Urethral
stricture
The causes of urethral stricture are:
• congenital;
• traumatic;
•
inflammatory:
— postgonorrhoeal;
— post urethral chancre;
— tuberculous;
• instrumental:
— indwelling catheter;
— urethral endoscopy;
• postoperative:
— open prostatectomy;
— amputation of penis.
Postgonorrhoeal
stricture
This is less common since the introduction of effective antibiotic
treatment for gonorrhoea. The stricture is most commonly in the bulbar urethra
but postmeatal strictures are also seen.
Pathology. Infection in the periurethral
glands persists after inadequately treated gonorrhoea. The infection spreads to
cause a perurethritis which heals by fibrosis to result in
Clinical
features
The first symptoms are usually those of
bladder outflow obstruction with straining to void and poor urinary stream. The
relative youthfulness of the patient often distinguishes these from the symptoms
of prostatic enlargement which characteristically occur after the age of 50.
As the stream becomes narrower, micturition is prolonged with dribbling
after it seems to have ended. This is due to urine trickling from the dilated
urethra proximal to the stricture. Increased urinary frequency by day and night
is also common, and is due to incomplete bladder emptying or infection, or both.
When
the stricture is well established, it may be possible to palpate the scarring
along the line of the urethra. If the stricture is tight enough, the patient
will go into acute retention. If this happens, there is a danger that ham-fisted
attempts to pass a urethral catheter will result in a false passage. If a patient has gone into retention because of a urethral stricture,
the urethra will be too narrow to allow even a tiny catheter to pass safely.
Urethroscopy allows the stricture to be viewed as a circumferential scar (Fig.
67.9).
The openings of false passages may be seen if there have been misguided attempts
to pass a urethral catheter.
Urethrography using a water-miscible gel containing contrast medium will show the
extent and severity of the stricture or failure of the medium to pass beyond
the tightness indicating complete stenosis (Figs 67.10 and
67.11).
Treatment of
urethral stricture is by:
•
dilatation:
— gum-elastic bougie;
— filiform
and follower;
— metal sounds;
— self-dilatation
with Nélaton catheter;
•
urethrotomy:
— internal
visual urethrotomy;
•
urethroplasty:
— excision
and end-to-end anastomosis;
— patch urethroplasty.
Intermittent dilatation is the traditional treatment for stricture. Under aseptic conditions, the urethra is stretched using a graduated series of dilators. With care and gentleness, the procedure can be performed under local urethral anaesthesia with lignocaine gel. The main drawback of dilatation is that it is performed ‘blind’ so there is always a danger of causing a false passage which will make the stricture worse. This is most likely to occur when the operator is inexperienced or unfamiliar with the complexities of an individual patient’s urethra. As with any instrumentation of the urinary tract, infection is a danger and fatal septicaemia has been known to follow a supposedly straightforward dilatation. Urethral dilatation still has a place in elderly gentlemen who have a short stricture which recurs at infrequent intervals. In these patients, occasional bouginage may be preferable to more complex procedures. It may be possible for some patients to dilate their own urethras by intermittently passing a soft Nélaton catheter.
Instruments.
Strictures have been treated by surgeons for centuries and there are many
different dilating instruments on the shelves of surgical museums, each with the
name of the surgeon who invented it. A simple stricture may be dilated using
metal sounds (Fig.
67.12), so called
because they were originally used to 'sound’ for stones in the bladder or
gum-elastic bougies (French
‘candle’) (Fig. 67.13). These must be wielded with great care as it is easy
to make a false passage with them. Filiform
are gum-elastic filaments which can be passed through the lumen of a
urethral stricture (Fig. 67.15).
This
is usually best done under direct vision using a urethroscope, although the
‘faggot method’ may be helpful if endoscopes are not available (Fig.
67.14).
Once the lumen has been located with its tip, the other end of the filiform is
screwed on to a ‘follower’: a
gum-elastic bougie with a screw thread at its tip for the purpose (Fig. 67.15). As the follower is
advanced the filiform guides it safely through the stricture. Once the stricture
has been partially dilated by followers of increasing size, it is often safe to
change to metal dilators. Patients who have had an optical urethrotomy are
sometimes taught to keep the stricture open by regular self-dilatation with a
urethral catheter of a suitable size.
Operative
treatment. Internal urethrotomy is
performed using the Sachse optical urethrotome. The stricture is cut under
visual control using a tiny knife passed through the sheath of a rigid
urethroscope. The stricture is usually cut at the 12 o’clock position taking
care not to cut too deeply into the vascular spaces of the corpus spongiosum
which surrounds the urethra. If one cut is insufficient, others can be made
until there is a wide passage through the strictured segment of urethra. After
the procedure, many surgeons leave a catheter for 1—2 days, but there is no
evidence that this makes a significant difference to the effectiveness of the
procedure. A single urethrotomy seems to give a permanent cure of uncomplicated
stricture in about 50 per cent of patients. The rest require further treatment
by urethrotomy, dilatation or urethroplasty. The main complications are
infection and bleeding. It is possible to get lost when trying to cut a way
through a very tight stricture. This is especially true when there are false
passages due to previous dilatation attempts. In these circumstances, it helps
to pass a guidewire to establish the true lumen of the urethra.
Urethroplasty.
The simplest urethroplasty involves excision of the stenosed length of urethra
and reanastomosis of the spatulated cut end (Fig. 67.6). This operation is only
possible if the stricture is relatively short because there must be no tension
at the suture line. If end-to-end anastomosis is not feasible, there is a large
number of different plastic surgical procedures to replace part or all of the
wall of the strictured urethra using free full-thickness or pedicled skin
grafts. The Orandi— Blandy operation makes use of a myocutaneous patch of
perineal skin and dartos muscle (Fig. 67.16): Turner-Warwick favours penile
skin.
Urethroplasty
should be considered when more simple means fail to give lasting relief of
symptoms. The procedure can be very demanding, especially when the stricture is
the result of pelvic trauma and the urethra is encased in woody, hard fibrosis.
A prolonged hospital stay is usual while the graft heals.
Other causes
of urethral stricture
Congenital
stricture has
been considered previously.
Traumatic
stricture. The stricture which follows neglected or untreated rupture of the
membranous urethra is sometimes a complete loss of continuity. These patients often need
a transpubic urethroplasty to bridge the gap.
Post instrumental
stricture. This follows endoscopy or catheterisation and may affect any part of
the urethra. Some surgeons recommend prophylactic dilatation or urethrotomy
before transurethral surgery to try to avoid this complication. Some cases of
stricture seem to be due to a sensitivity to chemicals from the catheter but
most are the result of a combination of trauma, infection and pressure necrosis.
Postoperative
stricture. Postoperative stricture develops after about 4 per cent of
prostatectomies, irrespective of the method employed. The stricture is usually
in the proximal part of the prostatic urethra and is also known as bladder neck
stenosis. If it cannot be managed by dilatation, bladder neck stenosis should be
treated by transurethral incision and resection of the stricture.
Postoperative
stricture is also a complication of amputation of the penis (see below).
Complications
of urethral stricture
Complications include:
•
retention of urine;
•
urethral diverticulum;
•
periurethral abscess;
•
urethral fistula;
•
hernia, haemorrhoids and rectal prolapse due to abdominal straining to
void urine.
Diverticulum
of the male urethra (syn. urethral pouch). This is usually congenital and
represents a partial duplication of the urethra. Acquired cases are uncommon.
They are sometimes seen as a result of increased intraurethral pressure behind a
stricture. Others are due to the longstanding presence of a foreign body such
as a stone or calculus in the urethra.
Treatment is by excision of the diverticulum and removal of the cause if possible.
Periurethral
abscess. Periurethral abscesses can be either penile, bulbar or chronic.
A
penile periurethral abscess usually arises as an acute gonococcal
infection of one of the glands of Littré. The tender induration felt on the
underside of the penis points and discharges externally, often leaving a
fistula.
Treatment. An anterior urethrotomy will encourage the abscess to burst into the
urethra. When the abscess lies behind a stricture, it should be opened
externally.
A
bulbar periurethral abscess is a spreading cellulitis due to
infection with streptococci and anaerobic organisms. It may or may not be
associated with a urethral stricture, and extravasation of urine is not unusual.
Clinical features. There is perineal pain with pyrexia, rigors and a rapid pulse rate.
Tenderness and swelling rapidly spread from the perineum to the penis and the
anterior abdominal wall.
Treatment. Appropriate antibiotics are essential. Collections of pus should be
drained and the urethra should be defuntioned by inserting a suprapubic urinary
catheter.
A
chronic periurethral abscess sometimes results from a long-standing
urethral stricture (Fig. 67.17). The multiple loculi of pus should be drained
and the stricture treated appropriately. Urethral fistula may occur either
spontaneously or as a result of incision of the abscess.
Urethral
fistula. The most frequent cause of urethral fistula is bursting or incision of
a periurethral abscess. If the fistulae arise behind a tight stricture, there
may be multiple openings (watering-can perineum). A fistula can also follow
urethroplasty if there is necrosis of part of the graft.
Treatment. If the stricture is cured, some fistulae heal themselves. Occasionally
urethroplasty is indicated.
Urethral
calculi. Urethral calculi can arise primarily behind a stricture or in an
infected urethral diverticulum. More commonly, the stone is a renal calculus
which has migrated to the urethra via the bladder.
Clinical features. Migratory calculi cause sudden pain in the urethra soon after an attack
of ureteric colic. There is blockage to the flow of urine and, if the stone is
small, the force of the jet will expel it from the external urethral meatus.
Larger stones become stuck and have to be removed endoscopically. It is
sometimes possible to feel the calculus as a hard lump in the urethra, but if
there is doubt the diagnosis is confirmed by urethroscopy.
A
stone formed within the urethra is less likely to cause recognisable symptoms
and is usually detected during urethroscopy or bouginage.
Treatment. A stone in the prostatic urethra is
displaced back into the bladder and treated by litholapaxy or suprapubic cystotomy
as if it were a bladder stone. Calculi in more distal parts of the urethra are
removed by basketing under vision or fragmented in
situ using the electrohydraulic or ultrasonic lithotriptor. It may be
necessary to perform a meatotomy to deliver the stone. Open removal by external
urethrotomy is rarely necessary.
Neoplasms
Polyps are
a relatively common finding in the prostatic urethra where they may result from
chronic infection.
Genital warts acquired by sexually transmitted infection are sometimes found in the
anterior urethra as an extension of warts on the skin of the glans penis.
Angioma of the urethra is a very rare cause of urethral bleeding.
Carcinoma of the urethra is relatively rare. Multifocal transitional cell cancers of the bladder are sometimes associated with tumours in the prostatic urethra and occasionally more distally. Although these tumours are usually superficial and can be destroyed locally by diathermy or laser, they seem to be associated with a tendency to distant spread. Squamous carcinoma can develop in an area of squamous metaplasia sometimes seen downstream of a urethral stricture. It carries a poor prognosis even if the patient is treated by radical surgery. A bloody discharge from the urethra in the absence of infection should raise the suspicion that the patient has a urethral tumour.
The female urethra
Abnormalities of the female urethra include:
•
prolapse;
•
stricture;
•
diverticulum;
•
carbuncle;
•
carcinoma.
Prolapse.
Prolapse occurs in later life and is usually symptomless. Prolapse of the
urethral lining also occurs as a congenital abnormality when it causes
discomfort proportional to the degree of prolapse.
Stricture.
This is uncommon in women but it may follow urethritis or, more commonly, the
trauma of a difficult labour. Urinary retention, usually chronic, is an
occasional result. True urethral strictures in women respond well to dilatation
and should not be confused with a spasm of the urethral muscle of obscure cause
which sometimes causes retention in women, particularly after they have had
unrelated surgery. The condition, which was described by Fowler and Kirby, is
associated with an abnormal myotonic discharge in the urethral sphincter which
can be detected on an electromyogram. The patients remain in retention after
urethral dilatation and many of them require intermittent self-catheterisation
for life.
Diverticulum
(syn. urethrocele). Diverticulum is more common in women than men. Some seem to
be congenital. Others are acquired by rupture of a distended urethral gland or
injury of the urethra during childbirth. Urine within the diverticulum becomes
infected causing local pain and repeated bouts of cystitis. Purulent urine is
discharged if the urethra is compressed with a finger placed in the vagina.
Excision of the diverticulum through the anterior vaginal wall is effective but
care must be taken not to damage the urethral sphincter.
Carbuncle.
This is common in elderly women. It presents as a soft, raspberry-like,
pedunculated granulomatous mass about the size of a pea attached to the
posterior urethral wall near the external meatus. It is composed of highly
vascular connective tissue stroma infiltrated with pus cells.
Clinical feature. There may be frequency of micturition and pain afterwards. Occasionally
there is bleeding. A urethral prolapse is less tender and is not pedunculated.
Treatment. Treatment is by excision and diathermy coagulation of the base of the stalk. The patient should be given antibiotics to treat the underlying chronic urethritis.
Papilloma
acuminata. Papilloma acuminata arc the same as the sexually transmitted warts
which occur on the penis. They are treated in the same way. In female Africans,
papilloma acuminata are common and may grow to such a large size during
pregnancy that they obstruct labour and necessitate a Caesarian section (Bowesman).
Carcinoma
of the urethra. This occurs twice as often in women as in men. Whether a
carbuncle can become malignant is disputed but they often occur in a similar
site. Malignant swellings of the urethra feel harder than benign ones.
Treatment
by radiotherapy or radical surgery is often ineffective. The overall prognosis
is poor.