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Urethral Stricture Diagnostic Evaluation

History and Physical Examination

The “history” is the patient’s report of his urinary symptoms, a description of any prior treatment, and general information such as medical illnesses, any prior surgeries, allergies etc. It is not unusual for our patients to have had failed prior urethral stricture treatment with dilations, incisions, and/or open surgery. We encourage patients to hand carry their medical records to their initial appointment. This guarantees that the records are available for review at the time of the visit. It is our experience when patients rely on records being faxed from other offices that the records are not received prior the scheduled appointment. When a surgery is performed, it is required that the surgeon dictate a detailed report called the “operative dictation”. This is then transcribed and it then becomes a part of the hospital chart. We find the operative dictations of prior urethral surgeries most useful and suggest that our patients bring these reports in particular to their initial visit.

During the complete physical exam, particular attention should be devoted to the appearance of the penile skin and the urethral opening. In some cases, an option for urethral reconstruction can be a repair using the penile skin as a “patch”, and when indicated, is performed when a man is uncircumcised with normal skin or is circumcised with some redundancy of the skin. When a man reports that the urethral opening appears narrow or that he developed a stricture towards the tip of the penis or whitish discoloration of the penile skin, and this is noted of physical exam, this can be diagnostic of Lichen Sclerosis, also called Balanitis Xerotica Obliterans (see section on Lichen Sclerosis).

Urethroscopy/Cystoscopy and Calibration

Bougie Calibration

When the opening of the urethra at the tip of the penis (urethral meatus) is narrow or if there is narrowing within the fossa navicularis, the portion of the urethra just deep to the opening, the best way to determine the actual caliber of the urethra of this portion of the urethra is with instruments called Bougie-a-boules.

Bougie set

Set of Bougie-a-Boules

Bougie urethra calibration

Bougie being used

These cone shaped instruments painlessly measure the circumference of the opening of the urethra the way feeler gauges precisely measure the gap on a spark plug. The measurement of the caliber of the urethra is in French size. French is a measurement of millimeters circumference, and the French size is generally 3 times the diameter. A normal adult urethra is greater than 30mm circumference (30 French, approximately 10mm or 1cm diameter) except at the fossa navicularis and meatus, where the opening is normally approximately 24 French.

When we calibrate the distal (the part closest to the tip) urethra is calibrated, numbing lubricant is placed at the opening of the urethra, and a very small bougie, generally 8 French, is advanced a short distance and then removed. Unless the distal urethra is less than 8 French, the instrument will pass without any resistance. A 9.5 French Bougie is then advanced. We continue the procedure with larger instruments until there is a slight resistance, generally felt as the instrument is removed given that bougies are cone shaped. Once there is very slight resistance, this is the caliber of the urethra. No further instruments are placed as to continue with larger instruments would only dilate/tear the urethra causing pain, and our objective is to painlessly measure the size of the opening.


This is a procedure where a small (16 French), flexible, and lubricated telescope is gently placed into the urethra with advancement to the stricture. This instrument is called a cystoscope or a “scope”. It is a flexible tube that has an eye piece at one end and an opening at the opposite tip that allows light to shine through. The procedure is often called cystoscopy, but technically, if the scope is just advanced into the urethra and not all the way to the bladder, the procedure is urethroscopy.

Flexible Scope

Flexible cystoscope

This study permits direct visualization of the inside of the urethra distal to the stricture (between the tip of the penis and the beginning of the stricture). Once the stricture that is smaller than the size of the scope is seen, the scope should be removed and no attempt should be made to advance the scope through the stricture if the objective is to evaluate the urethra as any forceful pushing to advance the scope through the area of disease towards the bladder will dilate and possibly tear the urethra.

When there is narrowing of the distal urethra that prevents the use of a 16 French scope, we use a 10 French pediatric instrument.

Peds Scope

Pediatric cystoscopy

The visualization is not as good when using this smaller instrument, but when the caliber of the distal urethra is between 10-16 French, the larger scope can’t be used. When the caliber of the distal urethra is less than 10 French, we do not attempt urethroscopy because we know that we cannot pass the instrument even a short distance.

Urethroscopy provides a direct visual assessment of the appearance along the length of the urethra up to the beginning of the stricture, and a direct visual assessment of the caliber of the distal aspect of the stricture (the portion of the stricture closest to the tip of the penis). However, since the scope cannot be advanced through the stricture without trauma, the exact length of the stricture and the presence or absence of any additional strictures cannot be determined with urethroscopy. This information is best obtained with X-ray contrast imaging (RUG-VCUG).

Urethral X-Ray Imaging (RUG-VCUG)


The standard procedures for urethral imaging are a retrograde urethrogram (RUG) and a voiding cystourethrogram (VCUG). Films are taken during injection, and during voiding. These studies, when properly performed, will always define the exact location and length of the urethral stricture. It is essential to know this information prior to treatment, as the treatment decision should be based on the nature of the disease.

Retrograde Urethrogram (RUG)

The RUG is performed with the patient in the oblique position. This means that the patient is tilted 45 degrees. An initial film (called a scout film) is obtained to confirm that the position and exposure is correct before any contrast is instilled. Then, gauze is gently wrapped around the head of the penis and gentle traction is applied to place the penis on stretch. This is painless. Then, contrast is gently instilled into the urethra using a specialized adaptor that gently forms a seal at the tip of the penis. No needles or catheters are required and no balloons are ever inflated in the urethra.

Gauze RUG

Gauze in place

RUG technique

Contrast slowly instilled

As contrast (clear fluid that appears white on an X-ray) is injected, a film is obtained. This study permits visualization of the entire urethra. This is an example of a RUG when the anterior urethra is normal.

Normal retrograde urethrogram

The RUG best evaluates the anterior urethra. As previously mentioned, this is the portion of the urethra between the tip of the penis and the beginning of the posterior urethra (the membranous and prostatic urethra and bladder neck). The RUG only provides very limited information about the posterior urethra. This is because during the injection of contrast, the patient is not voiding, and when a patient is not voiding, the sphincters along the posterior urethra are closed, and the prostatic urethra is narrow. It is normal for the posterior urethra to have a very small caliber as a RUG is performed. If the external sphincter muscle and prostate were visible on the film, the image would appear as shown.

The posterior urethra may be narrow because of a stricture, or may be narrow because it is normal. Therefore, while a RUG is the best imaging test to evaluate the anterior urethra, it is a poor study to evaluate the posterior urethra.

RUG with superimposed graphics demonstrating the prostate and external sphincter (red)

RUG graphic

In a patient with an anterior bulbar urethral stricture, contrast passes through the stricture and outlines the area of narrowing and the normal area proximal to the stricture.

Film demonstrating bulbar stricture

RUG bulbar stricture

Voiding Cystourethrogram (VCUG)

The VCUG is the best study to evaluate the posterior urethra. As the RUG is performed, some contrast enters the bladder, and this can be seen on the film. The patient is then asked to urinate, and during urination, a film is obtained. It is often the case that patients are unable to void after contrast is injected during the RUG as only 60cc of contrast is instilled for this study, and the patient simply may not feel the urge to urinate. Dr. Gelman will then instill additional contrast very, very slowly as to not cause pain. During urination the bladder neck and external sphincters of the posterior urethra are supposed to relax and open as the bladder is contracting. If the posterior urethra is widely patent during voiding, this confirms that this portion of the urethra is normal.

The following is a RUG and VCUG in a patient with a bulbar stricture. Graphics are superimposed (on the VCUG) to show the location of the prostate and external sphincter muscle (posterior urethra). Notice how the posterior urethra is closed off at rest but wide open during urination. This confirms that the posterior urethra is normal.

RUG bulbar stricture


VCUG graphic


However, if there is a narrowing within the posterior urethra during voiding, then this indicates a stricture. In this example, there is a bulbar stricture seen during injection. The posterior urethra is not wide open as would be expected at rest. However during voiding, the area of the membranous urethra remains very narrow.

Bulbar membranous stricture

In the above example, if the RUG were the only test performed, then the posterior stricture would have been missed. We do not want to risk missing strictures when doing imaging and being “surprised” to find additional strictures at the time of surgery. This could compromise the surgery, and it is for this reason that we perform complete imaging. Together, the RUG and VCUG provide an evaluation of the entire anterior and posterior urethra.

Other Tests

A non-invasive test to measure the flow rate is called a Uroflow. The patient urinates into a funnel shaped collection device in the restroom and this device measures the flow rate over time. This test documents just how fast the urine flows, and is totally non invasive, but does not provide specific information. Another test that can be performed is a bladder scan to check the Post Void Residual (PVR). After urination, an ultrasound probe is placed over the bladder and the bladder can be visualized, and the volume within the bladder can be calculated. The amount that remains in the bladder after urination is called the Post Void Residual or PVR. This does not provide any information about the urethra, but does provide information about possible bladder damage. The bladder should be empty immediately after urination and a high PVR suggests bladder damage. Ultrasound and MRI of the urethra are other imaging tests that can be utilized. However, we have not found those tests useful.

Poor Quality Studies, Examples

When patients report having prior urethral imaging, they are encouraged to bring both the films and the reports to their initial visits. If the films are adequate, they do not need to be repeated. However, over the years, we have observed that the vast majority (over 95%) of urethral imaging studies performed at outside facilities are inadequate and do not include both the RUG and VCUG. We are in the process of reviewing our observations and plan to submit our findings for publication given that this appears to be such a pervasive problem. Most General Urologists and Urologists who do not exclusively specialize in male urethral and penile surgery often do not personally perform urethral imaging. It is not practical for them to have X-ray equipment in their offices given that only a very small percentage of their practices are patients with strictures. We have observed that most patients are referred to Imaging Centers for their diagnostic urethral imaging. These Radiology Imaging Centers perform many diagnostic imaging tests such as chest X-rays, CT scans, abdominal ultrasounds etc. and rarely perform urethral imaging.

We have observed that over 90% of outside studies are performed using a technique where a catheter is advanced into the urethra a short distance, and a balloon is inflated to create a seal. This is a technique we never use. One problem is that some strictures are towards the tip of the penis and a catheter cannot be advanced even a short distance without creating trauma to the stricture. In addition, when the balloon is inflated in the , this dilates and can tear and damage normal urethra. We have used calipers to measure the French size (circumference) of a catheter balloon, and observed that inflation of a catheter balloon with only 2cc of air or water is associated with a balloon caliber of 50 French. A normal urethra is only approximately 24 French in the fossa and around 30 French in the penile portion. These balloons are generally inflated in the fossa navicularis, causing dilation and often very painful tearing of the fossa.

Retrograde urethrogram balloon
Retrograde urethrogram balloon chart

We have actually seen patients referred for strictures in the bulbar urethra who previously underwent imaging using a balloon technique and then developed a fossa stricture where the catheter was inflated. These patients then require reconstruction of both strictures. After the balloon is inflated, any traction on the catheter to place the penis on stretch can lead to the catheter being pulled out. Therefore, films are often obtained with the penis not on stretch, and the stricture length is underestimated. The following is an example of an outside study using a balloon inflated in the urethra with the penis not on stretch. The impression was that the stricture was 2cm in length. We repeated the study with the penis on stretch using our standard technique, and the stricture was actually 5 cm in length.

Example of Underestimation of Stricture Length Next to Proper Study

RUG short stricture
Retrograde bulbar stricture

We have seen a number of operative dictations from failed surgeries where it was indicated that the stricture length was longer than anticipated. In these cases, proper imaging would have accurately predicted the stricture length and location, allowing the proper procedure to be planned.

In addition, when the position is not sufficiently oblique, the urethra is seen “on end”, preventing proper assessment of the stricture length. This is the example of an outside film that suggested a 2 cm obliteration of the urethra. We repeated the study with the patient in the proper oblique position and the actual length of obliteration was 8 cm.

Example of On-End Film and Then the Proper Study

Urethra on end
RUG onend repeat

Almost all outside studies we see are performed using fluoroscopy, an imaging technique that allows many films to be taken in a short period of time. The problem with most fluoroscopic studies is that round images are produced with a very small field of view. Often, only a portion of the urethra is seen. The following are outside images in comparison to the repeat imaging performed at our center.

Flouro and then Repeat Image

Flouro Photoshop
Bulbous stricture

In some cases, the physicians and technicians attempt to fill the bladder by advancing a catheter into the bladder to instill contrast. However, this generally traumatizes the urethra when there is a stricture. This is a fluoroscopic image obtained after an attempt was made by the radiologist to advance a catheter through the stricture to then inject contrast. This caused a tear in the urethra and the contrast then leaked into the surrounding tissues. This patient was then referred to our center and the study was repeated as shown.

Example of Extravasation and Repeat Study

Urethra extravasation
Healed urethra image

When urethral imaging is performed by individuals without expertise in performing these studies, the images obtained suggest that there is a stricture, but do not allow definitive assessment of the exact length and location of the abnormal urethra. Urethral imaging is best performed by a physician with expertise in this procedure. Dr. Gelman strongly believes that it is best that Urologists who perform urethral reconstructive surgery personally perform or at least supervise urethral imaging procedures, as proper imaging is necessary to provide a specific diagnosis and formulate a correct treatment plan.

Our Diagnostic Approach at the Center for Reconstructive Urology

At the Center for Reconstructive Urology, the majority of our patients are referred by their local urologists for stricture evaluation and treatment. However, a referral is not required. In many cases when a patient is seen by a doctor for the first time, the visit is only a consultation and any tests that are indicated are then scheduled for another time. This is not our practice. All patients who seek care at the Center for Reconstructive Urology are contacted by Dr. Gelman. We determine if an evaluation at the time of consultation is appropriate. When indicated, we prefer to perform all of the above diagnostic procedures at the time of initial consultation, as the information provided permits an immediate definitive diagnosis and our patients can then be given definitive treatment recommendations. All testing is performed in a procedure room adjacent to the consultation room at UC, Irvine Medical Center, and Dr. Gelman personally performs all of the imaging studies. Over 1,000 urethral imaging studies have been performed at our Center. We have state-of-the-art imaging facilities that produce high resolution images that are saved as digital files, and also printed on high resolution 14 x 17 inch radiographic film and high resolution print images. One copy is placed in the chart, and when patients are referred, a copy is sent to the referring physician. Films are printed at the time of the procedure and then reviewed with the patient.

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