A pancreatic stent is a small, flexible tube placed temporarily or permanently inside the pancreatic duct to manage various conditions. Its primary function is to restore or maintain the proper flow of pancreatic juices. When the normal drainage pathway is blocked or disrupted, the stent provides an open channel, which helps to relieve pain and prevent further damage to the organ.
Conditions Requiring Pancreatic Stenting
A stent becomes necessary when the main pancreatic duct experiences an obstruction or a leak that prevents the normal transport of fluid. One common issue is a stricture, which is a narrowing of the duct, often caused by the inflammation associated with chronic pancreatitis. This narrowing can cause a build-up of pressure within the duct system, leading to significant abdominal pain that may be relieved by stenting to decompress the duct.
Pancreatic duct stones can also cause blockages that require stenting to bypass or facilitate removal. Stones larger than five millimeters may first require a procedure like extracorporeal shock wave lithotripsy (ESWL) to break them into smaller fragments before a stent is placed. The stent then aids in drainage following stone removal or holds the duct open if a stricture is present.
Ductal disruption, a tear or leak in the pancreatic duct, often requires a stent to bridge the gap and divert the flow of pancreatic juice away from the injured area. The stent allows the disrupted tissue to heal naturally around the tube. Stents are also used as a precautionary measure to prevent post-procedure pancreatitis in patients considered to be at high risk after an endoscopic procedure.
Finally, tumors, particularly those in the head of the pancreas, can compress the pancreatic duct, causing an obstruction. In these cases, a stent is often used as palliative care to relieve the blockage and ease symptoms such as pain. For patients with cancer, the decision to use a stent is based on the patient’s prognosis and whether the stent is intended to be a long-term solution or a temporary measure before surgery.
The Procedure for Placing a Pancreatic Stent
The most common method for placing a pancreatic stent is Endoscopic Retrograde Cholangiopancreatography (ERCP). This procedure involves a specialized, flexible endoscope that is passed through the mouth, down the esophagus and stomach, and into the duodenum. The endoscope is guided to the papilla of Vater, the small opening where the pancreatic and bile ducts empty into the intestine.
The physician uses the endoscope to inject a contrast dye into the pancreatic duct and take X-ray images, which helps to visualize blockages, stones, or strictures. A thin guide wire is then threaded through the papilla, past the obstruction, and deep into the pancreatic duct. The stent is advanced over this guide wire and positioned across the narrowed or damaged segment of the duct.
In situations where the standard transpapillary approach is impossible, such as with complex anatomy or an impassable stricture, an alternative technique called Endoscopic Ultrasound (EUS) may be utilized. EUS-guided drainage involves using an ultrasound probe on the end of an endoscope to puncture the pancreatic duct from the stomach or duodenum and then place the stent.
Stents are generally made from either plastic or metal, and the choice depends on the expected duration of treatment and the nature of the condition. Plastic stents are used for temporary drainage in benign conditions, such such as chronic pancreatitis strictures or leaks.
Metal stents are designed to remain open for a longer period due to their larger diameter and stronger material. These are typically reserved for malignant obstructions, where a long-term solution is necessary to relieve symptoms. Fully covered metal stents are sometimes used for benign strictures because their covering allows for easier removal or repositioning.
Stent Management and Follow-Up Care
After a pancreatic stent is placed, patients are closely monitored for a short period following the procedure to ensure there are no immediate complications, such as severe pain, bleeding, or infection. The most serious risk to monitor for is post-ERCP pancreatitis.
Adherence to the follow-up schedule is important, especially for patients with plastic stents, as these tubes are prone to clogging with pancreatic secretions. A clogged stent can lead to recurrent pain and infection. For temporary indications, the stent is often removed within one to two weeks.
In the case of chronic pancreatitis strictures, treatment involves a series of staged procedures where plastic stents are exchanged every three to six months. Stents may sometimes be progressively increased in size to gradually dilate the narrowed duct. If a stent is intended to be a long-term solution, such as a metal stent for a malignant tumor, it may remain in place for six to twelve months or longer due to its increased patency duration.
Patients must be educated on the signs that indicate a stent may be failing or blocked. These signs include the return of severe abdominal pain, a persistent fever, or the onset of jaundice. Recognizing these symptoms quickly is important, as a blocked stent requires immediate medical attention and a repeat endoscopic procedure for replacement or removal.