Urethral injury management

🗺️ Anatomy - The Urethral Blueprint

• Posterior Urethra: Proximal to the urogenital (UG) diaphragm. Injury often linked to pelvic fractures.
  • Prostatic: Surrounded by the prostate.
  • Membranous: Passes through the UG diaphragm; short and fixed.
• Anterior Urethra: Distal to the UG diaphragm. Injury often from straddle injuries or instrumentation.
  • Bulbous: Proximal, located in the perineum.
  • Penile (Spongy): Travels through the corpus spongiosum to the meatus.

⭐ The membranous urethra is the most common site of posterior urethral injury, typically from shear forces during a pelvic fracture.

💥 Pathophysiology - When Pipes Break

• Posterior Urethra (Prostatic/Membranous):
  • Mechanism: High-impact trauma, most commonly a pelvic fracture (e.g., MVA).
  • Anatomy: Disruption of the membranous urethra at the urogenital diaphragm.
  • Result: Urine/blood extravasates into the extraperitoneal retropubic space. May cause a "high-riding" prostate.
• Anterior Urethra (Bulbar/Penile):
  • Mechanism: Straddle injury or direct perineal blow.
  • Anatomy: Injury distal to the urogenital diaphragm.
  • Result (depends on Buck's fascia):
    • Intact: Hematoma/urine confined to the penis.
    • Ruptured: Spreads to superficial perineal space (scrotum, perineum, anterior abdominal wall), creating a "butterfly" hematoma.

⭐ Pelvic fractures are associated with posterior urethral injury in up to 10% of cases; suspect it with blood at the meatus after major trauma.

💧 Diagnosis - Finding the Leak

• Gold Standard: Retrograde Urethrogram (RUG) is the definitive initial test.
  • Performed before any Foley catheter attempt in suspected cases.
  • Positive Finding: Extravasation of contrast dye confirms and localizes the urethral tear.
• Concurrent Injury: A CT cystogram is often performed after RUG to rule out a concomitant bladder rupture, which is common with pelvic fractures.

⭐ NEVER blindly insert a Foley catheter if urethral injury is suspected (e.g., blood at meatus, high-riding prostate). This can convert a partial tear into a complete transection.

🛠️ Management - The Repair Crew

• Immediate Goal: Urinary diversion. First, stabilize the patient (ABCs).

⭐ First step in suspected urethral injury: Suprapubic catheter placement. Avoid blind Foley catheter insertion, which can convert a partial tear into a complete one or create false passages.

• Definitive Repair:
  • Posterior Injuries: Delayed repair (urethroplasty) at 3-6 months. Allows pelvic hematoma to resolve and stricture length to stabilize.
  • Anterior Injuries: Management is variable; can range from primary repair to delayed reconstruction.

⚡ Biggest Takeaways

• Posterior urethral injuries are linked to pelvic fractures; suspect with a high-riding prostate.
• Anterior urethral injuries typically result from straddle injuries or direct trauma.
• Key signs: blood at the meatus, inability to void, and perineal/scrotal hematoma.
• NEVER place a Foley catheter blindly if injury is suspected.
• Retrograde urethrogram (RUG) is the definitive diagnostic test.
• Initial management is suprapubic catheter placement to divert urine.
• Major long-term complications include urethral strictures and erectile dysfunction.