Single Plastic Stent Vs. Fully Covered Self-Expanding Metal Stent on Benign Biliary Stricture Secondary to Chronic Pancreatitis

The goal of this clinical trial is to compare the efficacy and safety of a single plastic stent versus a fully covered self-expanded metal stent in relieving benign biliary stricture secondary to chronic pancreatitis. The main questions it aims to answer is: Whether the efficacy of a single plastic stent is non-inferior to that of a fully covered metal stent in patients with benign biliary stricture secondary to chronic pancreatitis？ Participants will be randomly assigned to receive either a single plastic stent (SPS) placement or fully covered self-expanded metal stent placement treatment for 6 months, and they will be followed up for 18 months.

Although a number of previous studies have shown that the drainage and dilation effect of a single plastic stent is limited for benign biliary stricture (BBS) secondary to chronic pancreatitis (CP), the poor management of CP itself in most studies may explain the unsatisfactory efficacy of a single biliary plastic stent in relieving CP secondary BBS. Investigators believe that the effective management of CP is an important step to solve the BBS secondary to CP, especially the effective removal of pancreatic duct stones, the relief of pancreatic duct obstruction and the maintenance of pancreatic duct patency. Previous data showed that in CP patients treated with ESWL combined with ERCP, 72.4% could achieve complete removal of main pancreatic duct stones and 90.8% could achieve successful endoscopic decompression. Under the premise of effectively removing the stones of the main pancreatic duct at the head of the pancreas and maintaining the patency of the pancreatic duct, using a single plastic stent for stent drainage of BBS is effective, and a single plastic stent has potential advantages such as lower stent displacement rate and cheaper. Therefore, investigators design a single-center, prospective, open-label, randomized controlled, non-inferiority trial to compare the effectiveness, safety, and cost-effectiveness of a single plastic stent and fcSEMS for the removal of CP secondary BBS under the premise that the primary disease, i.e. CP itself, was effectively managed.