Diagnostic Approach to Urethral Injuries in Pelvic Trauma

Clinical Rationale

The American College of Surgeons recommends that patients with pelvic trauma, open book fracture, and blood at the urethral meatus undergo retrograde urethrography (RUG) before any urethral catheterization to evaluate urethral integrity and prevent catastrophic complications, with a reported 7-25% risk of posterior urethral disruption in such cases 1, 2.
The presence of blood at the urethral meatus is a critical indicator of urethral injury, mandating immediate investigation before catheter placement, as stated by the World Health Organization 1, 2, 3.

RUG is the gold standard for diagnosing urethral injuries in hemodynamically stable patients with suspected urethral trauma, as recommended by ATLS guidelines and the World Health Organization, with a high accuracy rate 1, 4.
The procedure involves instilling contrast medium into the urethra under fluoroscopy, which will demonstrate either complete disruption or partial injury, as described in the Journal of the American College of Radiology 6.

The World Journal of Emergency Surgery warns that never attempting urethral catheterization without prior RUG when blood is present at the meatus is crucial, as approximately 23% of urethral injuries are missed at initial evaluation, and blind catheterization increases morbidity 1, 5, 3.

The Journal of the American College of Radiology states that CT scan of the pelvis is valuable for evaluating pelvic fractures and hematoma but has limitations in detecting urethral injuries, and performing RUG before CT may actually increase false-negative rates on subsequent CT scans 2, 1.
The Journal of the American College of Radiology recommends that intravenous pyelogram has extremely low accuracy (15-25%) for urethral and bladder injuries and is not recommended in modern trauma management 4.
The World Journal of Emergency Surgery suggests that MRI of the pelvis may be useful for preoperative planning in stable patients but is inappropriate for acute trauma evaluation due to time constraints and limited availability 1.

The American College of Radiology recommends that first, a digital rectal examination should be performed to assess for high-riding or non-palpable prostate, which indicates urethral disruption with superior displacement 5.
The World Journal of Emergency Surgery states that second, retrograde urethrogram should be obtained using a urethral catheter inserted into the anterior urethra with the cuff inflated to 1-2 mL, instilling up to 350 mL of contrast under fluoroscopic guidance 2, 6.
The World Journal of Emergency Surgery advises that third, if urethral injury is confirmed, establish urinary drainage via suprapubic catheter rather than urethral catheterization 1.
The World Journal of Emergency Surgery recommends that finally, once hemodynamically stable, CT scan with delayed excretion phase can evaluate for associated bladder and ureteral injuries 1, 2.

The World Journal of Emergency Surgery suggests that if RUG confirms urethral injury, suprapubic catheter placement with delayed cystogram is recommended, and in hemodynamically unstable patients, all urethral investigations should be postponed and a suprapubic catheter placed immediately 1, 6.