Urethral Diverticulum

A urethral diverticulum is a saccular outpouching of the urethral mucosa that protrudes into the periurethral tissues. It communicates with the urethral lumen through a narrow ostium, usually on the posterior (vaginal) wall of the mid to distal urethra in women. Reported prevalence is 1 to 6 percent of women, usually diagnosed between 30 and 60 years.

It is mostly acquired. Recurrent infection of the periurethral (Skene) glands leads to obstruction, abscess formation and rupture into the urethra. Other causes include childbirth trauma, urethral instrumentation, and surgery. Congenital diverticula (Gartner duct remnants, Müllerian remnants) are less common.

In men, diverticula are rare and located in the ventral anterior urethra. They are congenital or acquired (after urethral stricture or hypospadias repair, or trauma).

Complications include:

• Recurrent infection.
• Stone formation (in about 1 to 10 percent).
• Urethrovaginal fistula.
• Carcinoma in 1 to 6 percent of diverticula. Adenocarcinoma accounts for 60 percent, with clear cell histology. Urothelial and squamous carcinoma also occur.

• The classic "three Ds": dysuria, dyspareunia and post-micturition dribbling (the dribble of urine after voiding as the diverticulum empties); only a minority have all three.
• Recurrent urinary tract infection, urinary frequency, urgency, urge and stress incontinence, and pelvic pain.
• A tender anterior vaginal wall mass, which may express pus or urine through the urethral meatus on palpation (in about 50 percent).
• Haematuria, vaginal discharge, and obstructive voiding symptoms.
• Asymptomatic, or incidental finding on imaging.
• Hard or irregular mass with bleeding suggests malignancy.

• Pelvic examination: a mass on the anterior vaginal wall under the urethra, tenderness, and discharge on urethral compression ("milking").
• MRI pelvis with endorectal or surface coil is the best test, with sensitivity above 90 percent. It shows a fluid filled saccule (bright on T2) with a narrow neck communicating with the urethra.
• MRI also shows wall detail, a circumferential "saddlebag" configuration, stones, tumour (enhancing nodule), and relationship to the bladder neck.
• Voiding cystourethrography (including double balloon positive pressure urethrography) shows the diverticulum filling during voiding. Sensitivity is lower than for MRI.
• Transvaginal or transperineal ultrasound; urethroscopy or cystoscopy to find the ostium on the posterior urethral wall.
• Urinalysis and urine culture; urine cytology and biopsy where malignancy is suspected.
• Urodynamics when incontinence is present (to evaluate stress incontinence and the effect on repair).

• Asymptomatic or incidental small diverticula: observation, with education.
• Conservative therapy for symptoms during an acute infection: culture guided antibiotics (for example ciprofloxacin 500 mg twice daily or trimethoprim-sulfamethoxazole 160/800 mg twice daily for 7 to 14 days), anti-inflammatory drugs, and sitz baths.
• Acute abscess: drainage via the vaginal approach.
• Surgical excision (urethral diverticulectomy) is the definitive treatment for symptomatic diverticula, recurrent infection, stones, or suspected malignancy.
• Technique: use a transvaginal approach in the lithotomy position, with a catheter in the urethra. Make an inverted-U or midline incision of the anterior vaginal wall and create a flap. Identify and open the periurethral fascia, dissect to the neck of the diverticulum, and completely excise the sac with the ostium.
• Close the urethral defect in a watertight fashion with 4-0 absorbable suture in three layers. The layers are urethral mucosa, periurethral fascia, then a Martius labial fat flap (interposition).
• Use the Martius flap for large or repeated surgeries, or if tissues are poor, to prevent fistula. Then close the vaginal wall without overlapping suture lines.
• Leave a catheter for 7 to 14 days. In complex cases, do a voiding cystourethrogram before catheter removal.
• Alternatives: transurethral unroofing or marsupialisation (for distal diverticulum) and transvaginal marsupialisation (Spence procedure) for distal sac; endoscopic ablation.
• Concurrent stress urinary incontinence: perform a suburethral sling after confirming the diagnosis, ideally in a staged manner or at the same time (with some risk of urethral erosion). Incontinence can worsen after surgery in 20 to 30 percent (de novo stress incontinence in about 16 percent).
• Malignancy: radical surgery (anterior pelvic exenteration or urethrectomy) with chemotherapy or chemoradiation depending on stage; the prognosis is poor.
• Complications: urethrovaginal fistula (1 to 8 percent), urethral stricture (about 5 percent), recurrence of the diverticulum (5 to 20 percent), recurrent infection, and stress incontinence.
• Follow up: review at 6 weeks and 3 months, symptom monitoring, and imaging if symptoms persist or recur. Results: symptom resolution in 70 to 90 percent.