The urethra is a tubular structure that helps transport urine out of the bladder during urination. Patients who have strictures (or narrowing) of their urethra can have significant and bothersome obstructive urinary symptoms which include a weak force of stream, straining during urination, incomplete bladder emptying, and hesitancy (difficulty initiating void). Interestingly, however, most female patients with urethral stricture disease present with irritative symptoms like urgency, frequency, and incontinence. Serious consequences of untreated urethral strictures include urinary retention (inability to urinate), recurrent urinary tract infections, bladder dysfunction, and even kidney failure. Women with urinary symptoms have roughly a 5% chance of having a true urethral stricture.
The female urethra is about 6-10 mm in diameter and 4 cm in length. It has a mucosal inner lining and a muscular outer lining. A group of muscles encircling the urethra, called the striated urethral sphincter, maintains voluntary voiding and urinary continence. It is located primarily at the proximal to mid urethra. Most strictures are distal to this sphincter.
Female urethral strictures can be caused by infection, trauma, instrumentation (like catheter placement), or prior surgery (i.e. cystoscopy, urethral dilation, sling surgery for urinary incontinence). The most common causes are therefore iatrogenic in origin. Although true urethral stricture disease (urethral tissue fibrosis/scarring leading to luminal narrowing) is rare, dilation is commonly and sometimes inappropriately performed[i]. Dilation may thus create more strictures than it treats.
DIAGNOSIS AND EVALUATION
As with any medical problem, performing a thorough history and physical is required. Specific assessment of a patient’s voiding symptoms, neurologic history, traumatic history, and surgical history aids in identifying urethral stricture disease. Sometimes, difficulty passing a urethral catheter at some point in the patient’s past medical history is all that is required to diagnose a stricture. Additional diagnostic tools include urinalysis (analysis of the urine to identify infection and/or blood), uroflowometry (tool that measures volume and rate of bladder emptying), and bladder ultrasounds (device that determines how well a patient empties their bladder after voiding). More invasive tests include cystoscopy and retrograde urethrogram (RUG: radiographic study that involves injecting contrast thru the urethra). These quickly identify the location, length, number, and severity of urethral strictures. We must emphasize that radiographic and cystoscopic confirmation of a suspected female urethral stricture is crucial prior to open surgical management.
In patients with a history concerning for a non-functional or neurogenic bladder, videourodynamics (diagnostic series of tests that evaluates bladder function) is also very helpful preoperatively. These patients include those with prior pelvic surgery, diabetes, stroke, spinal cord disease, and/or other neurologic disorders. They need verification of bladder contractility prior to surgery because it changes management in these patients. Patients with a non-functional bladder without urethral obstruction may need to be taught clean-intermittent catheterization (CIC) or get a suprapubic (SP) tube (lower abdominal skin catheter that enters the bladder directly). Those with a non-functional bladder and urethral stricture who choose CIC over SP tube may need periodic definitive dilation or open urethroplasty to facilitate future CIC. Patients who have a functional bladder and urethral stricture disease may choose repeated endoscopic treatment (dilation vs internal urethrotomy) or open surgery. Urodynamic parameters suggestive of urethral obstruction are a flow rate less than 12 cc/sec with bladder contractile pressure greater than 25 cm H2O[ii],[iii]. A concomitant voiding cystourethrogram (VCUG) will demonstrate a narrowed distal urethral lumen with a dilated proximal urethra and relaxed striated sphincter.
Management depends on stricture type, location, severity, length, patient preference and goals. Most female urethral strictures are treated with serial urethral dilation or internal urethrotomy. However, the stricture-free interval after dilation or internal urethrotomy is variable, and with time, almost all strictures will recur. Patients interested in definitive management with better long-term outcomes will need open reconstructive surgery. Patients with prior anti-incontinence procedures will need urethrolysis and possible sling removal.
Female urethroplasty is simplified by the fact that vaginal mucosa is often readily available and easy to access. Two techniques for vaginal mucosal flap urethral reconstruction are the Blandy and Orandi method. Other open techniques include the use of vaginal vestibular and labia minora flap creation[iv],[v]. These urethroplasties are inherently harder to perform than vaginal mucosal flap urethroplasties and therefore reserved for patients with inadequate vaginal mucosa.
The Blandy procedure for open urethral reconstruction in women is described in detail by Schwender et al[vi]. It involves making an inverted “U” incision (apex of U near urethral meatus) on the anterior vaginal mucosa to expose the underlying periurethral fascia. The fascia and urethra is then incised at the 6 o’clock position to cut thru the urethral stricture, creating a dorsal urethral plate. The newly developed vaginal mucosal flap is subsequently sewn to the urethral plate to retubularize the urethra. During a followup of 1-9 years, the investigators found that all 9 patients had subjective improvement in their urinary symptoms. Only one patient underwent repeat dilation after the Blandy urethroplasty with no further stricture recurrence. There were no serious complications.
Simonato et al describe a different type of vaginal mucosal flap based on the Orandi technique[vii]. They create vaginal mucosal flaps by making a “C” shaped incision on the anterior vagina that spans about 3 times the width of the urethra. The flap is carefully freed from the periurethral fascia to preserve the lateral vascular pedicle. Again a 6 o’clock incision is made thru the urethral stricture to make a dorsal urethral plate. The C flap is then partial de-mucosalized longitudinally in the central position. This allows the distal aspect of the flap to be sewn to the dorsal urethral plate mucosa-to-mucosa without overlapping suture lines. The authors believe this technique theoretically decreases fistula formation and urethral shortening when compared to the Blandy technique since their suture lines are staggered. Mean followup was 2 to 9 years and only one of the 6 patients required further dilation. The other 5 had improved uroflows and urinary symptoms.
Buccal mucosal graft (BMG) onlay urethroplasties are commonly used in male urethral stricture disease. Migliari et al reported on their small series of female BMG onlay urethroplasties and concluded that it was a feasible option[viii]. Tsivian et al described the use of free buccal or vaginal mucosal grafts in a similar small cohort of female stricture patients with excellent results[ix]. These procedures require freeing the urethra dorsally and making a longitudinal 12 o’clock incision thru the urethral mucosa. The mucosal graft is then sewn mucosa-to-mucosa to augment the urethra and quilted to the clitoris corpora.
For patients unfit for surgery, CIC is an acceptable option. For those unwilling or unable to perform CIC, SP tube urinary diversion is well-tolerated. Postoperative de-novo urinary incontinence after urethroplasty is a feared complication, but since most strictures are distal to the striated sphincter, incontinence is rare.
The true female urethral stricture is a rare disease made more common by widespread use of inappropriate urethral dilation. Conservative management includes dilation and internal urethrotomy. For recurrent disease or obstruction associated with anti-incontinence procedures, open urethral reconstruction and urethrolysis are required. CIC and SP tube urinary diversion is also a well-tolerated and acceptable option.
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[iii] Kuo HC. Urodynamic parameters for the diagnosis of bladder outlet obstruction in women. Urol Int. 2004;72:46.
[iv] Montorsi F, Salonia A, Centemero A, et al. Vestibular flap urethroplasty for strictures of the female urethra. Urol Int. 2002;69:12.
[v] Tanello M, Frego E, Simeone C, et al. Use of pedical flap from the labia minor for repair of female urethral strictures.
[vi] Schwender CE, Ng L, McGuire E, et al. Technique and results of urethroplasty for female stricture disease. J Urol. 2006;175:976.
[vii] Simonato A, Varca V, Esposito M, et al. Vaginal flap urethroplasty for wide female stricture disease. J Urol 2010, 184:1381.
[viii] Migliari R, Leone P, Berdonini E, et al. Dorsal buccal mucosa graft urethroplasty for female urethral strictures. J Urol. 2006;176:1473.
[ix] Tsivian A, Sidi AA. Dorsal graft urethroplasty for female urethral strictures. J Urol. 2006;176:611.