Ureteric Fistula

Ureteric fistula is an abnormal communication between the ureter and the skin, vagina, uterus, bowel or a blood vessel. Ureterovaginal and ureterocutaneous fistulae are the most frequent.

The commonest cause is ureteric injury during gynaecological or pelvic surgery. Ureterovaginal fistula occurs after roughly 0.1 to 0.5% of hysterectomies, and appears from 1 to 4 weeks after surgery.

Pathophysiology. Ureteric ischaemia, thermal injury, unrecognised transection or a ligature lead to a urine leak. Leaking urine tracks along the path of least resistance, with the vaginal vault after hysterectomy and the wound after abdominal surgery.

Causes:

• Gynaecological surgery (hysterectomy, caesarean section), colorectal and vascular surgery.
• Ureteroscopy and stone surgery.
• Radiotherapy and pelvic malignancy.
• Obstructed labour and obstetric trauma, common in regions with limited obstetric care.
• Infection (tuberculosis) and Crohn disease.
• Ureteroarterial fistula, with long term stents, pelvic radiotherapy and arterial reconstruction as risks.

Ureterovaginal fistula: continuous leakage of urine from the vagina with normal voiding, because the bladder still fills from the other ureter. Ureterocutaneous fistula: leakage through a wound, drain site or flank sinus.

Other features: flank pain, fever, urinoma, hydronephrosis, and skin excoriation. Ureteroarterial fistula presents with intermittent massive haematuria, which is life threatening and needs resuscitation and urgent vascular intervention.

• Compare the creatinine of the leaking fluid with serum creatinine.
• Three swab or double dye test: fill the bladder with methylene blue and place a vaginal tampon. A blue tampon indicates a vesicovaginal fistula. If the tampon is clean, give oral phenazopyridine or intravenous indigo carmine, and an orange or blue stain indicates a ureterovaginal fistula.
• CT urography with a delayed phase shows extravasation of contrast and hydronephrosis.
• Retrograde pyelography to locate the fistula and stent it, or antegrade pyelography through a nephrostomy.
• Cystoscopy and vaginal speculum examination. Diuretic renography for kidney function.
• Biopsy for cancer recurrence or tuberculosis where suspected. CT angiography for ureteroarterial fistula.

Differential diagnosis.

• Vesicovaginal fistula
• Urethrovaginal fistula
• Urinoma or lymphocele
• Enterocutaneous fistula
• Wound infection with serous drainage
• Urinary incontinence from other causes

• Control sepsis: drain collections and give culture directed antibiotics.
• Divert urine and attempt healing: retrograde double-J stent across the defect for 4 to 6 weeks, with a bladder catheter. About half of fistulae close. If the stent cannot cross, place a percutaneous nephrostomy, with antegrade stenting.
• Definitive repair for failed drainage:
  • Distal: ureteroneocystostomy with psoas hitch or Boari flap.
  • Mid-ureter: ureteroureterostomy.
  • Long defects: ileal ureter or autotransplantation.
  • Repair can be done early (within weeks) if infection is controlled, or delayed for 3 months. Excise the tract and close the vaginal side in layers where relevant. Interpose omentum or a vascularised flap in radiated tissue.
• Radiated or malignant fistula: stenting, nephrostomy or urinary diversion. Nephrectomy for a non-functioning kidney (function under about 10 to 15%).
• Ureteroarterial fistula: resuscitation, endovascular covered stent, and treatment of the ureter.
• Obstetric fistula in resource limited settings: referral to a fistula repair centre with experience.
• Antibiotic cover: single dose cefazolin 2 g intravenously (3 g if over 120 kg), or as directed by culture.

Special groups. Pregnancy related and obstructed labour fistulae need counselling about future delivery by caesarean section.

Monitoring. Creatinine and ultrasound at 2 weeks and 3 months, diuretic renography at 3 to 6 months, and stent removal after a study confirms healing, usually at 4 to 6 weeks. Surveillance for stricture for at least 1 year.

Referral and escalation. Refer to urology, with gynaecological and vascular input as needed. Urgent referral for sepsis, haemorrhage, bilateral injury, a solitary kidney or acute kidney injury.