Urethral strictures are more commonly seen in the anterior urethra. They are commonly seen secondary to gonococcal urethritis or trauma. The normal urethral lumen is 4mm or less in diameter and has small thin walls. A stricture appears as a segment of narrowed lumen with irregularity and thickening of the wall due to fibrosis and scarring.
2. Urethral strictures are more commonly seen in the anterior
urethra.
They are commonly seen secondary to gonococcal urethritis
or trauma.
The normal urethral lumen is 4mm or less in diameter and has
small thin walls.
A stricture appears as a segment of narrowed lumen with
irregularity and thickening of the wall due to fibrosis and
scarring.
3. Voiding cystourethrography (VCUG) and retrograde
urethrography(RGU) imaging are currently being
used for diagnosis of urethral strictures.
Among which Retrograde urethrography (RGU) is
considered Gold standard technique for evaluation of
anterior urethra.
4.
5. Sonourethrography is a simple and safe technique.
It provides comparable efficiency to retrograde urethrography in
detection of anterior urethral stricture disease.
Sonourethrography accurately estimates the stricture length,
diameter and periurethral fibrosis than any standard radiographic
procedures.
It can provide useful information particularly in patients in whom
the need for definitive surgical treatment is clear.
6. McAninch et al started sonourethrogrphy in 1985 at San
Francisco General Hospital to study urethral stricture length
estimation.
They demonstrated that radiographic technique consistently
underestimated the length of anterior urethral strictures compared
to intraoperative measurements, while sonourethrography
correlated well.
Using a 5 MHz linear probe in their earlier studies they showed
that the strictured area remained rigid during retrograde
installation of saline while normal urethra distended easily.
7. The glans penis and urethral meatus are disinfected.
Xylocaine jelly or sterile water (20-30ml) is injected
slowly by means of an appropriate catheter tip syringe in
the urethral meatus, taking care not to inject air bubbles.
Where it is not possible to catheterize the patient due to
meatal stenosis, an appropriate size feeding tube is used
to infuse the contrast material.
8. 7.5MHz frequency linear array transducer is used for
the procedure.
The transducer is applied directly over the ventral
surface of the penis, scrotum and the perineum after
ultrasound gel application.
9. Simultaneous real-time images of the urethra are obtained
sequentially from the pendulous urethra proximally towards
the deep bulbar area.
By dilating the anterior urethra with saline or xylocaine jelly
longitudinal and transverse images are obtained.
The length of the stricture, the intra-luminal diameter and the
wall thickness are determined accurately.
10. As the normal urethral wall and corpus spongiosum are
elastic, even at low pressure they are compressible to injection
of saline.
Corpus spongiosum is altered by stricture disease, it loses its
elasticity due to a higher collagen content and therefore is not
compressible and this causes a reduction of the inner diameter
of the urethra.
Even small strictures that have no urodynamic effect and are
not visible on radiographic examination may be visualized
ultrasonically.
11. No radiation hazard.
Contrast is not required.
Reproducible.
Short segment strictures can be identified.
Extent of spongiofibrosis can be assessed as therapeutic options
are based on this.
Soft tissues around the urethra can also be examined.
12. Estimation of length of stricture is an important determinant for
the selection of most optimal surgical procedure i.e. internal
urethrotomy versus dilatation.
Strictures <2 cm are generally repaired with excision and end-to-
end anastomosis.
For strictures 2–3 cm in length a graft-augmented anastomotic
procedure has been advocated.
Strictures >3 cm are usually repaired by patch urethroplasty
using a buccal mucosa graft.
13. 1. Minor bleeding.
2. Dysuria.
3. Intravasation of contrast.
4. Minor allergic reactions to
lignocaine jelly.
clots
urethral lumen
Clots within the urethra – complication.
14. Posterior urethra can not be assessed reliably.
Underestimates the length of stricture as long
strictures may not be imaged in a single field of view.
Balanitis xerotica obliterans – underestimates length.
15. RGU was introduced by Cunningham in 1910.
RGU is a standard imaging technique for visualizing the male
anterior urethra.
It is indicated for the evaluation of strictures, diverticulae,
fistulae, tumors and trauma.
16. RGU underestimates the length of the stricture.
RGU has sensitivity is 91% and specificity is 72% for anterior
urethral strictures.
It is not the ideal study for posterior urethral strictures & cannot
estimate periurethral fibrosis.
Risk of radiation exposure to patients.
For one RGU radiation exposure is 1-2 mSv which is equivalent
to 6 months of background radiation and 20 chest X-rays.
22. Sonourethrogram is a simple convenient, rapid, real time study
which can be repeated without radiation exposure to the
patients.
Both cross sectional and longitudinal images can be easily
obtained.
SGU procedure is well tolerated by patients.
Characterization of anterior strictures in terms of length,
diameter and periurethral pathologies, like spongiofibrosis and
false tracts, are done with greater sensitivity using
sonourethrography as compared with RGU.
23. The extent of spongiofibrosis can be delineated with SUG,
this scores SUG over AUG, as the degree of spongiofibrosis is
a key determinant in deciding urethroplasty vs dilatation.
SGU has added benefit of lower incidence of complications
compared to RGU.
Associated findings such as diverticulum and peri-urethral
abscess can be detected with higher sensitivity by SUG.
So sonourethrogram can be used in isolation or as an adjunct
to RGU in evaluation of anterior urethral strictures.
24. 1. Cunningham JH. The diagnosis of stricture of the urethra by
Roentgen rays.Trans Am Assoc Genitourin Surg 1910; 369.
2. Is ascending urethrogram mandatory for all urethral strictures?
Syed mamun mahmud, The karachi centre postgraduate institute.
3. Gallentine ML, Morey AF. Imaging of the male urethra for
stricture disease. Urol Clin North Am 2002: 29; 361-72.
4. Morey AF, McAninch JW. Role of preoperative
sonourethrography in bulbar urethral reconstruction. J Urol 1997;
158: 1376-79.