The bladder stores the urine produced by the kidneys until the proper time for emptying. At the moment of urination, the bladder muscle contracts to evacuate urine through the urinary canal, the urethra. The opening and closing of the urethra are controlled by the muscles that encircle it, the urethral sphincter.
The urine is evacuated outside the bladder by a muscular opening called a bladder neck, in a segment of the urethra surrounded by the prostate, called the prostatic urethra. The next segment, the membranous urethra, is surrounded by a muscle called the external urinary sphincter. This sphincter allows the person to hold their urine voluntarily and interrupt the jet during urination. Together, the prostatic and membranous segments form the posterior urethra which is approximately 2.5 to 5 cm (1-2 inches) in length.
The rest of the urethra is a channel that passes through the penis. The first portion, the bulbar urethra, is in the fork between the legs, while the penile urethra passes through the penis. The opening at the end of the penis is called the urethral meatus. The bulbar urethra, the penile urethra and the meatus compose the anterior urethra.
Urethral stenosis is a scar in or around the urethra that may decrease urine flow. Imagine a narrowing or elbow in a garden hose that would slow down the flow of water. Stenosis of the urethra can cause a decrease in jet pressure or a jet of watering, painful urination and occasionally blood from the urethra.
Urethral stenosis can occur anywhere along the urethra, from the bladder to its orifice. The most common cause of stenosis is trauma to the urethra. A fall or motor vehicle accident can cause pelvic fracture with tearing of the posterior urethra and sometimes stenosis at the time of healing. A straddling injury, such as a fall on the bar of a bicycle, can crush the anterior urethra and cause stenosis. This condition can also occur following an injury when installing a drainage tube (catheter), or after surgery performed through the urethra. Sometimes urethral strictures may be due to infections and, in rare cases, to a tumor. Nevertheless, it often happens that we can not identify any probable cause.
When urethral stricture is suspected, your doctor may recommend investigations to clarify the diagnosis. These could be urine tests for blood or infection. We could do a test of urinary flow and volume (flow measurement). Several imaging tests can be used to identify the location, length, and severity of a urethral stenosis. An X-ray of the urethra can be obtained using an injection of contrast medium in the canal (urethrography) to visualize the stenosis. Urethral ultrasound can also help to evaluate the amount of scar tissue. Urethroscopy is a procedure where the doctor gently inserts a thin, lubricated “endoscope” into the urethra to see the stenosis.
There are different therapeutic options for urethral stenosis, depending on the length, location and extent of scar tissue. These options include enlargement of the stenosis by gradual stretching (dilation), incision of the stenosis using an “endoscope” (internal urethrotomy) and surgical excision of the stenosis with reconstruction of the urethra (urethroplasty).
Urethral dilatation can often be performed at the urologist’s office under local anesthesia (“freezing the canal”). This consists of a gradual enlargement of the stenosis with dilators of increasing size. If the stenosis recurs quickly, it is possible to learn how to insert a catheter into the urethra periodically to keep the stenosis open. Often, dilatation alone will not be enough to cure the stenosis. Pain, bleeding or infection may occur following dilatation for stenosis.
Internal urethrotomy involves making an incision in the scar that causes the stenosis using a specialized instrument for the incision or using a laser. This can be done in a clinic with a local anesthetic, or in the operating room under spinal anesthesia (you are numb from the navel to the feet) or general (you are “asleep”), as the case may be. Your doctor will make an incision in the stenosis using a special endoscope (urethrotome) that can be passed through the urethra to the stenosis. A catheter can be left in the urethra to allow healing by keeping the stenosis open. This procedure can be very useful for stenosis of the bladder neck or urethra. Following the procedure, there may be blood in the urine and blood flowing through the meatus of the urethra as well as discomfort. Occasionally, an infection requires treatment with antibiotics. Unfortunately, the risk of stenosis recurrence following internal urethrotomy is significant.
Occasionally, after an internal urethrotomy, a guardian could be placed across the stenosis to keep it open. A guardian is a metal ring that can expand to prevent the stenosis from closing. This treatment may be useful for particular patients as guardian-related complications may occur and withdrawal may be difficult.
Urethroplasty is an incisional surgical procedure to repair stenosis of the posterior urethra or after other treatment options for stenosis of the anterior urethra or meatus have been shown to be ineffective. There are several different types of urethroplasty. The choice of repair depends on the location and length of the stenosis.
Open urethroplasty for short urethral stenosis may consist of surgery to remove the stenosis and simply reconnect the two ends. When the stenosis is too long, the missing urethra segment can be reconstructed using tissue taken elsewhere on the body. Different types of tissue can be used, such as the skin of a surrounding area or inside the mouth (oral mucosa).
These repairs can be a challenge and in some circumstances they will be executed in different stages.
Open urethroplasties are made from an incision in the fork (perineum) or on the penis. They should usually be done under general anesthesia and in short stay, or during a short hospital stay. A small flexible catheter could be left inside the penis for a period of about three weeks to ensure healing of the repair.
Since urethral strictures may reappear at any time, you should be followed by your doctor after the surgical repair. You may be advised to learn how to dilate the area with a catheter to delay or prevent the return of the stenosis. Periodic appointments to assess urinary function (the act of urinating) and a urine flow test may be necessary. X-rays or urethroscopy may be required to assess the area of repair. Some will require additional surgical procedures to maintain normal urination.
Urethral strictures are a common cause of voiding disorders. They can often be treated by your doctor with minor surgery.