Comprehensive Notes on Urinary Fistulas

Urinary Fistulas

Types of Urinary Fistulas

  1. Ureterovaginal Fistula: Connection between the ureter and the vagina.
  2. Vesicovaginal Fistula (VVF): Connection between the bladder and the vagina (most common).
  3. Urethrovaginal Fistula: Connection between the urethra and the vagina.

Diagnosis Based on Patient History

The type of fistula can often be determined based on the patient's symptoms.

Ureterovaginal Fistula
  • Complaint: Constant dribbling of urine from the vagina and normal urination.
    • Explanation: Urine from the affected ureter leaks into the vagina, while the other ureter functions normally, allowing for regular bladder filling and urination.
Vesicovaginal Fistula
  • Complaint: Constant dribbling of urine from the vagina and no normal urination.
    • Explanation: The bladder is directly connected to the vagina, so the bladder never fills normally, leading to continuous leakage.
Urethrovaginal Fistula
  • Complaint: No constant dribbling of urine, but urine comes from both the urethra and vagina during urination.
    • Explanation: The urethra is usually empty except during urination. The leakage occurs only when the bladder empties.

Methylene Blue Three Swab Test

This test helps to identify the location of the fistula.

  • Procedure:
    • Three cotton plugs are placed in the vagina: upper (urethrovaginal), middle (vesicovaginal), and lower. (urethrovaginal)
    • Methylene blue dye is injected into the bladder and urethra using a Foley's catheter.
    • Observe which swab gets stained.
  • Interpretation:
    • Ureterovaginal Fistula: Uppermost cotton swab is wet with unstained urine
      • Explanation: The dye is placed in the bladder and urethra and not in the kidneys, so the urine coming from the ureter is unstained.
    • Vesicovaginal Fistula: Middle cotton swab (or middle and lower) is wet and blue in color.
      • Explanation: Due to the location and proximity, sometimes the lower swab may also be stained.
    • Urethrovaginal Fistula: Lowermost cotton swab is wet and blue in color.

Vesicovaginal Fistula (VVF) - Additional Details

  • Most Common Type: VVF is the most common type of urinary fistula.
  • Causes:
    • Developed countries: Surgery, particularly hysterectomy.
    • Developing countries: Obstructed labor.
  • Investigation of Choice: Cystoscopy.
    • Determines the exact site, size, and number of fistulas.
  • Urine Collection: Best method for urine collection prior to surgery is suprapubic catheterization.
  • Hysterectomy as a Cause: Hysterectomy is a significant cause of VVF, with variations based on the type of hysterectomy performed.
  • Management: Surgical repair.
  • Timing of Repair:
    • Obstructed labor: After six weeks to allow inflammation and infection to subside.
    • Surgery:
      • Diagnosed within 24 hours: Immediate repair.
      • Diagnosed after 24 hours: Wait for six weeks.
    • Radiotherapy: Wait for twelve months.

Ureteric Fistulas - Key Considerations

  • Common Site of Injury: Two centimeters lateral to the internal os (water under the bridge) is the most common.
  • Second Most Common Site: The pelvic brim
  • Hysterectomy Risks:
    • Wertheim's hysterectomy carries the highest risk of ureteric injury due to removal of the medial half of the cardinal ligament, which is in close proximity to the ureter.
    • The most common cause of ureteric injury overall is simple hysterectomy (total abdominal hysterectomy) because it is the most frequently performed type of hysterectomy.
      Structures Removed During Hysterectomies:
      When performing a radical hysterectomy, surgeons remove the uterus, cervix, both ovaries and tubes, and the entire cardinal ligament. Verdheim's hysterectomy involves removing the uterus, cervix, one centimeter of the vagina, tubes, ovaries and the medial half of the cardinal ligament
  • Subtotal Hysterectomy: Involves removing only the uterus, leaving the cervix intact. Typically performed in obstetrics, specifically in cases of postpartum hemorrhage (PPH).
  • Most common route of surgery that causes ureteric Injuries: Laparoscopic hysterectomy
  • Timing of Repair: Immediate repair as soon as the injury is diagnosed.
  • Technique of Repair: Boire flap technique.

Urethrovaginal Fistula

  • Key diagnostic features are based on the chief complaint and the methylene blue three swab test results.

Mensouria (or Menorrhea)

  • Definition: Hematuria (blood in urine) at the time of menstruation.
  • Causes:
    • Endometriosis of the bladder
    • Uterovesical fistula (fistula connecting the uterus to the bladder).
      • The patient will complain that at the time of menstruation, there is hematuria.

New Classification for Genitourinary Fistulas

Based on the distance of the fistula from the external urinary meatus.

  • Type 4: Less than 1.5 cm from the external urinary meatus.
  • Type 3: Between 1.5 to 2.5 cm.
  • Type 2: Between 2.5 to 3.5 cm.
  • Type 1: More than 3.5 cm.

Each type (1, 2, 3, 4) is further subdivided into A, B, and C based on the size/diameter of the fistula:

  • A: Less than 1.5 cm.
  • B: 1.5 to 3 cm.
  • C: More than 3 cm.