EXPERIMENTAL AND CLINICAL TRANSPLANTATION

Biliary tract complications are a significant source of morbidity following living donor liver transplant, especially in pediatric patients. These complications are influenced by graft type, bile duct anatomy, and reconstruction techniques. For a hepaticojejunostomy, percutaneous intervention is the first option preferred. Here, we present a case report of the successful use of a percutaneous biodegradable stent to manage an intrahepatic biliary stricture in an 8-month-old patient who had previously undergone living donor liver transplant for biliary atresia, thereby creating a new biliary path. The patient developed a dominant biliary stricture of segment S2 postoperatively, which was refractory to conventional internal drainage. We created a new biliary path via a novel connection between the intrahepatic duct and the intestinal loop with minimally invasive surgery. The biodegradable stent provided temporary structural support while gradually degrading, which eliminated the need for removal and minimized long-term complications. At 18 month follow-up, the patient remained asymptomatic with satisfactory liver function tests and no evidence of restenosis. This case illustrates the feasibility, safety, and potential benefits of biodegradable stents in pediatric liver transplant recipients. The findings suggest that biodegradable stents could represent a significant advancement in the management of complex biliary tract complica-tions in children, although further studies are necessary to establish the long-term efficacy of this treatment and standardize the protocols.

Key words : Biliary tract complications, Hepaticojejunos-tomy stricture, Pediatric transplantation, Percutaneous treatment

Liver transplant (LT) remains the only treatment with curative intent for patients with biliary atresia. Despite the improvements in surgical techniques, biliary tract complications after pediatric LT remain common, with an incidence between 12% and 50%.^1,2 Early diagnosis and proper management improve long-term graft and patient survival, but the appropriate treatment will depend on the type of biliary reconstruction. In the case of duct-to-duct anastomosis, endoscopic intervention is the first-line approach; however, recipient size and the availability of technical expertise become the major limitations for its application. When a hepaticojejunostomy has been performed, a percutaneous approach is preferred.^1-4

We report the case of a pediatric patient who, after undergoing LDLT, developed an intrahepatic stric-ture of the segment S2 bile duct. Given that the Doppler ultrasonography results in the postoperative period showed vascular patency, we ruled out graft rejection. Based on the timing of the stenosis, we believed ischemic cholangiopathy (ischemia-mediated injury) was the likely cause, after other potential causes were excluded. The patient received multiple percutaneous interventions, including a communication between the intrahepatic biliary tree and the bowel loop, and then the creation a new biliary path (NBP) with a biodegradable stent.

An 8-month-old patient with biliary atresia since birth was referred to us with a failed Kasai procedure that had been performed at 4 months. The patient progressed to cirrhosis, and LT was indicated. Due to his small size (weight 5.20 kg; height 55 cm), LDLT was suggested. He received a left lateral segment from his grandmother, which was implanted using piggy-back technique. The graft had 2 bile ducts, and at the back table both ducts were syndactylized; hepaticojejunostomy was conducted with 7.0 polydioxanone stitches. The patient had an une-ventful postoperative period and was discharged 10 days after the procedure.

Four months later, the patient developed jaundice and progressive cholestasis (aspartate transaminase 93 U/L; alanine transaminase 57 U/L; alkaline phosphatase 980 U/L; total bilirubin 6.8 mg/dL; direct bilirubin 4.9 mg/dL; γ-glutamyl transferase 391 U/L). A Doppler ultrasonography exam showed adequate liver perfusion with good arterial and portal flows but with dilation of the intrahepatic biliary tract. Magnetic resonance imaging revealed a 2-cm-long stricture of the S2 biliary branch. Despite its proximity to S2 and even after syndactylization of the ducts and subsequent manipulations, the bile duct of segment S3 remained unaffected. This was confirmed through both static and dynamic imaging studies (Figure 1).

The case was discussed in a multidisciplinary team, and the decision was first to offer a percu-taneous biliary drainage. With ultrasonography and fluoroscopy guidance, an external 8.5F biliary drainage catheter was placed to decompress the S2 bile duct (Cook Medical). After 2 weeks, an unsuc-cessful attempt at internalization was performed, which confirmed a 2-cm stenosis of the intrahepatic biliary tree. After the biliary drainage, the patient’s condition improved; however, a new hospitalization for cholangitis was required. Due to the difficulty to obtain an internal biliary drainage, we decided to perform the NBP.

The concept of the NBP was to create a new communication between the patient's bile duct and the intestinal loop, then place an external-internal biliary catheter, and finally position a biodegradable stent.

Due to limited ultrasonography access that prevented a safe percutaneous approach, a hand-assisted technique via subcostal laparotomy was chosen. In this procedure, we carefully manipulated the jejunal loop to align with the path of the stylet used for the puncture, which allowed creation of a new path percutaneously through the abdominal wall and liver parenchyma using a Rosch-Ushida transjugular liver access set (Cook Medical). This approach nearly eliminated the possibility of vascular puncture or injury to adjacent organs. The puncture track between the biliary tree and the jejunum was dilated in a stepwise fashion with dilators to accept a biliary drainage catheter (8.5F) that was inserted into the anastomotic bowel loop, which was later replaced with a stent to maintain the patency of the NBP (Figure 2).

The drainage ensured good outflow of bile from the liver to the bowel, followed by normalized laboratory test results. The patient was discharged on day 4.

After this procedure, to maintain patency of the NBP while awaiting the custom-manufactured biodegradable stent, we used a double-lumen balloon biliary dilatation catheter (10 mm × 40 mm; Hurricane RX Biliary System) to perform 3 sessions of percu-taneous transcatheter dilatation. For each session, the balloon catheter was placed across the NBP and inflated for a period of 3 minutes until 8 ATM. After 3 minutes, the balloon was inflated twice. After the dilatations, a biliary catheter (8.5F) was placed. To achieve permanent patency of the NBP, we used a biodegradable stent (45 mm × 8 mm; ELLA-CS Ltd). The choice of stent size was based on the observed distance between the intrahepatic bile duct and the lumen of the previous hepaticojejunostomy intestinal loop. Four months after the last dilatation, the biode-gradable stent was placed by fluoroscopic guidance. The stent was well positioned and achieved a good emptying of the contrast substance after the procedure was completed (Figure 3). At the 18 month follow-up, the patient remained asymptomatic, with unremar-kable laboratory test results and no evidence of restenosis. He has not been hospitalized over the past year.

The type of allograft, the number of ducts to anastomose, and the method of biliary reconstruction significantly influence complication rates and subsequent management. Early intervention is essential to improve long-term graft and patient survival. Minimally invasive techniques are pre-sently the first-line approach. In patients with altered foregut anatomy, a percutaneous strategy should be considered. Although generally well tolerated, a limitation to consider is the multiple attempts that may be required to achieve the desired outcome.^1,4,5 In our case, multiple procedures were required to successfully manage the biliary stricture without surgery.

In patients with intrahepatic biliary stenosis, a more complex intrahepatic cholangiojejunostomy remained the only possible approach for many years, and this surgical intervention tends to be challenging, with high rates of postoperative morbidity and mortality. Therefore, a cholangiojejunostomy is reser-ved for cases in which percutaneous treatment has failed. The development of minimally invasive procedures has offered new options. So far, various algorithms for biliary dilatations have been described.^6-11 In our case, the stenosis of the bile duct was 2 cm and extended into the liver. Therefore, given the impossibility of passing a guide wire through the biliary stenosis, we were compelled to create the NBP. The challenge was to determine the best course of treatment to ensure this NBP would remain patent over time.

Recent advances in the development of poly-dioxanone biodegradable stents inspired us to consider its use in our patient. These stents are manufactured from a semi-crystalline biodegradable polymer that belongs to the polyester family of polymers, and a hydrolytic process causes its further degradation. As a consequence of this degradation process, the stent will experience a 50% loss of strength within 4 weeks, with complete absorption at between 3 and 6 months.^12-15

Because these biodegradable stents are designed to be absorbed, the potential of foreign body reactions is reduced, leading to fewer inflammatory responses and fewer additional procedures to remove the stent after it has served its purpose. Therefore, patients do not require an external drainage, the absence of which will further improve quality of life for these patients. Also, biodegradable stents will reduce the risks of long-term complications associated with permanent stents, such as stent migration or occlusion decreases.⁷ In pediatric patients, where growth is a crucial consideration, the use of biodeg-radable stents may allow for natural tissue growth and development, without the constraints imposed by nonresorbable stents.^13,15

Nevertheless, biodegradable stents could limit mechanical strength compared with nonresorbable stents. This limitation could affect the ability of biodegradable stents to provide adequate structural support during an extended period; therefore, there remains a major risk of re-stenosis before the biliary stenosis is adequately treated. All of these mentioned benefits require careful consideration of the stent cost and its customization. In some countries, like ours, among the major points to be weighed, the fact of being imported due to the lack of local manu-facturers should also be considered.

There is a scarcity of published reports on results after placement of biodegradable stents to treat anastomotic strictures. The overall clinical success rate ranges between 75% and 85%, with a morbidity of 30% and recurrence rate around 20%.^10,15 There are no previously published reports of biodegradable stent placement in transplant patients who are aged less than 1 year. Our case might be the first such case to combine the difficult combination of very young age and very small body size. The supplier of these stents manufactures on a case-by-case basis, but presently there is no availability of stents less than 8 mm in diameter. Therefore, based on global experience, we can assert that the advantages of this minimally invasive procedure are its safety, repro-ducibility, and effectiveness.

In conclusion, the use of percutaneous biodeg-radable stents to treat intrahepatic biliary strictures appears to be a viable option. The deployment of these devices could significantly reduce case of stent migration and complication rates associated with the use of traditional plastic or metal stents, in addition to the favorable absence of a removal procedure. Prospective randomized studies to validate these outcomes are needed.

Volume: 23 Issue: 6 June 2025

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