TRAUMA TO PENIS AND URETHRA
Beneath the deep layer of Colles fascia and Buck fascia (see Plate 2-4), the paired corpora cavernosal bodies of the penis are encased in a thick tunica albuginea layer. Rupture of the corpora cavernosa is rare but is encountered from direct trauma or penile fracture from vigorous intercourse or with the use of devices. Rupture of the tunica albuginea usually includes rupture of Buck fascia see Plate 2-4), in which case the penis quickly swells as a result of extravasation of blood. Early surgical repair of the ruptured tunica albuginea may prevent thrombosis and subsequent ﬁbrosis of the erectile tissue with consequent erectile dysfunction.
Isolated rupture of the urethra from trauma is not uncommon. It occurs as a result of three mechanisms: external or internal injury or obstructive disease. External blunt or penetrating injuries may involve the penile or bulbous urethra, more commonly the latter because of its immobility. Severe straddle injuries result from a blow to the perineum and bulbous urethra, usually after a fall astride a blunt or sharp object with the bulbous urethra crushed against the underside of the bony symphysis pubis. Pelvic fractures may physically separate the posterior (membranous) urethra from the bladder at the pelvic diaphragm or drive bone fragments into the urethra and corporal bodies where they attach to the pubic rami. The clinical presentation may include the inability to urinate and blood at the urethral meatus. Extensive injuries generally involve the corpus spongiosum surrounding the urethra and Buck fascia, with sub-cutaneous hematoma formation in the perineum and penis.
In cases of urethral tears limited to the mucosa, the only symptom may be blood at the urethral meatus. Abrasions and small tears generally cause blood at the meatus and hematuria, whereas more extensive lacerations result in periurethral and subcutaneous hematomas and urinary retention. With extensive injuries, a Foley catheter may be unable to be passed and there may be the appearance of a rapidly developing subcutaneous hematoma. With meatal blood, before a catheter is attempted, an emergent retrograde urethrogram will demonstrate discontinuity or rupture of the urethra. Immediate surgical exploration is possible if the patient is hemodynamically stable, and the severed ends of the urethra can be anastomosed over a urethral catheter. Otherwise, urinary diversion with a suprapubic tube and delayed reconstruction are undertaken either sooner (within 5 days) or later (several months) after the injury with excellent results.
Urination with a urethral injury can result in extravasation of urine into the subcutaneous tissues outside of Buck fascia and beneath Colles fascia, where it spreads along known anatomic pathways (see Plate 2-20). In subtle, unrecognized injuries, urinary extravasation can lead to periurethral abscess and cellulitis and even fasciitis and gangrene of the genitalia (Fournier gangrene). Stricture formation, urinary incontinence, and erectile dysfunction are late sequelae of urethral trauma (see Plate 2-26).
Internal urethral injuries result from the passage of sounds, catheters, or foreign objects via the urethra. The urethral mucosa is easily penetrated by catheters, especially when used with a metal stylet or catheter guide. The penetration usually results in a false passage posterior to the urethra within the corpus spongiosum. The tunica albuginea and Buck fascia may also be penetrated, in which case blood and urine may pass to the subcutaneous tissues. Typically, this occurs with attempts to dilate existing urethral strictures and is followed by a slowly developing periurethral abscess.
Spontaneous rupture of the urethra proximal to a preexisting urethral stricture may be due to increased intraurethral voiding pressure. Urethral rupture may be accompanied by chills and fever as urine and bacteria enter the circulation through the venous spaces of the corpus spongiosum (“urethral chill”). The most devastating complication of this phenomenon is the occurrence of perineal and genital fasciitis (tracking along Colles fascia) due to gram-negative rods or anaerobic bacteria, otherwise known as Fournier gangrene. This life-threatening infection requires immediate and repeated surgical drainage to avoid overwhelming sepsis and has measurable fatality rate in older, immunocompromised, or diabetic patients.