Bioresorbable biliary stents: A step forward

Abstract

The case report by Elsayed et al presented a multidisciplinary approach to treating recurrent biliary strictures following proximal bile duct injury. Bioresorbable biliary stents, an innovative option for managing biliary strictures in recent years, are a key part of this approach. Unlike traditional metal/plastic stents, bioresorbable stents made from materials like polylactic acid (PLA) or polycaprolactone gradually degrade in the body. This eliminates the need for endoscopic removal, reducing patient trauma and costs. Nondegradable stents often lead to complications such as restenosis, migration, or infection. In contrast, bioresorbable stents can have their degradation rate tailored to the bile duct healing process (e.g., PLA stents remained unobstructed for 25.7 weeks in a porcine model), minimizing long-term complications. We analyzed the advantages and disadvantages of bioresorbable stents, outlined future research directions, and aimed to offer valuable insights for clinical practice.

Key Words: Biliary stent; Biodegradable; Biliary stricture; Biliary injury; Benign biliary stricture

Core Tip: Biliary biodegradable stents are primarily used to treat benign and malignant conditions such as biliary strictures and bile duct injuries. We discuss a patient with postoperative biliary stricture who achieved significant symptom relief through treatment with a biodegradable stent. This report suggests that biodegradable stents may represent a promising new option worthy of further investigation.

INTRODUCTION

Biliary stricture is characterized by an abnormal narrowing of the bile duct. It can be caused by benign conditions like chronic inflammation and postoperative scars, as well as malignant obstructions such as cholangiocarcinoma. This stenosis often results in cholestasis, recurrent infections, and liver dysfunction. Traditionally, treatment involves endoscopic placement of plastic or metal prosthetic stents. However, repeated interventions are often necessary due to stent occlusion, migration, or tissue hyperplasia. Proximal bile duct injury (BDI) after laparoscopic cholecystectomy can lead to complex strictures and recurrent cholangitis. A 39-year-old woman experienced this. Even after hepaticojejunostomy and multiple interventions, she still had a biodegradable stent inserted in 2024 to continuously improve her condition[1]. This case highlights the difficulties in treating post-BDI strictures, the potential of biodegradable stents, and the need for multidisciplinary management and long-term follow-up. Bioresorbable biliary stents are an innovative option made from biodegradable polymers like polylactic acid. They offer temporary mechanical support and degrade over time. There is no need for secondary removal, which can reduce long-term complications and may also encourage tissue remodeling. Current research focuses on optimizing their mechanical strength, degradation kinetics, and anti-hyperplasia properties. More clinical trials are warranted to validate their safety and durability, and they are expected to transform minimally invasive biliary therapy.

ADVANTAGES AND DISADVANTAGES OF BILIARY BIODEGRADABLE STENTS

In recent years, biodegradable biliary stents have shown remarkable results and multiple advantages in treating biliary strictures. Their most prominent benefit is that they eliminate the need for secondary surgical removal, unlike traditional metal or plastic stents that often require repeated endoscopic procedures like endoscopic retrograde cholangio pancreatography (ERCP) due to long-term indwelling. This significantly eases patients' pain, cuts medical costs, and reduces the risk of related complications such as pancreatitis and cholangitis[2,3]. For example, when it comes to the treatment of benign biliary strictures, biodegradable stents have achieved a clinical success rate ranging from 85% to 95%, which outperforms the 70% success rate of traditional balloon dilation[4,5]. Additionally, these stents exhibit excellent biocompatibility and are typically made from polymers such as polydioxanone or polylactic acid (PLA). They can degrade in the body within a pre-determined period. The degradation rates progress from fast to medium and then to slow, and the degradation process lasts from 12 days to 11 weeks[6-8]. During degradation, the stents maintain stable mechanical properties and offer sufficient radial force to prevent stricture recurrence[7,9]. The application of 3D printing technology allows for personalized stent customization. Research conducted on porcine models has demonstrated it can effectively prevent postoperative biliary strictures without causing severe complications[10]. For patients with refractory conditions, such as those with anastomotic strictures after liver transplantation, biodegradable stents can extend drainage time, improve graft function, and enhance patients' quality of life[11,12]. For easy reference, we have summarized six promising biodegradable stents in Table 1. The silica-polycaprolactone (SiO₂-PCL) stent, manufactured via 3D printing, has a nanoporous surface that reduces bile adhesion, lowers the risk of bacterial biofilm formation, and indirectly inhibits hyperplastic stenosis[13]. Applying functional coatings such as hydrophilic polymers can further minimize bile stasis and secondary inflammation and slow down the hyperplastic process[14]. When it comes to material selection, PLA and PCL offer significant advantages in terms of controllable degradation rate. They can maintain the stent's mechanical strength during gradual degradation and reduce the hyperplastic reactions caused by long-term foreign body irritation[8]. Additionally, magnesium alloy stents, chitosan stents, and composite stents also hold significant potential[15-17].

Table 1 Six promising biodegradable stents.

Ref.	Stent type	Material composition	Degradation time	Clinical advantages	Application scenarios
Battistel et al[12]	PDO stent	PPDX	Medium degradation (approximately 20 days)	Great biocompatibility, moderate mechanical strength	Used for benign biliary strictures, technical success rate of 98%-100%
Zhang et al[8]	PLA stent	PLA	Slow degradation (11 weeks)	Long degradation cycle, suitable for long-term support	Patency time significantly better than PDO stents
Kim et al[10]	PCL stent	Polycaprolactone mixed with barium sulfate (3D printed)	Degradation rate adjustable via 3D printing	Supports personalized design, excellent radiopacity	Prevention of postoperative biliary strictures
Peng et al[15]	Magnesium alloy stent	Degradable magnesium (Mg)	Degradation time not specified, combines drainage and anti-cancer functions	Antibacterial, anti-tumor effects	Experiments show it can induce apoptosis in gallbladder cancer cells
Pan et al[16]	CS stent	Chitosan mixed with contrast agent (3D printed)	Potential for rapid degradation	Great biocompatibility	In development for pancreatic duct stents, biliary applications to be explored
Guerra et al[17]	Composite Stent	E.g., PLA/PDO blends, drug-coated stents	Adjusted based on material combination (e.g., PLA+PDO achieves varying degradation rates)	Multifunctional (e.g., drug release, anti-bile adhesion)	Anti-bile adhesion coatings, drug delivery

PDO: Polydioxanone; PPDX: Polydioxanone; PLA: Polylactic acid; CS: Chitosan.

However, biodegradable stents have limitations. Their long-term efficacy requires further clinical validation, as current studies mainly rely on small-scale clinical trials or animal experiments. Existing data indicates that the biliary patency rate may decrease to 72% after 60 months of follow-up[18]. Also, the synchronization between stent degradation time and tissue remodeling rate needs optimization[9,19]. There are technical challenges in stent design. For instance, the stent may have insufficient bend flexibility, the anti-bile adhesion coating may perform poorly[20,14], and rapid degradation can cause premature loss of radial force[6]. Currently, their indications primarily cover benign diseases, including postoperative strictures and chronic inflammation. However, there is no sufficient evidence regarding their effectiveness in treating malignant strictures[21]. Some biodegradable stents, like polydioxanone/magnesium alloy materials, generate microparticles during in vivo hydrolysis or corrosion. If these particles are not completely absorbed or excreted, they may migrate along with the bile flow and deposit at biliary stricture sites, such as the distal common bile duct, or in the pancreaticobiliary duct, causing mechanical obstruction[9,15,22]. Studies indicate that excessively rapid stent degradation heightens the risk of particle detachment, while slower-degrading designs, such as helical stents, can mitigate this issue[23,24].

RESEARCH TRENDS

Bibliometric analysis is a research methodology that applies statistical techniques to quantitatively analyze scientific literature data. It is primarily used to evaluate research results, track disciplinary trends, and assess academic impact[25]. We searched the Web of Science Core Collection database, restricting the search to English-language articles published between January 1, 2016, and April 11, 2025. Using the search topic “biliary stent*”, we identified 972 relevant articles. Then, we used VOSviewer software for analysis. VOSviewer, a professional bibliometric tool, can visualize and analyze academic publishing networks through co-occurrence mapping[26].

We extracted 2837 keywords from the 972 articles. Setting the minimum keyword occurrence threshold at 10, we conducted a co-occurrence analysis on 151 high-frequency keywords that met the criterion and created a network visualization of these keywords. As shown in Figure 1A, these high-frequency keywords are primarily divided into four color-coded clusters. By analyzing the keywords in each cluster, we identified the research focus areas. The red cluster focuses on cholangitis-related conditions, such as "cholangitis", "complications", "ERCP", and "management". The green cluster focuses on biliary system biliary system structural abnormalities, such as "strictures", "obstruction", and "drainage". The yellow cluster focuses on biliary stent-related topics, such as "stents", "biliary tract", and "placement". The blue cluster focuses on biliary and pancreatic cancers, such as "cancer", "pancreaticoduodenectomy", and "mortality".

Figure 1 Keyword analysis based on VOSviewer. A: Biliary Stent Clustering Diagram; B: Timeline of Biliary Stent Development. The statistical density (quantity) of high-frequency keywords represents research hotspots. In the map, the size of the nodes indicates the number of occurrences—the larger the node, the greater the total number of times the keyword or topic appears. The thickness of the connecting lines between nodes represents the degree of association between each keyword or topic.

The keyword time-trend analysis (Figure 1B) revealed that the current research focus is on developing materials with ideal degradation performance for clinical applications. The advancement of functional coatings is a significant trend, including research on anti-bile-adhesion and antibacterial/anti-biofilm coatings to reduce the risk of infection and restenosis. 3D printing technology is currently capable of manufacturing personalized stents. Looking ahead, 4D bioprinting is anticipated to develop dynamically responsive stents, like shape-memory stents, to adapt to anatomical changes.

CONCLUSION

In this editorial, we started with a clinical case of treating postoperative biliary stenosis with a biodegradable stent. We then analyzed the advantages and current limitations of these stents. Through bibliometric analysis, we examined the research scenario and emerging trends in biliary stent technology. We concluded that biodegradable biliary stents have the potential to become a pivotal treatment for biliary strictures in the near future.