What is the recommended management for an enterovesical fistula?

Management of Enterovesical Fistula

Enterovesical fistulae should be managed with initial medical control of inflammation followed by surgical resection, as this combined approach offers the best outcomes for morbidity and quality of life. 1

Initial Assessment and Stabilization

Obtain CT scanning as the primary diagnostic modality to define fistula anatomy, identify associated abscesses, and evaluate for complications including bowel obstruction or strictures. 2 CT has 80% sensitivity and is superior to other imaging for surgical planning. 2

Immediately assess for intra-abdominal abscess on imaging, as any collection must be drained before initiating anti-TNF therapy or proceeding to definitive surgery. 1

Critical First Steps:

• Treat any identified abscess with IV antibiotics and radiological drainage first - never start anti-TNF therapy before adequate drainage as this worsens sepsis and increases mortality. 1, 3
• Obtain urine culture, as recurrent urinary tract infection occurs in 73% of patients and guides antibiotic selection. 4
• Perform cystoscopy (87.5% positive) and colonoscopy to evaluate for malignancy, which accounts for 36% of cases and must not be missed preoperatively. 4, 2

Medical Management Strategy

Initiate medical therapy only after sepsis control and abscess drainage are complete. 1, 3

For Crohn's Disease-Related Fistulae:

• Start anti-TNF therapy (infliximab preferred) if the fistula is associated with active intestinal inflammation after all abscesses are drained. 1
• Medical therapy achieves complete fistula closure in 65.9% of enterovesical fistulae from Crohn's disease. 1
• However, only one-third achieve healing overall, and half of responders relapse over 3 years. 1, 3

Risk Factors Predicting Medical Failure (Proceed Earlier to Surgery):

• Sigmoid colon origin of fistula 1
• Small bowel obstruction 1
• Abscess formation 1
• Multiple fistula tracts (complexity) 1
• Associated stricture/stenosis 1
• Ureteric obstruction 1
• Recurrent urinary tract infections despite treatment 1

Surgical Management

Surgery is the definitive treatment and should be performed after a 3-12 month optimization period unless complications mandate earlier intervention. 5, 3

Absolute Indications for Surgery:

• Failure of medical therapy after adequate trial (typically 3-6 months) 1, 5
• Bowel obstruction or stricture 1, 5
• Persistent or recurrent abscess despite drainage 1, 5
• Malignancy (16-36% of cases) 4, 6
• Persistent urinary sepsis despite antibiotics 6, 7

Preoperative Optimization Protocol (Complete All Four Steps):

1. Fluid and electrolyte balance: Aggressive IV normal saline resuscitation if needed 5
2. Sepsis control: Complete drainage of all abscesses, IV antibiotics until resolved 5, 3
3. Nutritional optimization: Achieve BMI >20 kg/m² if possible; consider enteral or parenteral nutrition for malnourished patients 5, 8
4. Skin care: Protect peristomal skin with barrier products 5

Surgical Technique:

One-stage resection is the procedure of choice for patients who complete optimization without active sepsis or obstruction. 9, 6

• Resect the diseased bowel segment with the fistula tract - this is the critical step. 5, 9
• Separate the fistulized bowel from the bladder but formal bladder repair is usually unnecessary. 9
• Place Foley catheter for 7 days - this alone is sufficient for bladder healing in 68% of cases. 9
• Only repair the bladder defect if there is an overt large defect visible after bowel separation. 9, 7
• Perform primary anastomosis in healthy, well-vascularized bowel after adequate debridement. 5

Surgical Outcomes:

• One-stage resection achieves symptomatic cure in 88% of patients (22/25) with 8% complication rate and no mortality in benign disease. 2, 6
• All bladder defects managed with Foley catheter alone healed within 1 week. 9

Management Approaches by Clinical Scenario

Asymptomatic or Minimally Symptomatic Fistula:

• Conservative management with antibiotics is acceptable if the patient has minimal symptoms and is not a surgical candidate. 6, 7
• All 8 patients managed medically in one series remained free of fistula complications until death from other causes. 6
• Four asymptomatic patients managed conservatively remained symptom-free at follow-up. 7

Symptomatic Fistula with Good Surgical Candidacy:

• Proceed with medical optimization followed by one-stage surgical resection. 9, 6

Complicated Fistula (Abscess, Obstruction, Malignancy):

• Never perform diverting colostomy - all 8 patients treated with diversion had persistent fistulas and urinary sepsis. 6
• Drain abscess first, then proceed to resection after sepsis resolves. 1, 5
• For malignancy, resection is mandatory even if palliative intent. 4, 6

Critical Pitfalls to Avoid

• Never start anti-TNF therapy before draining abscesses - this worsens sepsis and increases mortality. 1, 3
• Never perform diverting colostomy without resection - this results in persistent fistula and urinary sepsis in 100% of cases. 6
• Never operate immediately without completing the four-step optimization protocol - this leads to poor outcomes and high mortality. 5, 3
• Never assume benign etiology - obtain tissue diagnosis as malignancy accounts for 16-36% of cases and is missed preoperatively in 50% of cancer patients. 4, 6
• Never bypass or defunctionalize the fistula - this results in persistent sepsis and mortality. 7

Multidisciplinary Team Requirement

All patients must be managed by a multidisciplinary team including gastroenterologist, colorectal surgeon, urologist, dietitian, and wound care specialist given the complexity and association with adverse outcomes. 1, 8, 3