Biliary and pancreatic stenting: Devices and insertion techniques in therapeutic endoscopic retrograde cholangiopancreatography and endoscopic ultrasonography

Current status and future perspectives for endoscopic treatment of local complications in chronic pancreatitis

Chronic pancreatitis is a progressive disease characterized by irregular fibrosis, cellular infiltration, and parenchymal loss within the pancreas. Chronic pancreatitis treatment includes lifestyle modifications based on disease etiology, dietary adjustments appropriate for each stage and condition, drug therapy, endoscopic treatments, and surgical treatments. Although surgical treatments of symptomatic chronic pancreatitis provide good pain relief, endoscopic therapies are recommended as the first-line treatment because they are minimally invasive. In recent years, endoscopic therapy has emerged as an alternative treatment method to surgery for managing local complications in patients with chronic pancreatitis. For pancreatic stone removal, a combination of extracorporeal shock wave lithotripsy and endoscopic extraction is used. For refractory pancreatic duct stones, intracorporeal fragmentation techniques, such as pancreatoscopy-guided electrohydraulic lithotripsy and laser lithotripsy, offer additional options. Interventional endoscopic ultrasound has become the primary treatment modality for pancreatic pseudocysts, except in the absence of disconnected pancreatic duct syndrome. This review focuses on the current status of endoscopic therapies for common local complications of chronic pancreatitis, including updated information in the past few years.

Bilio-Cecal Stent Migration Presenting as Massive Rectal Bleeding

Endoscopic biliary stenting is a well-established intervention for the treatment of biliary, hepatic, and pancreatic disorders. The common indications include strictures, neoplasms, stones, infections, and bile leaks. Stents can be occluded, predisposing patients to ascending cholangitis and biliary sepsis. Distal stent migration is another known complication of endoscopic stenting and is usually spontaneous. Bowel perforation, abscesses, bleeding, and pancreatitis are rare complications of distal stent migration and are usually limited to the duodenum. Herein, we describe an extremely rare case of bilio-cecal stent migration presenting as rectal bleeding.

Endoscopic interventions in pancreatic strictures and stones-A structured approach

Chronic pancreatitis (CP) is an irreversible disease of varied etiology characterized by destruction of pancreatic tissue and loss of both exocrine and endocrine function. Pain is the dominant and most common presenting symptom. The common cause for pain in CP is ductal hypertension due to obstruction of the flow of pancreatic juice in the main pancreatic duct either due to stones or stricture or a combination of both. With advances in technology and techniques, endoscopic retrograde cholangiography (ERCP) and stenting should be the first line of therapy for strictures of the main pancreatic duct (MPD). Small calculi in the MPD can be extracted by ERCP and balloon trawl. Extracorporeal shockwave lithotripsy (ESWL) remains the standard of care for large pancreatic calculi and aims to fragment the stones 3 mm or less that can easily be extracted by a subsequent ERCP. Single operator pancreatoscopy with intraductal lithotripsy is a technique in evolution and can be tried when ESWL is not available or is unsuccessful in producing stone fragmentation.

Adverse Events and Device Failures Associated with Pancreatic Stents: A Comprehensive Analysis Using the FDA's MAUDE Database

INTRODUCTION

Pancreatic duct stents (PDS) are widely used for the prevention of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis. However, there is a paucity of data regarding the adverse events associated with PDS placement. This study aims to investigate the reported adverse events and device failures related to PDS, utilizing the Manufacturer and User Facility Device Experience (MAUDE) database maintained by the U.S. Food and Drug Administration (FDA).

METHODS

Post-marketing surveillance data from January 2013 to December 8, 2023, were extracted from the FDA's MAUDE database to analyze the reports pertaining to the use of commonly used PDS. The primary outcomes of interest were device issues and patient-related adverse events. Statistical analysis was performed using Microsoft Excel 2010, with the calculation of pooled numbers and percentages for each device and patient adverse event.

RESULTS

A total of 579 device issues and 194 patient-related adverse events were identified. Device issues were primarily attributed to stent deformation (n = 72; 12.4%), followed by migration of the device into the pancreatic duct or expulsion out of the duct (n = 60; 10.4%), and stent fracture/breakage (n = 55; 9.4%). Among the patient-reported adverse events, inflammation was the most common (n = 26; 13.4%), followed by reports of stents becoming embedded in tissue (n = 21; 10.8%) and stent occlusion/obstruction (n = 16; 8.2%). The most prevalent device failures associated with Advanix stents were material deformation, with perforation (n = 3, 30%) being the most frequently reported adverse event. Concerning Geenen stents, migration or expulsion of the device (n = 34, 16.9%) constituted the most common device-related adverse events, while inflammation (n = 20, 16.7%) was the most frequently reported patient-related issue. For Zimmon stents, migration or expulsion of the device (n = 22, 8.8%) were the most frequently reported device-related problems, whereas perforation (n = 7, 10.9%) and bleeding (n = 7, 10.9%) were the most frequent patient-related adverse events.

CONCLUSION

Our findings highlight important device and patient adverse events that endoscopists and referring providers should be aware of before considering pancreatic stent placement.

Penetration of duodenal wall by proximal end of biliary straight plastic stent in a patient with ampullary carcinoma

A 70-year-old woman presented to our hospital with abdominal discomfort. Gastrointestinal endoscopy revealed an ampullary tumor, while a biopsy revealed a pathological diagnosis of adenocarcinoma. No distant metastases were observed and neoadjuvant chemotherapy and surgical resection were planned. Shortly thereafter, she developed obstructive jaundice due to the ampullary carcinoma. The patient underwent endoscopic retrograde cholangiopancreatography, during which a straight plastic stent was placed in the bile duct. The patient was discharged without complications. Neoadjuvant chemotherapy was initiated. Two months later, she was readmitted for surgery while asymptomatic. Endoscopic retrograde cholangiopancreatography was scheduled to replace the stent with a nasobiliary drainage tube for the surgery. Endoscopic imaging revealed that the proximal end of the stent had penetrated the duodenum on the oral side of the ampullary carcinoma. The distal end of the stent was grasped with forceps and the stent was successfully removed. A catheter was inserted into the bile duct orifice and cholangiography was performed, which revealed that the distal bile duct and the duodenum had formed a fistula. A guidewire was placed in the bile duct via the papilla and a nasobiliary drainage tube was placed. After endoscopic retrograde cholangiopancreatography, the patient exhibited smooth progress without issue. Pancreaticoduodenectomy was performed on the fourth day after the nasobiliary drainage tube placement, and the patient's postoperative course was uneventful. The proximal end of a biliary stent penetrating the duodenal wall is an infrequent phenomenon. This case report highlights a rare but noteworthy adverse event associated with straight biliary plastic stent placement.

Lumen-apposing metal stents versus traditional self-expanding metal stents for endoscopic ultrasound-guided drainage of pancreatic fluid collections: a systematic review and meta-analysis

BACKGROUND

Endoscopic drainage has become the preferred treatment for pancreatic fluid collections (PFCs). There is still a lack of reliable evidence to prove which metal stent is the best choice for endoscopic ultrasound (EUS)-guided drainage of PFCs. In this study, we aimed to evaluate the efficacy and safety of lumen-apposing metal stents (LAMS) compared to traditional self-expanding metal stents (SEMS) in meta-analysis.

METHODS

We systematically searched PubMed, Embase, Web of Science, and Cochrane Library up to July 15, 2023. Relevant publications that compared LAMS with traditional SEMS for drainage of patients' PFCs under EUS-guidance were included. This meta-analysis assessed endpoints using Review Manager 5.3 and Stata 14.0 statistical software.

RESULT

Nine citations comprising 707 patients with PFCs were included. The clinical success rate of LAMS tended to be higher than that of SEMS (RR = 1.07, 95%CI [1.00, 1.15], P = 0.05). LAMS had a lower technical success rate (RR = 0.97, 95%CI [0.94, 0.99], P = 0.02) and faster procedure time (minutes) (MD =  - 24.29, 95%CI [- 25.59, - 22.99], P < 0.00001) compared to SEMS. In addition, LAMS had fewer overall adverse events (RR = 0.64, 95%CI [0.48, 0.87], P = 0.004). For specific adverse events, LAMS had fewer migration (RR = 0.37, 95%CI [0.19, 0.72], P = 0.003), occlusion (RR = 0.43, 95%CI [0.22, 0.82], P = 0.01) and infection (RR = 0.38, 95%CI [0.20, 0.70], P = 0.002). There was no significant difference in bleeding and perforation between the two stents. For hospital stay (days), LAMS group was similar to SEMS group (MD =  - 3.34, 95%CI [- 7.71, - 1.03], P = 0.13). Regarding recurrence, LAMS group was fewer than SEMS group (RR = 0.41, 95%CI [0.21, 0.78], P = 0.007).

CONCLUSION

Compared to traditional SEMS, LAMS has a higher clinical success rate, faster procedure time, fewer adverse events, similar hospital stay and lower recurrence rate in EUS-guided drainage of PFCs. LAMS is a good choice with a high technical success rate over 95%, and using a shorter length or "one-step" operation can further improve it. Richer placement experience is required for LAMS placement under EUS-guidance.

Endoscopic retrograde cholangiopancreatography utilisation and outcomes in the first advanced endoscopy centre in Palestine at Al-Ahli Hospital: a retrospective cohort study

OBJECTIVE

To evaluate the utilisation and outcomes of endoscopic retrograde cholangiopancreatography (ERCP) procedures, success rates, incidence and risk factors for procedural-related complications in a single centre-based study.

STUDY DESIGN

Retrospective cohort study.

SETTING

First advanced tertiary endoscopy centre in Palestine.

PARTICIPANTS

A total of 1909 procedures on 1303 patients were included in the analysis: females were 57.9% of the cases (n=755), 1225 patients (94%) were from West Bank and Jerusalem and 78 (6%) were from Gaza Strip. All patients who underwent ERCP throughout the period from December 2017 to September 2022 were selected to participate in the study.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcomes of interest in our analysis were success rates, procedural outcomes and post- procedural complications including pancreatitis, bleeding and others. Two multivariate logistic regression models were performed to calculate the risk of post-ERCP complications and post-ERCP pancreatitis (PEP) in patients with certain risk factors like demographic factors, procedural techniques' variation, pancreatic duct manipulations and others. We also discussed the management of the failed procedures.

RESULTS

The overall complication rate was 5%, including PEP (n=43, 2.3%), infection/cholangitis (n=20, 1%), bleeding (n=9, 0.5%) and perforation (n=7, 0.4%). The mortality rate was 0.6% (n=11). Risk factors for adverse events included pancreatic duct cannulation and PEP (p<0.001, OR=3.64). Additionally, younger patients (≤45) were found to carry a higher risk for PEP when compared with older patients (≥65) (p=0.023, OR=2.84). In comparison with sphincterotomy, the double-wire technique was associated with a higher risk of complications (p=0.033, OR=2.29).

CONCLUSIONS

We summarised the utilisation and outcomes of ERCP among the Palestinian population in the first advanced centre in Palestine. Cannulation success rates are similar to the established standards and are acceptable compared with other centres worldwide. Perioperative complication rates of ERCP remain infrequent, and death is quite unusual and thus considered a safe procedure.

A retrospective analysis of the clinical efficacy of pancreatic duct stent implantation in the management of acute biliary pancreatitis requiring ERCP

BACKGROUND

This study aimed to investigate the feasibility, effectiveness, and safety of pancreatic duct stenting in managing acute biliary pancreatitis (ABP) necessitating endoscopic retrograde cholangiopancreatography (ERCP). It further aimed to provide valuable insights for subsequent clinical diagnosis and treatment.

METHODS

This research employs an observational retrospective case-control study design, encompassing patients with ABP who underwent ERCP at the hepatobiliary surgery department of the General Hospital of Ningxia Medical University between August 1, 2018, and December 31, 2020. A total of 229 cases were screened based on inclusion and exclusion criteria. Regardless of ABP severity, patients were categorized into the stent group (141) and the non-stent group (88). Changes in blood amylase (Amy), lipase (LIP), leukocyte count (WBC), total bilirubin (TBIL), alanine aminotransferase (ALT), hematocrit (HCT), and creatinine (CR) were compared between the two groups. Moreover, variables such as recovery time for oral feeding, hospitalization duration, hospitalization costs, local complications, systemic complications, and new organ failure were recorded to assess the therapeutic effect of pancreatic duct stenting.

RESULTS

No significant differences were observed in gender, age, Acute Physiology and Chronic Health Evaluation (APACHE) II score, ABP severity grade, organ failure (OF), cholangitis, or biliary obstruction between the pancreatic stent and non-stent groups (P > 0.05). There was no significant difference in the incidence of complications related to acute pancreatitis between the two groups (P > 0.05). The median fasting and hospitalization times of patients in the stent group were significantly shorter than those in the non-stent group (P < 0.05). No significant differences between the groups were observed in hospitalization costs and in-hospital mortality (P > 0.05). There were no significant variations in white blood cell (WBC) count, TBIL, ALT, and creatinine (Cr) at admission, 72 h, and in the differences between the two groups (P > 0.05). The levels of Amy at admission and 72 h in the stent group were significantly higher than those in the non-stent group (P < 0.05). The differences in LIP and HCT in the stent group were considerably higher than in the non-stent group (P < 0.05). Although no significant differences were observed in mean Amy and LIP between the two groups (P > 0.05), the mean 72-h HCT in the stent group was 38.39% (95% confidence interval [CI] 37.82%-38.96%) was lower than that in the non-stent group (39.44%, 95% CI 38.70-40.17%) (P < 0.05).

CONCLUSION

In the stent group, feeding time and hospital stay were significantly shorter than those in the non-stent group. No significant differences were observed between the two groups in the incidence of complications and mortality. The HCT value decreased more rapidly in the stent group. Early pancreatic stent implantation demonstrated the potential to shorten the eating and hospitalization duration of patients with ABP, facilitating their prompt recovery.

TRIAL REGISTRATION

This study was registered as a single-center, retrospective case series (ChiCTR1800019734) at chictr.org.cn.

Factors associated with patency of self-expandable metal stents in malignant biliary obstruction

INTRODUCTION

Endoscopic self-expandable metal stent (SEMS) placement is the key endoscopic treatment for unresectable malignant biliary obstruction. The benefit of covered SEMS over uncovered SEMS remains unknown as are risk factors for SEMS dysfunction. This study aimed to determine the factors associated with patency of SEMS.

METHODS

Patients with unresectable malignant biliary obstruction who underwent endoscopic SEMS placement at Ramathibodi Hospital, during January 2012 to March 2021 were included. Patient characteristics, clinical outcomes and patency of SEMS were collected. The primary outcome were stent patency and factors associated with patency of SEMS. The factors were analyzed by univariate and multivariate analyses. Median days of stent patency, median time of patient survival, rate of reintervention and complications after SEMS placement were collected.

RESULTS

One hundred and fourteen patients were included. SEMS dysfunction was found in 37 patients (32.5%). Size of cancer (Hazard ratio (HR), 1.20, (95% CI 1.02, 1.40), p 0.025), presence of stones or sludge during SEMS placement (Hazard ratio (HR), 3.91, (95% CI 1.74, 8.75), p 0.001), length of SEMS, 8 cm (HR 2.96, (95% CI 1.06, 8.3), p 0.039), and total bilirubin level above 2 mg/dL at one month after SEMS placement (HR 1.14, (95% CI 1.06, 1.22), p < 0.001) were associated with SEMS dysfunction. The median stent patency was 97 days. The median patient survival was 133 days, (95% CI 75-165). The rate of reintervention was 86% in patients with SEMS dysfunction.

CONCLUSION

The size of cancer, presence of stones or sludge during SEMS placement, the length of SEMS, and total bilirubin level above 2 mg/dL at 1 month after SEMS placement were associated with SEMS dysfunction. The median time of stent patency were not statistically different in each type of stent, covered stent, partially covered stent and uncovered stent. Median survival time of patients did not associate with SEMS patency or dysfunction.

Research on the Current Application Status of Magnesium Metal Stents in Human Luminal Cavities

The human body comprises various tubular structures that have essential functions in different bodily systems. These structures are responsible for transporting food, liquids, waste, and other substances throughout the body. However, factors such as inflammation, tumors, stones, infections, or the accumulation of substances can lead to the narrowing or blockage of these tubular structures, which can impair the normal function of the corresponding organs or tissues. To address luminal obstructions, stenting is a commonly used treatment. However, to minimize complications associated with the long-term implantation of permanent stents, there is an increasing demand for biodegradable stents (BDS). Magnesium (Mg) metal is an exceptional choice for creating BDS due to its degradability, good mechanical properties, and biocompatibility. Currently, the Magmaris® coronary stents and UNITY-BTM biliary stent have obtained Conformité Européene (CE) certification. Moreover, there are several other types of stents undergoing research and development as well as clinical trials. In this review, we discuss the required degradation cycle and the specific properties (anti-inflammatory effect, antibacterial effect, etc.) of BDS in different lumen areas based on the biocompatibility and degradability of currently available magnesium-based scaffolds. We also offer potential insights into the future development of BDS.

A clinician's guide to gallstones and common bile duct (CBD): A study protocol for a systematic review and evidence-based recommendations

Background and Aims

Gallstones are one of the most common and costly diseases of the gastrointestinal tract and occur when a combination of deposits consisting of fat or minerals accumulate in the gallbladder or common bile duct (CBD). This paper provides a comprehensive review of gallstone epidemiology, diagnosis, and management, focusing on current clinical guidelines and evidence-based approaches.

Methods

A systematic literature review gathered information from various sources, including PubMed, Trip, Google Scholar, Clinical Key, and reputable medical association websites. Keywords related to gallstones, CBD stones, cholelithiasis, choledocholithiasis, and guidelines were used to extract relevant recommendations. Expert consultations and consensus meetings localized the recommendations based on the target population and available resources.

Results

The paper discusses demographic factors, dietary habits, and lifestyle influences contributing to gallstone formation. Gallstones are categorized into cholesterol and pigment types, with varying prevalences across regions. Many individuals with gallstones remain asymptomatic, but complications can lead to serious and potentially life-threatening conditions. Diagnosis relies on history, physical examination, laboratory tests, and transabdominal ultrasound. Specific predictive factors help categorize patients into high, moderate, or low probability groups for CBD stones.

Conclusion

Evidence-based recommendations for gallstone diagnosis and management are presented, emphasizing individualized treatment plans. Surgical interventions, nonsurgical treatments like oral litholysis with UDCA, and stenting are discussed. The management of gallstones in pregnant women is also addressed, considering the potential risks and appropriate treatment options during pregnancy.

Use of lumen-apposing metal stents in treating gastrojejunal anastomotic strictures in bariatric patients

BACKGROUND

Gastrojejunal strictures (GJS) are rare but significant adverse events following Roux-en-Y Gastric Bypass, with limited options for effective non-operative interventions. Lumen-apposing metal stents (LAMS) represent a new therapy for treatment of intestinal strictures, but the effectiveness in treating GJS is unknown. This study aims to evaluate the safety and effectiveness of LAMS in GJS.

METHODS

This is a prospective, observational study of patients with prior Roux-en-Y Gastric bypass who underwent LAMS placement for GJS. The primary outcome of interest is resolution of GJS following LAMS removal defined by toleration of bariatric diet after LAMS removal. Secondary outcomes include need for additional procedures, LAMS-related adverse events, and need for revisional surgery.

RESULTS

Twenty patients were enrolled. The cohort was 85% female with median age of 43. 65% had marginal ulcers associated with the GJS. Presenting symptoms included nausea and vomiting (50% of patients), dysphagia (50%), epigastric pain (20%), and failure to thrive (10%). Diameter of LAMS placed were 15 mm in 15 patients, 20 mm in 3 patients, and 10 mm in 2 patients. LAMS were placed for a median of 58 days (IQR 56-70). Twelve patients (60%) achieved resolution of GJS after LAMS removal. Of the eight patients without GJS resolution or with recurrence, seven (35%) required repeat placement of LAMS. One patient was lost to follow up. One perforation and two migrations occurred. Four patients required revisional surgery after LAMS removal.

CONCLUSION

LAMS placement is well-tolerated and effective with most patients achieving short-term symptom resolution and with few reported complications. While stricture resolution occurred in over half the patients, nearly 1/4th of patients required revisional surgery. More data is needed to predict who would benefit from LAMS versus surgical intervention.

Endoscopic luminal stenting: Current applications and future perspectives

Endoscopic luminal stenting (ELS) represents a minimally invasive option for the management of malignant obstruction along the gastrointestinal tract. Previous studies have shown that ELS can provide rapid relief of symptoms related to esophageal, gastric, small intestinal, colorectal, biliary, and pancreatic neoplastic strictures without compromising cancer patients’ overall safety. As a result, in both palliative and neoadjuvant settings, ELS has largely surpassed radiotherapy and surgery as a first-line treatment modality. Following the abovementioned success, the indications for ELS have gradually expanded. To date, ELS is widely used in clinical practice by well-trained endoscopists in managing a wide variety of diseases and complications, such as relieving non-neoplastic obstructions, sealing iatrogenic and non-iatrogenic perforations, closing fistulae and treating post-sphincterotomy bleeding. The abovementioned development would not have been achieved without corresponding advances and innovations in stent technology. However, the technological landscape changes rapidly, making clinicians’ adaptation to new technologies a real challenge. In our mini-review article, by systematically reviewing the relevant literature, we discuss current developments in ELS with regard to stent design, accessories, techniques, and applications, expanding the research basis that was set by previous studies and highlighting areas that need to be further investigated.

Development of devices for interventional endoscopic ultrasound for the management of pancreatobiliary diseases

A variety of devices have been developed for interventional endoscopic ultrasound (EUS). EUS-guided drainage of the bile duct and pancreatic duct, as well as fluid collection adjacent to the gastrointestinal tract, is performed by a procedure involving puncture, guidewire manipulation, tract dilation, and stent placement. Devices specialized for interventional EUS are being developed for each step of the procedure. Mechanical dilators such as bougie, balloon, and electrocautery dilators are used for tract dilation. Various types of plastic stents, self-expandable metal stents, and lumen-apposing metal stents specifically designed for interventional EUS are now available, including one-step devices developed to improve the efficacy and safety of interventional EUS. In addition, radiofrequency ablation and the placement of fiducial markers and radioactive seeds under EUS guidance are now becoming established for pancreatic neoplasms. Such development of specialized devices has expanded the indications for interventional EUS, increased the success rate, and lowered the adverse event rate.

Distal Biliary Stent Migration in Patients with Irretrievable Bile Duct Stones: Long-Term Comparison Between Straight and Double-Pigtail Stents

BACKGROUND

Prolonged biliary stenting may be considered in high-risk patients with irretrievable bile duct stones (IBDS). Distal stent migration (DSM) is a known complication, although data beyond the recommended interval of temporary stenting (3-6 months) are lacking. We compared the long-term incidence of DSM between straight and double-pigtail stents in patients with IBDS.

METHODS

Consecutive patients with IBDS undergoing plastic biliary stenting (1/2009-12/2019) were retrospectively reviewed. DSM was confirmed on follow-up examination when the stent was no longer present at the papillary orifice nor fluoroscopically visible in the bile duct. Kaplan-Meier and Cox regression analyses were used to determine estimates and predictors of DSM.

RESULTS

Overall, 618 biliary stenting procedures (410 patients) were included: 289 with a straight stent (group A) and 329 with a double-pigtail (group B). By Kaplan-Meier analysis, the DSM rates were 8.4 and 14.6% at 6 months, 21.4 and 27.7% at 12 months, 27 and 43.5% at 18 months, and 37.2 and 60.4% at 24 months, for groups A and B, respectively (p = 0.004). Double-pigtail stents were at higher risk for DSM (HR = 7.38, p = 0.04), whereas an inverse correlation was noted with age (HR = 0.97, p = 0.0001). Considering only temporary stenting procedures (≤ 6 months; n = 297), the probability of DSM was not significantly different between the two groups (p = 0.07).

CONCLUSIONS

In a setting of prolonged stenting for IBDS, the probability of DSM appears to be higher when a double-pigtail stent is used and in younger patients. A relative anti-migratory advantage of double-pigtail over straight stents appears negligible in this study.

Endoscopic Ultrasound-Guided Biliary Interventions

Endoscopic ultrasound (EUS)-guided biliary interventions have evolved to become an integral part of advanced gastrointestinal endoscopy units. EUS-guided biliary drainage is an accepted alternative for patients with failed ERCP or altered surgical anatomy. The potential advantages of EUS-guided interventions include choice of biliary access from stomach or duodenum, choice of stent exit in stomach and duodenum, and possibility of avoiding traversing through the obstruction. A variety of procedures have been described depending on the level of obstruction. Maximum evidence is available for distal malignant obstruction, and more studies are needed for hilar obstruction and benign indications.

Characterization and preliminary in vivo evaluation of a self-expandable hydrogel stent with anisotropic swelling behavior and endoscopic deliverability for use in biliary drainage

We demonstrate the potential of a novel self-expandable biliary stent comprised of poly(vinyl alcohol) (PVA) hydrogel with anisotropic swelling behavior and endoscopic deliverability in vivo, using a porcine stent model. The mechanism underlying the anisotropic swelling behavior and endoscopic deliverability (i.e., flexibility) was investigated by scanning electron microscopy (SEM), small-angle X-ray scattering (SAXS), evaluation of the water content and swelling ratio, and three-point bending tests. The in vivo experiment using a porcine stent model indicated that the tube-shaped PVA hydrogel could effectively expand the biliary tract, without disturbing bile flow. SEM and SAXS showed that PVA hydrogels prepared by drying under extension showed structural orientation along the extension axis, leading to anisotropic swelling. The water content of the PVA hydrogel was found to be crucial for maintaining flexibility as well as endoscopic deliverability. In conclusion, this study demonstrated the novel concept of using a hydrogel stent as a self-expandable biliary stent.

Endoscopic Ultrasonography-Specific Stents

The evolution of the endoscopic ultrasonography (EUS) technique has necessitated the development of EUS-specific accessories and stents. In the earlier period, EUS-guided interventions mostly relied on borrowed accessories and stents from therapeutic endoscopy in particular ERCP. Traditional stents do not serve the purpose of EUS-guided transluminal stenting in all cases due to the length of the stent, no anchoring mechanism, and chance of migration. From 2011 onward, several EUS-specific stents became available, bringing a paradigm shift in interventional EUS. This article reviews current EUS-specific stents, indications, strengths, and weaknesses.

A Computational Framework Examining the Mechanical Behaviour of Bare and Polymer-Covered Self-Expanding Laser-Cut Stents

PURPOSE

Polymer covered stents have demonstrated promising clinical outcomes with improved patency rates compared to traditional bare-metal stents. However, little is known on the mechanical implication of stent covering. This study aims to provide insight into the role of a polymeric cover on the biomechanical performance of self-expanding laser-cut stents through a combined experimental-computational approach.

METHODS

Experimental bench top tests were conducted on bare and covered versions of a commercial stent to evaluate the radial, axial and bending response. In parallel, a computational framework with a novel covering strategy was developed that accurately predicts stent mechanical performance. Different stent geometries and polymer materials were also considered to further improve understanding on covered stent mechanics.

RESULTS

Results show that stent covering causes increased initial axial stiffness and up to 60% greater radial resistive force at small crimp diameters as the cover folds and self-contacts. The incorporation of a cover allows stent designs without interconnecting struts, thereby providing improved flexibility without compromising radial force. It was also shown that use of a stiffer PET polymeric covering material caused significant alterations to the radial and axial response, with the initial axial stiffness increasing six-fold and the maximum radial resistive force increasing four-fold compared to a PTFE-PU covered stent.

CONCLUSION

This study demonstrates that stent covering has a substantial effect on the overall stent mechanical performance and highlights the importance of considering the mechanical properties of the combined cover and stent.

Fully covered metal biliary stents: A review of the literature

Fully covered self-expandable metal stents (FCSEMS) represent the latest advancement of metal biliary stents used to endoscopically treat a variety of obstructive biliary pathology. A large stent diameter and synthetic covering over the tubular mesh prolong stent patency and reduce risk for tissue hyperplasia and tumor ingrowth. Additionally, FCSEMS can be easily removed. All these features address issues faced by plastic and uncovered metal stents. The purpose of this paper is to comprehensively review the application of FCSEMS in benign and malignant biliary strictures, biliary leak, and post-sphincterotomy bleeding.

Biliary stent migration: why, how, and what?

BACKGROUND AND PURPOSE

The frequency, risk factors as well as the sites of biliary stent migration are variable in the literature. This retrospective study investigated the frequency of biliary stent migration, why biliary stents migrated, how the migrated stents affected the patients, and what are the different techniques retrieved the migrated stents.

PATIENTS AND METHODS

Out of 876 stented patients, 74 patients (8.4%) had their stents migrated. Patients with and without migrated stents were compared regarding endoscopy and stent-related parameters. The sequels of stent migrations were reported. Furthermore, the methods used for stent retrieval were reviewed.

RESULTS

Proximal and distal stent migration occurred at a rate of 3 and 5.5%, respectively. The independent predictors for stent migration were moderate to marked common bile duct (CBD) dilation, complete sphincterotomy, the use of balloon dilation, and stent insertion for more than 1 month. Cholangitis and stent obstruction was the most commonly reported adverse event (n = 18, 24.3%). Distal stent migration associated with two cases of bleeding due to duodenal wall injury, and two cases of duodenal perforation. All the retained migrated stents in the current study were retrieved by endoscopy using extraction balloon, Dormia basket, snares, and foreign body forceps.

CONCLUSION

Biliary stent migration occurs at a rate of 8.4%. Stents do migrate because of dilated CBD, wide sphincterotomy, and biliary balloon dilation. Furthermore, wide, straight stents inserted for more than 1 month easily migrate. The migrated stents migrated intraluminal in the CBD, duodenum or the colon. All the retained migrated stents were retrieved endoscopically.

A finite element investigation on design parameters of bare and polymer-covered self-expanding wire braided stents

Self-expanding covered braided stents are routinely used across a diverse range of clinical applications, but few computational studies have attempted to replicate their complex behaviour. In this study, a computational framework was developed to predict the functional performance of bare and covered self-expanding wire braided stents, with a systematic evaluation on the effect of various braid and cover parameters presented. Simulated radial force and kink deformation tests show good agreement to experimental data for covered braided stents across a range of braid angles and cover thicknesses. Our results demonstrate that braid angle is a key governing parameter that dictates the radial and kink performance of both bare-metal and covered wire braided stents. It was also demonstrated that addition of a polymeric cover to a wire braided stent causes a stiffer radial response across all braid angles, particularly when thicker and/or stiffer covering systems were considered. This study represents the first experimentally-validated computational model for covered wire braided stent systems and has excellent potential to be used in future design of these devices for a range of applications.

Interventional Endoscopic Ultrasound: Current Status and Future Directions

The evolution of endoscopic ultrasound (EUS) from a diagnostic to a therapeutic procedure has resulted in a paradigm shift toward endoscopic management of disease states that previously required percutaneous or surgical approaches. The past few years have seen additional techniques and devices that have enabled endoscopists to expand its diagnostic and therapeutic capabilities. Some of these techniques initially were reported more than a decade ago; however, with further device development and refinement in techniques there is potential for expanding the application of these techniques and new technologies to a broader group of interventional gastroenterologists. Lack of formalized training, devices, and prospective data regarding their use in addition to a scarcity of guidelines on implementation of these technologies into clinical practice are contributing factors impeding the growth of the field of interventional EUS. In April 2019, the American Gastroenterological Association's Center for Gastrointestinal Innovation and Technology conducted its annual Tech Summit and a key session focused on interventional EUS. This article is a White Paper generated from the conference, discusses the published literature pertaining to the topic of interventional EUS, and outlines a proposed framework for the implementation of interventional EUS techniques into clinical practice. Three primary areas of interventional EUS are addressed: (1) EUS-guided access; (2) EUS-guided tumor ablation; and (3) endohepatology. There was general agreement among participants on several key components. The introduction of these novel interventions requires better tools, more data on safety/outcomes, and improved training for endoscopists. Participants also agreed that widespread implementation and use of these techniques will require support from Gastrointestinal Societies and other key stakeholders including payers. Continued work by the Gastrointestinal Societies and manufacturers to provide training programs, appropriate equipment/work environments, and policies that motivate endoscopists to adopt new techniques is essential for growing the field of interventional EUS.

Outcomes of a single-step endoscopic ultrasound-guided drainage of pancreatic-fluid collections using an electrocautery-enhanced coaxial lumen-apposing, self-expanding metal stent with and without fluoroscopy

Background

Fluoroscopy is often used during the endoscopic drainage of pancreatic-fluid collections (PFCs). An electrocautery-enhanced coaxial lumen-apposing, self-expanding metal stent (ELAMS) facilitates a single-step procedure and may avoid the need for fluoroscopy. This study compares the treatment outcomes using ELAMS with and without fluoroscopy.

Methods

Patients with PFCs who had cystogastrostomy from January 2014 to February 2017 were enrolled. Two groups were studied based on fluoroscopy use. Technical success was defined as uneventful insertion of ELAMS at time of procedure. Clinical success was defined as (i) clinical resolution of symptoms after the procedure and (ii) >75% reduction in cyst size on computed tomography 8 weeks after stent placement. Adverse events including bleeding, stent migration, and infection were recorded.

Results

A total of 21 patients (13 males) had PFCs drainage with ELAMS in the study period. The mean age was 51.6 ± 14.2 years. Thirteen patients had walled-off necrosis while eight had a pancreatic pseudocyst. The mean size of the PFCs was 11.3 ± 3.3 cm. Fluoroscopy was used in seven cases (33%) and was associated with a longer procedure time compared to non-fluoroscopy (43.1 ± 10.4 vs 33.3 ± 10.5 min, P = 0.025). This association was independent of the size, location, or type of PFCs. Fluoroscopy had no effect on the technical success rates. In fluoroless procedures, the clinical resolution was 91% as compared to 71% in fluoroscopy procedures (P = 0.52) and the radiologic resolution was 57% as compared to 71% in fluoroscopy procedures (P = 0. 65). Three cases of stent migration/displacement occurred in the fluoroless procedures.

Conclusions

ELAMS may avoid the need for fluoroscopy during cystogastrostomy. Procedures without fluoroscopy were significantly shorter and fluoroscopy use had no impact on the technical or clinical success rates.

Advances in Interventional Endoscopic Ultrasound (EUS): A Technical Review

Endoscopic ultrasound (EUS) has become the therapeutic intervention of choice for multiple diseases and continues to evolve rapidly. Its increasing use has allowed the development and adaptation of multiple, revolutionary devices and tools. Currently, there is paucity of randomized clinical trials evaluating multiple EUS-guided interventions and the vast majority of published data is heterogenous. However, the available literature on EUS-guided therapeutic interventions continues to expand and demonstrate its safety, efficacy and cost effectiveness in carefully selected patients when performed by expert endosonographers. The future of interventional EUS appears to be bright!

Endoscopic intervention in pancreatitis: perspectives from a gastroenterologist

The last decade has seen a dramatic paradigm shift for the treatment of pancreatitis and its related complications away from surgery to minimally invasive endoscopic approaches. In this review, we provide an overview of the indications, techniques and outcomes of endoscopic interventions in the management of acute and chronic pancreatitis. Emphasis is placed on drainage of pancreatic pseudocysts and treatment of pain in chronic pancreatitis.

Biomaterials in Gastroenterology: A Critical Overview

In spite of the large diversity of diagnostic and interventional devices associated with gastrointestinal endoscopic procedures, there is little information on the impact of the biomaterials (metals, polymers) contained in these devices upon body tissues and, indirectly, upon the treatment outcomes. Other biomaterials for gastroenterology, such as adhesives and certain hemostatic agents, have been investigated to a greater extent, but the information is fragmentary. Much of this situation is due to the paucity of details disclosed by the manufacturers of the devices. Moreover, for most of the applications in the gastrointestinal (GI) tract, there are no studies available on the biocompatibility of the device materials when in intimate contact with mucosae and other components of the GI tract. We have summarized the current situation with a focus on aspects of biomaterials and biocompatibility related to the device materials and other agents, with an emphasis on the GI endoscopic procedures. Procedures and devices used for the control of bleeding, for polypectomy, in bariatrics, and for stenting are discussed, particularly dwelling upon the biomaterial-related features of each application. There are indications that research is progressing steadily in this field, and the establishment of the subdiscipline of "gastroenterologic biomaterials" is not merely a remote projection. Upon the completion of this article, the gastroenterologist should be able to understand the nature of biomaterials and to achieve a suitable and beneficial perception of their significance in gastroenterology. Likewise, the biomaterialist should become aware of the specific tasks that the biomaterials must fulfil when placed within the GI tract, and regard such applications as both a challenge and an incentive for progressing the research in this field.

Influence of Electrical Field Collector Positioning and Motion Scheme on Electrospun Bifurcated Vascular Graft Membranes

Currently, electrospinning membranes for vascular graft applications has been limited, due to random fiber alignment, to use in mandrel-spun, straight tubular shapes. However, straight, circular tubes with constant diameters are rare in the body. This study presents a method to fabricate curved, non-circular, and bifurcated vascular grafts based on electrospinning. In order to create a system capable of electrospinning membranes to meet specific patient needs, this study focused on characterizing the influence of fiber source, electrical field collector position (inside vs. outside the mandrel), and the motion scheme of the mandrel (rotation vs. rotation and tilting) on the vascular graft membrane morphology and mechanical properties. Given the extensive use of poly(ε-caprolactone) (PCL) in tubular vascular graft membranes, the same material was used here to facilitate a comparison. Our results showed that the best morphology was obtained using orthogonal sources and collector positioning, and a well-timed rotation and tilting motion scheme. In terms of mechanical properties, our bifurcated vascular graft membranes showed burst pressure comparable to that of tubular vascular graft membranes previously reported, with values up to 5126 mmHg. However, the suture retention strength shown by the bifurcated vascular graft membranes was less than desired, not clinically viable values. Process improvements are being contemplated to introduce these devices into the clinical range.

Primary Clinical Application of Y-Shaped Jogged Stent Implantation in Patients with Malignant Hilar Biliary Obstruction

OBJECTIVE

To assess the feasibility, safety, and efficacy of Y-shaped jogged stent in patients with malignant hilar biliary obstruction.

METHODS

A total of 196 patients with malignant hilar biliary obstruction treated by biliary tract stent implantation from August 2010 to August 2017 were retrospectively reviewed. Seventeen consecutive patients who were treated with Y-shaped jogged stent implantation were identified as the Y-shaped jogged stent implantation group. Seventeen matched patients undergoing unilateral stent placement combined with percutaneous transhepatic cholangial drainage (PTCD) were enrolled as the control group. Baseline characteristics of patients, stent patency time, and survival time were compared.

RESULTS

There was no significant difference in the age, gender, tumor type and stage, biliary obstruction classification, bilirubin level at diagnosis, presence of metastasis, or chemotherapy between the Y-stent group and the control group (P > 0.05). One week after surgery, the reduction rate of bilirubin was significantly higher in the Y-stent group (88.2% vs 53.0%, P < 0.05). The mean stent patency time was longer in the Y-stent group (7.3 ± 1.0 months vs 5.7 ± 0.9 months, P < 0.05). The mean survival time of the Y-stent group (9.1 ± 1.5 months) was longer than the control group (7.2 ± 1.1 months, P > 0.05). There was no severe complication occurred in both two groups.

CONCLUSION

Y-shaped jogged stent implantation was a safe, feasible, and effective approach in the treatment of patients with malignant hilar biliary obstruction, with the significantly prolonged stent patency time and survival time.

Success and safety of endoscopic treatments for concomitant biliary and duodenal malignant stenosis: A review of the literature

Synchronous biliary and duodenal malignant obstruction is a challenging endoscopic scenario in patients affected with ampullary, peri-ampullary, and pancreatic head neoplasia. Surgical bypass is no longer the gold-standard therapy for these patients, as simultaneous endoscopic biliary and duodenal stenting is currently a feasible and widely used technique, with a high technical success in expert hands. In recent years, endoscopic ultrasonography (EUS) has evolved from a diagnostic to a therapeutic procedure, and is now increasingly used to guide biliary drainage, especially in cases of failed endoscopic retrograde cholangiopancreatography (ERCP). The advent of lumen-apposing metal stents (LAMS) has expanded EUS therapeutic options, and changed the management of synchronous bilioduodenal stenosis. The most recent literature regarding endoscopic treatments for synchronous biliary and duodenal malignant stenosis has been reviewed to determine the best endoscopic approach, also considering the advent of an interventional EUS approach using LAMS.

Advanced endoscopic interventions on the pancreas and pancreatic ductal system: a primer for radiologists

In recent years, technological advancements including endoscopic ultrasound (EUS) guidance and availability of specifically designed stents further expanded the indications and possibilities of interventional endoscopy. Although technically demanding and associated with non-negligible morbidity, advanced pancreatic endoscopic techniques now provide an effective minimally invasive treatment for complications of acute and chronic pancreatitis.

Aiming to provide radiologists with an adequate familiarity, this pictorial essay reviews the indications, techniques, results and pre- and post-procedural cross-sectional imaging appearances of advanced endoscopic interventions on the pancreas and pancreatic ductal system. Most of the emphasis is placed on multidetector CT and MRI findings before and after internal drainage of pseudocysts and walled-off necrosis via EUS-guided endoscopic cystostomy, and on stent placement to relieve strictures or disruption of the main pancreatic duct, respectively in patients with chronic pancreatitis and disconnected pancreatic duct syndrome.

Endoscopic biliary self-expandable metallic stent in malignant biliary obstruction with or without sphincterotomy: systematic review and meta-analysis

Background and aim  To assess the rate of adverse events and the technical success rate of biliary stenting with or without EBS.  Methods  A literature search up to February 2017 was performed. Studies assessing adverse events (AEs) and technical success rates of stenting with or without EBS were considered. Results  Seven studies (870 patients; 12 treatment arms) were included. Early AEs, i. e. those occurring within 30 days, were significantly lower in no-EBS vs. EBS-group (11 % vs . 20.1 %; OR: 0.36, 95 %CI: 0.13 - 1.00). Rates of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis were not significantly different in the two groups (no-EBS vs . EBS: 6.1 % vs 5 %; OR: 1.33, 95 %CI: 0.68 - 2.59). The rate of bleeding was significantly lower in patients without EBS (no-EBS vs EBS: 0 % vs 5 %; OR: 0.12, 95 % CI: 0.03 - 0.45). Rates of cholangitis were significantly lower in patients without EBS (no-EBS vs . EBS: 3.3 % vs. 7.4 %; OR: 0.38, 95 %CI: 0.17 - 0.83). Both late AEs and mortality rates did not significantly differ between no-EBS and EBS patients (19.9 % vs. 18.9 %; OR: 0.93, 95 %CI: 0.56 - 1.53, and 2.5 % vs. 2.9 %; OR: 1.18, 95 %CI: 0.22 - 6.29, respectively). The technical success rate for stent insertion also did not differ (98 % vs. 97.6 %; OR: 1.05, 95 %CI: 0.42 - 2.63). Conclusion  EBS seems to be associated, in the first 30 days after the procedure, with an increased risk of cholangitis and bleeding. No difference was observed in the rate of post-ERCP pancreatitis.

Single brand, fully-covered, self-expandable metal stent for the treatment of benign biliary disease: when should stents be removed?

The two most relevant endoscopic treatable benign biliary diseases (BBD) are benign biliary strictures (BBSs) and biliary leaks (BLs), often associated with high morbidity. The most common endoscopic treatment for biliary strictures involves placement of multiple plastic stents (PSs), with or without balloon dilation, followed by planned exchange of the stents. Thus, there continues to be high interest in pursuing alternative endoscopic approaches that may achieve better results with fewer interventions. In this setting, the use of a fully-covered, self-expandable metal stent (FCSEMS) is an attractive alternative to single or multiple PSs for the treatment of BBDs. A single metal stent can remain in place for a longer period of time before removal; however, the maximum time the stent can be remain in place is still not well defined. The aim of this review is to determine the removal time of the TaeWoong® FCSEMS, placed for BBD. According to our data analysis, considering the absence of loss of the covering of the FCSEMS and of any adverse events during and after stent removal, leaving the TaeWoong medical FCSEMS in situ for an 8 months' period seems to be acceptable for benign biliary diseases. Further studies need to evaluate their removability at 1 year.

Lumen-Apposing Metal Stents: Which One and Why?

Numerous lumen-apposing metal stents (LAMS) have been designed for transluminal applications, including complex pancreatic fluid collections (PFCs) and difficult biliary access. Limited high-quality data exist directly comparing the various LAMS models, and their use remains largely dependent on availability and operator expertise. LAMS placement has been streamlined by the addition of electrocautery, allowing for single-step or modified "hot" approach, if desired. Therapeutic endoscopists continue to explore the application of this technology in a variety of clinical scenarios, and future innovations will be needed to meet these evolving clinical demands.

Interventional radiology-operated endoscopy-assisted retrograde transnasal placement of a retrievable transhepatic covered biliary stent

Biliary stent placement is an adjunct for complex biliary intervention. Patients with benign biliary strictures or aversion to external drainage may benefit from placement of retrievable biliary stents. This report describes a patient with a working diagnosis of benign biliary stricture who underwent interventional radiology-operated endoscopy-guided transnasal placement of a fully covered retrievable biliary stent.

Metal stents placement for refractory pancreatic duct stricture in children

AIM

To evaluate the use of fully covered self-expandable metal stents (FCSEMSs) for pancreatic duct strictures in children with chronic pancreatitis.

METHODS

Eight patients with refractory benign dominant stricture of the main pancreatic duct (MPD) were enrolled through chart reviews between December 2014 and June 2017 in a single center. Endoscopic retrograde cholangiopancreatography (ERCP) with placement of a 6-mm FCSEMS with dual flaps was performed. Endoscopic removal of FCSEMSs was performed with a snare or rat-tooth forceps. All procedures were performed by a pediatric gastroenterologist. For the assessment of outcomes, technical and clinical success, adverse events, and stent patency were evaluated retrospectively.

RESULTS

The placement and removal of the FCSEMSs were successful in all 8 patients. Five patients were boys and 3 were girls. The median age at initial FCSEMS placement was 12 years (range, 5-18 years). The diameters of all the inserted stents were 6 mm, and the lengths were 4-7 cm. The median indwelling time was 6 mo (range, 3-10 mo). No pancreatic sepsis, pancreatitis, cholestasis, or mortality occurred. There was no proximal and distal migration. All subjects showed a patent stent. On follow-up ERCP, the mean diameter of the stricture improved from 1.1 mm to 2.8 mm (P < 0.05), whereas that of upstream dilation improved from 8.4 mm to 6.3 mm (P < 0.05).

CONCLUSION

This initial experience showed that temporary FCSEMS placement is feasible and safe for the management of refractory benign MPD stricture in children.

Lumen apposing metal stents for pancreatic fluid collections: Recognition and management of complications

For patients recovering from acute pancreatitis, the development of a pancreatic fluid collection (PFC) predicts a more complex course of recovery, and introduces difficult management decisions with regard to when, whether, and how the collection should be drained. Most PFCs resolve spontaneously and drainage is indicated only in pseudocysts and walled-off pancreatic necrosis when the collections are causing symptoms and/or local complications such as biliary obstruction. Historical approaches to PFC drainage have included surgical (open or laparoscopic cystgastrostomy or pancreatic debridement), and the placement of percutaneous drains. Endoscopic drainage techniques have emerged in the last several years as the preferred approach for most patients, when local expertise is available. Lumen-apposing metal stents (LAMS) have recently been developed as a tool to facilitate potentially safer and easier endoscopic drainage of pancreatic fluid collections, and less commonly, for other indications, such as gallbladder drainage. Physicians considering LAMS placement must be aware of the complications most commonly associated with LAMS including bleeding, migration, buried stent, stent occlusion, and perforation. Because of the patient complexity associated with severe pancreatitis, management of pancreatic fluid collections can be a complex and multidisciplinary endeavor. Successful and safe use of LAMS for patients with pancreatic fluid collections requires that the endoscopist have a full understanding of the potential complications of LAMS techniques, including how to recognize and manage expected complications.