“Outpouchings of the urethral lumen into the surrounding connective tissue”
“Urine filled periurethral cystic structures adjacent to urethra, connected via an ostium”
“Sac-like protrusion composed of the entire urethral wall or only the urethral mucosa, situated between the periurethral tissues and anterior vaginal wall”
Anatomical points on female urethra
- Innermost layer – transitional urothelium, which becomes squamous distally
- Submucosa – vascular spongy tissue – paraurethral glands within submucosa, mostly proximally and draining/opening distally
- Smooth muscle – inner longitudinal and outer circular – continuous with bladder and making up involuntary sphincter
- Skeletal muscle – EUS – forms horseshoe ventrally, strongest mid urethra
- Female urethra is supported laterally by attachments to endopelvic fasciae and ATFP, anteriorly by pubourethral ligaments and posteriorly by anterior vaginal wall
- Mixed blood supply from inferior vesical, vaginal and internal pudendal arteries
Epidemiology
Prevalence 1 – 6 %
Probably under-recognised and under-reported.
Pathophysiology
Thought to arise from obstruction +/- infection of paraurethral glands, and subsequent rupture into urethral lumen, resulting in an epithelialized cavity.
More than 90 % of diverticula have the ostium located posterolaterally in the mid-distal urethra, which is where paraurethral glands open into urethra normally.
Repeated infection and obstruction can cause enlargement and symptoms.
An alternate theory is from urethral damage or trauma secondary to surgery, instrumentation or childbirth.
Classification
| Location | Communication | Configuration | Continence |
| Mid-urethra
Distal Proximal Full length |
Mid-urethral
Distal Proximal Non communicating |
Single
Multi-loculated Saddle shaped Circumferential |
Continent
SUI Post mict dribble MUI |
Pathology / histology
- Lining may be urothelial, squamous, columnar or mixed. In some cases, there is no epithelium and the cavity is surrounded by fibrous tissue.
- Two-thirds have inflammatory change.
- Pre-malignant and malignant changes are rare but seen – approx. 10 % may have histological abnormality including metaplasia, dysplasia or carcinoma.
- Most common malignancy is adenocarcinoma, then urothelial and SCC (cf. primary urethral cancer which is usually SCC)
- No consensus on management – local excision + radiation, cystourethrectomy +/- radiation
- Calculi within UD may be seen 4 – 10 %
Presentation
3rd – 7th decade.
Varying symptoms which can be largely unpredictable.
3 ‘D’s – dysuria, dyspareunia and dribbling – rare to have all three.
Symptoms include:
- Dysuria / dyspareunia / post void dribble
- Palpable mass
- Irritative LUTS
- Haematuria
- UTIs
- Vaginal discharge
- Incidental
- Urinary retention
Symptoms do not correlate well with size or complexity of diverticulum.
Differential diagnosis of anterior vaginal wall mass
Urethral:
- Urethral diverticulum
- Urethral prolapse
- Urethral caruncle
- Skene gland infection or cyst (do not communicate with urethral lumen, more distal and cause displacement of urethra)
- Urethral cancer
- Urethral bulking agent e.g Macroplastique
- Ectopic obstructed ureter
Vaginal:
- Gartner duct cyst or infection
- Vaginal leiomyoma
- Bartholin’s cyst
- Mullerian cyst
- Condyloma
- Vaginal wall cysts (e.g. epithelial cysts)
Work-up
History
- Symptoms including continence, duration, UTIs, level of bother, baseline sexual function
- O+G history
- Medical and surgical history (bulking agents, slings)
Exam:
- Mass location, tenderness, size, mobility, presence of calculus, expression of secretions/pus
- Most UD are ventrally and a bit lateral, mid-proximal urethra, 1 – 3 cm inside introitus.
- Oestrogenisation
- Demonstation of stress incontinence
Investigations
Urine culture
-
- Post void residual
- MRI – best test – hyperintense on T2 (water is white) same as bladder, hypointense on T1. Can be done independent of voiding and free of radiation.
- Ultrasound – can show location and size of masses with transvaginal ultrasound
- Double balloon catheter (Trattner catheter) dye test largely historic.
- VCUG can provide good images but invasive, radiation and may not always pick up diverticulum during or post void.
Cystourethroscopy – usually performed in conjunction with EUA. Helpful to know location of ostia for pre-operative planning. But only seen in 40 % cases. Use zero degree lens
Management
Conservative management or observation is acceptable in asymptomatic patients or those with low levels of bother – but they should be warned that there is a small risk of cancer within the diverticulum (and perhaps be encouraged to ‘milk’ or strip the diverticulum.
Reported non excisional surgical options:
- Marsupialisation – opens cyst on vaginal side and dissolvable sutures to leave open and allow drainage – reported in pregnant patients mainly. Risk of urethrovaginal fistula.
- Endoscopic incision – only rarely reported.
Principles of diverticulectomy
- Mobilisation of well vascularised anterior vaginal wall flaps
- Preservation of the periurethral fascia as a separate layer
- Identification and excision of the neck/ostium
- Removal of the entire diverticulum sac
- Watertight urethral closure
- Multilayered, non overlapping, absorbable sutures
- Closure of dead space
- Preservation or creation of continence
Technique:
- IDC. Cystoscopy if not done prior. Lonestar retractor. Headlight.
- Hydrodissection with lignocaine/adrenaline.
- Inverted U incision.
- Raise anterior vaginal wall flap with metz and traction / keep periurethral fascia intact
- Once mobilised completely, transverse incision in periurethral fascia over UD
- Complete excision of UD – grasp with Allis or similar.
- IDC often on show after excision – close with interrupted 4-0 PDS or monocryl over catheter.
- Martius flap if needed (complex, poor tissues, re-operation)
- Close periurethral fascia (vicryl)
- Close anterior vaginal wall incision (vicryl, not rapide).
- IDC for 1-2 weeks (+/- VCMG). Vaginal packing overnight.
Risks
- Recurrence– 10 – 20 %
- De novo SUI 1 – 16 %
- Bleeding / pain.
- UTI
- Urethrovaginal fistula – if proximal to sphincter will be continually incontinent.
- Stricture
Concomitant SUI
OK to proceed with combined excision of UD + sling – don’t use synthetic mesh sling, use rectus fascia or fascia lata. Consider Martius flap. Sometimes SUI gets better after excision of UD alone. Retention risk and perhaps higher risk of fistula. Counselling crucial.