Urethral injury

Urethral injuries can result in long-term morbidity and most commonly result from trauma. The male urethra is much more commonly injured than the female urethra and is the focus of this article.

Clinical presentation

In the setting of trauma, the classic triad of blood of the external urethral meatus or vaginal introitus may be seen but is an unreliable sign, as is hematuria. Inability to void may be seen in complete urethral disruption. Examination may reveal blood on digital rectal exam and perineal ecchymosis. 

Dysuria, urinary urgency and suprapubic discomfort can ensue in the chronic stages of incomplete urethral injury due to complicating strictures.

Pathology

Male urethral injuries are divided into anterior (penile/bulbar) and posterior (membranous/prostatic) urethral injuries. Injuries may be partial or complete. There are a variety of causes:

• blunt trauma: due to shearing/straddle injuries

  • posterior urethral injury is caused by a crushing force to the pelvis due to the urethra fixed attachment to pelvic bones ⁸. Such injury is associated with pelvic fractures (~10%) and bladder injury

  • anterior urethral injury is usually caused by a straddle injury and is an isolated injury

• penetrating trauma: e.g. stab wounds, gunshot wounds, dog bites

  • more commonly affect the anterior urethra

• iatrogenic

  • catheterization, Foley catheter removal without balloon deflation, cystoscopy

  • post-surgical (e.g. surgery for benign prostatic hyperplasia)

Classification

See: Goldman classification of urethral injuries.

Radiographic features

Fluoroscopy

Voiding cystourethrography is the most appropriate way to evaluate the posterior part of the male urethra and injuries to the female urethra.

Retrograde urethrography is the modality of choice to investigate urethral injuries. It will demonstrate extraluminal contrast, which has extravasated from the urethra at the site of injury. It is important to determine if this is above the urogenital diaphragm (posterior urethra) or below it (anterior urethra). Patients with incomplete injuries may represent subsequently with strictures.

The extent of injury can be categorized:

• contusion: radiographically normal

• partial disruption: extravasation of contrast with maintenance of normal urethral continuity

• complete disruption: extravasation of contrast with loss of urethral continuity and lack of proximal urethral filling

CT

CT cystography can be performed but this is much less specific for urethral vs. bladder injury. Other features of urethral injury include retropubic and perivesical hematoma and obscuration of the urogenital fat plane.

Treatment and prognosis

Treatment is variable and ranges from urinary diversion (e.g. suprapubic catheter) to primary or delayed urethral anastomosis depending on the severity (i.e. tear vs. complete rupture) of the injury.

Urethral stricture is the most common long-term complication.