STRICTURES
Strictures of the male urethra may involve any segment, including the
meatus, penile, bulbar, membranous, and prostatic urethra. The urethral
narrowing may be mild, such that a stent or small cystoscope may pass, or
severe, such that even a guidewire cannot be passed. Stricture length also
varies from a short, simple narrowing to a long, complex stricture. Strictures may
be single or multiple.
Strictures
may develop following bacterial, viral, or sexually transmitted (Chlamydia and
gonorrhea) infections or as a complication of indwelling catheters. Infections
tend to lead to long, inflammatory strictures, with 50% occurring in the bulbar
urethra, 30% in the penile urethra, and the rest elsewhere. Straddle injuries,
penile trauma, punctures, and tears from improper use of sounds, catheters,
stylets, and cystoscopes may also lead to severe, short strictures, generally
in the bulbar urethra, with significant periurethral scar tissue that responds
poorly to repeated dilation.
The
degree and duration of urethral inflammation and individual propensity to form
scar tissue all affect stricture onset and severity. Urethral strictures
consist of poorly vascularized scar tissue that often responds to the trauma of
repeated dilation with further inflammation and scar tissue. Scar tissue within
the penile urethra usually occurs on the floor, whereas in the bulbar urethra,
scar tissue is often located on the roof and may be palpable as an indurated
mass that may invade the corpus spongiosum. Periurethral scar tissue can be
extensive and of such long duration that the underlying urethral mucosa is
completely denuded and appears stark white cystoscopically. The urethra
proximal to a stricture may become dilated as a consequence of obstruction to
urinary flow, resulting in bilateral hydronephrosis and renal insufficiency.
The most
common symptoms are small caliber and weak or split urinary stream, urinary
frequency, dysuria, and occasionally gross hematuria, pyuria, and urinary tract
infection. Severe strictures may also lead to post-void dribbling of urine.
Acute urinary retention may also occur. Strictures are often complicated by
infections that include prostatitis, epididymitis, cystitis, and, occasionally,
pyelonephritis. Urethral abscess may develop with spontaneous extravasation of
urine proximal to the blocked area, resulting in one or more urethrocutaneous
fistulae often referred to as “watering pot perineum.” Fistulae may heal
spontaneously but then recanalize when abscesses recur. Granulation tissue
usually lines the fistulous tracts. Extensive fistulae may open into the buttock
and groin as well as the perineum. With chronic extravasation, virulent
bacteria may lead to extensive penile, scrotal, and perineal cellulitis as well
as gangrenous fasciitis (Fournier gangrene) (see Plate 2-20).
Urethral
strictures are diagnosed in several ways. Often it is not possible to pass a
urethral catheter. Or, the catheter may pass entirely, but as it enters the
strictured area, it is held tightly and needs more force to pass. A
nontraumatic retrograde urethrogram with a plain film of the tilted pelvis can assess the
severity and length of the strictured urethral lumen. High-frequency penile or
perineal ultrasound is particularly good at assessing the extent of damage to
associated corpus spongiosal tissue for surgical planning. Repeat dilation is
usually only palliative treatment, as this may worsen scar tissue. For fine
strictures of the bladder neck after radical prostatectomy, balloon dilation
may often be sufficient. For other simple strictures, cystoscopy and optical urethrotomy
is effective in 80% of cases. If strictures recur after endoscopic treatment, formal
urethroplasty in which all scarred tissue is excised and healthy urethra
reanastomosed is often performed. The excision of long strictures may not allow
end-to-end reconnection of the urethral tissue; in such cases, onlay or
replacement tubular grafts with penile or preputial skin or bladder or buccal
mucosa are routinely used with excellent and durable success.
