Urethral Stricture Disease
Urinary obstruction can occur for many reasons. In particular, obstruction of urine, as it flows from the bladder through the urethra, may be caused by a narrowing caused by scar. It occurs rarely in women, and is seen more commonly in men. A number of things can lead to stricture formation, and the most important of these are: trauma/injury (straddle injury, pelvic fracture), infection (sexually transmitted disease), post-instrumentation (eg. traumatic catheter placement, transurethal surgery) and malignancy/cancer (rare). Following injury to the urethra by the above methods, the scar may take many years to develop. As such, a significant number of men will present later in life with an unknown etiology.
Strictures located at the tip of the penis/urethra (urethral meatus) may be caused by trauma; however, another common reason is an inflammatory skin condition known as lichen sclerosis (previously balanitis xerotica obliterans).
In general, urethral strictures are divided into two main categories:
1. Anterior urethra (from the sphincter [control muscle] to the tip of the penis)
Posterior urethra (from the bladder to the urethral sphincter)
Men who develop urethral strictures describe symptoms associated with the inability to adequately empty their bladder: weak urinary stream, straining to urinate, spraying of the stream, incomplete emptying, dribbling, urinary tract infection and inability to void. Rarely is pain associated with this condition, unless it relates to the acute injury. Blood in the urine is rare but may be associated with a stricture.
The diagnosis of urethral stricture begins with a history and physical exam. Patients will often describe certain risks factors (see above), and for those patients with the symptoms, described above, a thorough investigation is required to rule out urethral stricture or complications related to one.
Urinanalysis (U/A): performed to rule out hematuria (blood in the urine), infection or other urinary abnormalities.
Urine culture: studies the urine for evidence of infection, which may occur in some people with a urethral stricture.
Uroflowmetry/Peak flow urine study: individuals are asked to void into a special toilet, which measures the speed at which urine flows from the bladder to the end of the urethra. Many individuals with a stricture will have a diminished rate of flow.
Post-void Residual Urine Study: an ultrasound of the bladder is performed, measuring the amount of urine that remains after a "normal" void (urination).
Retrograde Urethrogram (RUG) with Voiding Cystourethrogram (VCUG): X-ray constrast (dye) is used to fill the urethra and bladder as images are obtained, identifying the level of blockage. Men are then asked to void (VCUG) and again x-rays are taken to better outline the level of stricture.
Cystoscopy: using a fiberoptic telescope the urinary tract from the tip of the penis to the bladder can be inspected. This can help rule-out other causes of obstruction or allow the urologist to better characterize the stricture.
Sonourethrogram: This test is usually done in the operating room as part of the pre-operative surgical planning. It involves an ultrasound probe to image the stricture, measure stricture length and assess the degree of urethral scarring.
Most patients will have a urinalysis, urine culture, uroflowmetry, post-void residual study and a RUG/VCUG. Cystoscopy may not be required and its need will be determined by the doctor.
There are no medical treatments for urethral stricture, though early treatment of urethritis or UTI's with antibiotics is an important part of the treatment of strictures. The treatment of urethral strictures can be divided into three main categories:
1. Nonoperative: For many men the stricture is not severe enough or bothersome, and the risk of complications remains low. In these men, doing nothing may be the best option, avoiding the need for surgery. This strategy may also be adopted for men with significant medical illnesses that place them at a greater risk for having surgery. A strategy, in which the patient self-catheterizes, may be used to slow the rate of narrowing from the stricture. Sometimes a urinary catheter will be placed through the skin of the lower abdomen (suprapubic tube) to drain the urine, for individuals who are very sick or have impassable strictures prior to surgery.
2. Minimally invasive/endourological: When the stricture becomes severe enough to block the urine flow or cause complications, a procedure to dilate/open-up the stricture is required. This may be performed in the office using urethral sounds (metal dilating rods), a cystoscope and urethral dilators or in the operating room, where the stricture is cut using a knife or laser (internal urethrotomy). In general, a catheter will be placed for 1-10 days after each of these procedures. Deciding which procedure to use first depends on the nature of the stricture.
Depending on the length of the stricture, the success of these procedures is in the range of 50% for "first-time" attempts. In addition, successful treatment (defined as permanent resolution of the blockage) best occurs in the setting of a short stricture (< 1-2 cm). Individuals who redevelop a stricture after one of these procedures may require more formal reconstruction, because success of subsequent minimally invasive treatments is significantly lower. Current research using temporary urethral stents (metal coils which hold the urethra open while it heals after dilation) is being conducted, but their use remains investigational at this point.
3. Open Surgical Reconstruction: In carefully selected patients, who fail other forms of management, reconstruction is the preferred form of management.
a. For short strictures (<2.0 cm) in the bulbar urethra, removing the stricture and then reconnecting the ends of urethra (excision with primary re-anastomosis) has success rates of 90-95%.
b. Strictures may require more complex forms of reconstruction due to significant scarring, length (>2.0 cm), location (posterior urethra, meatus/penile tip, or pendulous urethra/shaft). Tissue transfer techniques may be combined with re-anastomosis to achieve a good repair. The most commonly used tissue that is used to aid in reconstruction is buccal mucosa, taken from the inside lining of the cheek and "grafted" into the urethra. This allows the surgeon to develop a urethral lumen that is wider. Skin from the penis may also be used, and when used it usually remains attached to its own blood supply (aka, a ‘flap’). This surgical technique can be very useful for very difficult to treat strictures. Success rates for graft and flap procedures in the bulbar urethra range from 80-90%.
For the most complex strictures of the anterior urethra, including the urethral meatus, a staged surgical approach is adopted, removing the stricture then placing a graft in the open space. This is allowed to heal open to the air for a period of 6-12 months, before it is "re-tubularized" into a urethra. This is usually reserved for individuals with strictures in the pendulous urethra, very scarred strictures, repeated failures, and very long strictures.
People who have sustained an injury to the urethra are encouraged to follow-up with a urologist or primary care provider, especially if they develop urinary symptoms related to obstruction. Self-dilating may help slow the rate at which strictures reform after dilation. For those individuals at risk for contracting STDs, use of barrier contraception (condoms) is strongly encourage, as is prompt treatment of urethritis with antibiotics.