ABSTRACT
Endoscopic biliary plastic stent (PS) insertion is standard for maintaining bile flow, but migration and dislodgement persist as important challenges. We developed the cross range flap stent (CRF stent), a 7 Fr, 7 cm straight‐type PS. Unlike conventional stents with flaps at both ends, the CRF stent features flaps and flap holes at the intestinal end and the center to improve stability and to prevent migration. This report describes three consecutive early cases for which the CRF stent was used for distal malignant biliary stricture caused by pancreatic cancer, acute cholangitis caused by common bile duct stones, and prevention of cholangitis after endoscopic papillectomy. In all cases, the CRF stent was placed easily using its integrated delivery system. No migration or occlusion was observed during the observation periods. The unique centrally located flap appears to be particularly effective for short obstructions and for various clinical conditions. Further largescale comparative studies must be conducted, but the CRF stent has shown potential to minimize stentrelated adverse events.
Keywords: biliary obstruction, biliary stricture, common bile duct stone, migration, plastic stent
1. Introduction
Endoscopic biliary plastic stent (PS) insertion, a well‐established and widely used modality, maintains bile flow in both benign and malignant conditions such as irretrievable choledochal stones, benign biliary strictures (BBS), malignant biliary strictures (MBS), and post‐operative biliary leaks [1]. Biliary stent improvement and development are underway to extend patency and to prevent stent‐related adverse events. Recently, we devised and released a new straight‐type PS to prevent dislodgement and migration. This new biliary PS, called a cross range flap stent (CRF stent; Gadelius Medical K.K., Tokyo, Japan), is an Amsterdam‐type (straight‐type) PS, but the flap position differs from that of conventional stents (Figure 1). Conventional stents have flap holes for drainage and flaps to prevent migration and displacement at the liver and intestinal ends. By contrast, the newly developed stent has flaps and flap holes located at the intestinal end and center of the stent. That particular flap placement is expected to reduce migration and dislodgement, especially in cases of short bile duct obstruction, common bile duct (CBD) stones, and duodenal papilla tumors. The PS features two flap openings, which serve as the primary conduits for drainage. Although it is available in only one size, 7 Fr 7 cm, it is expected to be effective in various cases, especially those with short bile duct strictures.
FIGURE 1.
Cross range flap (CRF) stent. The newly developed biliary plastic stent has flaps and flap holes located at the intestinal end and center of the stent (arrow), which are expected to reduce migration and dislodgement. Composed of polyethylene, this device is compatible with guide wires of up to 0.035‐inch diameter. Furthermore, this delivery system features an integrated stent and pusher tube design, allowing for retraction as needed; it is easy for even novice operators to use. However, it is available in only one size: 7 Fr 7 cm.
We herein report three consecutive early cases for which the new PS was used.
2. Case Report
This case series includes three consecutive early cases of CRF stent use for distal malignant biliary stricture caused by pancreatic cancer, acute cholangitis caused by CBD stones, and prevention of cholangitis after endoscopic papillectomy (EP). A summary and videos of the three cases are presented in the Supporting Information.
2.1. Case 1
A 64‐year‐old man was diagnosed with pancreatic head cancer and was scheduled for surgery. When neoadjuvant chemotherapy was initiated, obstructive jaundice was noted. Drainage by endoscopic retrograde cholangiopancreatography (ERCP) was performed. Cholangiography revealed a short 5 mm stricture in the distal bile duct (Figure 2a), leading to a diagnosis of malignant biliary stricture caused by pancreatic head cancer. The stricture was quite short. A CRF stent was selected as the appropriate intervention. After endoscopic sphincterotomy, a 7 Fr 7 cm CRF stent was placed in the bile duct. The central flap was placed just on the liver side of the stricture (Figure 2b). After jaundice improved following treatment, the patient was discharged on the fourth hospital day without adverse events. He subsequently underwent neoadjuvant chemotherapy. Pancreaticoduodenectomy was performed 68 days after CRF stent placement. He had not developed cholangitis until the day of surgery. A CT scan taken the day before surgery confirmed that no CRF stent migration or obstruction had occurred (Figure 2c,d).
FIGURE 2.
Case 1: pancreatic head cancer. (a) Endoscopic retrograde cholangiography showed a 5 mm distal malignant biliary stricture (white arrowhead). Because the stricture was quite short, a cross range flap (CRF) stent was selected as the appropriate intervention. (b) The central flap was placed just slightly to the liver side of the stricture (yellow arrow). (c) Contrast‐enhanced computed tomography taken the day before surgery. The central flap (yellow arrow) is visible within the bile duct. (d) The distal flap was observed in the duodenum (blue arrow), confirming that the stent had not migrated.
2.2. Case 2
A 66‐year‐old man visiting our hospital complaining of abdominal pain, fever, and jaundice had undergone endoscopic treatment for CBD stones approximately 3 months prior. After detailed examination, he was diagnosed with CBD stone cholangitis. An emergency ERCP was performed. A cholangiogram revealed a recurrent CBD stone (Figure 3a). Endoscopic sphincterotomy had already been performed during the earlier ERCP. A CRF stent was placed (Figure 3b) with the central flap positioned directly over the stones to prevent migration and to optimize drainage (Figure 3c). No adverse event occurred. He was discharged 3 days later. He underwent cholecystectomy approximately 1 month after discharge. One month thereafter, the CRF stent was removed endoscopically. The stone was removed. Approximately 73 days had passed since the CRF stent had been placed, but plain radiographs showed little change from its initial placement (Figure 3d).
FIGURE 3.
Case 2: acute cholangitis caused by common bile duct stones. (a) Endoscopic retrograde cholangiography showed two common bile duct stones in the distal bile duct. (b) Endoscopic image of the cross range flap (CRF) stent in place. (c) A CRF stent was placed. The central flap (yellow arrow) was positioned directly over the stone (white arrowhead). The distal flap is observed in the duodenum (blue arrow). (d) Approximately 73 days had passed since the CRF stent was placed, but plain radiographs showed little change in its position compared to when the stent was placed (yellow arrow, central flap; blue arrow, distal flap).
2.3. Case 3
A 58‐year‐old man was diagnosed with a duodenal papillary tumor, which was identified histologically as an adenoma (Figure 4a). He underwent EP. Following papillectomy, ERCP was performed to place biliary and pancreatic PS to prevent cholangitis and acute pancreatitis. The biliary orifice was identified from the resection surface. A catheter was used to intubate the bile duct. A CRF stent was placed at the bile duct orifice to prevent stricture. This specific stent was selected to minimize the risk of migration. Migration is often more likely to occur because of the post‐EP loss of the sphincter of Oddi anchoring function. In addition, a PS with a flap was placed at the pancreatic duct orifice (Figure 4b,c). No postoperative adverse event occurred. The patient was discharged on the sixth day. The CRF stent was removed endoscopically 65 days later. During the period leading up to removal, no cholangitis occurred. Fluoroscopy showed that the pancreatic stent had dislodged, but that the CRF stent remained in place (Figure 4d). The patient has had no symptoms after stent removal.
FIGURE 4.
Case 3: After endoscopic papillectomy (EP). (a) Duodenal papilla adenoma before EP. (b) A cross range flap (CRF) stent was placed at the bile duct orifice to prevent stricture (arrow). Loss of the anchoring function of the sphincter of Oddi because of endoscopic papillectomy increases the risk of distal migration of biliary plastic stents. (c) Abdominal radiograph taken immediately after treatment. A CRF stent was placed in the bile duct (yellow arrow, central flap). A plastic stent (PS) with a flap was placed in the pancreatic duct. (d) The biliary stent was removed 65 days after EP. Fluoroscopy confirmed that the pancreatic duct stent had dislodged, but the CRF stent remained in place (yellow arrow, central flap; blue arrow, distal flap).
3. Discussion
Benefits of biliary PS include its (1) low cost, (2) simple procedures leading up to placement, (3) easy positioning, removal, and replacement after placement, as well as (4) the ability to place multiple stents [2, 3]. Biliary PS are currently available in various shapes and lengths. The choice depends largely on the endoscopist's preference. Along with the many PS benefits as described above, an important shortcoming is that the small diameter of the PS lumen (7–10 Fr) can lead to early stent occlusion. Stent occlusion during the waiting period for surgery in preoperative biliary drainage is particularly problematic [4].
In addition, biliary stent migration can occur in 5%–10% of patients with endoscopic biliary stenting [5]. A retrospective study of BBS and MBS interpreted the rate of migration as 8.58% (proximal 4.58%, distal 4.00%). In BBS, short stents migrated proximally more frequently; long stents migrated distally more frequently [6]. Johanson et al. [5] stated that “The finding that shorter stents are at increased risk of migrating proximally is not surprising. Longer stents are less likely to migrate because the length of the CBD is finite and therefore their propensity to migrate proximally is limited. On the other hand, shorter stents have greater liberty to migrate proximally.” A key feature of this new stent is that its proximal flap is located at the center of the stent. Conventional stents have a shorter distance from the flap to the proximal end: the distance from the flap to the proximal end of this new stent is approximately 4 cm. Because of this greater flap—proximal end length, this new stent is less likely to migrate proximally. However, depending on the distance from the proximal end of the stenosis to the liver, this greater length might yield no benefit. This matter must be clarified based on findings of future largescale case studies.
The usefulness of a 12 Fr straight PS for MBS has been reported in recent years [7]. However, because of the stent's large size and non‐integrated delivery system, inserting it into the bile duct requires skill. The CRF stent might present a promising option for preventing stent migration, but its clinical effectiveness should be evaluated based on findings from larger prospective studies.
Several points are noteworthy when using the CRF stent. Caution must be observed for cases with hilar involvement or strictures exceeding 3 cm. In such instances, the flap might catch on the narrowed segment, potentially leading to stent migration. Moreover, although the CRF stent is effective for standard CBD stones, caution must be observed for a huge stone or multiple stones extending to the hepatic hilum because the central flap might cause stent migration in such cases.
The three cases described herein involved different diseases. The stent was used for both malignant and benign conditions. Even in cases where the stenosis was quite short, imaging showed almost no stent migration. No symptom or finding suggestive of occlusion was observed at the time of stent removal or during the waiting period for surgery. Because this study examines only a few cases, the frequencies of stent migration and occlusion remain unknown, but the CRF stent might represent a promising option for reducing stent migration, although comparative studies are needed. For future studies, we expect it will be necessary to accumulate many cases and to compare treatment outcomes to those obtained using existing Amsterdam‐type stents.
Author Contributions
Fumi Sakuma and Atsushi Irisawa wrote the manuscript. Koh Fukushi, Takumi Maki, Shogo Yamamoto, and Ken Kashima summarized the clinical course. Akira Yamamiya, Yasunori Inaba, Ryuichi Maki, and Yasuhito Kunogi set up the endoscopic imaging and collected the literature.
Funding
The authors have nothing to report.
Ethics Statement
This case report was conducted in accordance with the ethical standards established in the 1964 Declaration of Helsinki and its later amendments.
Conflicts of Interest
The authors declare no conflicts of interest.
Supporting information
Supporting Table 1: Summary of three cases using CRF stents.
Supporting Video 1: Case 1: Demonstrates ERCP for distal malignant biliary stricture and placement of the CRF stent with the central flap positioned above the stricture.
Supporting Video 2: Case 2: Demonstrates ERCP for a common bile duct stone and placement of a CRF stent with the central flap just above the common bile duct stone.
Supporting Video 3: Case 3: ERCP performed after endoscopic papillectomy and CRF stent placement.
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Associated Data
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Supplementary Materials
Supporting Table 1: Summary of three cases using CRF stents.
Supporting Video 1: Case 1: Demonstrates ERCP for distal malignant biliary stricture and placement of the CRF stent with the central flap positioned above the stricture.
Supporting Video 2: Case 2: Demonstrates ERCP for a common bile duct stone and placement of a CRF stent with the central flap just above the common bile duct stone.
Supporting Video 3: Case 3: ERCP performed after endoscopic papillectomy and CRF stent placement.