A urinary fistula is an extra-anatomic communication between two or more epithelial- or mesothelial-lined cavities or the skin surface. Successful management follows shared principles and corrects reversible contributors before (and during) repair.
Management Principles
- Reversible factors — "Fistula TO MIIND" (8): Foreign body, Technical surgical problems, urinary Obstruction, Malignancy (biopsy if prior cancer), Ischemia/Infection, Nutrition, and Drainage (unobstructed drainage/stenting).
- Surgical repair principles (11): adequate exposure; debride devitalized tissue; remove foreign bodies; anatomically separate the cavities; watertight closure; well-vascularized healthy tissue flaps; multilayer closure; tension-free non-overlapping suture lines; adequate drainage/stenting; treat/prevent infection; maintain hemostasis.
Urogynecologic Fistulae
Vesicovaginal Fistula (VVF)
VVF accounts for 75% of acquired urinary-tract fistulae. Causes — "Radical, Obstetrical Colleagues' Trauma Causes Incontinence Fistula" (radiation, obstetric, cancer, trauma, postsurgical, external trauma, congenital/inflammatory/foreign body):
- Industrialized world — most common (>75%) is surgical bladder injury, usually at hysterectomy (iatrogenic cystotomy ~0.5–1.0%; fistula after hysterectomy ~0.1–0.2%), typically from an unrecognized cystotomy near the vaginal cuff → urinoma → drainage through the cuff.
- Developing world — most common is prolonged obstructed labor (pressure necrosis); obstetric fistulae tend to be larger, more distal, and involve the bladder neck/proximal urethra.
- Radiation fistulae can appear decades later — any fistula after radiation for malignancy may represent recurrence.
- Clear vaginal discharge after hysterectomy is not invariably a urinary fistula (also normal secretions, peritoneo-/lymphatic fistula, vaginitis, tubal fluid).
Diagnosis (4): history/physical (most common complaint is constant vaginal urinary drainage; pain is uncommon; post-hysterectomy VVFs lie along the anterior wall at the cuff); urinalysis ± culture; imaging — lower tract (cystogram/VCUG; non-diagnostic without voiding/postvoid images) and upper tract (CT urography — up to 12% of postsurgical VVFs have associated ureteral injury/ureterovaginal fistula); and cystoscopy.
- Dye test (optional): instill methylene blue/indigo carmine per urethra and watch a vaginal pack — proximal staining = VVF, distal = UI/urethrovaginal. If the pack is dye-free, give IV indigo carmine — proximal staining = ureterovaginal fistula. The double-dye (tampon) test (oral phenazopyridine + intravesical blue): yellow-orange at top = ureterovaginal, green in the middle = VVF, blue at the bottom = urethrovaginal.
Management:
- Conservative — a trial of indwelling catheter + anticholinergic for 2–3 weeks (spontaneous closure ~13%; favorable if <2–3 mm and non-devascularized). Tracts open ≥3 weeks despite drainage are unlikely to resolve.
- Fulguration — for small epithelialized fistulae <3–5 mm (± catheter); risks failure/enlargement with a thin septum, large/non-oblique tract, or inflammation. Fibrin sealant is adjunctive.
- Surgery — transvaginal or transabdominal (transvesical); success is similar and depends most on surgeon experience. Transvaginal: shorter operative time/stay, less blood loss (but limited cuff exposure, possible vaginal shortening with Latzko). Abdominal: for concurrent intra-abdominal pathology or complicated/large (>5 cm) fistulae. Tract excision isn't always necessary. Tissue interposition (recurrence, radiation, ischemic/obstetric, large, or tenuous repairs): transvaginal Martius flap or peritoneum; transabdominal omentum or peritoneum.
- Martius flap (labial fat pad) — blood supply: external pudendal (superior), obturator (lateral), posterior labial/internal pudendal (inferior); preferred for low/distal fistulae (trigone, bladder neck, urethra).
- Peritoneal flap — preferred for high post-hysterectomy VVF; omental flap (gastroepiploic supply) useful with infection/inflammation.
- Drainage — most use both urethral and suprapubic catheters; obtain a postoperative cystogram (with voiding/postvoid images) at 2–3 weeks. Simple-VVF repair success >90%; obstetric/large/radiation fistulae do worse; persistent severe sphincteric incontinence can remain despite successful closure. Non-candidates: urinary diversion or percutaneous ureteral occlusion with permanent nephrostomy.
Ureterovaginal Fistula
From surgical injury to the distal third of the ureter, most commonly at hysterectomy for benign disease (iatrogenic ureteral injury ~0.5–2.5%). Presents with constant incontinence 1–4 weeks postop while normal voiding is maintained (the other kidney still fills the bladder). Imaging: CT urography typically shows ureteral obstruction/dilation; retrograde pyelography may allow stenting; cystography excludes coexistent VVF. Management: prompt upper-tract drainage (stent or PCN); stenting may promote closure; if unsuccessful or with complete occlusion, surgical repair (usually ureteroneocystostomy, >90% success).
Vesicouterine Fistula
Among the least common; most commonly after Cesarean section. May or may not cause constant incontinence (cervical sphincter-like activity), except with an incompetent postpartum cervix. Management: prolonged catheterization/fulguration for small immature fistulae, hormonal induction of menopause (uterine involution), and surgery per fertility wishes (transabdominal hysterectomy + bladder closure, or uterine-sparing repair).
Urethrovaginal Fistula
Mostly iatrogenic in industrialized countries (not associated with hysterectomy); from obstructed labor in the developing world. Proximal fistulae cause SUI or (at the bladder neck) continuous leakage; distal fistulae may be asymptomatic or splay the stream. Diagnose on exam, cystourethroscopy, and VCUG; associated VVF in up to 20%. Manage by excising foreign material and using soft-tissue flaps (most commonly Martius); SUI may persist.
Uroenteric Fistulae
Vesicoenteric Fistula
Diverticulitis is the most common cause of colovesical fistula (also colon cancer, Crohn's; less often radiation/infection/trauma). Pneumaturia is the most common presenting symptom; Gouverneur syndrome = suprapubic pain + frequency + dysuria + tenesmus; recurrent/refractory cystitis is suggestive. CT with contrast is the most sensitive/specific test — bladder-wall thickening adjacent to thickened colon, air in the bladder, and colonic diverticula; 80–100% have a cystoscopic abnormality (bullous edema is suggestive). Bourne test and oral activated charcoal are adjuncts. Management: non-operative (TPN, bowel rest, antibiotics) for selected non-toxic, minimally symptomatic, non-malignant cases (preferred initially in Crohn's); otherwise operative single-stage (resect, close, primary reanastomosis) or two-stage (with temporary diverting colostomy).
Ureteroenteric Fistula
Most common cause is IBD (Crohn's), usually right-sided involving the terminal ileum (rarely diverticulitis/UC; also trauma, urothelial carcinoma, radiation, urolithiasis, TB). Unlike vesicoenteric fistula, it presents more with bowel than urinary symptoms. CT/MRI are more useful than retrograde pyelography. Management: ureterolysis ± bowel resection.
Pyeloenteric Fistula
Historically from chronic inflammation (XGP); increasingly iatrogenic after percutaneous renal surgery/PCNL. Right-sided usually involves the duodenum; left-sided the descending colon. Non-specific symptoms. Manage with a large nephrostomy, bowel rest/suction, antibiotics, foreign-body (stone) removal, and stenting; a poorly functioning kidney → primary bowel closure + nephrectomy.
Rectourethral Fistula
In men, most commonly after radical prostatectomy (low incidence, but common given operative frequency; rectal injury at RP <1–2%; also cryotherapy, radiation, anorectal surgery). Presents with fecaluria, hematuria, UTI. VCUG/RUG is usually diagnostic; exclude ureteral injury; biopsy if prior pelvic malignancy. Given the location, persistent severe SUI risk after repair. Management: some close with catheter drainage/bowel rest/hyperalimentation (after open/lap prostatectomy); fecal diversion sometimes needed; staged repair for large/radiation-related/infected/immunocompromised cases or inadequate bowel prep. The York-Mason procedure (transrectal transsphincteric) is effective with low morbidity.
Urovascular Fistulae
- Renovascular/pyelovascular — most commonly after PCNL (or long-term nephrostomy). Presents with life-threatening hemorrhage/shock or intermittent gross hematuria; ~75% have an abdominal bruit. Manage by replacing/Foley-tamponading the tract, then transcatheter embolization; ~70% of biopsy-induced fistulae close spontaneously within 18 months (expectant management); RCC-related fistulae warrant nephrectomy.
- Ureterovascular — most are ureteroiliac artery fistulae; risk factors are prior vascular disease, radiation/pelvic surgery, and indwelling ureteral stents. May present with hematuria of any degree or life-threatening hemorrhage. Stable: radiographic evaluation then reconstruction/embolization; unstable: early surgery.
- Other — nephropleural/nephrobronchial and cutaneous fistulae (evaluate for distal obstruction in new urocutaneous fistulae).
Self-Test
1. Risk factors for fistula recurrence after repair (reversible factors)? "Fistula TO MIIND": foreign body, technical problems, obstruction, malignancy, ischemia/infection, nutrition, inadequate drainage.
2. Principles of fistula repair? Exposure, debridement, foreign-body removal, organ separation, watertight multilayer tension-free non-overlapping closure, healthy vascularized flaps, drainage/stenting, infection control, hemostasis.
3. Most common acquired urinary fistula? Vesicovaginal fistula (75%).
4. Causes of VVF — most common in developed vs developing world? Developed: hysterectomy (surgical bladder injury, >75%); developing: obstructed labor.
5. Investigations for suspected VVF and ureterovaginal fistula? VVF: cystogram/VCUG with voiding/postvoid images, CT urography, cystoscopy, ± dye test. Ureterovaginal: upper-tract imaging (CT urography), retrograde pyelography, cystography to exclude VVF.
6. Most common cause of vesicouterine fistula? Cesarean section.
7. Most common cause of colovesical fistula, its symptoms, and the most common one? Diverticulitis; suprapubic pain, frequency, dysuria, tenesmus (Gouverneur), pneumaturia, recurrent UTI — pneumaturia is most common.
8. Preferred imaging in colovesical fistula and its signs? CT with contrast — bladder-wall thickening adjacent to thickened colon, air in the bladder, colonic diverticula.
9. Most common cause of ureteroenteric fistula and the segment involved? Crohn's disease; terminal ileum (right-sided).
10. How does ureteroenteric fistula presentation differ from vesicoenteric? Ureteroenteric — more bowel symptoms; vesicoenteric — more urinary symptoms.
11. Segment most involved in pyeloenteric fistula? Right → duodenum; left → descending colon.
12. Most common cause of rectourethral fistula? Radical prostatectomy.
13. Most common cause of pyelovascular fistula? PCNL (percutaneous renal access).