2 | CASE PRESENTATION
A 65-year-old man was admitted to our hospital for a periodic medical examination for CP. He also underwent periodic imaging examinations during 10 years follow-up on the benign biliary stricture caused by CP. Magnetic resonance cholangiopancreatography (MRCP) conducted as a part of these examinations revealed multiple CBD stones (Figure 1a). Contrast-enhanced computed tomography performed 6 months before the MRCP did not reveal the CBD stones, but instead revealed gallbladder stones. It was presumed that the gallbladder stones had progressively moved to the CBD. Therefore, we performed an endoscopic therapy for the CBD stones.
An endoscopic cholangiography revealed a distal CBD stricture and four CBD stones. The shortest diameter of each of the four CBD stones (6 mm, 5 mm, 4 mm, and 3 mm) was larger than the diameter of the distal CBD lumen (Figure 1b); therefore, the extraction of the stones was challenging. After endoscopic sphincterotomy (EST) (Figure 1c), we attempted to remove the CBD stones using a basket catheter, which is often used for the destruction of stones, too. However, the movement of the basket catheter was limited by the biliary stricture. Therefore, the basket catheter could only hold a small stone but could not extract them. The distal biliary duct was extremely narrow. Therefore, there was a possibility that either the placement of multiple biliary plastic stents would be difficult, or it would not sufficiently dilate the distal biliary stricture to remove the CBD stones. Additionally, no pancreatic atrophy was observed during imaging examinations. Considering the risk of injury to the pancreatic parenchyma, we did not perform dilatation with a balloon catheter. Taking into consideration all of the abovementioned factors, a CSEMS was placed to dilate the distal CBD stricture (Figure 1d–e). The CSEMS used in this case was BONASTENT M-intraductal 8 mm 7 cm (Standard Sci Tech, Seoul, Korea). The stent has a dumbbell shape, with an 8-mm diameter at both ends, and a 6-mm diameter at the center (Figure 2). The distal tip of the stent was pushed out from the duodenum to prevent proximal stent migration. Owing to the flared tips of the BONASTENT M-intraductal, the risk of proximal migration of the stent is reduced. The diameter of the CSEMS (8 mm) was the same as the diameter of the CBD. The length of the distal biliary stricture was 3 cm. A 7- or 6-cm-long stent had a mid-portion length of 2 cm, which is the longest version of the BONASTENT M-intraductal available commercially. In this case, the superior portion of the distal biliary stricture was slightly narrow. Therefore, we selected a longer stent of 7-cm length. Additionally, a pancreatic stent was placed in the main pancreatic duct to prevent post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis.11-19
A week after the first session, the second endoscopic cholangiography procedure was performed. We observed that all the CBD stones detected in the first session had disappeared spontaneously (Figure 3a). After the CSEMS was removed, the biliary sludge was removed using a balloon catheter (Figure 3b). Finally, it was confirmed that there were no CBD stones, and the stricture of the distal CBD had slightly improved (Figure 3c).
Approximately a year after the CBD stones were removed using the CSEMS, no recurrence of the CBD stones was observed on the follow-up imaging at an outpatient clinic.