What is the recommended treatment for symptomatic or infected walled off pancreatic necrosis (WOPN) using Endoscopic Ultrasonography (EUS) guided drainage?

EUS-Guided Drainage for Walled Off Pancreatic Necrosis

EUS-guided cystogastrostomy with lumen-apposing metal stent (LAMS) placement is the preferred initial approach for symptomatic or infected walled-off pancreatic necrosis (WOPN), as it achieves superior outcomes with shorter hospital stays and better quality of life compared to surgical or percutaneous approaches. 1, 2

Initial Assessment and Diagnosis

Before proceeding with drainage, confirm the diagnosis and characteristics of the collection:

• Use EUS or MRI to differentiate WOPN from simple pseudocysts, as WOPN contains solid necrotic debris requiring more aggressive management than fluid-only collections 3, 4
• Perform CT-guided fine-needle aspiration with culture and Gram stain when infection is suspected (clinical deterioration, persistent fever after 7-10 days, gas in collection on imaging) 3, 4
• Wait at least 4 weeks from pancreatitis onset to allow maturation of the collection wall before intervention, as earlier intervention increases mortality 1

Clear Indications for Intervention

Proceed with drainage when any of the following are present:

• Clinical deterioration with confirmed or strongly suspected infected necrosis 1
• Ongoing organ failure persisting beyond 4 weeks 1
• Mechanical complications: gastric outlet, biliary, or intestinal obstruction 1
• Disconnected pancreatic duct syndrome 1
• Persistent pain and discomfort beyond 8 weeks 1

Technical Approach: EUS-Guided Drainage

The optimal technique is EUS-guided transmural drainage with LAMS placement:

• Use 20-mm LAMS rather than 15-mm LAMS when available, as this achieves equivalent clinical success (92.2%) but requires significantly fewer direct endoscopic necrosectomy sessions (mean 1.3 vs 2.1 sessions) without increased bleeding risk 5
• Consider multiple transluminal gateway technique (MTGT) for complex cases: create 2-3 transmural tracts with one for saline irrigation via nasocystic catheter and others for stent deployment, which achieves 91.7% success versus 52.1% with conventional single-tract drainage 6
• Transmural drainage alone suffices for pseudocysts, but WOPN typically requires adjunctive direct endoscopic necrosectomy (DEN) to remove solid necrotic debris 2, 7

Safety Considerations

Critical technical requirements to minimize complications:

• Only drain collections with mature walls located within 1 cm of the GI lumen 7
• Correct any coagulopathy before the procedure 7
• Administer prophylactic antibiotics to prevent secondary infection of sterile collections 7
• Tailor antibiotic therapy based on culture results from fine-needle aspiration when infection is documented 4

When Endoscopic Drainage Is Not Optimal

Consider percutaneous catheter drainage (PCD) instead for:

• Large, complex collections involving the pancreatic tail 3, 1
• Collections not in direct communication with the pancreas 3, 1
• Collections not abutting the stomach wall (endoscopy works best for central collections against the greater gastric curvature) 3, 1
• Patients who are poor surgical candidates requiring temporizing measures 3

However, recognize PCD limitations: cure rates of only 14-32%, higher reintervention rates, longer hospital stays, and more follow-up imaging compared to endoscopic approaches 3, 1. Complete pancreatic duct occlusion central to the collection predicts PCD failure 3, 4.

Surgical Intervention

Reserve surgery only for endoscopic/percutaneous failure, as randomized trials demonstrate endoscopic approaches achieve shorter hospital stays and superior patient-reported physical and mental outcomes 3, 1. Additional surgical indications include abdominal compartment syndrome, acute bleeding when endovascular approaches fail, and bowel complications or fistulas extending into the collection 1.

Critical Pitfalls to Avoid

• Do not mistake WOPN for simple pseudocysts – the internal necrotic debris requires different management, and simple drainage without debridement predisposes to infection 3, 4
• Do not intervene before 4 weeks unless there is clinical deterioration, as premature intervention increases mortality 1
• Do not use size alone as an intervention criterion – symptomatic status and complications drive treatment decisions 1
• Do not manage infected necrosis at community hospitals – these patients require centers with specialist endoscopic, radiologic, and surgical expertise 3, 4