, right hepatic lobectomy and radical resection were performed. Bile duct invasion in hepatocellular carcinoma is rare and often difficult to diagnose by computed tomography or conventional endoscopic retrograde cholangiopancreatography. However, endoscopic ultrasound and peroral cholangioscopy enable safe and accurate diagnosis of the extent of invasion.

Peroral cholangioscopy for the evaluation of bile duct stricture in hepatocellular carcinoma on a preoperative examination

Objective: Bile duct tumor thrombosis in hepatocellular carcinoma (HCC) is a relatively rare event with a poor prognosis. Furthermore, bile duct tumor thrombus in HCC may be misdiagnosed when only imaging modalities are used. The efficiency of peroral cholangioscopy (POCS) in evaluating bile duct lesions has been reported. Patients: We present three cases of HCC with bile duct strictures in which POCS was performed as a preoperative evaluation. Results: In these three cases, diagnosing whether the lesion was a bile duct tumor thrombus on CT and endoscopic retrograde cholangiopancreatography was difficult. We performed POCS in three cases and were able to diagnose the presence of bile duct tumor thrombus of HCC, including differentiation from extrinsic compression of the bile duct. Conclusion: POCS for HCC with bile duct features is useful for the preoperative diagnosis of bile duct tumor thrombus, especially in cases where the surgical procedure depends on the presence of bile duct tumor thrombus.

Gallbladder perforation following peroral cholangioscopy-guided lithotripsy: A case report

Peroral cholangioscopy-guided lithotripsy is highly effective in clearing difficult bile duct stones. It can cause adverse events, such as cholangitis and pancreatitis; however, gallbladder perforation is extremely rare. Herein, we describe the case of a 77-year-old woman who developed gallbladder perforation following peroral cholangioscopy -guided lithotripsy. She was referred to our hospital to treat multiple large bile duct stones. She underwent peroral cholangioscopy-guided lithotripsy because of conventional lithotripsy failure. After a cholangioscope was advanced into the bile duct, saline irrigation was used for visualization. Electronic hydraulic lithotripsy was performed, but it took time for fragmentation because the calculus was hard. The 2-h endoscopic procedure did not completely remove the stone, and treatment was discontinued after placing a biliary plastic stent and nasobiliary tube. After the endoscopic procedure, she started experiencing right hypochondrial pain, which worsened the next day. Computed tomography showed a gallbladder wall defect in the gallbladder fundus with pericholecystic fluid. She was diagnosed with gallbladder perforation and underwent emergency surgery. A perforation site was found at the gallbladder fundus. Open cholecystectomy, choledochotomy, and extraction of residual bile duct stones were performed. The patient was discharged 9 days post-surgery without any complications. The saline irrigation used for visualization may have caused a surge in intra-gallbladder pressure, resulting in gallbladder perforation. Therefore, endoscopists may need to conserve irrigation water during peroral cholangioscopy-guided lithotripsy.

Direct peroral cholangioscopy with red dichromatic imaging 3 detected the perihilar margin of superficial papillary extension in a patient with intraductal papillary neoplasm of the bile duct

Intraductal papillary neoplasms of the bile duct (IPNB) are a tumor derived from bile duct epithelium that tends to spread laterally and non‐invasively. Surgery is the first‐choice treatment for IPNB. It is extremely important to accurately diagnose the extent of lateral tumor extension. Although peroral cholangioscopy (POCS) is a potentially useful modality for detecting tumor range with direct observation, poor image quality is a limitation of POCS. Recently, a new‐generation endoscopy system (EVIS X1) was equipped with functions such as red dichromatic imaging to improve image quality. A 75‐year‐old man with cholangitis was referred to our department. Various imaging studies showed a mass in the middle to lower bile duct and dilatation of the common bile duct and the intrahepatic bile duct. Endoscopic retrograde cholangiopancreatography was performed. A biopsy of the main tumor in the lower common bile duct revealed IPNB. It was difficult to determine the extent of superficial tumor extension with modalities such as contrast‐enhanced computed tomography, magnetic resonance imaging, and endoscopic ultrasonography but the detailed evaluation was possible using POCS with red dichromatic imaging 3. The patient underwent hepatopancreatoduodenectomy. This case suggests the usefulness of direct observation using POCS with red dichromatic imaging 3 to determine the range of IPNB.

Identification of bleeding points after bile duct biopsy using red dichromatic imaging during peroral cholangioscopy: A case report

Red dichromatic imaging is a new image-enhancement technology that clarifies the differences in blood concentrations and improves the visibility of the bleeding point. A 71-year-old man was presented with a common bile duct stone, which was completely removed using electrohydraulic shock wave lithotripsy with peroral cholangioscopy. During peroral cholangioscopy, a nodular lesion was found at the confluence of the cystic duct, and a forceps biopsy was performed. It was difficult to confirm the bleeding point using white-light imaging because of the pooling of blood. After switching to red dichromatic imaging mode 2 and washing the bile duct with saline solution, the bleeding point was observed in darker yellow than the surrounding blood, allowing the identification of the bleeding point. Red dichromatic imaging can be used in the future to maintain hemostasis during peroral cholangioscopy.

Detection and endoscopic classification of intraductal neoplasms of the bile duct by peroral cholangioscopy with narrow-band imaging (with videos)

BACKGROUND AND AIMS

Indirect diagnostic modalities are unsatisfactory for detecting intraductal neoplasm of the bile duct (IN-B), which can be detected by peroral cholangioscopy (POC) with narrow-band imaging (NBI). We investigated the POC findings of IN-B and developed a feasible endoscopic classification system.

METHODS

A total of 471 patients who underwent direct POC from April 2008 to July 2020 were enrolled. Intraductal superficial lesions of the bile duct (ISL-Bs) were classified according to surface structure and microvascular pattern on POC with NBI and correlated to histologic findings after POC-guided forceps biopsy (POC-FB) or surgery. The primary outcome was the detection rate of IN-Bs, and the secondary outcomes were the associations of POC findings with IN-B, the technical success rates of POC and POC-FB, and adverse events (AEs).

RESULTS

Direct POC was successful in 458 of 471 patients (97.2%). Among the patients, 131 (27.8%) exhibited ISL-Bs. The technical success rate of POC-FB was 94.7% (124 of 131). Among the 124 patients who underwent POC-FB, IN-B was revealed in 54 (43.5%), for a detection rate of 11.8% (54 of 458). Papillary lesion (P = 0.041), nodular lesion (P = 0.044), and irregularly or regularly dilated and tortuous vessels (P = 0.004; P = 0.006) were POC findings associated with IN-B. The area under the receiver operating characteristic curve of the novel classification system was 0.899.

CONCLUSIONS

POC with NBI can be useful for the detection of IN-Bs. Our novel classification system based on both surface structure and microvascular pattern may allow differentiation of IN-B from ISL-Bs.

[Endoscopic treatment of obstructive jaundice in patients with Klatskin tumor]

OBJECTIVE

To improve treatment outcomes in patients with Klatskin tumor and obstructive jaundice by using of endoscopic bilioduodenal stenting.

MATERIAL AND METHODS

There were 1904 transpapillary interventions between August 2017 and February 2022. Endoscopic bilioduodenal stenting was performed in 250 patients including 25 (10%) ones with Klatskin tumor.

RESULTS

Bilioduodenal plastic and self-expanding stents were installed in 19 (76%) and 6 (24%) patients, respectively. In Klatskin tumor type I, 11 patients (44%) underwent bilioduodenal stenting of common hepatic duct with plastic stent; 5 (20%) patients with Klatskin tumor type II received self-expanding stents. In case of tumor type IIIA, 3 (12%) patients underwent stenting of the right lobar duct with plastic stent. Four (16%) patients with Klatskin tumor type III B underwent stenting of the left lobar duct. Two 2 (8%) patients with Klatskin tumor type IV underwent bilateral bilioduodenal stenting with plastic and bifurcation self-expanding stents. Peroral cholangioscopy using the SpyGlass DS system was performed in 4 (16%) patients. No intraoperative complications were identified. One (4%) patient developed gastrointestinal bleeding in 2 postoperative days after retrograde intervention that did not require surgery. Moreover, 1 (4%) patient with distal dislocation of plastic bilioduodenal stent required redo bilioduodenal stenting. Three (12%) patients died from multiple organ failure despite adequate biliary decompression, and 22 (88%) patients were discharged in 8±5 days after retrograde intervention.

CONCLUSION

Bilioduodenal stenting as minimally invasive and physiological method was highly effective for obstructive jaundice in patients with Klatskin tumor. Peroral cholangioscopy using the SpyGlass system provides effective and safe direct visualization of the biliary tract, as well as biopsy for morphological verification and prescription of chemotherapy in patients with intraductal growth of tumor.

Clinical Outcomes of Digital Cholangioscopy-Guided Procedures for the Diagnosis of Biliary Strictures and Treatment of Difficult Bile Duct Stones: A Single-Center Large Cohort Study

Although Spy DS (SpyGlass DS Direct Visualization System) is considered to be useful for the diagnosis of bile duct strictures and the treatment of bile duct stones, there is limited data to date validating its efficacy. We hence retrospectively evaluated the clinical outcomes of the use of Spy DS in a large number of patients. A total of 183 patients who underwent Spy DS-guided procedures for indeterminate bile duct strictures (n = 93) and bile duct stones (n = 90) were analyzed retrospectively. All patients (93/93) with bile duct strictures successfully underwent visual observation, and 95.7% (89/93) of these patients successfully underwent direct biopsy. The sensitivity, specificity, and overall accuracy were 94.7%, 83.3%, and 90.3%, respectively, for visual impression; 80.9%, 100%, and 89.2%, respectively, for histopathological analysis of a direct biopsy; and 96.5%, 91.7%, and 94.6%, respectively, for visual impression combined with biopsy. Successful visualization of the stones was achieved in 98.9% (89/90) of the patients, and complete stone removal was achieved in 92.2% (83/90) of the patients, with an average of 3.3 procedures. The adverse events rate was 17.5% (32/183; cholangitis in 15 patients, fever the following day in 25, pancreatitis in 1, hemorrhage in 1, and gastrointestinal perforation in 1). No administration of antibiotics before the procedure was found to be a statistically significant risk factor for the development of fever after the procedure (p < 0.01). Spy DS-guided procedures are effective for the diagnosis and treatment of bile duct lesions and can be performed with a low risk of serious adverse events.

Peroral Cholangioscopy-Guided Forceps Mapping Biopsy for Evaluation of the Lateral Extension of Biliary Tract Cancer

Background: Peroral cholangioscopy (POCS)-guided forceps mapping biopsy (FMB) is a method for the accurate preoperative identification of the extent of the disease of biliary tract cancer (BTC). However, the diagnostic value of POCS-FMB is still uncertain. Objectives: We evaluated the diagnostic utility of POCS-FMB for the identification of lateral extension—superficial intraductal spread longitudinally and continuously from the main lesion—of BTC. Methods: In the retrospective study, patients who received POCS-FMB and surgery for curative resection of BTC between September 2016 and August 2019 at our medical institution were enrolled. The diagnostic accuracy of POCS-FMB for the identification of lateral extension of BTC was evaluated. Furthermore, we also evaluated the factors affecting the diagnostic accuracy of POCS-FMB. Results: A total of 23 patients with BTC were enrolled, and 24 procedures of POCS-FMB from 96 sites of biliary tracts were performed. The sensitivity, specificity, and accuracy of POCS-FMB were 53.8%, 63.9%, and 63.1%, respectively. In the multivariate logistic regression analyses, the biopsy from the bifurcation of biliary tracts was a significant factor affecting the diagnostic accuracy of POCS-FMB (odds ratio 3.538, 95%; confidence interval 1.151–10.875, p = 0.027). Conclusions: The diagnostic accuracy of POCS-FMB for the identification of lateral extension of BTC was insufficient. The biopsy from the bifurcation of biliary tracts was a positive factor affecting the diagnostic accuracy of POCS-FMB.

Personalized Endoscopy in Complex Malignant Hilar Biliary Strictures

Malignant hilar biliary obstruction (HBO) represents a complex clinical condition in terms of diagnosis, surgical and medical treatment, endoscopic approach, and palliation. The main etiology of malignant HBO is hilar cholangiocarcinoma that is considered an aggressive biliary tract's cancer and has still today a poor prognosis. Endoscopy plays a crucial role in malignant HBO from the diagnosis to the palliation. This technique allows the collection of cytological or histological samples, direct visualization of the suspect malignant tissue, and an echoendoscopic evaluation of the primary tumor and its locoregional staging. Because obstructive jaundice is the most common clinical presentation of malignant HBO, endoscopic biliary drainage, when indicated, is the preferred treatment over the percutaneous approach. Several endoscopic techniques are today available for both the diagnosis and the treatment of biliary obstruction. The choice among them can differ for each clinical scenario. In fact, a personalized endoscopic approach is mandatory in order to perform the proper procedure in the singular patient.

Efficacy and Safety of Digital Single-Operator Cholangioscopy in the Diagnosis of Indeterminate Biliary Strictures by Targeted Biopsies: A Systematic Review and Meta-Analysis

BACKGROUND

Biliary strictures are frequently encountered in clinical practice. The determination of their nature is often difficult. This study aims to systematically evaluate the efficacy and safety of the second generation of digital single-operator cholangioscopy (SpyGlass DS, DSOC) in indeterminate biliary strictures (IBDS) through biopsies.

METHODS

All relative studies published in Medline, the Cochrane Library, Web of Science, and EMBASE were included. The diagnostic tests for IBDS were compared to the surgical histology, autopsy, or long-term clinical follow-up. The methodological quality of the included studies was evaluated by the Quality Assessment of Studies of Diagnostic Accuracy Included in Systematic Reviews (QUADAS-2).

RESULTS

A total of 11 studies, which involved 356 patients diagnosed through biopsies, were included. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio were 0.74 (95% CI: 0.67-0.80), 0.98 (95% CI: 0.95-1.00), 10.52 (95% CI: 5.45-20.32), 0.31 (95% CI: 0.23-0.41), and 65.18 (95% CI: 26.79-158.61), respectively. The area under the curve (AUC) was 0.9479, and the pooled adverse event rate was 7%. The sensitivity and specificity in the heterogeneity analysis were I2 = 48.1% and I2 = 25.4%, respectively.

CONCLUSION

SpyGlass DS is a safe and effective technique for IBDS. However, future randomized trials are needed to determine optimal number of biopsies.

Peroral Cholangioscopy-Guided Forceps Biopsy and Endoscopic Scraper for the Diagnosis of Indeterminate Extrahepatic Biliary Stricture

Background: Peroral cholangioscopy (POCS) has become a widely-used technique in diagnosing indeterminate biliary strictures, enabling optical viewing of the biliary system and targeted biopsies under direct vision. The diagnostic utility of the new endoscopic scraper, Trefle^®, for extrahepatic cholangiocarcinoma (ECC) has also been reported. However, the diagnostic utility of POCS-guided and Trefle^®-assisted tissue acquisition for ECC has never been compared empirically. We evaluated the efficacy and safety of Trefle^®-assisted tissue acquisition for diagnosing ECC compared with POCS-guided tissue sampling. Methods: Patients who underwent Trefle^®-assisted tissue acquisition or POCS-guided forceps biopsy to differentiate ECC from benign biliary disease between April 2014 and March 2018 were enrolled retrospectively. We evaluated the diagnostic performance of Trefle^®-assisted tissue acquisition and POCS-guided forceps biopsy based on pathological evaluation. We also compared adverse events associated with Trefle^®-assisted tissue acquisition with those of POCS-guided forceps biopsy. Results: We enrolled 34 patients with biliary disease and performed Trefle^®-assisted tissue acquisition and POCS-guided forceps biopsy in 14 and 20 patients, respectively. Sensitivity, specificity, and accuracy of Trefle^®-assisted tissue acquisition were 87.5%, 83.3%, and 85.7%, respectively, and for POCS-guided forceps biopsy, these were 90.0% each. Statistical values of Trefle^®-assisted tissue acquisition and POCS-guided tissue acquisition were not significantly different. There were no significant differences in the occurrence of adverse events between the Trefle^®-assisted tissue acquisition and the POCS-guided forceps biopsy (35.7% vs. 25.0%, p = 0.770). Compared with patients who underwent POCS procedure, endoscopic sphincterotomy was performed for fewer patients who underwent Trefle^®-assisted tissue acquisition (p < 0.001). Conclusions: The diagnostic ability of Trefle^®-assisted tissue acquisition for ECC is similar to that of POCS-guided tissue acquisition. Trefle^®-assisted tissue acquisition might also help to preserve the sphincter of Oddi and its digestive function.

A new hybrid anchoring balloon for direct peroral cholangioscopy using an ultraslim upper endoscope

BACKGROUND AND AIM

Large impacted or residual invisible common bile duct (CBD) stones after mechanical lithotripsy are challenging. We aimed to evaluate the feasibility and success rate of a new hybrid anchoring balloon-guided direct peroral cholangioscopy (POC) for these conditions using an ultraslim endoscope.

METHODS

Sixty-five patients with large or residual invisible CBD stones for direct POC from July 2012 to July 2016 were identified, including six cases in whom an additional interventional procedure was required. There were altogether 55 cases undergoing a procedure with our new device, with a 0.021-inch guidewire tied to a balloon catheter at its distal end in this single-center retrospective study. Technical success, procedure time, diagnostic and therapeutic efficacy of direct POC, and procedure-related complications were studied.

RESULTS

The hybrid anchoring balloon-guided direct POC was successful in 51/55 (92.7%) procedures, including 18 cases in whom the conventional wire-guided method failed within 25 min. Mean time for technical success by our method was 12.4 ± 3.4 min. In total, of the 43 cases with previous removal of CBD stones, seven (16.3%) were found to have residual stones ≥4 mm, excluding three cases in whom direct POC failed. In another 25 cases for difficult stones, 24 lithotripsies were carried out, resulting in 23 complete fragmentations. No significant procedure-related complications were observed.

CONCLUSION

The new hybrid anchoring balloon device performs well in facilitating direct POC using an ultraslim endoscope for evaluation and extraction of residual or large impacted CBD stones.

Current endoscopic strategies for managing large bile duct stones

Common bile duct stones are a relatively common occurrence and can often lead to devastating complications. Endoscopic retrograde cholangiopancreatography was introduced in the 1970s for management of common bile duct stones. Most common bile duct stones can be removed with simple techniques such as endoscopic sphincterotomy and balloon trawling. However, large bile duct stones continue to pose some difficulty in achieving complete extraction. In this article, we will review some of the established techniques such as the use of endoscopic papillary large balloon dilatation, mechanical lithotripsy, and cholangioscopy-assisted techniques. We will look at the recent literature to help clarify the particular methods and answer some of the questions surrounding these methods.

Novel ex vivo training model for freehand insertion using a double-bending peroral direct cholangioscope

BACKGROUND AND AIM

Several experts of direct peroral videocholangioscopy (D-PVCS) using a conventional ultraslim endoscope have reported its usefulness for the diagnosis and therapy of biliary tract diseases. We have additionally developed a dedicated double-bending D-PVCS technique for freehand scope insertion. In this study, we developed an ex vivo training model for the freehand double-bending D-PVCS technique and compared it with the technique using a conventional ultraslim endoscope.

METHODS

The ex vivo model was made for training using a U-shape insertion pattern. A third prototype endoscope and an ultraslim upper gastrointestinal endoscope were used. Two experts and nine non-experts performed D-PVCS using the freehand technique.

RESULTS

The two experts could not advance the tip of the endoscope to the hilar portion using the freehand technique, but they could achieve technical successful insertion to the hilar portion with the third prototype cholangioscope using the freehand technique alone. The non-experts could not advance the tip of the endoscope to the bile duct using the freehand technique. On the other hand, two (22.2%) non-experts could advance the tip of the third prototype cholangioscope using the freehand technique before the training conducted by the experts. After the training, all the non-experts could advance the tip of the third prototype cholangioscope to the hilar portion.

CONCLUSIONS

The novel ex vivo model using a third prototype cholangioscope was useful for training in the use of the freehand D-PVCS technique.

Prospective evaluation of digital single-operator cholangioscope for diagnostic and therapeutic procedures (with videos)

BACKGROUND AND AIM

Recently, the digital single-operator cholangioscope (SPY-DS) has become available. This system may allow diagnosis by direct visualization and allow performance of various therapeutic procedures. The aim of the present study was to prospectively evaluate the clinical utility of DSOCS for diagnostic and therapeutic procedures for biliary disease.

METHODS

Technical success was defined as successful visualization of target lesions in the biliary tract and carrying out forceps biopsy as a diagnostic procedure, and successfully carrying out treatment such as guidewire insertion for the area of interest, electrohydraulic lithotripsy (EHL), or migrated stent removal. Also, the present study aimed at investigating diagnostic yield of the cholangioscopic findings and biopsy specimens.

RESULTS

A total of 55 consecutive patients were prospectively enrolled in this study; a diagnostic procedure was done in 33 patients, and a therapeutic procedure was done in 22 patients. Overall accuracy of visual findings was 93%, with a sensitivity of 83%, a specificity of 89%, positive predictive value (PPV) of 83%, and negative predictive value (NPV) of 100%. However, the overall accuracy of forceps biopsy was 89%, with a sensitivity, specificity, and PPV of 100%, and NPV of 90%. Overall technical success rate of therapeutic procedures such as selective guidewire insertion, EHL or migrated stent removal was 91% (20/22). Finally, adverse events were seen in two cases in the diagnostic group, but were not seen in the therapeutic group.

CONCLUSION

Although additional cases and a randomized, controlled study with another cholangioscope are needed, diagnostic and therapeutic procedures using SPY-DS appear to be feasible and safe.

A feasibility study of digital single-operator cholangioscopy for diagnostic and therapeutic procedure (with videos)

Recently, the novel SpyGlass DS Direct Visualization system (SPY DS) has become available. This system offers several advantages over the conventional SPYGlass system. This study evaluated the clinical feasibility and efficacy of diagnostic and therapeutic procedures for biliary disorder using SPY DS.In this retrospective study, consecutive patients who had biliary disorder were enrolled between November 2015 and February 2016. All patients could not be diagnosed or treated by standard endoscopic retrograde cholangiopancreatography in our hospital or at another hospital.A total of 28 consecutive patients (21 men and 7 women; median age, 73 years; age range, 55-87 years) were retrospectively enrolled in this study. Among them, diagnostic procedure was performed in 20 patients, and 8 patients underwent therapeutic procedures. The technical success rate for diagnostic procedures was 100% (20/20). Diagnostic accuracy was 100% (19/19). The technical success rate for therapeutic procedures was 88% (7/8). Among these 8 patients, 4 patients with common bile duct stones underwent electrohydraulic lithotripsy. One patient successfully underwent guidewire insertion to remove a migrated plastic stent. The 3 remaining patients underwent SPY DS to insert a guidewire for left bile duct obstruction and for posterior bile duct branch. In the patient who underwent guidewire insertion for left hepatic bile duct obstruction cause by primary sclerosing cholangitis, we could not advance the guidewire into the left hepatic bile duct. No adverse events were seen. Median SPY DS insertion time was 21 min (range, 8-32 min).Single-operator cholangioscopy using SPY DS was feasible and had a marked clinical impact in patients with biliary disease. Additional case reports and prospective studies are needed to examine further applications of this system.

A review of treatment options for bile duct stones

Approximately 10-15% of bile duct stones cannot be treated using conventional stone removal techniques. For difficult common bile duct stones (CBDS), various endoscopic techniques have been developed. This review covers technical tips and endoscopic treatments including Endoscopic retrograde cholangiopancreatography (ERCP), particularly under Endoscopic ultrasound (EUS) guidance. Areas covered: Literatures about endoscopic treatment for bile duct stone were searched in Pub Med. As novel methods, EUS-guided approaches have also been reported, although long-term results and prospective evaluation are not yet sufficient. Large stones may need fragmentation prior to removal, to prevent stone impaction. To perform fragmentation, mechanical lithotripsy, extracorporeal shock wave lithotripsy or laser lithotripsy techniques are available. Expert commentary: Despite the fact that most bile duct stones can be treated using endoscopic techniques, endoscopists should remind to be able to select the temporary biliary stenting or percutaneous transhepatic cholangiodrainage as an option.

Development of an in vivo swine model of biliary dilatation-based direct peroral cholangioscopy

A reproducible in vivo swine model of bile duct dilation (BDD) was recently established and reported for preclinical testing of newly developed biliary devices or endoscopic techniques. The aim of the present study was to develop a more advanced large animal model in which it is possible to direct examination of the biliary tree. Methods Six mini pigs were prepared for the study. BDD models were first made by closure of the Vater's ampulla in all swine. Then endoscopic papillary balloon dilation (EPBD) was done in the animals. Feasibility of single-operator peroral cholangioscopy without assistance of accessories was evaluated using an ultra-slim upper endoscope in the animals. Results EPBD could be implemented using a dilation balloon catheter (10~13.5 mm) in all BDD models (6/6, 100%). Success rate of freehand direct insertion of an ultra-slim endoscope into the common bile duct was 100% (6/6), and access to the common hepatic duct with examination was possible using direct peroral cholangioscopy in five animals (5/6, 83.3%). None of the animals died. In the cholangioscopic examination, a bile duct polyp and a benign biliary stricture occurred naturally, respectively, in two of the six swine. Conclusion An in vivo swine model of biliary dilatation-based direct peroral cholangioscopy was established. This novel animal model may be useful for preclinical research of new materials or devices because direct visualization of the biliary tree is feasible.

Recent developments in choledochoscopy: technical and clinical advances

Peroral cholangioscopy has become an important tool in the diagnosis and treatment of a variety of biliary diseases, ranging from indeterminate biliary strictures to bile duct stones. Although the first cholangioscopy was performed in the 1970s, recent technological advances have provided us with cholangioscopes that yield high-resolution images, possess single-operator capability, and have ultrathin design to allow easier maneuverability and detailed imaging of the biliary tract. We review here the currently available devices for peroral cholangioscopy, their clinical applications, limitations, and complications.

Recent advances in endoscopic management of difficult bile duct stones

Endoscopic treatment is now recognized worldwide as the first-line treatment for bile duct stones. Endoscopic sphincterotomy combined with basket and/or balloon catheter is generally carried out for stone extraction. However, some stones are refractory to treatment under certain circumstances, necessitating additional/other therapeutic modalities. Large bile duct stones are typically treated by mechanical lithotripsy. However, if this fails, laser or electrohydraulic lithotripsy (EHL) is carried out under the guidance of conventional mother-baby cholangioscopy. More recently, direct cholangioscopy using an ultrathin gastroscope and the newly developed single-use cholangioscope system - the SpyGlass direct visualization system - are also used. In addition, extracorporeal shock wave lithotripsy has also been used for stone fragmentation. Such fragmentation techniques are effective in cases with impacted stones, including Mirizzi syndrome. Most recently, endoscopic papillary large balloon dilationhas been introduced as an easy and effective technique for treating large and multiple stones. In cases of altered anatomy, it is often difficult to reach the papilla; in such cases, a percutaneous transhepatic approach, such as EHL or laser lithotripsy under percutaneous transhepatic cholangioscopy, can be a treatment option. Moreover, enteroscopy has recently been used to reach the papilla. Furthermore, an endoscopic ultrasound-guided procedure has been attempted most recently. In elderly patients and those with very poor general condition, biliary stenting only is sometimes carried out with or without giving subsequent dissolution agents.