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.
