Benign biliary strictures refractory to standard bilioplasty treated using polydoxanone biodegradable biliary stents: retrospective multicentric data analysis on 107 patients

Biosynthetic Plastics as Tunable Elastic and Visible Stent with Shape-Memory to Treat Biliary Stricture

Common biliary tract is ≈4 mm in diameter to deliver bile from liver to small intestine to help digestion. The abnormal narrowing leads to severe symptoms such as pain and nausea. Stents are an effective treatment. Compared with non-degradable stents which require repeated removal, biodegradable stents have the advantage of reducing secondary injury related to endoscopic operation and patient burden. However, current biodegradable materials may cause tissue hyperplasia and the treatment method does not target etiology of stricture. So recurrence rates after biodegradable stent implantation are still high. Here, a biodegradable helical stent fabricated from biosynthetic P(3HB-co-4HB) is reported. Tunable properties can be acquired through altering culture substrates. Stent shows shape memory in various solvents. The stent has an optimized design with helical structure and outer track. The self-expanding of helical structure and double drainage realized by outer track greatly improve drainage of bile. Importantly, stent-loading triamcinolone acetonide can inhibit proliferation of fibroblasts and reduce incidence of restricture. Therapeutic effect is also demonstrated in minipigs with biliary stricture. The results of minipig experiments show that biliary duct in treatment group is unobstructed and tissue hyperplasia is effectively inhibited.

Biodegradable biliopancreatic stents could help conserve health care resources during the COVID-19 pandemic: An observational multicenter study

BACKGROUND

Considering limited resources for follow-up due to COVID-19, we used biodegradable stents (BPBS) for a range of biliopancreatic diseases.

AIMS

This observational multicenter study aimed to evaluate technical safety and give first insights into clinical utility.

METHODS

Technical success, clinical success, and necessity of follow-up visits for BPBS placed at three Austrian tertiary care hospitals between April 2020 and January 2021 were retrospectively analyzed.

RESULTS

63 stents were deployed in 60 patients. Main indications were prophylaxis of post-ERCP pancreatitis (PEP; n = 30/63; 48%) and bridging of prolonged waiting times to cholecystectomy (n = 21/63; 33%). Median time to surgery was 47 days (range: 136 days). The technical success rate was 94% (n = 59/63; 95% CI [0.84, 0.98]). Technical difficulties primarily arose with dislocations. Clinical success was achieved in 90% (n = 57/63; 95% CI [0.80, 0.96]). Clinical failure despite successful deployment was caused by papillary bleeding (1 patient) and cholestasis (1 patient). Both required reinterventions. No follow-up visits were needed in 97% of cases (n = 57/59; 95% CI [0.88, 1.00]).

CONCLUSION

Biodegradable stents could help conserve health care resources without compromising treatment standards for PEP prophylaxis, which is particularly valuable in times of restricted resources. First insights into feasibility as bridging to cholecystectomy indicate a favorable safety profile.

Feasibility and safety of a novel 3D-printed biodegradable biliary stent in an in vivo porcine model: a preliminary study

To assess the feasibility and safety of a novel 3D-printed biodegradable biliary stent using polycaprolactone (PCL) in an in vivo porcine model. In this animal study using domestic pigs, biodegradable radiopaque biliary stents made of polycaprolactone (PCL) and barium sulfate were produced using 3D printing and surgically inserted into the common bile duct (CBD) of pigs (stent group, n = 12). Another five pigs were allocated to the control group that only underwent resection and anastomosis of the CBD without stent insertion. To check the position and status of the stents and stent-related complications, follow-up computed tomography (CT) was performed every month. The pigs were sacrificed 1 or 3 months after surgery, and their excised CBD specimens were examined at both the macroscopic and microscopic levels. Three pigs (one in the stent group and two in the control group) died within one day after surgery and were excluded from further analysis; the remaining 11 in the stent group and 3 in the control group survived the scheduled follow-up period (1 month, 5 and 1; and 3 months, 6 and 2 in stent and control groups, respectively). In all pigs, no clinical symptoms or radiologic evidence of biliary complications was observed. In the stent group (n = 11), stent migration (n = 1 at 3 months; n = 2 at 1 month) and stent fracture (n = 3 at 2 months) were detected on CT scans. Macroscopic evaluation of the stent indicated no significant change at 1 month (n = 3) or fragmentation with discoloration at 3 months (n = 5). On microscopic examination of CBD specimens, the tissue inflammation score was significantly higher in the stent group than in the control group (mean ± standard deviation (SD), 5.63 ± 2.07 vs. 2.00 ± 1.73; P = 0.039) and thickness of fibrosis of the CBD wall was significantly higher than that of the control group (0.46 ± 0.12 mm vs. 0.21 ± 0.05 mm; P = 0.012). Despite mild bile duct inflammation and fibrosis, 3D-printed biodegradable biliary stents showed good feasibility and safety in porcine bile ducts, suggesting their potential for use in the prevention of postoperative biliary strictures.

Research Priorities in Percutaneous Image and Endoscopy Guided Interventions for Biliary and Gallbladder Diseases: Proceedings from the Society of Interventional Radiology Foundation Multidisciplinary Research Consensus Panel

Recent technological advancements including the introduction of disposable endoscopes have enhanced the role of interventional radiology (IR) in the management of biliary/gallbladder diseases. There are unanswered questions in this growing field. The Society of Interventional Radiology Foundation convened a virtual Research Consensus Panel consisting of a multidisciplinary group of experts, to develop a prioritized research agenda regarding percutaneous image and endoscopy guided procedures for biliary and gallbladder diseases. The panelists discussed current data, opportunities for IR and future efforts to maximize IR's ability and scope. A recurring theme throughout the discussions was to find ways to reduce the total duration of percutaneous drains and to improve the patients' quality of life. Following the presentations and discussions, research priorities were ranked based on their clinical relevance and impact. The research ideas ranked top three were as follows: 1- Percutaneous multimodality management of benign anastomotic biliary strictures (Laser vs endobiliary ablation vs cholangioplasty vs drain upsize protocol alone); 2- Ablation of intraductal cholangiocarcinoma with and without stenting; and 3- Cholecystoscopy/choledochoscopy and lithotripsy in non-surgical patients with calculous cholecystitis. Collaborative retrospective and prospective research studies are essential to answer these questions and to improve the management protocols for patients with biliary/gallbladder diseases.

Biliary complications in pediatric liver transplantation: findings of percutaneous transhepatic cholangiography in a large single-center cohort

BACKGROUND

Although biliary complications after orthotopic liver transplantation represent a common source of morbidity and mortality, decreasing graft survival, consensus is lacking on their management in the pediatric population.

OBJECTIVE

The aim of this study was to present the prevalence of such biliary complications and their interventional radiologic management with representative images.

MATERIALS AND METHODS

This retrospective study reports our experience with percutaneous transhepatic cholangiography in the management of biliary complications after orthotopic liver transplantation in pediatric patients. This study enrolled all pediatric patients (<18 years old) who underwent percutaneous transhepatic cholangiography for the management of biliary complications after orthotopic liver transplantation at a tertiary care center between January 2010 and December 2020. Diagnosis of biliary complications and indication to perform percutaneous transhepatic cholangiography were based on clinical, laboratory or radiologic data.

RESULTS

Among the 301 orthotopic liver transplantations, 78 (26%) developed biliary complications that were managed by interventional radiology: these included 52 (17.3%) biliary strictures, 19 (6.3%) bile leaks, 5 (1.7%) biliary stones, 1 (0.3%) iatrogenic biliary obstruction and 1 (0.3%) vanishing syndrome. The median time interval between orthotopic liver transplantation and the diagnosis of biliary complications was 6.0 years (interquartile range [IQR] 8.2 years). Percutaneous transhepatic cholangiography and biliary duct catheterization were successful in all cases, with low rates of complications that were variable among subgroups.

CONCLUSION

A wide spectrum of biliary complications can occur after pediatric orthotopic liver transplantation. In this large single-center experience, we highlight the value of percutaneous transhepatic cholangiography in their diagnosis and management. Percutaneous treatments in pediatric patients are safe and effective, providing resolution or serving as a bridge to surgery, including re-transplantation.

A Complex In Vitro Degradation Study on Polydioxanone Biliary Stents during a Clinically Relevant Period with the Focus on Raman Spectroscopy Validation

Biodegradable biliary stents are promising treatments for biliary benign stenoses. One of the materials considered for their production is polydioxanone (PPDX), which could exhibit a suitable degradation time for use in biodegradable stents. Proper material degradation characteristics, such as sufficient stiffness and disintegration resistance maintained for a clinically relevant period, are necessary to ensure stent safety and efficacy. The hydrolytic degradation of commercially available polydioxanone biliary stents (ELLA-CS, Hradec Králové, Czech Republic) in phosphate-buffered saline (PBS) was studied. During 9 weeks of degradation, structural, physical, and surface changes were monitored using Raman spectroscopy, differential scanning calorimetry, scanning electron microscopy, and tensile and torsion tests. It was found that the changes in mechanical properties are related to the increase in the ratio of amorphous to crystalline phase, the so-called amorphicity. Monitoring the amorphicity using Raman spectroscopy has proven to be an appropriate method to assess polydioxanone biliary stent degradation. At the 1732 cm⁻¹ Raman peak, the normalized shoulder area is less than 9 cm⁻¹ which indicates stent disintegration. The stent disintegration started after 9 weeks of degradation in PBS, which agrees with previous in vitro studies on polydioxanone materials as well as with in vivo studies on polydioxanone biliary stents.

A New Biodegradable Stent to Improve the Management of Biliary Strictures in Pediatric Split Liver Transplantation

PURPOSE

Cholestasis due to benign biliary strictures is the most common biliary complication after pediatric split liver transplantation (SLT), decreasing graft survival, but consensus about its management lacks. Percutaneous transhepatic cholangiography, bilioplasty and internal-external biliary drainage (IEBD) are standard treatments. The aim of this report is to present the preliminary experience with a new biodegradable biliary stent in the management of post-SLT biliary strictures.

MATERIALS AND METHODS

Between September 2020 and April 2021, SLT patients with a single anastomotic benign biliary stricture underwent percutaneous transhepatic implantation of an innovative 10F helical-shaped biodegradable biliary stent, featuring a slow degradation profile, in addition to the standard treatment with bilioplasty and IEBD. The device is unique and the first to be CE-marked for the use in this indication.

RESULTS

Six pediatric patients (4 males; median age 8.6 years, interquartile range 3.7 years) underwent percutaneous stent implantation, without complications nor clinical cholestasis during a median follow-up of 271 days (IQR 120.25). Stent dislodgement occurred in one case.

CONCLUSION

Preliminary data suggest that implantation of a new biodegradable biliary stent may be considered in the management of post-SLT cholestasis in pediatric patients. Some technical tips are useful during implantation. This device may prolong biliary drainage, potentially relieving the discomfort of long-term IEBD.

A new biodegradable stent in bilio-pancreatic diseases: A prospective multi-center feasibility study

Introduction Biodegradable stents of various designs are reportedly used in pancreato-biliary conditions with promising results. Their major advantage is the avoidance of a repeat endoscopic procedure for stent removal thereby reducing overall cost along with ERCP associated adverse events. To evaluate the feasibility and safety of a new biodegradable stent in patients with pancreato-biliary diseases. Methods Prospective multicenter pilot study. All consecutive patients 18 years-old who underwent biliary or pancreatic stenting using the new biodegradable Archimedes stent were included. There were three biodegradation profiles. Technical and clinical success, feasibility and safety were assessed during a pre-established follow-up schedule. Results Fifty-three patients (mean age: 48.54±19.29, 66% male) having biliary (n=29, 54.7%%) or pancreatic (n=24, 45.3%) indications were included. The distribution of stents used according to degradation properties were as follows: fast (n=11, 20.8%), medium (n=16, 30.2%) and slow (n=26, 49.1%). The technical and clinical success were 100% and 77.8%. Thirty-five patients were followed for a median of 26 weeks (range: 4-56, 66%). There were 9 procedure-related adverse events (17%), all mild, including one uneventful stent-related event (external migration). Conclusion The biodegradable Archimedes stent placement is feasible and safe in pancreato-biliary diseases.

Emerging Trends in Biliary Stents: A Materials and Manufacturing Perspective

Biliary stent technology has come a long way since its inception. There have been significant advancements in materials used, designs, and deployment strategies. Options have expanded from thermoplastic and metallic...

Bio-Degradable Stents: Primary Experience in a Tertiary Hepatopancreaticobiliary Center in the United Kingdom

BACKGROUND

Management of benign biliary strictures (BBS) post bilioenteric anastomoses requires a multidisciplinary approach including surgical, radiological, and/or endoscopic input. Patients often need multiple hospital visits for treatment with the long-term possibility of restenosis. Conventionally BBS have been treated with serial percutaneous transhepatic biliary dilatations necessitating repeat procedures for drain exchange or removal. Surgery may become necessary in refractory strictures. In the last decade, there have been increasing reports of the use of biodegradable stents (BDS) in treating biliary strictures mainly to address the need for repeated procedures for drain exchange.

AIM

 This study aimed to report the early outcomes in patients with BBS treated with BDS.

METHODS

Retrospective analysis of prospectively collected data was performed in patients who had a bilioenteric anastomosis presenting with an anastomotic stricture and were intended to be treated with BDS. The primary endpoints reported were technical success (defined as a successful resolution of stricture on repeat cholangiogram) and clinical success (defined as the absence of repeated cholangitis). Clavien-Dindo (CD) grade of complication was reported.

RESULTS

Twelve patients presented with BBS and nine patients had BDS. Three patients were not considered suitable for BDS due to a non-traversable stricture and had surgery. The male-female ratio was 1:2. There was 100% technical and clinical success with one patient having stent migration not needing intervention. The procedure took an average of 45 min. In seven (77.7%) patients, it was safely performed under local anesthesia with sedation. Two patients preferred general anesthesia. There was no restenosis noted at a median follow-up of 11 months.

CONCLUSION

The use of BDS in the treatment of BBS is a safe and effective procedure. Longer-term follow-up with multi-institutional reporting on a national database is needed to assess its long-term benefits.

Percutaneous Balloon Dilatation for Hepaticojejunostomy Stricture Following Paediatric Liver Transplantation: Long-Term Results of an Institutional "Three-Session" Protocol

PURPOSE

The aim of this study was to report the long-term results of an institutional protocol of percutaneous biliary balloon dilatation (PBBD) on paediatric patients with benign anastomotic stricture after liver transplantation. As a secondary objective, we evaluated risk factors associated with post-treatment re-stricture.

MATERIALS AND METHODS

Fourteen paediatric, post-liver transplant patients with benign anastomotic stricture of Roux-en-Y hepaticojejunostomy were included. All patients underwent the same treatment protocol of three PBBD procedures with 15-day intervals. Clinical outcome was analysed using the Terblanche classification. Primary patency rate was assessed with the Kaplan-Meier test.

RESULTS

All patients had an initial successful result (Terblanche grade, excellent/good) after PBBD. At the end of the follow-up time of 35.7 ± 21.1 months (CI95%, 23.5-47.9), 10 patients persisted with excellent/good grading, while the remaining 4 had re-stricture, all of the latter occurring within the first 19 months. Patency rate after percutaneous treatment at 1, 3, and 5 years were 85.7%, 70%, and 70%, respectively. History of major complication after liver transplantation was associated with 5 times higher risk of re-stricture, HR 5.48 [95% CI, 2.18-8.78], p = 0.018.

CONCLUSION

In paediatric patients with benign anastomotic stricture of hepaticojejunostomy after liver transplantation, the "Three-session" percutaneous biliary balloon dilatation protocol is associated with a high rate of long-term success. In this limited series, the history of post-liver transplant major complication, defined as complications requiring a reintervention under general anaesthesia or advanced life support, seems to be an independent risk factor for stricture recurrence.

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.

Indian College of Radiology and Imaging Evidence-Based Guidelines for Percutaneous Image-Guided Biliary Procedures

Percutaneous biliary interventions are among the commonly performed nonvascular radiological interventions. Most common of these interventions is the percutaneous transhepatic biliary drainage for malignant biliary obstruction. Other biliary procedures performed include percutaneous cholecystostomy, biliary stenting, drainage for bile leaks, and various procedures like balloon dilatation, stenting, and large-bore catheter drainage for bilioenteric or post-transplant anastomotic strictures. Although these procedures are being performed for ages, no standard guidelines have been formulated. This article attempts at preparing guidelines for performing various percutaneous image-guided biliary procedures along with discussion on the published evidence in this field.

Percutaneous Management of Benign Biliary Strictures

Benign biliary strictures are often due to a variety of etiologies, most of which are iatrogenic. Clinical presentation can vary from asymptomatic disease with elevated liver enzymes to obstructive jaundice and recurrent cholangitis. Diagnostic imaging methods, such as ultrasound, multidetector computed tomography, and magnetic resonance imaging (cholangiopancreatography), are used to identify stricture location, extent, and possible source of biliary obstruction. The management of benign biliary strictures requires a multidisciplinary team approach and include endoscopic, percutaneous, and surgical interventions. Percutaneous biliary interventions provide an alternative diagnostic and therapeutic approach, especially in patients who are not amenable to endoscopic evaluation. This review provides an overview of benign biliary strictures and percutaneous management by interventional radiologists. Diagnostic evaluation with percutaneous transhepatic cholangiography and treatment options, including biliary drainage, balloon dilation, retrievable/biodegradable stents, and other innovative minimally invasive options, are discussed.

The Exploration of a Novel Biodegradable Drug-Eluting Biliary Stent: Preliminary Work

PURPOSE

To explore the degradation, drug release, and mechanical properties of drug-incorporated films made of different ratios of poly(lactic-co-glycolic acid) (PLGA) and different amounts of paclitaxel (PTX), which may serve as the material platform for the manufacturing of biodegradable drug-eluting biliary stents.

MATERIALS AND METHODS

PLGA of different lactic acid/glycolic acid ratios (50/50, 70/30, and 80/20) and 0%, 10, 20, and 30% weight by weight (w/w) PTX was mixed to make PLGA films, which were then cut into small pieces for further testing. Films were immersed in phosphate-buffered saline (pH 7.4) for a maximum of 11 weeks. Samples were taken randomly at Day 2, 4, 6, 8, 10, 12, 14, and weekly thereafter until Week 11 to test tensile strength, weight loss, pH value of the soaking solution, and drug release. The morphology of films was observed using scanning electron microscope (SEM).

RESULTS

At Week 10 of degradation, PLGA 80/20 still withstood a tensile strength of 9.7 newton (N), while PLGA 50/50 and 70/30 cracked spontaneously since Day 4. At Week 11, weight loss of PLGA 50/50, 70/30, and 80/20 was 95.15, 82.32, and 16.17%, respectively; and the lowest pH value of soaking solution was 1.87, 1.95, and 6.58, respectively. Drug release of 10, 20, and 30% PTX groups was 3.52-4.48%, 1.90-2.26%, and 1.44-2.06%, respectively. SEM proved smooth films before degradation; however, after the tensile strength was lost, cracks could be seen.

CONCLUSION

The degradation rate of PLGA can be controlled by altering lactic acid/glycolic acid ratio. Overall, PLGA 50/50 and 70/30 degrade significantly faster than 80/20. PLGA can serve as an effective drug carrier for PTX while being the stent strut, and PTX can be slowly released as PLGA degrades.

Advances in stent therapy for malignant biliary obstruction

Malignant biliary obstruction (MBO), result of pancreatobiliary diseases is a challenging condition. Most patients with MBO are inoperable at the time of diagnosis, and the disease is poorly controlled using external-beam radiotherapy and chemotherapy. Biliary stent therapy emerged as a promising strategy for alleviating MBO and prolonging life. However, physicians find it difficult to determine the optimal type of biliary stent for the palliation of MBO. Here, we review the safety and efficacy of available biliary stents, used alone or in combination with brachytherapy, photodynamic therapy and advanced chemotherapeutics, in patients with pancreatobiliary malignancies and put forward countermeasures involving stent obstruction. Furthermore, 3D-printing stents and nanoparticle-loaded stents have broad application prospects for fabricating tailor-made biliary stents.

Percutaneous Treatment of Benign Biliary Anastomotic Strictures: Retrievable Covered Self-Expandable Metal Stent with Fixation String Versus Large-Bore Catheters

PURPOSE

To retrospectively compare the safety and efficacy of a covered self-expandable metal stent (CSEMS) with a transhepatic fixation string and a large-bore catheter for benign biliary anastomotic stricture after hepatobiliary surgery.

MATERIALS AND METHODS

From March 2012 to June 2017, 49 patients with benign biliary anastomotic strictures, untreatable with endoscopy, were included. Twenty-three patients (catheter group) were treated with a large-bore catheter (with progressive catheter upsizing to 16-18 Fr), whereas 26 patients (stent group) were treated by CSEMS (10-mm stent) placement. Technical success, clinical success, primary patency, recurrent strictures, complication rate, and catheter or stent indwelling time were compared between the groups.

RESULTS

Technical success and clinical success were achieved in all patients. In the stent group, stent retrieval was successful in all patients. The overall complication rate was 24.5% (catheter group vs. stent group, 30.4% vs. 19.2%; P = .363). Stent migration occurred in 1 patient during follow-up (1/26, 3.8%). The mean indwelling time was 10.3 ± 3.0 months (range, 8-16 months; median, 10 months) in the catheter group and 4.0 ± 1.2 months (range, 3-7 months; median, 4 months) in the stent group (P < .001). Recurrent strictures occurred in 10 (43.5%) patients in the catheter group and 4 (15.4%) patients in the stent group (P = .030). The 1- and 3-year primary patency rates were 82.6% and 69.3% in the catheter group and 92.3% and 84.4% in the stent group (P = .042).

CONCLUSIONS

Percutaneous placement of a retrievable CSEMS showed superior intermediate-term outcomes over a large-bore catheter in patients with benign biliary anastomotic strictures.

New biliary and pancreatic biodegradable stent placement: a single-center, prospective, pilot study (with video)

BACKGROUND AND AIMS

In recent years, the feasibility and safety of endoscopic placement of different biodegradable biliary stents have been investigated. New, helicoidally shaped, biliary and pancreatic biodegradable stents have been developed for endoscopic use. Stents are provided in different sizes and with 3 expected speeds of degradation: slow (11 weeks), medium (20 days), and fast (12 days). The aim of this study was to evaluate degradation time, technical outcomes, and safety of these stents.

METHODS

This was a single-center, prospective, pilot study (August 2018 to January 2019) of consecutive patients with indication for biliary or pancreatic plastic stent positioning during ERCP. The primary outcome was the evaluation of degradation time of the stents, which was controlled by abdominal radiograph. Secondary outcomes were the evaluation of specific stent-related technical features (loadability, pushability, and fluoroscopic visibility) as compared with commonly used plastic stents and adverse events (AEs).

RESULTS

Thirty-eight patients (11 women [28.9%]; median age, 68.05 ± 10.74 years) who received 53 biodegradable stents (34 [64.2%] biliary and 19 [35.8%] pancreatic stents) were enrolled in the study. Thirty-five (66%) slow-degrading stents, 6 (11.3%) medium-degrading stents, and 12 (22.6%) fast-degrading stents were used. At time 1, partial degradation of the stents was present in 48 cases (90.6%). Five stents (9.4%) prematurely migrated. At the subsequent time 2 evaluation, complete degradation occurred in 100% of cases. Stent loadability was defined as excellent in all cases. Pushability of the stent was scored as excellent in 48 cases (90.5%), good in 4 cases (7.5%), and fair in 1 case (1.9%). Fluoroscopic visualization was excellent in 11 cases (20.8%), good in 39 cases (73.6%), and fair in 3 (5.6%). Only 1 AE of mild post-ERCP pancreatitis occurred.

CONCLUSIONS

The results of our study suggest that the biodegradation of the new biliary and pancreatic stents is reliable and in line with expected times and technically successful in a variety of indications. Further randomized multicenter studies are required to validate our preliminary findings. (Clinical trial registration number: NCT03767166.).

Benign Biliary Strictures: A Systematic Review on Endoscopic Treatment Options

Benign biliary strictures can be difficult to manage. Untreated biliary strictures can lead to complications, such as chronic cholestasis, jaundice, recurrent sepsis, and secondary biliary cirrhosis, which can have severe ramifications. The management landscape is constantly evolving, with the development of modifiable self-expandable metal stents and biodegradable stents. This review critically appraises current endoscopic treatment strategies, in particular focusing on the shortfalls, such as stent migration and stricture recurrence. It also proposes a treatment algorithm based on aetiologias and the location of the strictures.

Absorbable stents for treatment of benign biliary strictures: long-term follow-up in the prospective Spanish registry

OBJECTIVES

Benign strictures of the bile duct may be difficult to treat endoscopically due to altered bowel anatomy. Furthermore, recurrence of stenosis and symptoms remains high. The aim of the Spanish Prospective Registry BiELLA study was to investigate the safety and efficacy of absorbable stents in the treatment of benign biliary strictures and their outcomes on the medium and long-term follow-up.

METHODS

A prospective, multicenter, observational, non-randomized study (the BiELLA study) was conducted from January 2014 to September 2018. One hundred fifty-nine patients with benign biliary strictures, mostly postsurgical, were enrolled for implantation of absorbable biliary stents in the 11 participating Spanish tertiary hospitals. The average patient follow-up was 45.4 ± 15.9 months (range, 12-60 months). The follow-up data included symptoms, biochemical parameters, and ultrasound images at 1, 6, and 12 months and then yearly for up to 60 months.

RESULTS

The immediate technical and clinical success rates were 100%. In all patients, stent placement resulted in improvement of clinical symptoms and biochemical parameters. The primary mean patency for stent was 86.7, 79.6, and 78.9% at 12, 36, and 60 months, respectively (95% CI). Biliary restenosis and occlusion occurred in 40 (26.6%) patients. Of the 40 patients, 18 (12%) patients were treated with a second stent and 22 (14.6%) patients had operative repair of the recurrent strictures. There were no major complications associated with stent implantation.

CONCLUSIONS

Implantation of an absorbable polydioxanone biliary stent is safe and effective for treatment of benign biliary strictures refractory to balloon dilatation or other biliary intervention.

KEY POINTS

• Percutaneous implantation of biodegradable prostheses for the treatment of benign postsurgical biliary strictures is a safe and effective procedure. • More than 75% of the patients presented patency of the stented biliary tree at 5 years follow-up. • Absorbable stents improved clinical symptoms and signs (jaundice, itching, fever), and laboratory parameters in a few days after stent placement.

Pediatric Hepatobiliary Interventions in the Setting of Intrahepatic Vascular Malformations, Portal Hypertension, and Liver Transplant

Within the broad spectrum of pediatric hepatobiliary disorders, hepatic vascular malformations, portal hypertension, and hepatic transplant interventions pose numerous challenges. The role of interventional radiology within each of these conditions is discussed herein, beginning with endovascular management of high flow hepatic vascular malformations. Next, while becoming less common in adult populations, surgical portoportal and portosystemic shunts remain prevalent in many pediatric centers. Shunt anatomy is reviewed along with endovascular management techniques for shunt dysfunction. Next, the growing experience with pediatric transjugular intrahepatic portosystemic shunt placement is reviewed along with tips for success in pediatric patients. Finally, pediatric hepatic transplant interventions are discussed with technical notes pertinent to split liver anatomy.

Biodegradable biliary stents preferable to plastic stent therapy in post-cholecystectomy bile leak and avoid second endoscopy

BACKGROUND

The treatment of post-cholecystectomy bile leak is endoscopic retrograde cholangiography (ERC) with plastic stent (PS) insertion combined with external drainage. Self-expanding biodegradable biliary stents (BDBS) have only recently become available.

AIM

The aim was to compare success rate, adverse events and costs of BDBS with PS in the treatment of post-cholecystectomy cystic duct leak Materials and methods: Patients recruited prospectively for treatment with BDBS during the period 2014-2017 were compared to a control group treated with PS in a non-randomized setting.

RESULTS

Altogether 32 patients (median age 68, range 33-88, 59% male) were treated for Strasberg A bile leak over a period of 3.5 years, accounting for 1.8% of all ERCs. Eight patients were treated with BDBS and 24 with PS. Treatment with BDBS was safe; rate of readmissions and 30-day adverse events were 13% in both groups. There was no statistical difference in the clinical success rate. All cases with laparoscopic lavation or re-ERC with stent exchange occurred in the PS group. Total drain output was lower in BDBS patients (330ml vs 83ml, p=.002). All PS patients required another endoscopy for stent removal, whereas all BDBS patients were spared repeated endoscopy.

CONCLUSION

Treatment of cystic duct leak with BDBS is highly successful and as safe as traditional treatment with PS. The most obvious benefit of BDBS is that it avoids stent removal. The lower drain output after ERC with a trend for fewer unplanned interventions may indicate more efficient leak resolution with the large bore BDBS.

3D Printing for Bio-Synthetic Biliary Stents

Three-dimensional (3D) printing is an additive manufacturing method that holds great potential in a variety of future patient-specific medical technologies. This project validated a novel crosslinked polyvinyl alcohol (XL-PVA) 3D printed stent infused with collagen, human placental mesenchymal stem cells (PMSCs), and cholangiocytes. The biofabrication method in the present study examined 3D printing and collagen injection molding for rapid prototyping of customized living biliary stents with clinical applications in the setting of malignant and benign bile duct obstructions. XL-PVA stents showed hydrophilic swelling and addition of radiocontrast to the stent matrix improved radiographic opacity. Collagen loaded with PMSCs contracted tightly around hydrophilic stents and dense choloangiocyte coatings were verified through histology and fluorescence microscopy. It is anticipated that design elements used in these stents may enable appropriate stent placement, provide protection of the stent-stem cell matrix against bile constituents, and potentially limit biofilm development. Overall, this approach may allow physicians to create personalized bio-integrating stents for use in biliary procedures and lays a foundation for new patient-specific stent fabrication techniques.

Management of Biliary Strictures: State-of-the-Art Review

Biliary strictures can be broadly classified as benign or malignant. Benign biliary strictures are most commonly iatrogenic in nature and are a consequence of hepatobiliary surgery. Cholangiocarcinoma and adenocarcinoma of the pancreas are the most common causes of malignant biliary obstruction. This article reviews state-of-the-art minimally invasive techniques used to manage these strictures. In addition, the roles of (a) recently introduced biodegradable biliary stents in the management of benign biliary strictures and (b) intraprocedural imaging and navigation tools, such as cone-beam CT, in percutaneous reconstruction of the biliary-enteric anastomosis are discussed.

Percutaneous treatment of benign bilioenteric anastomotic strictures: temporary covered stent placement versus balloon dilatation

OBJECTIVES

To compare percutaneous temporary covered stent placement with balloon dilatation in the treatment of benign stricture of bilioenteric anastomosis.

METHODS

From November 2004 to August 2017, 56 patients with benign bilioenteric anastomotic strictures underwent percutaneous transhepatic treatment. A temporary covered stent designed for spontaneous migration was placed in 23 patients (stent group). Balloon dilatation was performed in 33 patients (balloon group). The technical success, percutaneous transhepatic biliary drainage (PTBD) indwelling times, stent indwelling times and patency rates were retrospectively compared between the two groups.

RESULTS

Technical success was achieved in all patients in the stent group and in 96.8% (32/33) of patients in the balloon group. All stents spontaneously migrated into the jejunum, and stent indwelling times were 3-9 months (median, 6 months). The PTBD indwelling time was shorter for the stent group than for the balloon group (median, 7 vs. 71 days, p = 0.001). Recurrent strictures occurred more frequently in the balloon group than in the stent group (54.5% vs. 13.0%, p = 0.002; hazard ratio 3.7). The 1- and 3-year primary patency rates were 90.2% and 84.9% for the stent group and 75.1% and 52.8% for the balloon group, respectively (p = 0.04).

CONCLUSIONS

Percutaneous temporary covered stenting is an effective treatment in patients with benign bilioenteric anastomotic strictures. It provides longer patency and shorter PTBD indwelling time compared with balloon dilatation.

KEY POINTS

• A temporary covered stent designed for spontaneous migration is a feasible and effective treatment for patients with benign bilioenteric anastomotic strictures. • Percutaneous temporary covered stents provide longer patency and shorter drainage catheter indwelling time compared with conventional balloon dilatation. • A covered stent with flared ends spontaneously migrated after 3-9 months.

A Novel Rabbit Model for Benign Biliary Stricture Formation and the Effects of Medication Infusions on Stricture Formation

BACKGROUND

Benign biliary stricture (BBS) is highly refractory. Currently, there is no effective strategy for prevention of BBS recurrence. The aim of this study is to establish a novel BBS rabbit model and to investigate the efficacy of biliary infusion with anti-proliferative medications for treating BBS.

METHOD

A BBS model was established via surgical injury and biliary infection. The biliary infusion tube was inserted into the common bile duct via the stump of cystic duct after cholecystectomy. Biliary infusions with Rapamycin, Pirfenidone and Fasudil were performed daily during the 4 weeks following the surgery. The wall thickness and luminal area of the bile duct were assessed.

RESULTS

All rabbits formed BBS after surgery. The mortality rate was 13% (8/60) and tube withdrawal rate was 4% (2/48). The thickness of the bile duct wall was significantly reduced; whereas the luminal area of the bile duct was dramatically enlarged in the Rapamycin or the Pirfenidone treated group, compared to the saline treated group. Furthermore, the local treatment significantly decreased the levels of proliferation makers, including PCNA, Collagen I and fibrogenic mediators, including ACTA2 and TGF-beta.

CONCLUSION

We have established a novel animal model for BBS formation. We have further demonstrated that biliary infusion with Rapamycin or Pirfenidone limits the biliary strictures through inhibiting the proliferation of the bile duct wall in this model. This may represent a new avenue for preventing biliary restenosis.

A systematic review of biodegradable biliary stents: promising biocompatibility without stent removal

Biodegradable self-expanding stents are an emerging alternative to standard biliary stents as the development of endoscopic insertion devices advances. The aim was to systematically review the existing literature on biodegradable biliary stents. In-vivo studies on the use of biodegradable stents in the biliary duct were systematically reviewed from 1990 to 2017. Despite extensive research on the biocompatibility of stents, the experience so far on their clinical use is limited. A few favorable reports have recently been presented on endoscopically and percutaneously inserted self-expanding biodegradable polydioxanone stents in benign biliary strictures. Another potential indication appears to be postcholecystectomy leak of the cystic duct. The main benefit of biodegradable stents is that stent removal can be avoided. The biocompatibility of the current biodegradable stent materials, most prominently polydioxanone, is well documented. In the few studies currently available, biodegradable stents are reported to be feasible and safe, also in humans. The initial results of the endoscopic use of these stents in benign biliary stricture management and for treating postcholecystectomy bile leaks are promising. Further controlled studies on long-term clinical results and cost-effectiveness are needed.

A pilot study of endoscopically inserted biodegradable biliary stents in the treatment of benign biliary strictures and cystic duct leaks

BACKGROUND AND AIMS

Self-expanding biodegradable biliary stents (BDBSs) have recently become available for use in endoscopic retrograde cholangiography (ERC). The aim was to evaluate the effectiveness and safety of novel BDBSs in iatrogenic cystic duct leaks and benign biliary strictures (BBSs).

METHODS

Patients providing informed consent were recruited for the prospective study. Braided self-expanding poly-dioxanone BDBSs were inserted using ERC during from 2014 to 2016. Repeated liver function tests and magnetic resonance imaging were performed during follow-up. The main outcomes were treatment success and adverse events.

RESULTS

Thirteen patients, 5 women, median age 67 years (range, 43-79) underwent BDBS insertion for iatrogenic cystic duct leak (n = 7) or BBS (n = 6). Stent insertion using ERC was successful in all cases. All bile leaks were treated uneventfully with BDBSs. In BBSs, the clinical success rate of BDBS therapy was 83% in a median of 21 months of follow-up (range, 14-25). Early ERC-related adverse events included 1 cholangitis (8%) and 1 pancreatitis (8%), both in the stricture group. During the first 90 days, 23% of patients were readmitted for mild cholangitis.

CONCLUSIONS

The short- and long-term safety of endoscopically inserted poly-dioxanone BDBSs was satisfactory. The management of cystic duct leaks and benign distal common bile duct strictures was highly successful. Episodes of mild cholangitis during stent indwelling seemed to be typical of BDBSs. The advantage of BDBSs is the avoidance of repeated endoscopy for stent removal. (Clinical trial registration number: NCT02353286.).