What causes a ureterovaginal fistula?

Causes of Ureterovaginal Fistula

The primary cause of ureterovaginal fistula is iatrogenic injury during pelvic surgery, particularly gynecological procedures such as hysterectomy, where an initially unrecognized ureteral injury can present in a delayed manner as a ureterovaginal fistula. 1

Main Causes

• Gynecological surgery: Total abdominal hysterectomy and other gynecological operations are the leading cause of ureteral injury and subsequent formation of ureterovaginal fistulas 2
• Obstetric/vaginal trauma: Accounts for a significant portion of cases (88% of rectovaginal fistulas are caused by obstetric or vaginal trauma, and similar mechanisms can lead to ureterovaginal fistulas) 1
• Penetrating pelvic trauma: Can directly damage the ureter and lead to fistula formation 1
• Radiation therapy: Pelvic radiation for gynecological malignancies can cause tissue damage leading to fistula formation 1
• Pelvic malignancies: Advanced tumors can invade the ureter and vagina, creating a pathological connection 1

Pathophysiology and Presentation

• Ureterovaginal fistulas represent an abnormal connection between the ureter and vagina 2
• Most patients experience no symptoms immediately after the causative procedure, with sudden onset of urinary incontinence occurring 1-4 weeks postoperatively 3
• Common symptoms include:
  • Continuous leakage of urine from the vagina
  • Flank pain
  • Fever
  • Recurrent urinary tract infections
  • Potential loss of renal function if left untreated 4

Diagnostic Considerations

• Diagnosis is typically established through a combination of:
  • Excretory urography
  • Cystography
  • Cystoscopy
  • Retrograde pyeloureterography
  • Dye studies 3
• CT with intravenous contrast and delayed imaging is currently the most common method for evaluating urinary extravasation 1
• Water-soluble contrast may be used to opacify fistulous tracts 1

Management

• According to the American Urological Association (AUA) guidelines, patients with ureterovaginal fistula should be initially managed with ureteral stent placement when possible 1
• Ureteral stenting has become the first-line treatment in uncomplicated ureterovaginal fistulas, with success rates of 64-100% 1, 2
• In cases of stent failure, surgical intervention is recommended, which may include:
  • Ureteroneocystostomy (ureteral reimplantation)
  • Boari flap
  • Psoas hitch
  • Transureteroureterostomy 1, 3
• Surgical approaches may be open, laparoscopic, or robot-assisted, with success rates approaching 100% for reimplantation procedures 1, 2
• In select cases, vaginal repair of ureterovaginal fistula may be suitable as a minimally invasive option 5

Important Clinical Considerations

• Early recognition of ureteral injury during pelvic surgery is crucial to prevent fistula formation
• Delayed diagnosis and treatment can lead to serious complications including loss of renal function 4
• Ureterovaginal fistulas should be distinguished from other types of urogenital fistulas (vesicovaginal, urethrovaginal) which have different etiologies and management approaches 6
• Preventive measures during pelvic surgery, including careful identification of ureters, can significantly reduce the risk of this complication