What is the assessment and plan for a colovesical fistula?

Assessment and Plan for Colovesical Fistula

Assessment

Colovesical fistula should be diagnosed primarily through CT with intravenous contrast (sensitivity 76.5%), combined with colonoscopy to rule out malignancy, rather than relying on multiple redundant investigations. 1, 2

Clinical Presentation

• Pathognomonic symptoms occur in 87.5% of patients and include: 3
  • Pneumaturia (50.1%) 4
  • Fecaluria (40.9%) 4
  • Recurrent urinary tract infections (46.6%) 4

Diagnostic Workup

• CT with IV contrast is the gold standard imaging modality, demonstrating enhancing tract(s) with or without gas extending from colon to bladder wall, associated focal bladder wall thickening 1, 2
• CT cystography provides additional presurgical planning information regarding fistula size and location 1, 2
• Colonoscopy is mandatory (sensitivity 100% for detecting underlying colonic malignancy) to exclude cancer as the etiology 3
• Cystoscopy is performed in 55.9% of cases but adds limited diagnostic value beyond CT and colonoscopy 4
• Avoid over-investigation: Barium enema and contrast studies have lower sensitivity than CT and should not be routinely performed 1, 3

Etiology Classification

• Diverticular disease: 72.9-91% of cases 4, 3, 5
• Colorectal cancer: 10.8% 3
• Crohn's disease, trauma, iatrogenic: remaining cases 4, 6

Plan

Surgery is strongly recommended for colovesical fistulas, with single-stage resection of the involved bowel segment, primary anastomosis, and bladder drainage being the preferred approach. 7

Surgical Management

Preferred Approach: Single-Stage Resection

• Resect the fistula in continuity with any distal colorectal stricture 8
• Perform primary bowel anastomosis with bladder drainage 8
• Bladder management: Primary repair or partial cystectomy in 53.2% of cases; simple drainage often sufficient 4
• This approach results in no recurrences and low morbidity at 5-year follow-up 8

Laparoscopic vs. Open Surgery

• Laparoscopic approach is safe and feasible in high-volume centers, offering significant benefits: 5
  • Reduced surgical site infections 5
  • Decreased medical complications 5
  • Lower overall morbidity 5
• Open surgery remains appropriate (used in 63.3% of cases) when laparoscopic expertise unavailable or anatomy prohibitive 4
• Conversion rate: 2 of 17 laparoscopic cases required conversion to laparotomy 5

Multi-Stage Approach (Reserved for High-Risk Patients)

• Indications for staged procedure: 6
  • Pelvic abscess present 6
  • Advanced malignancy 6
  • Previous radiation therapy 6
  • Patient unfit for bowel resection 6
• Defunctioning stoma alone may improve quality of life in patients unfit for resection 6

Expected Outcomes

• Anastomotic leak rate: 4% 4
• Bladder leak rate: 1.8% 4
• Reoperation rate: 3.1% 4
• Overall morbidity: 8-49% 4
• 30-day mortality: Variable, with significant comorbidity burden 8
• Recurrence rate: 1.2% at median 5-68 month follow-up 4

Critical Pitfalls to Avoid

• Do not delay surgery for extensive diagnostic workup once CT and colonoscopy confirm diagnosis and exclude malignancy 3
• Do not miss underlying malignancy: Always perform colonoscopy preoperatively 3
• Do not attempt bladder closure if tissue quality poor: Simple drainage with catheter often sufficient 4, 8
• Recognize high comorbidity burden: Most patients die from unrelated causes within years, influencing surgical decision-making 8