Urethral Strictures Flashcards
What is the anatomy of the male urethra
Itis about 20.5cm long and serves as a conduit for both urine and semen. It is anatomically divided into the anterior and posterior urethra. The anterior urethra, 15cm long, lies below the urogenital diaphragm and is surrounded by the corpus spongiosum. It consists of three parts: bulbar, pendulous or penile and glandular urethra. The posterior urethra lies above the urogenital diaphragm and consists of the prostatic urethra, 3.0cm long and 1 cm wide, and the membranous urethra, 2.Scm long and surrounded by the external sphincter. The membranous urethra is the most fixed portion of the urethra because it traverses the triangular ligament and, apart from the external meatus, it is the narrowest and least dilatable part.
The epithelium of the urethra is stratified or pseudo-strati-fied in the glans and transitional proximal to the glans.
Lymphatics from the deep urethra drain into the hypogas-tric and common iliac nodes whilst those of the meatus drain into the inguinal nodes.
What is the anatomy of the female urethra
The adult length is about 4cm. The epithelial lining is squamous at the distal portion and pseudo-stratified or transitional in the remainder. The function of the proximal urethra is to maintain urinary continence whilst the epithelium of the distal urethra prevents ascending infection from the introitus.
The state of estrogen activity affects the morphology of the cells of the distal urethra. The blood supply and lymphatics are as in the male urethra.
What is a urethral stricture
Urethral stricture is an abnormal narrowing or loss of distensibility of any part of the urethra as a result of fibrosis at the site of injury or inflammation. The causes are listed in Table 46-8. It is the commonest cause of retention of urine in Tropical Africa.
What are some causes of urethral strictures
- CONGENITAL
Pin-hole meatus
Non-meatal stricture - TRAUMATIC
External trauma
Urethral instrumentation
Foreign body or urethral calculus
Douching in women. - POSTOPERATIVE
Transurethral surgical procedures
Vaginal repair - INFLAMMATORY
Acute or chronic gonorrhea
Non-specific urethritis
Tuberculous urethritis
Schistosomiasis.
What is the pathology and the pathogenesis of urethral strictures
Urethral stricture is formed when the urethra heals by proliferation of fibroblasts which later contract. Post-inflam-matory strictures are confined to the anterior urethra and may be single or multiple. Most of them (60-70%) occur in the bulbous urethra because the dilatation and angulation of the urethra in this area results in diminution of the flushing power of the urinary stream. The pendulous urethra is next in order and the glandular urethra the least involved.
Instrumental injury usually occurs at the bulb but stricture following prostatic surgery is found at the bladder neck.
Urethral stricture leads to:
1. Dilatation of the urethra proximal to the stricture.
2. Compensatory changes in the bladder musculature resulting in hypertrophy, trabeculation, sacculation and diverticular formation.
3. Hypertrophy of the uretero-trigonal complex or vesico-ureteral reflux causing hydroureters and hydronephro-sis.
4. Stasis of urine and subsequent infections of the urinary tract such as periurethral abscess, prostatitis, cystitis and pyelonephritis, and formation of caleuli in the urethra or bladder. Urinary fistulae may follow rupture of periurethral abscesses.
What are some clinical features of urethral strictures
Although stricture following urethritis is formed within a year, it takes on an average about 20 years for symptoms to become apparent. Traumatic strictures on the other hand are symptomatic in two months.
Symptoms are usually of insidious onset and of lower urinary tract obstruction: increasing difficulty in micturition, diminution of force and calibre of the urinary stream, forking and spraying of urinary stream, frequency, hesitancy, drib-bling, and acute or chronic urinary retention.
It may present as a periurethral abscess, periurethral, scrotal or perineal fistulae with dribbling of urine and as extravasation of urine. When infection occurs, symptoms of cystitis, prostatitis, epididymitis and pyelonephritis may arise.
In untreated cases uraemia may result from pyelonephritis and hydronephrosis.
Signs: Examination of the external genitalia may reveal periurethral induration, periurethral abscess, perineal urinary fistulae or extravasation of urine. A visible or palpable bladder may be found if urinary retention occurs. Digital rectal examination is done for the state of the prostate.
What are some investigations to be made if a urethral stricture is suspected
Investigations
1. International Prostate Symptoms Score (IPSS).
2. Peak Urine Flow Rate (PFR) using flow meter.
3. Post Void Residual urine using ultrasound.
4. Urinalysis:- If infection occurs pus and bacteria are found in the urine.
5. Impairment of renal function is associated with anaemia, azotaemia, rise in serum creatinine levels and a fall in glomerular filtration rate. (Creatinine clearance rate)
6. Imaging:
(i) Urethrosonography - Extent of spongiofribrosis and obstruction are seen.
(il) Plain pelvic orabdominal X-rays may reveal bladder or urethral calculi.
(iii) Retrograde urethrogram and voiding cystourethrogram (with suprapubic catheter in situ) may reveal narrowing of the urethra at the site of the stricture (Fig 46-4), complete obstruction of contrast flow or extravasation of contrast if fistulae are present. Obstruction to contrast flow due to urethral spasm may sometimes occur in urethrography and in such cases urethroscopy will be required to exclude true urethral obstruction.
(iv) I. V.U. or abdominal ultrasonography may reveal hydronephrosis, hydroureters, thickened bladder wall, bladder diverticula and a high residual urine.
7. Instrumental examination:- Under sterile conditions an average size urethral catheter or metal bougie (18Ch) will be arrested at the site of a stricture.
8. Urethroscopy is the most reliable examination for the diagnosis of urethral stricture as the stricture will be visualized and the arrest of contrast or urethral catheter by urethral resistance can be excluded. It enables biopsy of a suspicious lesion which may be carcinoma ab initio or in association with stricture. Urethrocystoscopy after urethral dilation or internal urethrotomy may show trabeculation, diverticula or vesical calculi and occasionally an associated bladder or urethral tumour.
What are some differential diagnosis of a urethral stricture
Bladder neck obstruction from other causes such as benign prostatic hyperplasia, carcinoma of the bladder and carcinoma of the prostate produces similar symptoms. In these cases a urethral catheter can usually pass into the bladder; there may be an enlarged benign or hard prostate on rectal examination.
In difficult cases benign prostatic hyperplasia and carcinoma of the bladder can only be differentiated after successful urethrocystoscopy/cystoscopy.
In 1% of 1004 consecutive patients with retention at Kore Bu Teaching Hospital, Accra, urethral stricture was associ ated with benign prostatic hyperplasia and in 1 % with prostati: carcinoma. Urethral stricture, however, occurs in a younge age group with a mean age of 50 years whilst the mean age of those with benign prostatic hyperplasia is 66 years and of those with carcinoma of prostate 70.
What are some complications of urethral strictures
- Infections: Prostatitis, cystitis, epididymo-orchitis and pyelonephritis; a periurethral abscess may be localized c rupture and cause urethro-cutaneous fistulae.
- Urethral or vesical calculi.
- Urinary retention.
- Extravasation of urine results from urine which bursts out behind a stricture. It may lead to infective necrosis of the surrounding tissue and a fistula.
- Fistulae may result from sloughing of the skin over an abscess or drainage of a periurethral collection of urine.
Multiple fistulae in the scrotum or perineum - “watering can’
- may provide escape for urine. - Carcinoma of the urethra (Fig. 46-8) may be associated with urethral stricture.
What is the management for urethral strictures
- Temporary Measures
(i) Urinary retention
In acute or chronic urinary retention due to impassable strictures, emergency suprapubic tap using cystofix or supra-pubic needle is done. Where definitive treatment such a internal urethrotomy or urethroplasty is not immediately available, the retention can be relieved by a stab suprapubic cystostomy using trocar and canula or formal suprapubic cystostomy with an indwelling suprapubic Foley’s or Malecal catheter.
(i) Ertravasation of urine
The patient is managed initially by stab or open suprapubic cystostomy and continuous bladder drainage until the extrava-sation completely subsides before definitive surgical treatment of the stricture is undertaken. (iti) Watering can scrotum
Urinary diversion by suprapubic cystostomy is required until the fistulae heal and the perineum and scrotum become bealthy for formal urethroplasty. (iv) Uraemia and urinary retention
Stab or open suprapubic cystostomy is done and continuous bladder drainage maintained. Definitive treatment for the stricture is undertaken when the blood urea becomes normal.
2. Specific Measures
(i) Dilatation
It can be performed with:
(a) Flexible filiform bougies and followers.
(b) Curved steel bougies.
(c) Flexible bougies made of plastic or gum elastic.
Dilatation is palliative but adequate for most patients. It is performed for passable incomplete strictures. It is repeated at increasing intervals e.g. at 2 weeks, I month, 3 months and 6 months and done indefinitely. Occasionally it is curative in patients with minimal stricture and minimal spongiofibrosis.
Dilatation is done under strict aseptic conditions using local urethral (xylocaine gel) or general anaesthesia. Filiforms and followers are preferred for tight strictures. Small size metal bougies should not be used as they can cause urethral rupture.
Bougies should be passed gently.
The complications of urethral dilation are bleeding, clot retention, rupture of the urethra, occurrence of false passage, urethritis, prostatitis, cystitis, epididymo-orchitis, pyelone-piritis, bacteraemia, septicaemia, endotoxic shock and rupture of the prostate in patients with associated prostatic enlargement.
(in) Endoscopic Direct Vision Internal urethrotomy
This involves incising of the stricture under direct vision sing a cold blade urethrotome e.g. Sache’s. It is suitable for short uncomplicated impassable strictures. It is, however, not used in cases complicated by fistulae, extensive fibrosis or calculi. After internal urethrotomy, it is advisable to splint the urethra with an indwelling catheter for 2-7 days and longer 14-21 days for difficult strictures. Thereafter, patency is assessed by check catheterization or uroflowmetry. Internal urethro-tomy is not a permanent cure but some patients obtain lasting benefit. Too quick a re-narrowing is managed by regular dilatation or open urethral reconstruction.
Complications are bleeding, clot retention and extravasa-ton of irrigation fluid, and urinary tract infection.
(in) Urethroplasty
It is open plastic repair of the urethra.
Indications for urethroplasty are - reasonably fit patients with
a) Failed conservative measures-dilatation or direct vision internal urethrotomy
b)
Urethral stricture with extensive spongiofibrosis.
c)
Complicated strictures with periurethral abscess, fibrosis, calculi or neoplasia.
d
Very long or complete strictures.
External Meatus
Meatal stenosis may be treated by dilatation or more effectively by meatotomy or meatoplasty. il) Strictures of the anterior urethra
Urethroplasty is indicated in strictures which are com-plete, difficult to dilate or are complicated by extensive fibrosis, calculi or fistulae.
(a) Excision and end to end anastomosis:- This is suitable for short strictures caused by injury but not for long post-inflammatory strictures. Anastomotic urethroplasty is more suited to the bulbar urethra and generally not to the penile urethra where its use may produce chordee.
(b)
Two-Stage Urethroplasty:- This is necessary in cases with severe extensive spongiofibrosis, fistulae, ab-scesses, calculi etc. Different techniques may be employed.
Inthe Swinney technique, the first stage consists of laying open the stricture from end to end (Fig. 46-11). The second stage is performed after the first stage has healed usually 6-12 months interval. A buried skin or full thickness skin is used to reconstitute the urethra.
Another technique utilizes free grafts (either buccal mucosa or postauricular full thickness skin) as a patch graft on the bed of the excised urethra (in complete stricture) in the first stage. The second stage, which may be undertaken after an interval of 6 months or more, involves tubularization of the now firmly taken graft into a neourethra.
(c) Skin island flap implantation: - This is a single stage urethroplasty where a strip of skin vascularized on a pedicle of subcutaneous tissues is used as a buried viable flap for the repair of the urethra. The vascularized penile flaps used are, Dorsal, transverse penile/preputial island flap
(Quartey’s - for bulbous stricture).
Ventral longitudinal island flap (Orandi) - for strictures of the pendulous urethra
Dorsal transverse preputial island flap (Duckett) for strictures of the pendulous and distal bulbous urethra.
- Hairless scrotal island flap (Jordan) for bulbo membranous strictures.
(d) Free graft urethroplasty: The tissue grafts which are currently associated with the best results include buccal mucosa and postauricular full thickness skin (for both one-stage and two-stage repair) and mesh split thickness skin graft (for two-stage repair only). The one-stage procedures employing grafts, which are best used as a patch, take a shorter operating time and give good results. (jii) Posterior urethral strictures:
(a) Anastomotic urethroplasty: Excision and end to end anastomosis is appropriate for the management of most posterior urethral strictures.
(b) Quartey’s or Jordan’s vascularized penile/scrotal (hairless) skin flap is useful also for difficult posterior strictures which are not amenable to end to end repair.
(c) Inverted U-shaped scrotal flap operation (Blandy & Tressider/Leadbetter): - This is a two-staged operation. At the first stage an inverted -shaped incision is made. The stricture is exposed and incised and the flap of scrotal skin sewn into the defect. At the second stage a full thickness skin tube is formed.
Because scrotal skin is hairy, it is prone to form hairballs and stones. This technique is therefore no longer popular.
What are some results of utheroplasty
Results of some relatively new modes of treatment are now becoming available: These include:
() Implantation of urethral stents (urolume): Its use is limited due to attendant problems such as perineal pain, erectile pain, recurrent UTI, stent obstruction and encrusta-
tion.
(ii) Laserurethrotomy: Laser types used include carbon dioxide, argon, Nd:Yag etc. Trials with this modality are continuing.
The main complications are infection, haematoma, fistulae and restenosis. Hairs regrow in the new urethra (if the flap or graft tissue is hirsute) and may form a hair-ball or calculus.
Carcinoma of the urethra may also occur
