A Systematic Review of Surgical Techniques Used in the Treatment of Female Urethral Stricture

Abstract

Context

Female urethral stricture (FUS) is a rare and challenging clinical entity. Several new surgical techniques have been described for the treatment of FUS, although with the limited number of reports, there is no consensus on best management.

Objective

We evaluated the evidence for surgical interventions reported for treating FUS.

Evidence acquisition

We performed a systematic review of the PubMed and Scopus databases, classifying the results by surgical technique and type of graft in the case of graft augmentation urethroplasty.

Evidence synthesis

A total of 221 patients have been reported on with outcome measures after intervention for FUS. The mean age of women was 51.8 yr of age (range: 22–91). All studies were retrospective case series. There was no consistent definition of FUS nor unified diagnostic criteria. Most studies used a combination of diagnostic tests. Where aetiology was defined, idiopathic and iatrogenic stricture were the two most common causes. Ninety-eight patients underwent prior intervention for FUS, mostly urethral dilatation or urethrotomy. Success was defined as the lack of need for further intervention. Urethral dilatation, assessed in 107 patients, had a mean success rate of 47% at a mean follow-up of 43 mo. Fifty-eight patients had vaginal or labial flap augmentation, with a mean success rate of 91% at 32.1 mo of mean follow-up. Vaginal or labial graft augmentation had a mean success rate of 80% in 25 patients at a mean follow-up of 22 mo. Oral mucosal augmentation, performed in 32 patients, had a mean success rate of 94% at 15 mo of mean follow-up. No instances of de novo stress incontinence were reported.

Conclusion

The techniques of urethroplasty all have a higher mean success rate (80–94%) than urethral dilatation (<50%), although with shorter mean follow-up. Urethroplasty in experienced hands appears to be a feasible option in women who have failed urethral dilatation, although there is a lack of high-level evidence to recommend one technique over another.

Introduction

Female urethral strictures (FUSs) are a rare and challenging reconstructive urologic problem. Despite urethral dilatation being commonly practiced in women with lower urinary tract symptoms (LUTS) or recurrent urinary tract infections (UTIs), the true incidence of FUS appears to be low [1]. From selected populations of women undergoing urodynamic studies, FUS represents 4–13% of the causes of bladder outlet obstruction (BOO) [2], [3]. BOO itself in women is considered uncommon, being reported on the basis of a high voiding pressure/low flow pattern in 2.7–8% of women referred for voiding LUTS [4], but there are no agreed-upon, specific urodynamic diagnostic criteria because of the considerable variation in normal female voiding function, in particular resulting from the variable degree of vesicourethral prolapse, which may contribute to obstruction [5]. Recently, interest has increased in urethral reconstructive techniques for FUS, such as vaginal flap urethroplasty, which was first described by Harris in 1935 [6] for urethrovaginal fistula and later modified by Ellis and Hodges [7].

The female urethra usually measures 4 cm in length [8] and may become strictured at any point along its length. It is sphincter-active throughout most of its length and has two smooth muscle coats consisting of an outer circular and inner longitudinal layer. This muscle thins as it traverses distally, especially the outer circular layer. The last quarter of the urethra is minimally compliant, and here the muscle layers terminate in a thick collagenous ring, a thickening of which is thought to be the basis for Lyon's ring, described in girls with voiding problems and recurrent UTI [9]. The striated urethral sphincter muscle lies external to the smooth muscle and extends the whole length of the urethra; it is critical to the continence mechanism. It is thickest in the middle third of the urethra, mainly located dorsally (at 12 o’ clock relative to the urethra) and relatively underdeveloped ventrally, giving the muscle a horseshoe configuration. The other anatomic relations of surgical relevance are the clitoral tissue, which surrounds the urethrovaginal complex and supports the urethra along its dorsal aspect, and the neurovascular bundles (NVBs) traversing along the ischiopubic ramus [10].

The aetiopathogenesis of FUS is poorly understood. Multiple factors can clearly be implicated, including infection, trauma, instrumentation, and prior urethral surgery. Making the diagnosis necessitates a high index of suspicion because the presentation is often nonspecific, including LUTS (eg, difficulty voiding, urinary frequency, incomplete emptying), urinary retention, or recurrent UTI. There is currently no accepted definition of or diagnostic criteria for FUS. Using a symptom-based diagnosis, many women in the past underwent unnecessary and often overzealous urethral dilatation, which led to an incidence of stricture, presumably resulting from bleeding and urine extravasation [11].

Due to its rarity and the proximity of important structures, FUS can present a considerable challenge to the reconstructive urologist. Over the past decade, there has been an increase in reports of different surgical techniques for FUS. We sought to perform a systematic review of the treatment interventions for FUS to evaluate the success and complication rates reported.