Female Urethral Diverticulum

Fig. 15.1

(a) Transvaginal ultrasound of a proximal saddlebag urethral diverticulum. (b) VCUG of a proximal urethral diverticulum. (c) Axial T2- weighted MRI of the same proximal saddlebag urethral diverticulum

The presentation of female urethral diverticula is diverse and can range from incidental findings on physical exam or cross sectional imaging, to frequent urinary tract infections, dyspareunia, incontinence or malignancy. The most common presentations include vaginal mass, irritative lower urinary tract symptoms, and recurrent urinary tract infections [1, 3, 5]. Up to 20 % of patients lack symptoms, with urethral diverticula being an incidental finding on imaging. The vague and overlapping nature of symptoms can delay the diagnosis of urethral diverticulum up to 2–5 years, with the mean interval between onset of symptoms and diagnosis of 5.2 years [1, 3, 6, 7].

The differential diagnosis of periurethral masses includes: vaginal wall cysts, leimyoma, Skene gland abnormalities (Refer to Videos 15.1 Excision of Skene’s Gland Cyst (Zimmern P) and 15.2 Urethral Diverticulum Repair (Zimmern P)), Gartners duct abnormalities, urethral prolapse, and urethral caruncle in addition to urethral diverticulum. A thorough pelvic exam with palpation of the anterior vaginal wall for tenderness or discharge may not be sufficient in making a diagnosis. In such instances, and for operative planning, further cystoscopic and radiographic evaluation is warranted.

When urethral diverticulum is suspected, cystourethroscopy offers the opportunity to visualize the location of the diverticular ostium and to evaluate for other causes of irritative or obstructive voiding symptoms. Visualization of the diverticular ostium on cystourethroscopy is variable and reported in 15–89 % of cases [1, 6–9]. The ostium is usually found in a posterolateral position in the proximal or middle third of the urethra and can be visualized by slowly withdrawing the cystoscope through the urethra.

Radiologic modalities for evaluation of urethral diverticula include ultrasound, VCUG, and MRI (Fig. 15.1). Transperineal and transvaginal ultrasound have reported sensitivity of up to 95–100 % and may be useful in the intra-operative identification of the diverticulum in difficult dissections (Fig. 15.1a) [1, 6, 10]. It should be noted, however, that the sensitivity of this imaging modality is predicated on the skill of the sonographer, with some studies reporting a less than 50 % sensitivity in evaluation of known diverticula [1, 3]. VCUG offers the ability to visualize the diverticulum if the ostium is patent, with reported sensitivity of 67–95 % (Fig. 15.1b) [1, 11]. As VCUG is invasive, uncomfortable, and carries an increased risk of infection, the optimal study for diagnosis and operative planning is MRI. MRI offers excellent anatomic detail for surgical planning without radiation or catheterization. T2 weighted imaging will display the diverticulum as a bright, fluid filled entity adjacent to the urethra (Fig. 15.1c).

Urodynamics may be beneficial in patients with a urethral diverticulum who endorse incontinence to clarify if genuine stress urinary incontinence is present or if the apparent incontinence is actually due to post-void dribbling as a result of residual urine in the diverticulum after voiding.

Surgical Indications

The natural history of untreated urethral diverticula is unknown. Whether such lesions enlarge, become more symptomatic or are associated with other complications such as malignant degeneration, is unknown. Up to 10 % of diverticula show atypical pathologic findings without any obvious imaging findings [5, 12], with malignancy being found in 1–6 % of urethral diverticula [3, 8, 13, 14]. The most common malignancies reported are adenocarcinoma, transitional cell carcinoma and squamous cell carcinoma. Patients who are not surgical candidates and those who do not desire surgical excision should be counseled as to the risk of malignant transformation and should undergo continued monitoring. If malignancy is found, pelvic exenteration, lymphadenectomy and urinary diversion is pursued for curative intent when applicable. Minimally symptomatic patients and those who desire non-operative management may be placed on antibiotic prophylaxis. In such individuals, post-void stripping of the anterior vaginal wall would be expected to empty the UD cavity and potentially reduce post-void dribbling and recurrent UTIs.

Once the diagnosis is confirmed in symptomatic patients, the treatment of UD usually consists of surgical excision and reconstruction. Indications for surgical excision and reconstruction of urethral diverticula include refractory symptoms such as pelvic pain, dyspareunia, irritative voiding symptoms and recurrent urinary tract infections.

Urethral diverticulum and stress urinary incontinence (SUI) often co-exist, with reports of anywhere between 10–57 % of patients with urethral diverticulum also presenting with SUI [13, 15]. Only approximately 50 % of these patients were found to have true SUI versus post-void dribbling. On the contrary, urethral diverticulum can also mask SUI due to mass effect in 10–33 % of patients, especially when the urethral diverticulum is proximal and greater than 3 cm in size [13]. As such, there is no consensus on appropriate timing of surgical management of these two conditions. When treating concomitant urethral diverticula and stress urinary incontinence, some surgeons favor a staged procedure while others recommend simultaneous pubovaginal sling placement. Concomitant autologous pubovaginal sling placement has been found to be safe and effective for treatment of stress urinary incontinence at the time of urethral diverticulectomy and should be decided on an individualized basis [5, 15]. The use of synthetic materials as a concomitant sling material is not recommended due to the risk of erosion of the synthetic graft [16].

Surgical Consent and Discussion

Patients are counseled prior to surgery regarding the various surgical and non-surgical treatment options, expected recovery process (detailed later in this chapter) and the most common post-operative complications.

As noted previously, some patients may elect for non-operative management with low dose suppressive antibiotics and digital stripping of the anterior vaginal wall following micturition to prevent post-void dribbling and to reduce the risk of urinary tract infection due to stasis in the diverticulum. Such patients are counseled regarding the unknown natural history of untreated UD, as well as the potential for malignant change, and scheduled for routine annual follow-up.

For patients with very distal urethral diverticulum who do not desire extensive surgical reconstruction, marsupialization of the diverticulum into the vagina via a deep incision into the ventral urethra is an option (Spence-Duckett procedure). Patients are counseled that there is a risk of stress urinary incontinence as proximal incision of the ventral urethra may result in injury of the urethral sphincter and de novo postoperative SUI.

Rarely, in pregnant women or in patients with a highly symptomatic or infected urethral diverticulum in whom elective excision and reconstruction should be postponed, a transvaginal incision directly into the urethral diverticulum (“diverticulotomy”) can be performed to create a temporary urethrovaginal fistula traversing the UD cavity and thereby decompress the urethral diverticulum until such time that elective excision and reconstruction can be performed. Such patients are counseled that if the UD is located proximally and/or they have an incompetent bladder neck, to expect the possibility of constant leakage of urine per the vagina through the iatrogenic urethrovaginal fistula until definitive reconstruction is performed.

Patients are extensively counseled regarding the expected postoperative course, risks of surgery, as well as potential outcomes. Surgical excision of the diverticulum with appropriate tension-free, multi-layered closure is the gold-standard treatment with most studies reporting success rates greater than 90 % [1, 3, 5, 8, 17]. There is an increased risk of recurrence in patients who have multiple or circumferential diverticula, proximal diverticula or have had prior UD surgery [1, 17].

Patients are counseled that complications may occur postoperatively. The most common complications after urethral diverticulectomy include urinary tract infection, de novo stress urinary incontinence, and de novo irritative lower urinary tract symptoms. The risk of urethrovaginal fistula and urethral stricture are less common but can be difficult to manage and may require additional surgical intervention [1, 3, 5, 6, 8, 17]. Post-operative complication and recurrence rates are highly variable in the literature and vary depending on surgeon experience, complexity of the UD anatomy, and surgical technique. These are further discussed below.

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