URETHROVAGINAL FISTULA

Chapter 79 URETHROVAGINAL FISTULA



Urethrovaginal fistula (UVF) presents a challenging diagnostic and therapeutic dilemma for the reconstructive surgeon. Because of its uncommon occurrence, much of what is known about this entity is derived from small series and case reports. Consequently, most UVFs are seen and treated in specialized centers, whether they manifest alone or in combination with a vesicovaginal fistula. The underlying cause, number of prior repairs, and damage to the continence mechanism are key factors in approaching the patient with a UVF. This chapter reviews the common causes, diagnostic modalities, and therapeutic options for UVFs.



ETIOLOGY



Postoperative Iatrogenic Factors


Traumatic fistulas resulting from obstetric deliveries account for most UVFs in underdeveloped nations, whereas in industrialized nations,1 UVFs occur as a complication of urethral diverticulectomy, anterior colporrhaphy, or other periurethral procedures. Some direct injuries are recognized at the time of the original surgery. In this instance, closure of the urethral lumen without verifying water-tightness, overlapping suture lines, lack of consideration for tissue interposition, insufficient bladder drainage, or a combination of these factors can contribute to the secondary formation of a UVF. Indirect mechanisms are less common but have been reported after periurethral collagen injection2 and an anterior colporrhaphy during which tight suburethral plication resulted in tissue necrosis and secondary fistula formation.3 An unrecognized urethral injury, which can occur during urethrolysis and particularly in the setting of dense periurethral scar tissue after a sling procedure, is another indirect mechanism. Most contemporary series on synthetic slings using tension-free vaginal tape or transobturator tape report a low incidence of urethral injuries and secondary urethral erosions, which can result in UVFs.46





DIAGNOSIS




Imaging


Visualization of the fistula tract may be accomplished by voiding cystourethrography8,9 or by double-balloon urethrography, but these techniques require high resolution to see the tract and true lateral views (Fig. 79-1). Upper tract imaging may be necessary for large or multiple fistulas to exclude ureteral obstruction or an associated ureterovaginal fistula. Urethral magnetic resonance imaging is of limited benefit to identify a fistula tract and is occasionally helpful in case of suspected residual diverticulum pocket associated with a UVF after urethral diverticulectomy.





MANAGEMENT


The decision on how and when to best manage a UVF largely depends on the cause of the fistula, the quality of the surrounding tissues, the correction of risk factors for poor tissue healing whenever possible, and the number of prior repairs. Experience with urethral reconstruction procedures is paramount to achieving a good technical outcome. A large armamentarium of additional procedures to secure continence and prevent fistula recurrence should be available to the repairing surgeon.




Surgical Repair


The goals of UVF repair are to close the tract, prevent recurrence of the fistula, and restore continence as indicated. In the case of a small distal fistula tract producing a split urinary stream with minimal or no incontinence, a simple marsupialization procedure to create a hypospadiac opening (i.e., Spence procedure) may correct the problem.12 We review two scenarios for transvaginal repair of a UVF, one involving a simple primary closure for a small nonirradiated UVF and the other a larger UVF necessitating more advanced techniques of urethral reconstruction and flap interposition for continence and closure.



Primary Closure with a Vaginal Flap


A primary repair using layered closure was first described by Collis,13 and it is ideal in the setting of a small to medium-sized UVF in nonirradiated tissues. Sterile urine must be obtained preoperatively, and antibiotic administration must be continued perioperatively. Several elements are necessary to facilitate a successful repair, as listed in Table 79-1. Patient positioning varies between advocates of the prone position14 and those preferring a high lithotomy position. Maximum perioperative urinary drainage is best achieved with a urethral and a suprapubic catheter. Exposure is facilitated by a Lonestar retractor (Lone Star Medi-cal Products, Stafford, TX) or other self-retaining retractor, a weighted vaginal speculum, a headlight, and even magnifying glasses if available. Passage of a Teflon guidewire over a 5-Fr open-ended ureteral catheter through the tract can facilitate the dissection of the tract (Fig. 79-2

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Jun 4, 2016 | Posted by in ABDOMINAL MEDICINE | Comments Off on URETHROVAGINAL FISTULA
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