Diagnosis and Evaluation of Urethral Strictures

Patients with urethral strictures most often present with obstructive voiding symptoms or urinary tract infections, such as prostatitis or epididymitis; some will also present with urinary retention. On close inquiry, many of these patients have tolerated obstructive voiding symptoms for prolonged periods before progressing to complete obstruction.

If a patient cannot void, an attempt should be made to pass a urethral catheter; if the catheter does not pass, dynamic retrograde urethrography should be performed to determine the nature of the obstruction. Most cases are managed with acute dilation; however, this is not the best treatment course in many cases. If the appropriateness of management with acute dilation is unclear, a suprapubic cystostomy catheter should be placed acutely while an appropriate treatment plan is devised. Although detailed imaging is not always available, flexible endoscopy is almost universally available in the US, and the stricture can at least be visualized and a guidewire passed through the lumen under direct vision. The practice of blind passage of filiforms and blind dilation without knowledge of the anatomy of the urethral stricture is no longer acceptable medical practice.

Knowledge of the location, length, depth, and density of the stricture (i.e., spongiofibrosis) are critical to planning appropriate treatment. Radiographs, urethroscopy, and ultrasound can be used to determine stricture location and length; physical examination and ultrasound will reveal the depth and density of the scar in the spongy tissue. The appearance of the urethra can be determined in contrast studies and the amount of elasticity noted on urethroscopy.

Contrast studies of the urethra are best carried out under the direct supervision of the treating surgeon. Radiographic studies should be dynamic vs static, best accomplished by imaging during retrograde injection of contrast material and while the patient is voiding (O Fig. 8.3A, B). It should be kept in mind that more than one projection may be necessary to visualize a stricture with contrast urethrography (O Fig. 8.4). Even using a gentle technique, extravasation during retrograde urethrography can occur in patients with a markedly inflamed urethra (O Fig. 8.5); therefore, only contrast material suitable for intravenous injection should be used. Contrast materials thickened with lubricating jelly can be problematic and do not significantly enhance radiographic studies; however, real-time ultrasound evaluation of the bulbous urethra filled with a lubricating jelly may allow more accurate determination of stricture length, which could be important when planning an anastomotic repair.

Endoscopic examination may be required after contrast studies. Use of a flexible cystoscope has simplified this evaluation, and minimal discomfort is associated with the procedure when local anesthesia is administered. The scope can be passed to the stricture - it is usually unnecessary to pass it beyond that level. It is generally not necessary or beneficial to dilate the stricture at the time of the initial endoscopic evaluation. Pediatric endoscopic equipment is valuable for examining the urethra proximal to a narrow-caliber area without dilation and, in a patient who cannot void and has a suprapubic tube, combined contrast studies with endoscopy can help define the stricture anatomy.

In contrast, to ensure that all the involved urethra is included in the reconstruction, it is imperative to completely evaluate the urethra proximal and distal to the stricture with endoscopy and bougienage during surgery. Although hydraulic pressure generated by voiding can keep segments proximal to the stricture patent, unless they are included in the repair, they are at risk for contraction after the narrow-caliber segment obstruction is relieved with reconstruction. Therefore, areas of the urethra proximal to a narrow-caliber segment of the stricture must be treated with suspicion. If the lumen does not appear to demonstrate evidence of diminished compliance, it is presumed to be uninvolved in active stricture disease; however, coning down of the urethra suggests scar involvement.

8.2 • Diagnosis and Evaluation of Urethral Strictures

Normal Retrograde UrethrogramRetrograde Urethrogram Segments

O Fig. 8.3. A Diagram of dynamic retrograde urethrogram. B Diagram of a dynamic voiding urethrogram. (Adapted from McCallum Urol. Clinics N.A., 1979) C Normal retrograde urethrogram. D Normal voiding urethrogram.

Normal Retrograde Urethrogram Images

□ Fig. 8.4A, B. Retrograde urethrogram. A A right posterior oblique dynamic retrograde urethrogram does not define the situation; contrast material flows past an irregular area in the posterior bulb and through the tonic external sphincter outlining the verumontanum. B A left posterior oblique dynamic retrograde urethrogram shows the stricture in the same patient with intervening diverticulum

O Fig. 8.5. Venogram of the penis, pelvis, and inferior vena cava following gentle retrograde urethrogram

The potential for continued constriction after reconstruction in the urethra proximal to a narrow area may be unclear in some patients. In select patients, a suprapubic tube placed to defunctionalize the urethra is useful. If an area that was hydrodilated with voiding is going to be constricted, it should be apparent after 6-8 weeks.

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