Benign biliary strictures can be endoscopically treated with plastic or self-expandable metal stents (SEMS). The purpose of the prospective randomized study is to compare the safety and feasibility of covered SEMS with multiple plastic stents in the treatment of benign biliary stricture caused by chronic pancreatitis.

All consecutive patients admitted for ERCP and treated for benign biliary stricture caused by chronic pancreatitis are prospectively enrolled in the study.

At the initial ERCP, an endoscopic sphincterotomy will be performed and one 10 Fr plastic stent will be inserted for the initial treatment of cholestasis in all patients.Pancreatic stent will be inserted if indicated. One to three months after the initial ERCP the patients will be randomized into two groups: those who receive cSEMS and those who receive multiple plastic stents into the bile duct. For the randomization, sealed envelopes will be used. As for cSEMSs, removable cSEMSs with diameter of 10 mm will be placed. A dilation with a 8-10mm balloon will be performed before and after the stent placement to secure the stent expansion. As for plastic stents, minimum three simultaneous 10 Fr stents will be inserted after 8-10 mm balloon dilation.

After three months a further ERCP will be performed. The number of plastic stents will be increased maximally to six 10 Fr stents after dilation if possible. In the group with cSEMS, the position of the stent will be controlled.

Once the cSEMS or plastic stents have been in place for minimum six months, the stents will be removed at the last ERCP.

Follow-up

Clinical response (adequate biliary drainage) is the primary endpoint of the study. Therefore, blood liver function tests (bilirubin, alkaline phosphatase) as well as the minimum diameter of the common bile duct in the area of the stricture, the maximum diameter of the common bile duct above the stricture and the length of the stricture are measured at ERCPs at the time of the initial plastic stent insertion (i.e. the first ERCP) and at removal of cSEMS or multiple plastic stents (the last ERCP). In addition, blood liver function tests are measured and abdominal ultrasonography performed in the follow-up six months and two years after the stent removal.

Morbidity and mortality are additional endpoints of the study. Therefore, complications (deaths, stent occlusions, dislodgements or migrations, cholangitis, hemobilia, stone formation above the stent), management of complications, admission times, surgical interventions and any additional care needed are monitored and recorded during the follow-up time. Patients are asked to contact the physician at any time if symptoms such as fever, abdominal pain or jaundice occur.

Inclusion Criteria:

• Benign biliary stricture caused by chronic pancreatitis

Exclusion Criteria:

• Malignancy, cirrhosis acute/chronic hepatitis or abnormal hepatic imaging. First attack of acute pancreatitis.

All consecutive patients admitted for ERCP and treated for benign biliary stricture caused by chronic pancreatitis are prospectively enrolled in the study.