Biliary and pancreatic stents

Safety and Efficacy of a Large-Bore Biliary Metallic Stent for Malignant Biliary Obstruction

Self-expandable metallic stents (SEMSs) are typically inserted in patients with unresectable malignant biliary obstruction. However, SEMSs are susceptible to occlusion. To overcome this issue, we developed a large-bore, dumbbell-shaped, fully covered SEMS (FCSEMS-L) and compared its efficacy and safety with those of a conventional FCSEMS (FCSEMS-C) in patients with malignant biliary obstruction. Methods: Patients with unresectable distal malignant biliary obstruction were retrospectively enrolled between January 2011 and February 2021. All patients underwent endoscopic insertion of FCSEMSs. Recurrent biliary obstruction (RBO), patient survival time, complications, and prognosis were analyzed. Results: RBO occurred in 31 patients (35.6%) who received an FCSEMS-L, and in 34 (45.9%) who received an FCSEMS-C. Stent occlusion occurred in 19 patients (21.8%) who received an FCSEMS-L, and in 22 (29.7%) who received an FCSEMS-C. Stent migration occurred in 12 patients (13.8%) with an FCSEMS-L and 12 (16.2%) with an FCSEMS-C. The median time to RBO (TRBO) was 301 days with an FCSEMS-L and 203 days with an FCSEMS-C. The median survival time was 479 days with an FCSEMS-L and 523 days with an FCSEMS-C. The TRBO and patient survival time did not significantly differ between the two groups. Conclusions: There were no significant differences in efficacy and complication rates between the fully covered large bore SEMSs and conventional fully covered SEMSs.

Mechanical properties and degradation process of biliary self-expandable biodegradable stents

OBJECTIVES

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.

CONCLUSION

Our results showed that PDO/PLLA BS maintained their original shape and radial force for a relatively long time and minimized adverse events.

[A Recent Update on Endoscopic Drainage of Advanced Malignant Hilar Obstruction]

Malignant hilar obstruction (MHO) is considered an aggressive perihilar obstruction caused by cholangiocarcinoma, gallbladder cancer, or metastatic malignancies and has a poor prognosis. Although surgical resection is the only curative treatment method, the majority of patients with MHO do not undergo surgery due to an advanced inoperable state at presentation. Currently, effective biliary drainage provides the necessary palliation for symptomatic improvement. Among the drainage methods, percutaneous access may be preferred, especially for advanced MHO because of the technical difficulty involved with other techniques. Recently, primary endoscopic palliation using plastic or metal stents has been shown to have higher technical feasibility and clinical success without increasing adverse events even in patients with high-degree MHO. The development of various accessories, endoscopic ultrasonography, and advances in techniques have facilitated primary endoscopic intervention. However, some aspects continue to be debated such as the palliation methods, appropriate stents, the number of stents, the deployment methods, and additional local ablation therapies. Therefore, this review discusses the current optimal endoscopic treatment methods for advanced MHO based on reported literature.

Hindman NM, Arif-Tiwari H, Kamel IR, Al-Refaie WB, Bartel TB, Cash BD, Chernyak V, Goldstein A, Grajo JR, Horowitz JM, Kamaya A, McNamara MM, Porter KK, Srivastava PK, Zaheer A, Carucci LR. ACR Appropriateness Criteria® Jaundice

Jaundice is the end result of myriad causes, which makes the role of imaging in this setting particularly challenging. In the United States, the most common causes of all types of jaundice fall into four categories including hepatitis, alcoholic liver disease, blockage of the common bile duct by a gallstone or tumor, and toxic reaction to a drug or medicinal herb. Clinically, differentiating between the various potential etiologies of jaundice requires a detailed history, targeted physical examination, and pertinent laboratory studies, the results of which allow the physician to categorize the type of jaundice into mechanical or nonmechanical causes. Imaging modalities used to evaluate the jaundiced patient (all etiologies) include abdominal ultrasound (US), CT, MR cholangiopancreatography, endoscopic retrograde cholangiopancreatography and endoscopic US. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

[Mechanisms and prevention of biliary stent occlusion]

One of significant achievements of modern endoscopy is development of retrograde biliary stenting for obstructive jaundice. This method ensured widespread application of endoscopic decompression in the treatment of patients with malignant biliary obstruction as preparation before radical surgery and final palliative care. Endoscopic retrograde transpapillary stenting firmly took its place together with antegrade and percutaneous stenting. There are certain advantages of this technique including minimally invasiveness and favorable quality of life. However, this approach is associated with some drawbacks associated with stent occlusion and difficult correction of this complication. The maximum diameter of the plastic stent (PS) is determined by the width of the working channel of the duodenoscope. In this regard, self-expandable metal stents (SEMS) were developed to increase the diameter of bile drainage channel. SEMS are associated with prolonged function. However, there is another problem. It is a germination of SEMS followed by impossible removal of the stent for its subsequent replacement. A further step in development of endoscopic biliary stents was the use of special SEMS coating to exclude tumor or granulation ingrowth. The problem of biliary stent occlusion remains relevant despite some improvement of stenting results. Mechanisms of occlusion of biliary stents and prevention of these events are discussed in this review.

EUS-guided drainage of pancreatic fluid collections using lumen apposing metal stents: An international, multicenter experience

INTRODUCTION

Lumen apposing metal stents (LAMS) have been used increasingly for drainage of pancreatic fluid collections (PFC). We present an international, multicenter study evaluating the safety and efficacy of LAMS in PFCs.

METHODS

Consecutive patients undergoing LAMS placement for PFC at 12 international centers were included (ClinicalTrials.gov NCT01522573). Demographics, clinical history, and procedural details were recorded. Technical success was defined as successful LAMS deployment. Clinical success was defined as PFC resolution at three-month follow-up.

RESULTS

192 patients were included (140 males (72.9%), mean-age 53.8 years), with mean follow-up of 4.2 months ± 3.8. Mean PFC size was 11.9 cm (range 2-25). The median number of endoscopic interventions was 2 (range 1-14). Etiologies for PFC were gallstone (n = 82, 42.7%), alcohol (n = 50, 26%), idiopathic (n = 26, 13.5%), and other (n = 34, 17.7%). Technical success was achieved in 189 patients (98.4%). Clinical success was observed in 125 of 135 patients (92.6%). Adverse events included bleeding (n = 11, 5.7), infection (n = 2, 1%), and perforation (n = 2, 1%). Three or more endoscopy sessions were a positive predictor for PFC resolution and the only significant predictor for AEs.

CONCLUSION

LAMS has a high technical and clinical success rate with a low rate of AEs. PFC drainage via LAMS provides a minimally invasive, safe, and efficacious procedure for PFC resolution.

Spontaneous Closure of a Large Transmural Gastric Defect After Removal of a Migrated AXIOS Stent

Pancreatic fluid collections occur in 5%-15% of acute complicated pancreatitis cases. Endoscopic drainage using lumen-apposing metal stents has become the treatment of choice with less incidence of complications, shorter hospital stays, and less cost. The AXIOS stent has proven to be safe and effective in several studies. Despite a low complication rate, bleeding, perforation, and stent migration were still reported. In this case, a patient presented for delayed AXIOS stent removal and was found to have stent migration with embedment in the gastric wall. The transmural defect that resulted after endoscopic stent removal was observed to close spontaneously without further need for intervention.

Evaluation of valve function in antireflux biliary metal stents

Background

To overcome duodenobiliary reflux induced by biliary stents, antireflux valve (ARV) biliary stents have been developed and showed improvement in stent patency. However, negative study results have also been reported because stent patency may be decreased by the malfunction of ARV itself. Given such mixed results, the true efficacy of ARV remains unknown and the mechanism of its dysfunction needs to be clearly elucidated. The aim of this study was to investigate the exact mechanism of ARV dysfunction using in vitro phantom models.

Methods

Two experimental models were designed to evaluate two important environmental factors suspected to cause ARV malfunction, i.e. bile flow and pH. Three types of ARV metal stents from different companies were used for the experiments: a funnel type ARV, a windsock type ARV, and a wine glass-shaped ARV. Ten stents of each type were tested (five stents in the bile flow phantom model, and another five stents in the duodenal pH environmental model). To determine ARV malfunction, ARV-induced flow resistance was measured using a custom-made testing device. All stents from the two models were removed every 2 weeks for 12 weeks after stent insertion and were evaluated on morphological and functional changes of the ARV.

Results

Only ARV of wine glass-shaped ARV was morphologically changed due to silicone bond detachment in the bile flow model. All types of ARV were morphologically changed in the pH model. The morphological changes of ARV influenced the flow resistance. The antegrade pressure gradients were increased over time in the pH model (p < 0.05).

Conclusions

Morphological change of the ARVs may induce dysfunction of ARV metal stents, which is mainly due to duodenal pH environment. In the future, development of new ARV that is not affected by duodenal environmental factors can be expected to improve stent patency.

Electronic supplementary material

The online version of this article (10.1186/s12876-018-0878-8) contains supplementary material, which is available to authorized users.

Lumen Apposing Metal Stents (LAMSs) for Drainage of Pancreatic and Gallbladder Collections: A Meta-analysis

BACKGROUND AND AIMS

Endoscopic ultrasound-guided transmural drainage using lumen apposing metal stents (LAMSs) is becoming a popular and promising therapeutic approach for drainage of intra-abdominal fluid collections. There has been an increasing number of studies evaluating LAMS for drainage of pancreatic pseudocysts (PP), walled-off pancreatic necrosis (WOPN), and gallbladder (GB) drainage. The aim of this meta-analysis is to analyze the literature to date regarding the clinical success, technical success, and adverse events of LAMS in treatment of pancreatic fluid collections and GB drainage.

METHODS

A comprehensive search of multiple literature databases through November 2016 was performed. Human studies with at least 10 subjects that examined the clinical success, technical success, and adverse events of LAMS in treating PP, WOPN, and GB drainage were included.

RESULTS

A total of 993 patients (608-WOPN; 204-PP; 181-GB drainage) underwent drainage from 20 trials. For drainage of WOPN, the pooled technical success was 98.9% [95% confidence interval (CI): 98.2% to 99.7%] and clinical success was 90% (95% CI: 87% to 93%) (τ=0.001). For drainage of PP, the pooled technical success was 97% (95% CI: 95% to 99%) and clinical success was 98% (95% CI: 96% to 100%), (τ=0.001). For GB drainage, the pooled technical success was 95% (95% CI: 91% to 99%) and clinical success was 93% (95% CI: 90% to 97%), (τ=0.001). Total adverse events occurred in 11% of patients with higher complication rates observed in GB drainage. There was no evidence of publication bias in this meta-analysis.

CONCLUSIONS

Endoscopic ultrasound-guided transmural drainage using LAMS is becoming a widely accepted therapeutic approach for the treatment of PP, WOPN, and GB drainage with high clinical and technical success rates and acceptable adverse events. Further prospective randomized trials reporting long-term clinical efficacy and cost-effectiveness are needed to validate LAMS as a therapeutic modality for pancreatic and GB collections.

Bile Flow Phantom Model and Animal Bile Duct Dilation Model for Evaluating Biliary Plastic Stents with Advanced Hydrophilic Coating

Background/Aims

The efforts to improve biliary plastic stents (PSs) for decreasing biofilm formation and overcome short patency time have been continued. The aim of this study is to evaluate the effect of advanced hydrophilic coating for patency and biodurability of PS.

Methods

Using an in vitro bile flow phantom model, we compared patency between prototype PS with hydrophilic coating (PS+HC) and prototype PS without hydrophilic coating (PS−HC). We performed an analysis of the degree of luminal narrowing by microscopic examination. Using an in vivo swine bile duct dilation model made by endoscopic papillary closure and stent insertion, we evaluated biodurability of hydrophilic coating.

Results

In the phantom model, PS+HC showed less biofilm formation and luminal narrowing than PS−HC at 8 weeks (p<0.05). A total of 31 stents were inserted into the dilated bile duct of seven swine models, and 24 stents were successfully retrieved 8 weeks later. There was no statistical difference of stent patency between the polyethylene PS+HC and the polyurethane PS+HC. The biodurability of hydrophilic coating was sustained up to 8 weeks, when assessing the coating layer by scanning electron microscopy examination.

Conclusions

Advanced hydrophilic coating technology may extend the patency of PS compared to uncoated PS.

The Stent Patency and Migration Rate of Different Shaped Plastic Stents in Bile Flow Phantom Model and In Vivo Animal Bile Duct Dilation Model

BACKGROUND/AIM

In research and development of biliary plastic stents (PS), continuous efforts have been made to overcome short patency time and high rate of migration. The aim of this study was to evaluate the patency and migration rate of different PS shapes for a given period of time.

METHODS

Using an in vitro bile phantom model, we compared the patency among different shapes of PS (three straight PS, four double-pigtail PS, and a new screw-shaped PS). We performed an analysis of the degree of luminal narrowing by light microscopic examination. Using an in vivo swine model, we compared the patency and migration rate among the three different types of PS.

RESULTS

Eight weeks after the bile exposure in the bile flow phantom model, 80 PS were retrieved and analyzed. The straight PS showed less biofilm formation and luminal narrowing than other types of PS (p < 0.05). Forty-nine PS were inserted into the dilated bile ducts of 10 swine models, and 39 PS were successfully retrieved 8 weeks later. The stent migration occurred less frequently in the double-pigtail PS and the screw-shaped PS than it did in the straight PS (11.1, 10, and 27.3%, respectively). However, there was no statistical difference in stent patency among the different shapes.

CONCLUSIONS

Stent patency may not be significantly different depending on the shape of PS for 8 weeks. The screw-shaped PS showed similar patency and migration rate to the double-pigtail PS. These results may help guiding future PS development and clinical decisions.

Time Sequence Evaluation of Biliary Stent Occlusion by Dissection Analysis of Retrieved Stents

BACKGROUND AND AIMS

Multiple factors can affect the occlusion of plastic stents. Previous data demonstrate that side holes may induce more biofilm formation probably via microturbulence and bile flow disturbances that could lead to occlusion. These results, however, have not been replicated in subsequent clinical studies with different methods. The objective of this study is to evaluate the physical characteristics of plastic stent occlusion over time.

METHODS

This is a plastic stent sequential analysis study. Biliary stents removed via ERCP from February 24, 2015, to June 2, 2015, were included. One hundred and forty-eight retrieved straight-type plastic stents were longitudinally cut by a custom-made cutting device. These dissected stents were then evaluated in detail with regard to the location of stent occlusion and the stent patency period. Location of stent occlusive debris was the primary outcome in this study.

RESULTS

Biofilm formations and occlusions by debris were sequentially but separately tallied. Biofilm formations were initially seen around the side hole areas within 30 days and spread to the entire stent by 60 days. Then, occlusion process by debris was mainly initiated by 80 days and progressed to full occlusion by median of 90 days. Although some occlusions were also observed around the side hole areas within 30 days, affected areas were more widely observed after biofilm formation.

CONCLUSIONS

This study is the first to attempt to describe the distribution of stent occlusions over time. These observations may help guide future stent development.

EUS-guided drainage of peripancreatic fluid collections and necrosis by using a novel lumen-apposing stent: a large retrospective, multicenter U.S. experience (with videos)

BACKGROUND AND AIMS

EUS-guided drainage of peripancreatic fluid collection (PFC) (pancreatic pseudocyst [PP] or walled-off necrosis [WON]) by using a novel lumen-apposing, fully covered, self-expandable metal stent (LAMS) has been promising, but few of these data are from the United States. The aim of this study was to evaluate clinical outcomes and safety of EUS-guided drainage of pancreatic pseudocysts and WON by using the LAMS.

METHODS

We conducted a multicenter, retrospective study on 82 patients with symptomatic PFC who underwent EUS-guided drainage by using the LAMS at 4 U.S. tertiary care centers. Outcomes evaluated included successful placement of the LAMS, the number of patients in whom complete resolution of PPs or WON was achieved, the number of procedures performed per patient to achieve PFC resolution, and adverse events.

RESULTS

The mean size of the PFC was 11.8 cm. LAMSs were successfully placed in 80 patients (97.5%). Twelve patients had PP and 68 had WON. The median stent in-dwelling time was 2 months (range 1-3 months). Endoscopic debridement with the LAMS in WON was performed in 54 patients. The patency of the stent was maintained in 98.7% of the patients (77/78). There was spontaneous dislodgment of 2 LAMSs. Successful endoscopic therapy by using the LAMS was successful in 12 of 12 patients (100%) with PP compared with 60 of 68 patients (88.2%) with WON. All stents were endoscopically removed from all patients after peripancreatic fluid collection (PFC) resolution. There was 1 PFC recurrence during the 3-month median follow-up period. Procedure-related adverse events occurred in 8 patients (9.8%), and included stent maldeployment (n = 2), and self-limited bleeding (n = 6). In 1 patient with stent maldeployment gastric perforation developed, and the patient underwent surgical repair.

CONCLUSION

EUS-guided drainage of PFCs by using the novel LAMS has high technical and long-term success rates. Due to its ease of use, the LAMSs may simplify and streamline EUS-guided management of PFCs, particularly for the endoscopic debridement of WON, and may help in its widespread adoption as an alternative to surgery.

Mechanisms of Biliary Plastic Stent Occlusion and Efforts at Prevention

Biliary stenting via endoscopic retrograde cholangiopancreatography has greatly improved the quality of patient care over the last 30 years. Plastic stent occlusion limits the life span of such stents. Attempts to improve plastic stent patency duration have mostly failed. Metal stents (self-expandable metal stents [SEMSs]) have therefore replaced plastic stents, especially for malignant biliary strictures. SEMS are at least 10 times more expensive than plastic stents. In this focused review, we will discuss basic mechanisms of plastic stent occlusion, along with a systematic summary of previous efforts and related studies to improve stent patency and potential new techniques to overcome existing limitations.

Endoscopic drainage of pancreatic fluid collections using a fully covered expandable metal stent with antimigratory fins

BACKGROUND AND OBJECTIVES

Endoscopic drainage is the first consideration in treating pancreatic fluid collections (PFCs). Recent data suggests it may be useful in complicated PFCs as well. Most of the available data assess the use of plastic stents, but scarce data exists on metal stent management of PFCs. The aim of our study to evaluate the efficacy and safety of a metal stent in the management of PFCs.

PATIENTS AND METHODS

Data were collected prospectively on 47 patients diagnosed with PFCs from March 2007 to August 2011 at 3 tertiary care centers. These patients underwent endoscopic transmural placement of a fully covered self-expanding metal stent (FCSEMS) with antimigratory fins of 10 mm diameter.

RESULTS

The stent was successfully placed in all patients, and left in place an average of 13 weeks (range 0.4-36 weeks). Etiology of the PFC was biliary pancreatitis (23), pancreas divisum (2), trauma (4), hyperlipidemia (3), alcoholic (8), smoking (2), idiopathic (4), and medication-induced (1). PFCs resolved in 36 patients, for an overall success rate of 77%. Complications included fever (3), stent migration (2) and abdominal pain (1).

CONCLUSIONS

The use of FCSEMS is successful in the majority of patients with low complication rates. A large sample-sized RCT is needed to confirm if the resolution of PFCs is long-standing.

Safety and efficacy of endoscopic ultrasound-guided drainage of pancreatic fluid collections with lumen-apposing covered self-expanding metal stents

BACKGROUND & AIMS

Plastic stents, placed via endoscopy to drain pancreatic fluid collections (PFCs), require repeat access. Covered metal stents are larger in diameter and can be inserted in a single step, but can migrate. We evaluated the safety and efficacy of a lumen-apposing, covered, self-expanding metal stent (LACSEMS) for PFC drainage.

METHODS

We performed a prospective study of the outcomes of stent placement in 33 patients (18 men; age, 53 ± 14 y; 28 with chronic pancreatitis) with symptomatic pancreatic pseudocysts and walled-off necrosis (≥ 6 cm with ≥ 70% fluid content). Subjects were enrolled at 7 tertiary care centers (6 in the United States and 1 in Europe) from October 2011 through August 2013. Cystenterostomies were created based on endoscopist preference. Safety outcomes included infection, bleeding, perforation, tissue injury, and stent migration. Efficacy end points included LACSEMS placement, patency, and removal, as well as 50% or more reduction in PFCs.

RESULTS

The mean size of the patients' PFCs was 9 ± 3.3 cm. LACSEMSs were placed successfully via endoscopic ultrasound guidance in 30 patients (91%); the remaining 3 patients received 2 double-pigtail stents. One subject could not be evaluated because of a pseudoaneurysm. In the patients receiving LACSEMS, PFCs resolved in 27 of 29 (93%). Overall, PFCs resolved in 30 of 33 patients (91%). Endoscopic debridement through the LACSEMS was conducted in 11 subjects. Complications (15%) included abdominal pain (n = 3), spontaneous stent migration, back pain (n = 1), access-site infection, and stent dislodgement (n = 1).

CONCLUSIONS

LACSEMS were placed successfully in 91% of subjects with PFCs. Overall, 93% had PFC resolution. Advantages of LACSEMSs over other stents include single-step deployment and the ability to perform endoscopic debridement with minimal stent migration. Clinicaltrials.gov: NCT01419769.

Bilateral metallic stenting in malignant hilar obstruction

Endoscopic palliative biliary drainage is considered as a gold standard treatment in advanced or inoperable hilar cholangiocarcinoma. Also, metal stents are preferred over plastic stents in patients with >3 months life expectancy. However, the endoscopic intervention of advanced hilar obstruction is often more challenging and complex than that of distal malignant biliary obstructions. In this literature review, we describe the issues commonly encountered during endoscopic unilateral (single) versus bilateral (multiple) biliary stenting for malignant hilar obstruction. Also, we provide technical guidance to improve the technical success rates and patient outcomes, focusing on bilateral metallic stenting techniques such as stent-in-stent or side-by-side deployment.

Functional self-expandable metal stents in biliary obstruction

Biliary stents are widely used not only for palliative treatment of malignant biliary obstruction but also for benign biliary diseases. Each plastic stent or self-expandable metal stent (SEMS) has its own advantages, and a proper stent should be selected carefully for individual condition. To compensate and overcome several drawbacks of SEMS, functional self-expandable metal stent (FSEMS) has been developed with much progress so far. This article looks into the outcomes and defects of each stent type for benign biliary stricture and describes newly introduced FSEMSs according to their functional categories.

Technical tips and issues of biliary stenting, focusing on malignant hilar obstruction

Although there is no survival advantage, inoperable hilar cholangiocarcinoma managed by palliative drainage may benefit from symptomatic improvement. In general, biliary drainage is divided into endoscopic or percutaneous approaches and surgical drainage. Plastic or metal stent is the most preferred device for palliative drainage in endoscopic approach. Considering cost-effectiveness, use of metallic stent is preferred than plastic stents in patients with more than 3 months of life expectancy with inoperable malignant biliary obstruction. In patients with unresectable malignant hilar obstruction, the endoscopic approach with biliary stent placement by experts has been considered as the treatment of choice. However, the endoscopic management of hilar obstruction is often more challenging and complex than distal malignant biliary obstructions. There is still a lack of clear consensus on the use of plastic versus metal stents and unilateral versus bilateral drainage since the decision should be made under many grounds such as the volume of liver drainage more than 50%, life expectancy, and expertise of the facility.

Biliary stent therapy for dominant strictures in patients affected by primary sclerosing cholangitis

The diagnosis and the treatment of dominant strictures (DS) in patients with primary sclerosing cholangitis (PSC) is challenging and the scientific literature on the subject is quite limited. Only level II and level III evidence is available to guide physicians managing patients with DS and PSC. For the diagnosis, intraductal endoscopic ultrasound is the most sensitive (64%) and specific (95%) test. However, the majority of cases require a combination of several different diagnostic tests, as there is no single investigation that can rule out malignancy in this group of patients. For the treatment, serial endoscopic or percutaneous dilatations provide 1- and 3-year biliary duct patency in 80 and 60% of patients, respectively. Dilatation and stenting are the most common interventions, although the optimal duration of treatment has still not been clearly defined. Bile duct resection and/or bilioenteric bypass are currently indicated only for patients with preserved liver function. For all other patients, benign DS can be treated with endoscopic dilatation with short-term stenting. This approach is effective and safe and does not increase the risk of malignant transformation or complications for liver transplant candidates. During the last decade, the use of self-expandable metallic stents for benign diseases has become an innovative option. The aim of this article is to review the diagnostic and therapeutic strategies for patients affected by PSC and DS with specific emphasis on the outcomes of patients treated with temporary stents.

Otaru consensus on biliary stenting for unresectable distal malignant biliary obstruction

Endoscopic biliary drainage with biliary stent placement is the treatment of choice for palliation in patients with malignant biliary obstruction caused by unresectable neoplasms. Various biliary stent designs have become available, but lack of a clear consensus persists on the use of covered versus uncovered metal stents in malignant distal bile duct obstructions, and plastic versus metal stents. In 2012, the European Society of Gastrointestinal Endoscopy indicated guidelines for biliary stenting. Accordingly, the consensus meeting for biliary stenting was held at the Endoscopic Forum Japan 2012, and four selected statements related to stent placement for distal malignant biliary obstruction were discussed to produce a consensus. Two of four statements (related to the usefulness of self-expandable metallic stents, and reintervention after stenting) were agreed upon by almost all participants. Nevertheless, our opinions were divided on the other two statements (necessity of sphincterotomy for stenting, and covered metal stent versus uncovered metal stent). We herein report the results of the meeting, and present proposed new statements via discussion.

Cholangiocarcinoma treatment

Cholangiocarcinoma (CCA) is a tumor of the bile ducts that usually presents with biliary obstruction and has a poor prognosis. The treatment of CCA is challenging as the tumor is usually diagnosed late and the treatments are not very effective except when complete surgical resection is possible. In carefully selected patients, liver transplant can be a curative therapy. In the majority of cases, complete surgical resection is not possible and palliation is the mainstay of treatment. Stenting, using plastic or metallic stents, allows for biliary drainage. Photodynamic therapy plays a role in palliation and might play a role in adjuvant or neoadjuvant therapy. While radiation and chemotherapy can be beneficial, newer ablative techniques and targeted chemotherapies are promising.

Endoscopic stent placement in the palliation of malignant biliary obstruction

Biliary drainage with biliary stent placement is the treatment of choice for palliation in patients with malignant biliary obstruction caused by unresectable neoplasms. In such patients, the endoscopic approach can be initially used with percutaneous radiological intervention. In patients with unresectable malignant distal bile duct obstructions, endoscopic biliary drainage with biliary stent placement has now become the main and least invasive palliative modality, which has been proven to be more effective in >80% of cases with lower morbidity than surgery, and perhaps may provide a survival benefit. In patients with unresectable malignant hilar obstruction, the endoscopic approach for biliary drainage with biliary stent placement has also been considered as the treatment of choice. There is still a lack of clear consensus on the use of covered versus uncovered metal stents in malignant distal bile duct obstructions and plastic versus metal stents and unilateral versus bilateral drainage in malignant hilar obstructions.

Expandable metal stents for malignant hilar biliary obstruction

Most patients with malignant hilar stenoses are candidates for palliation. For this purpose, biliary drainage plays a major role in improving liver function and managing or avoiding cholangitis. Endoscopic interventions are less invasive than the percutaneous approach and should be considered as the first-line drainage procedures in most cases. Transhepatic interventions should be reserved for endoscopic failures or performed as a complementary approach in a combined procedure. After successful endoscopic access to biliary obstruction, implantation of self-expandable metal stents offers advantages over plastic endoprostheses in terms of stent patency and number of reinterventions.

Stent-in-stent through a side hole to prevent biliary metallicstent migration

The covered self-expandable metallic stent (SEMS) has been developed to overcome the problem of tissue in­growth, However, stent migration is a well-known com­­plication of covered SEMS placement. Use of a double pigtail stent to lock the movement of the SEMS and prevent migration has been advised by many ex­perts. Unfortunately, in our case this technique led to an in­cidental upward migration of the SEMS. We used APC to create a side hole in the SEMS for plastic stent insertion as stent-in-stent. This led to a successful pre­ven­tion of stent migration.

Therapeutic pancreatic endoscopy

Although the common indications for therapeutic pancreatic endoscopy - management of ductal strictures and calculi - have remained constants, the last decade has witnessed the emergence of several new endoscopic techniques for managing pancreatic disorders. While many of the advances in therapeutic pancreatic endoscopy have paralleled the shift of endoscopic ultrasound from a purely diagnostic to therapeutic modality, other new techniques are simply modifications on existing procedures. Despite these exciting times in therapeutic endoscopy, it is important to recognize that the endoscopist is one part of an interdisciplinary team of experts - a model which is essential in the successful management of patients with pancreatic disorders.

Endoscopic biliopancreatic investigations and therapy

The management of most biliopancreatic diseases benefits from endoscopic treatment. Forty years after the first endoscopic cannulation of the ampulla of Vater, the overall effectiveness and safety of endoscopic retrograde cholangiopancreatography (ERCP) can be evaluated using the quality assurance programs that have recently been developed for gastrointestinal endoscopy, including ERCP. Such evaluation does not mean simply reporting therapeutic success and complication rates; rather, it involves a complex analysis of the entire gastrointestinal unit, of the medical practises, and of patient satisfaction. The overall quality of ERCP has been analysed and many quality deficits identified, even in referral centres. Training for such a specialised procedure is difficult and expensive. Competence in ERCP requires as many as 200 ERCP procedures. Quality assurance programs can help to improve the overall quality of endoscopic practise, including training of young endoscopists.

A novel biodegradable biliary stent in the endoscopic treatment of cystic-duct leakage after cholecystectomy

BACKGROUND

A bile leak is a common complication after a cholecystectomy.

OBJECTIVE

The use of a novel, self-expanding, radiopaque polylactide-barium sulphate biodegradable stent and a polyethylene stent was investigated in 12 pigs with cystic-duct leakage.

DESIGN

Prospective animal study.

SETTING

After cholecystectomy, the cystic duct was left without ligation, and then the foramen of Winslow was drained extra-abdominally. During the duodenoscopy, a biodegradable or a polyethylene biliary stent was inserted into the bile duct.

MAIN OUTCOME MEASUREMENTS

The bile-drain output was measured daily, and when it was below 20 mL/d, the drain was removed. The animals were followed by repeated abdominal radiographs and serum determinations until they were euthanized at 6 months, when histologic evaluation of the bile duct and surrounding tissues was performed.

RESULTS

In the biodegradable stent group, the total external output of bile was significantly smaller (median [range], 165 mL [100-1740 mL] vs 710 mL [355-1020 mL]; P<.01) and the drains could be removed earlier (5 days [4-5 days] vs 7 days [6-7 days] after surgery; P<.05) compared with the plastic stent group. In the abdominal radiograph, a biodegradable or polyethylene stent was seen to be in place in all animals at 3 months and in 0 of 6 (biodegradable biliary stent group) and 1 of 5 (polyethylene biliary stent group) animals at 6 months. One polyethylene stent was found to be clotted at the necropsy at 6 months. The rest of the stents had disappeared by 6 months, and there was no significant difference in the bile-duct inner diameter or the histology between the groups.

CONCLUSIONS

This novel biodegradable stent is applicable, safe, and effective in the endoscopic treatment of postcholecystectomy cystic-duct leakage. In addition, the subsequent removal of the stent can be avoided. These encouraging experimental results warrant further clinical trials.

Endoscopic palliation of cholangiocarcinoma

PURPOSE OF REVIEW

The current endoscopic palliative modalities for unresectable cholangiocarcinoma are reviewed, focusing on the emergent methods of endoscopic palliation.

RECENT FINDINGS

Cholangiocarcinoma is a rare malignant tumor arising from biliary epithelium. Endoscopic retrograde cholangiopancreaticography can provide histological diagnosis through brush cytology of the bile duct, and newer cytologic techniques such as digital image analysis and fluorescent in-situ hybridization may improve the cytologic accuracy for diagnosing cholangiocarcinoma. Endoscopic ultrasonography can play an adjunctive role in the diagnosis and staging by facilitating tissue acquisition through fine needle aspiration of the tumor and surrounding lymph nodes. Most patients present with unresectable disease and features of biliary obstruction. This has led to an emphasis on the role of palliative care. Biliary stent placement is an effective method of palliating obstructive jaundice. Newer modalities such as photodynamic therapy, intraluminal brachytherapy, and high-intensity ultrasound therapy may result in improved survival and play a future role as an adjunctive therapy to surgical resection.

SUMMARY

Several endoscopic palliative modalities have recently emerged. Among these, photodynamic therapy in addition to biliary stent placement appears to be a promising step towards the management of locally unresectable cholangiocarcinoma. Randomized, controlled trials are required, however, to further evaluate these therapies.

Cholangiocarcinoma

Cholangiocarcinoma is an uncommon malignant tumor arising from biliary epithelium. The incidence increases with age and usually affects individuals in their sixth or seventh decade of life. Most patients clinically present with features of biliary obstruction. Although surgical resection offers the only hope for cure, the majority of patients are found to have unresectable disease on initial presentation and carry extremely grim prognosis. This has lead to an emphasis on the role of palliative care, with the relief of biliary obstruction being the primary goal in the management of these patients. Surgical bypass was once considered as the primary means of palliating biliary obstruction, but nonsurgical placement of biliary stents is associated with lower morbidity and mortality. Newer modalities such as photodynamic therapy, brachytherapy, and high-intensity ultrasound therapy may result in improved survival and play a future role as an adjunctive therapy to surgical resection.