A randomized controlled trial to determine the optimal placement duration of pancreatic duct stents (PDS) inserted during ERCP: 2 vs 4 weeks

Endoscopic pancreatic duct stenting has been increasingly used for the treatment of a variety of pancreatic disorders including chronic pancreatitis, pancreatic duct stricture, drainage of pseudocysts, and the prevention of pancreatitis following endoscopic retrograde cholangiopancreatography (ERCP). Several randomized, controlled trials and meta-analyses have proven a significant reduction in incidence and severity of post-ERCP pancreatitis (PEP) with prophylactic pancreatic duct stenting. The US and European guidelines recommend that pancreatic duct stents (PDS) be placed between 7-10 days and 5-10 days, respectively, in order to prevent PEP in some situations. Therefore, the placement of PDS has been an established essential procedure for preventing a fatal complication, PEP. Furthermore, PDS placement can facilitate difficult common bile duct cannulation. It may help not only to straighten papillary anatomy but also to identify the location of the biliary orifice.

However, PDS tends to become occluded easily due to protein content, calcium carbonate crystals, and bacteria in the pancreatic juice. The occluded PDS can cause acute pancreatitis or abdominal pain. For this reason, the guidelines recommend PDS be placed within 10 days. Because of this policy, the patient must take the inconvenience of undergoing another endoscopic procedure to remove the PDS. However, all patients with occluded PDS do not have symptoms such as pain. In one series, only 6 percent of patients with clogged PDS developed symptoms. The low incidence of symptoms despite a high rate of stent occlusion suggests that the stent may function as a wick around which pancreatic juices continue to drain. In addition, the rate of spontaneous stent dislodgement was relatively high (65-86%) within 30 days according to a previous study. A recent study also reported that prolonged retention of prophylactic pancreatic stents is not associated with increased complications.

Taken together, PDS placed during ERCP do not need to be removed until any symptom develops. In particular, if the investigators can observe PDS for about a month without removing them, the PDS are more likely to pass out spontaneously, which could reduce unnecessary procedures. However, to date, there have been few randomized controlled studies on the optimal placement duration of PDS inserted during ERCP.

Inclusion Criteria:

• Patients who underwent the pancreatic duct stent placement during ERCP

Exclusion Criteria:

• Patients who had pancreatic duct stent for the purpose of pancreatic interventions
• Patients who underwent simultaneous bile duct stenting