Urethral stricture disease

The term urethral stricture refers to anterior urethral disease, a scarring process involving the spongy erectile tissue of the corpus spongiosum also referred to as spongiofibrosis (Figure 158.4). Under the urethral epithelium lies the spongy erectile tissue of the corpus spongiosum and, in some cases, scarring can extend through the tissues of the corpus spongiosum and into adjacent tissues. As the scar contracts, it reduces the diameter of the urethral lumen. The normal urethra measures 30 Fr, and its diameter is approximately 10 mm. The calculated luminal area is approximately 78 mm². If scarring has resulted in a urethra that measures 15 Fr, the lumen is only 55 mm², or 29% reduced. Scar contraction caused by anterior urethral stricture disease can be markedly asymptomatic early in the process, but as the scarring process and contracture continues and the urethral lumen is further reduced, marked voiding symptoms can develop. This process may occur anywhere within the anterior urethra.

Posterior urethral “strictures” are, in fact, not referred to as strictures at all. By consensus of the World Health Organization conference, the term stricture is limited to the anterior urethra, while distraction defects are those processes of the membranous urethra associated with pelvic fracture and other narrowing of the posterior urethra, urethral contractures, or stenosis [2]. These processes do not involve spongiofibrosis and are thus commonly referred to as stenoses instead of strictures. As with anterior urethral strictures, posterior urethral stenosis is an obliterative process that has resulted in fibrosis and luminal narrowing. This process has usually been initiated by a distraction injury, whether due to trauma or surgical manipulation. Although in some cases these stenoses can be lengthy, the actual process involving the tissues of the urethra is usually well confined. Conditions that result in posterior urethral stenosis include membranous urethral stenosis, prostatic urethral stenosis, bladder neck contracture, vesicourethral distraction, and posterior urethral distraction defects.

Etiology

Any process that injures the urethral epithelium and/or the underlying corpus spongiosum to the point that healing results in a scar causes a urethral stricture or stenosis. Anterior urethral strictures most commonly result from trauma, infection, inflammatory conditions, or urethral manipulation. In many cases, the inciting event goes unrecognized by the patient until they present with obstructive voiding symptoms.

Traumatic injuries such as straddle injuries are a common example. Penetrating injuries, such as gunshot or stab wounds, may be appropriately treated initially and still lead to development of delayed stricture disease. Iatrogenic trauma is a known etiology of urethral strictures, but with the development of smaller scopes and the recognition of the importance of careful technique, fewer of these cases are now being seen.

The inflammatory dermatosis lichen sclerosus is a commonly seen disease process in patients with anterior urethral strictures. This condition behaves differently from traumatic strictures, recurring quite readily, and thus requires special consideration when contemplating treatment options. Typically, the initial presentation is that of meatal stenosis associated with skin inflammation of the glans penis and prepuce. The inflammation then progresses proximally, perhaps due to distal obstruction, high pressure voiding, and subsequent microextravasation of urine into the corpus spongiosum and glands of Littre.

Infectious strictures associated with gonorrhea, which were commonly seen in the past, are now much less common. With the advent of more effective antibiotics and widely available medical care, gonococcal urethritis today rarely progresses to urethral stricture disease. As we understand the processes currently, nonspecific urethritis due to Chlamydia or other organisms does not lead to urethral strictures. The condition of idiopathic urethrorrhagia has in the past been felt to be related to urethral stricture because children were endoscoped for diagnosis. In years past, before the minification of endoscopes, it was felt that those stricture were iatrogenic. However, now there is accumulating evidence that the entity itself can cause proximal bulbous urethral stricture disease [3].

Finally, there are so‐called congenital strictures. These strictures occur in infants, are short in length, noninflammatory, and not associated with potential for traumatic etiology. They are the rarest of all strictures.

Posterior urethral stenoses and anterior urethral strictures have many similar causes, although there are also several etiologies specific to the posterior urethra. Membranous strictures may result from urethral manipulation or radiation. Larger French resectoscopes, such as are used for transurethral resection procedures, may cause tearing of the membranous urethra as it departs the corpus spongiosum. Brachytherapy seeds placed distal to the apex of the prostate can lead to radiation damage to this portion of the urethra as well. Prostatic urethral stenosis is rarely encountered, although when seen it may result from iatrogenic endoscopic manipulation of the prostate. Bladder neck stenosis is seen commonly after transurethral resection or radical prostatectomy. It is usually manifest as a short‐length stenosis of varying caliber at the junction of the urethra and bladder. In some instances, endoscopic procedures for prostatic enlargement (whether traditional transurethral resection or laser prostatectomy) are performed when there is an unrecognized underlying element of voiding dysfunction. In these cases, the symptoms that prompted treatment will certainly recur. Bladder neck stenosis typically responds well to endoscopic management, by gentle dilation or incision using cold knife, electrocautery, or laser techniques. A more severe form of bladder neck stenosis termed vesicourethral distraction stenosis can be a devastating consequence of radical prostatectomy. It occurs when the vesicourethral anastomosis is disrupted and leads to a longer defect that is quite resistant to endoscopic treatment. Posterior urethral distraction defects are commonly seen with anterior pelvic arch fractures. It has been classically taught that these fractures cause the prostatic apex to separate from the membranous urethra in the manner in which one would remove the stalk from an apple. Newer data, however, shows that these injuries typically occur more distally than the level of the prostatic apex. The level of the distraction defect is usually found just proximal to the departure of the membranous urethra from the corpus spongiosum and thus spares the external urinary sphincter. As in a vesicourethral distraction, this injury leads to extensive fibrosis interposed between the two distracted ends of urethra and is resistant to endoscopic management.

Diagnosis and evaluation

Patients who have urethral strictures most often present with obstructive voiding symptoms, urinary tract infections, hematuria, dysuria, or urinary retention. Compensatory hypertrophy of the detrusor may initially allow patients to void through a narrowed urethral lumen with few symptoms. In addition, some degree of decreased urethral caliber may not significantly affect the flow dynamics. Patients may not develop significant symptoms until a reduced urethral caliber of 10–12 Fr is reached. Many of these patients will relate an insidious onset of voiding symptoms before progressing to obstructive symptoms or complete obstruction.

First, it is important to question the patient as to history of trauma, especially straddle trauma. A history of urethral infection, previous urethral, prostate or bladder surgeries, and previous catheterizations should be noted. A thorough genital exam should also be performed. Stigmata of hypospadias, lichen sclerosis, previous surgical interventions, and spongiofibrosis may be found. These clues revealed by history and physical exam may give the practitioner additional information as to the etiology of the disease process. This is important to know, as strictures of different etiologies may behave differently when treated.

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