Overview
Urethral diverticulum (UD) is a condition in which a variably sized “pocket” or outpouching forms next to the urethra. Because it most often connects to the urethra, this outpouching repeatedly gets filled with urine during the act of urination thus causing symptoms.
UD is much more common in females then in males and usually appears between the ages of 40 and 70. Occurrence in children is extremely rare in the absence of prior urethral surgery.
With the development of sophisticated imaging techniques, the diagnosis of UD has become increasingly common. However, the true prevalence in any given population is still not known since many cases are missed or misdiagnosed simply because no one suspected it.
The origin of acquired UD has recently been attributed to repeated infections and/or obstruction of the periurethral glands with subsequent obstruction eventually evolving into UD. Although some earlier studies have suggested congenital causes or trauma experienced during childbirth.
Symptoms
Although symptoms are highly variable, the most common symptoms are irritative (i.e., frequency, urgency and dysuria) lower urinary tract symptoms (LUTS). Dyspareunia will be noted by 12 to 24 percent of patients and approximately five to 32 percent of patients will complain of post-void dribbling. Recurrent cystitis or urinary tract infection is also a frequent symptom in one-third of patients. Other complaints include pain, hematuria, vaginal discharge, obstructive symptoms or urinary retention and incontinence (stress or urge). Up to 20 percent of patients diagnosed with UD may not have noticeable symptoms. Some patients may also have a tender anterior vaginal wall mass, which upon gentle compression may reveal retained urine or pus discharge through the urethral opening.
It is important to note that the size of the UD does not correlate with symptoms. In some cases, very large UD may result in minimal symptoms, and conversely, some UD that are non-palpable may result in considerable discomfort and distress.
Finally, symptoms may come and go and may even disappear for long periods of time.
Diagnosis
Since many of the symptoms associated with UD are non-specific, patients may often be misdiagnosed and treated for years for a number of unrelated conditions before the diagnosis of UD is made. This may include therapies for interstitial cystitis, recurrent cystitis, vulvodynia, endometriosis, vulvovestibulitis and other conditions.
The diagnosis and complete evaluation of UD can be made through a combination of thorough history, physical examination, appropriate urine studies, endoscopic examination of the bladder and urethra and selected radiologic imaging.
A number of imaging techniques have been applied to the study of UD and no single study can be considered the gold standard or optimal imaging study for the evaluation of UD. Each technique has relative advantages and disadvantages, and the ultimate choice of diagnostic study in many centers often depends on several factors including local availability, cost and the experience and expertise of the radiologist. Currently available techniques for the evaluation of UD include double-balloon positive-pressure urethrography (PPU), voiding cystourethrography (VCUG), ultrasound (US) and magnetic resonance imaging (MRI) with or without an endoluminal coil (eMRI).
A urodynamic study may also be used in selected cases and may document the presence or absence of stress urinary incontinence prior to repair. A videourodynamic study may also be used as a diagnostic tool. The type of study combines both a voiding cystourethrogram and a urodynamic study thus consolidating the diagnostic evaluation and decreasing the number of required urethral catheterizations during a patient’s clinical work-up. In addition, videourodynamic evaluation may be able to differentiate true stress incontinence from pseudo-incontinence related to emptying of a UD with physical activity.
During physical examination, the urethra may be “milked” distally in an attempt to express pus or urine from the UD cavity. For females, during physical examination, the anterior vaginal wall may be carefully felt for masses and tenderness.
Treatment
Although often highly symptomatic, not all urethral diverticula require surgical excision (removal). Some patients may not have noticeable symptoms and the UD was incidentally diagnosed on imaging for another condition or during a routine physical examination. While other patients may be unwilling or medically unable to undergo surgical removal.
Very little is known regarding the natural history of untreated UD-whether they will grow in size, complexity or if symptoms will increase over time is unknown. For these reasons, and due to the lack of symptoms in selected cases, some patients may not desire surgical treatment. However, there have been recent reports of carcinomas arising in UD thus patient counseling and ongoing monitoring is recommended in patients who elect not to undergo surgical treatment.
Surgical options include transurethral incision of the diverticular neck, marsupialization (creation of permanent opening) of the diverticular sac into the vagina [often referred to as a Spence procedure], and surgical excision.
Surgical excision is the treatment of choice but it should be performed with caution. The diverticular sac may be quite attached to the adjacent urethral lumen and careless removal of the sac may result in a large urethral defect requiring construction of a new urethra. Other important considerations during surgery include identification and closure of the diverticular neck (connection to the urethral lumen), complete removal of the mucosal lining of the diverticular sac to prevent recurrence, and a multiple layered closure to prevent postoperative urethrovaginal fistula formation (formation of an abnormal opening between the urethra and vagina).
Post-treatment
For those patients who elect not to undergo surgical treatment, it is recommended that they continue to be monitored by their urologist.
Patients who are treated surgically can expect to be on antibiotics for 24 hours postoperatively and discharged home with both urethral and suprapubic catheters. Antispasmodics are used liberally to reduce bladder spasms. A VCUG is obtained at 14 to 21 days postoperatively. If there is no extravasation, the catheters are removed. If extravasation is seen, then the urethral catheter is reinserted and repeat VCUGs are performed weekly until resolution is noted. In the vast majority of cases, extravasation will resolve in several weeks with this type of conservative management. Common implications may arise from surgical treatment and may include recurrent UTIs, urinary incontinence or recurrent UD. In females, urethrovaginal fistula is a devastating complication of urethral diverticulectomy and deserves special mention.
Some patients will have persistence or recurrence of their preoperative symptoms postoperatively. The finding of a UD following a presumably successful urethral diverticulectomy may occur as a result of a new UD, or alternatively, as a result of recurrence. Recurrence of UD may be due to incomplete removal of the UD, inadequate closure of the urethra or residual dead space or other technical factors. Repeat urethral diverticulectomy surgery can be challenging, as anatomic planes may be difficult to identify.