Biodegradable biliary stent in the endoscopic treatment of cystic duct leak after cholecystectomy: the first case report and review of literature

Biliary stents for active materials and surface modification: Recent advances and future perspectives

Demand for biliary stents has expanded with the increasing incidence of biliary disease. The implantation of plastic or self-expandable metal stents can be an effective treatment for biliary strictures. However, these stents are nondegradable and prone to restenosis. Surgical removal or replacement of the nondegradable stents is necessary in cases of disease resolution or restenosis. To overcome these shortcomings, improvements were made to the materials and surfaces used for the stents. First, this paper reviews the advantages and limitations of nondegradable stents. Second, emphasis is placed on biodegradable polymer and biodegradable metal stents, along with functional coatings. This also encompasses tissue engineering & 3D-printed stents were highlighted. Finally, the future perspectives of biliary stents, including pro-epithelialization coatings, multifunctional coated stents, biodegradable shape memory stents, and 4D bioprinting, were discussed.

Futuristic Developments and Applications in Endoluminal Stenting

Endoscopic stenting is a well-established option for the treatment of malignant obstruction, temporary management of benign strictures, and sealing transmural defects, as well as drainage of pancreatic fluid collections and biliary obstruction. In recent years, in addition to expansion in indications for endoscopic stenting, considerable strides have been made in stent technology, and several types of devices with advanced designs and materials are continuously being developed. In this review, we discuss the important developments in stent designs and novel indications for endoluminal and transluminal stenting. Our discussion specifically focuses on (i) biodegradable as well as (ii) irradiating and drug-eluting stents for esophageal, gastroduodenal, biliary, and colonic indications, (iii) endoscopic stenting in inflammatory bowel disease, and (iv) lumen-apposing metal stent.

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.).

From in vitro evaluation to human postmortem pre-validation of a radiopaque and resorbable internal biliary stent for liver transplantation applications

The implantation of an internal biliary stent (IBS) during liver transplantation has recently been shown to reduce biliary complications. To avoid a potentially morbid ablation procedure, we developed a resorbable and radiopaque internal biliary stent (RIBS). We studied the mechanical and radiological properties of RIBS upon in vivo implantation in rats and we evaluated RIBS implantability in human anatomical specimens. For this purpose, a blend of PLA₅₀-PEG-PLA₅₀ triblock copolymer, used as a polymer matrix, and of X-ray-visible triiodobenzoate-poly(ε-caprolactone) copolymer (PCL-TIB), as a radiopaque additive, was used to design X-ray-visible RIBS. Samples were implanted in the peritoneal cavity of rats. The radiological, chemical, and biomechanical properties were evaluated during degradation. Further histological studies were carried out to evaluate the degradation and compatibility of the RIBS. A human cadaver implantability study was also performed. The in vivo results revealed a decline in the RIBS mechanical properties within 3 months, whereas clear and stable X-ray visualization of the RIBS was possible for up to 6 months. Histological analyses confirmed compatibility and resorption of the RIBS, with a limited inflammatory response. The RIBS could be successfully implanted in human anatomic specimens. The results reported in this study will allow the development of trackable and degradable IBS to reduce biliary complications after liver transplantation. STATEMENT OF SIGNIFICANCE: Biliary reconstruction during liver transplantation is an important source of postoperative morbidity and mortality although it is generally considered as an easy step of a difficult surgery. In this frame, internal biliary stent (IBS) implantation is beneficial to reduce biliary anastomosis complications (leakage, stricture). However, current IBS are made of non-degradable silicone elastomeric materials, which leads to an additional ablation procedure involving potential complications and additional costs. The present study provides in vitro and human postmortem implantation data related to the development and evaluation of a resorbable and radiopaque internal biliary stent (RIBS) that could tackle these drawbacks.

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.).

A biodegradable non-covered self-expandable stent to treat pancreatic duct strictures in chronic pancreatitis: a proof of principle

BACKGROUND AND AIMS

In chronic pancreatitis (CP), fibrotic pancreatic duct (PD) strictures pose a therapeutic challenge, because endoscopic dilatation requires multiple procedures with suboptimal results. Biodegradable self-expandable stents (BD-SESs) may serve as an alternative in this setting.

METHODS

Patients with CP were eligible for this proof-of-principle study if at least 6 months of endoscopic dilatation with plastic stents had failed to resolve their PD stricture. The non-covered BD-SESs were expected to degrade within 3 to 6 months. Patients were followed at 3-monthly intervals for 1 year. Placement success and safety were the primary outcome parameters. Stricture resolution was assessed by ERCP after 6 months.

RESULTS

BD-SESs were successfully placed in all 19 patients without adverse events. In 2 cases, stent occlusion with sludge and stones was treated by a balloon swipe. One stent disintegrated during this procedure, after which placement of the plastic stent was resumed. A hyperplastic response was observed in 2 patients but did not result in functional obstruction. Stricture resolution was accomplished in 11 patients (technical success rate 58%). Six patients required further treatment of their PD stricture, 4 endoscopically and 2 surgically. Three additional patients underwent surgery for other reasons: 2 Whipple procedures for CP-related adverse events and one tail resection for an intraductal papillary mucinous neoplasm. The remaining 10 patients did not require further PD drainage (clinical success rate 52%).

CONCLUSIONS

These preliminary results show that BD-SESs are safe to use and able to resolve fibrotic PD strictures in CP. These encouraging outcomes warrant further testing.

Meta-Analysis of the Long Term Success Rate of Different Interventions in Benign Biliary Strictures

Background

Benign biliary stricture is a rare condition and the majority of the cases are caused by operative trauma or chronic inflammation based on various etiology. Although the initial results of endoscopic, percutaneous and surgical treatment are impressive, no comparison about long term stricture resolution is available.

Aims

The goal of this study was to compare the long term disease free survival in benign biliary strictures with various etiology after surgery, percutaneous transhepatic—and endoscopic treatment.

Methods

PubMed, Embase, and Cochrane Library were searched by computer and manually for published studies. The investigators selected the publications according to the inclusion and exclusion criteria, processed the data and assessed the quality of the selected studies. Meta-analysis of data of 24 publications was performed to compare long term disease free survival of different treatment groups.

Results

Compared the subgroups surgery resulted in the highest long term stricture resolution rate, followed by the percutaneous transhepatic treatment, the multiple plastic stent insertion and covered self-expanding metal stents (SEMS), however the difference was not significant. All compared methods are significantly superior to the single plastic stent placement. Long term stricture resolution rate irrespectively of any therapy is still not more than 84%.

Conclusions

In summary, the use of single plastic stent is not recommended. Further randomized studies and innovative technical development are required for improving the treatment of benign biliary strictures.

Endoscopic biodegradable biliary stents in the treatment of benign biliary strictures: First report of clinical use in patients

The first clinical experience of endoscopically inserted polydioxanone biodegradable biliary stents (BDBS) in the treatment of benign biliary strictures is reported. Two patients with a benign common bile duct stricture were endoscopically treated with 8-mm-bore BDBS during endoscopic retrograde cholangiography. Both BDBS insertions were technically successful and without adverse events. At 6 months, the stricture resolution was excellent and BDBS degradation was predicted in repeated magnetic resonance imaging. The first experience with endoscopic BDBS seems promising in the treatment of benign biliary strictures. During 6 months of follow up, BDBS seemed sufficient for remodeling and resolution of strictures. Further studies are needed to confirm the effectiveness of biodegradable biliary stents in endoscopic management of benign biliary strictures.

Biodegradable biliary stents have a different effect than covered metal stents on the expression of proteins associated with tissue healing in benign biliary strictures

BACKGROUND

Benign biliary strictures (BBS) are primarily treated endoscopically with covered self-expandable metal stents (CSEMS). Biodegradable biliary stents (BDBS) may be the future of endoscopic therapy of BBS. The aim was to assess the expression of proteins related to tissue healing in BBS compared with the intact bile duct (BD), and to study the protein expression after therapy with CSEMS or BDBS.

METHODS

Pigs with ischemic BBS were endoscopically treated either with BDBS or CSEMS. Samples were harvested from pigs with intact BD (n = 5), untreated BBS (n = 5), and after six months of therapy with BDBS (n = 4) or CSEMS (n = 5) with subsequent histologic analysis. Two-dimensional electrophoresis with protein identification was performed to evaluate protein expression patterns.

RESULTS

In BBS, the expression of galectin-2 and annexin-A4 decreased, compared to intact BD. Treatment with biodegradable stents normalized galectin-2 level; with CSEMS therapy it remained low. Transgelin expression of intact BD and BBS remained low after BDBS treatment but increased after CSEMS therapy. Histologic analysis did not show unwanted foreign body reaction or hyperplasia in the BD in either group.

CONCLUSIONS

The expression of proteins related to tissue healing in BBS is different after treatment with biodegradable stents and CSEMS. Treatment with biodegradable stents may bring protein expression towards what is seen in intact BD. BDBS seem to have a good biocompatibility.