Is leaving a long-term (3-4 weeks) percutaneous drain in abscesses related to colonic diverticular (diverticulitis) rupture more likely to lead to fistulization to the bowel compared to draining as much of the abscess as possible within 1-2 weeks then removing it?

Management of Percutaneous Drains in Colonic Diverticular Abscesses

Removing percutaneous drains within 1-2 weeks is preferable to longer-term (3-4 weeks) drainage in abscesses related to colonic diverticular rupture, as prolonged catheterization increases the risk of fistula formation to the bowel.

Drainage Duration and Fistula Risk

The duration of percutaneous drainage is a critical factor in managing diverticular abscesses:

• According to the World Journal of Emergency Surgery guidelines (2020), percutaneous drainage catheters should be removed "when the output has ceased or decreased substantially" 1
• A retrospective study found that fistula formation occurred in 38% of cases following percutaneous drainage of diverticular abscesses, with a mean drainage duration of 8 days 2
• Prolonged catheter contact with inflamed bowel increases the risk of erosion into the intestinal wall, potentially creating iatrogenic fistulas

Evidence-Based Approach to Drain Management

When to Remove Drains

• Remove drains when:
  • Catheter output has decreased to <10-20 cc per day 1
  • Resolution of the abscess is confirmed on repeat imaging 1
  • Patient shows clinical improvement with resolution of signs of infection 1
  • Typically within 1-2 weeks for uncomplicated cases

Monitoring During Drainage

• Perform CT scan with water-soluble contrast via the drain before removal in doubtful cases 1
• If no identifiable cavity remains, remove the catheter 1
• If resolution is not achieved and the patient shows no clinical improvement, consider:
  • Catheter repositioning
  • Further drainage
  • Possible surgical intervention 1

Complications of Prolonged Drainage

• Fistula formation is a significant risk with longer-term drainage (3-4 weeks)
• Studies show that in cases of enteric communication, percutaneous drainage provides only temporary palliation and often requires definitive surgery 3
• A 2008 study demonstrated that fistula formation following drainage occurred in 38% of diverticular abscess cases 2

Special Considerations

• For small abscesses (<4-5 cm), antibiotic therapy alone may be sufficient 4
• For larger abscesses (≥4-5 cm), percutaneous drainage plus antibiotics is recommended 4
• If feculent drainage develops (indicating fistula formation), early operation and fecal diversion may be necessary 5
• In cases where the abscess does not resolve with percutaneous drainage, surgical intervention should be considered 1

Follow-up After Drain Removal

• Plan an early colonic evaluation (4-6 weeks) after non-operative treatment of diverticular abscesses 1
• This is recommended to rule out underlying malignancy, which can occasionally present as a colonic localized abscess 1

Pitfalls to Avoid

• Leaving drains in place for extended periods (3-4 weeks) when output has already ceased
• Failing to recognize signs of fistula formation (persistent drainage, feculent material)
• Not performing imaging before drain removal in complex cases
• Overlooking the need for surgical consultation when drainage is inadequate or fistulas develop

The evidence suggests that a shorter duration of percutaneous drainage (1-2 weeks) with timely removal once the abscess has resolved is the optimal approach to minimize the risk of fistula formation while effectively treating diverticular abscesses.