Editing Functional: Urinary Fistulae (section)

=== Vesicovaginal fistula ===

* '''<span style="color:#ff0000">75% of acquired urinary tract fistula are VVF</span>'''

==== Causes ====
*'''<span style="color:#0000ff">Radical Obstetrical Colleagues’ Trauma Causes Incontinence Fistula (7):</span>''' 
*# '''<span style="color:#0000ff">R</span><span style="color:#ff0000">adiation</span>'''
*#* '''May occur several decades after completion of the radiation therapy'''
*#* '''<span style="color:#ff0000">Any fistula after radiation therapy for malignancy may represent a recurrence of the malignancy</span>'''
*# '''<span style="color:#0000ff">O</span><span style="color:#ff0000">bstetric</span>'''
*#* Causes: obstructed labor, forceps laceration, uterine rupture, cesarean section injury to bladder
*#** '''<span style="color:#ff0000">In the developing world,</span>''' where routine perinatal obstetric care may be limited, '''<span style="color:#ff0000">VVF most commonly occurs as a result of prolonged obstructed labor</span>''' resulting from cephalopelvic disproportion, with resulting pressure necrosis to the anterior vaginal wall, bladder, bladder neck, and proximal urethra from the baby.
*#*** Typically, these occur in individuals who are young primigravidas with a narrow bony pelvis.
*#*** The constellation of problems resulting from obstructed labor is not limited to VVF and has been termed the obstructed labor injury complex.
*#* '''Obstetric fistulae are more likely to be:'''
*#** '''Larger'''
*#** '''Located distally in the vagina'''
*#** '''Involve large portions of the bladder neck and proximal urethra'''
*#** Because of their size and extensive ischemia of the surrounding tissues, these fistulae are often difficult to repair.
*# '''<span style="color:#0000ff">C</span><span style="color:#ff0000">ancer</span>'''
*# '''<span style="color:#0000ff">T</span><span style="color:#ff0000">rauma</span>'''
*#* '''Postsurgical''': abdominal hysterectomy, vaginal hysterectomy, anti-incontinence surgery, anterior vaginal wall prolapse surgery (e.g., colporrhaphy), vaginal biopsy, bladder biopsy, endoscopic bladder resection, laser therapy in bladder, other pelvic surgery (e.g., vascular, rectal)
*#** '''<span style="color:#ff0000">In the industrialized world, the most common cause (>75%) is injury to the bladder at the time of surgery, the most common of which is hysterectomy</span>'''
*#*** The rate of iatrogenic bladder injury during abdominal hysterectomy is ≈0.5-1.0%; the rate of incidence of fistula after hysterectomy is ≈0.1-0.2%.
*#*** '''Post-hysterectomy VVFs are thought to result most commonly from an incidental unrecognized iatrogenic cystotomy near the vaginal cuff'''.
*#**** If unrecognized intraoperatively, a pelvic urinoma may develop and ultimately drain out through the vaginal cuff. Ongoing urinary drainage along this tract results in a fistula.
*#*** Other potential mechanisms for post-hysterectomy VVF include tissue necrosis from:
*#**** Cautery
*#**** A suture placed through both the bladder and vaginal wall during closure of the vaginal cuff
*#**** An attempt to control pelvic bleeding by suture ligature
*#*** Tissue ischemia and then necrosis promotes fibrosis and induration, finally resulting in an epithelial or mucosal lining of the tract and the development of a fistula tract.
*#*** '''Clear vaginal discharge after hysterectomy does not invariably represent a urinary fistula or incontinence. Other than normal vaginal secretions, less common causes include a peritoneovaginal fistula, lymphatic fistula, vaginitis, and fallopian tube fluid'''
*#* '''External trauma''' (e.g., penetrating, pelvic fracture, sexual)
*# '''<span style="color:#0000ff">C</span><span style="color:#ff0000">ongenital</span>'''
*# '''<span style="color:#0000ff">I</span><span style="color:#ff0000">nfectious or </span><span style="color:#0000ff">I</span><span style="color:#ff0000">nflammatory cause</span>'''
*# '''<span style="color:#0000ff">F</span><span style="color:#ff0000">oreign body </span>(vaginal mesh for prolapse repair)'''

==== Differential Diagnosis ====

* '''Other causes of urinary incontinence''', including SUI, urge (bladder) incontinence, and overflow incontinence, as well as ureterovaginal fistula.

==== Diagnosis and Evaluation ====

===== UrologySchool.com Summary =====

* '''<span style="color:#ff0000">Recommended (4)</span>'''
# '''<span style="color:#ff0000">History and Physical Exam</span>'''
# '''<span style="color:#ff0000">Labs</span>'''
##'''<span style="color:#ff0000">Urinalysis +/- culture</span>'''
#'''<span style="color:#ff0000">Imaging:</span>'''
## '''<span style="color:#ff0000">Lower tract imaging (with cystogram and/or voiding cystourethrogram (VCUG))</span>'''
## '''<span style="color:#ff0000">Upper tract imaging (with CT urography)</span>'''
# '''<span style="color:#ff0000">Other</span>'''
## '''<span style="color:#ff0000">Cystoscopy</span>'''

* '''<span style="color:#ff0000">Optional</span>'''
** '''<span style="color:#ff0000">Dye test</span>'''

===== Recommended =====
* '''History and Physical Exam'''
** '''History'''
*** '''<span style="color:#ff0000">Most common complaint is constant urinary drainage per vagina</span>'''
**** The amount of urinary leakage can vary considerably from patient to patient and may be proportional to the size of the fistula tract.
*** '''Pain is uncommon'''
** '''Physical exam'''
*** '''A pelvic examination with a speculum should always be performed'''.
**** '''VVFs after hysterectomy are most commonly located along the anterior vaginal wall at the level of the vaginal cuff'''
*** '''<span style="color:#ff0000">Visual and manual assessment of inflammation surrounding the fistula is necessary,</span>''' because it may affect timing of the repair. 
****Significant inflammation, infection, or induration around the fistula may mitigate against immediate repair.

* '''Laboratory'''
** '''<span style="color:#ff0000">Urinalysis +/- culture, when indicated</span>'''
**Cytology, when indicated

* '''Imaging'''
** '''<span style="color:#ff0000">Lower tract imaging (with cystogram and/or voiding cystourethrogram (VCUG))</span>'''
*** '''A cystogram that fails to demonstrate a suspected VVF but lacks voiding images or postvoid images should be considered non-diagnostic.'''
** '''<span style="color:#ff0000">Upper tract imaging (with CT urography)</span>'''
***'''Up to 12% of postsurgical VVFs have an associated ureteral injury or ureterovaginal fistula'''

* '''Other'''
** '''<span style="color:#ff0000">Cystoscopy</span>'''
*** '''<span style="color:#ff0000">Should be performed in patients for whom a suspicion of VVF is present</span>'''

===== Optional =====
* '''Dye test'''
** '''The presence of a VVF may be confirmed by instilling a colored solution, such as methylene blue or indigo carmine into the bladder per urethra and observing whether vaginal drainage is discolored'''
*** Small or occult fistulae may be identified in this fashion.
*** '''Staining at the introital (distal) end of the packing suggests urinary incontinence or a urethrovaginal fistula, whereas proximal staining suggests a VVF'''
*** '''If the vaginal packing remains dye-free with this maneuver, then the possibility of a ureterovaginal fistula can be investigated''' with the use of clean vaginal packing, '''IV indigo carmine (or other vital dye),''' and a repeat pad test. '''Blue staining at the proximal end of the pad after this maneuver suggests the presence of a ureterovaginal fistula'''
*** '''A double dye''' or tampon '''test''' may confirm the diagnosis of urinary fistula, as well as suggesting the possibility of an associated ureterovaginal or urethrovaginal fistula. In one variation of the double dye test, a tampon is placed per vagina. Oral phenazopyridine is administered, and vital blue dye is instilled into the bladder. If the tampon is discolored 
****Yellow-orange at the top, it is suggestive of a ureterovaginal fistula
****Green (a combination of blue and yellow) discoloration in the midportion of the tampon suggests VVF
****Blue staining at the bottom suggests a urethrovaginal fistula

==== Management ====
* '''<span style="color:#ff0000">Options (3):</span>'''
*# '''<span style="color:#ff0000">Indwelling catheter</span>'''
*# '''<span style="color:#ff0000">Fulguration</span>'''
*# '''<span style="color:#ff0000">Fibrin sealant</span>'''
*#'''<span style="color:#ff0000">Surgery</span>'''

===== Indwelling catheter =====
* '''<span style="color:#ff0000">A trial of indwelling catheterization and anticholinergic medication for at least 2-3 weeks may be warranted in selected patients with newly diagnosed VVF,</span>''' because spontaneous healing may result (spontaneous closure rate ≈13%)
** Drainage of the bladder should start immediately to prevent epithelialization of the fistula tract.
** '''<span style="color:#ff0000">Characteristics associated with favorable outcomes</span>'''
*** '''<span style="color:#ff0000">Size <2-3 mm</span>'''
*** Simple injuries to the bladder that do not involve devascularization or thermal injury spread that result in interrupted blood supply to the area
* '''<span style="color:#ff0000">Fistulous tracts that remain open ≥3 weeks after adequate catheter drainage are unlikely to resolve without further intervention</span>'''

===== Fulguration =====
* '''Patients with small epithelialized fistulae, usually <3-5 mm in diameter,''' '''may benefit from a minimally invasive treatment involving disruption of the epithelial layer of the fistula tract.'''
* A small cautery electrode is passed into the fistula tract endoscopically as far as possible. The electrode is slowly withdrawn from the tract with the electrode set on coagulation.
* Catheterization may be combined with minimally invasive electrocoagulation of the fistula tract.
* Fulguration risks failure and the possibility of enlarging the size of the fistula in patients with:
*# Thin vesicovaginal septum
*# Large VVF
*# Non-oblique fistula tract
*# Significant inflammation around the fistula tract.

===== Fibrin sealant =====

*'''Has been used as an adjunctive measure to treat VVF'''

===== Surgery =====
* '''<span style="color:#ff0000">Pre-operative Counselling</span>'''
**'''<span style="color:#ff0000">Sexual activity should be documented</span>'''
*** '''Some vaginal procedures, including the Latzko procedure, may result in vaginal shortening and postoperative dyspareunia'''
** '''Pre-operative estrogen supplementation may be beneficial in the postmenopausal patient with vaginal atrophy; topical estrogen preparations may improve vascularity and local tissue quality'''
* '''Technique'''
** '''<span style="color:#ff0000">Approaches (2):</span>'''
**#'''<span style="color:#ff0000">Transvaginal</span>'''
**#'''<span style="color:#ff0000">Transabdominal (transvesical)</span>'''
**#* '''Success rates are similar between the two approaches'''
**#** The most important factor is the experience of the operating surgeon
**#* '''Advantages of transvaginal approach (3):'''
**#** Shorter operative times
**#** Shorter hospital stay
**#** Less blood loss
**#* '''Disadvantages of transvaginal approach (3):'''
**#** Relative lack of familiarity of the vaginal cuff anatomy to many urologists
**#** Potential for vaginal shortening, especially with the Latzko approach
**#** Difficulty in exposing high or retracted fistulae located near the vaginal cuff, especially in deep, narrow vaginas, or in those without any apical prolapse (though these are not contraindications)
**#* '''Advantages of abdominal approach (2):'''
**#** Other intra-abdominal pathology requiring repair
**#** Complicated fistulae including those associated with multiple prior failed attempts at repair, or those that are large (>5cm)
**#* No difference in risk of ureteral injury in transabdominal vs. transvaginal approach
**'''Excision of the fistula tract itself is not always necessary and may even compromise the repair in some patients'''
** Transvaginal approach to VVF repair uses a 3-4 layer closure
**'''<span style="color:#ff0000">Tissue interposition</span>'''
***'''The interposition of a healthy, well-vascularized tissue flap during VVF repair may be beneficial under certain circumstances, such as (6):'''
***#Recurred after a prior attempt at repair
***#Related to previous radiotherapy
***#Ischemic or obstetric fistulae
***#Large fistulae
***#Associated with a difficult or tenuous closure because of poor tissue quality
*** '''<span style="color:#ff0000">Most commonly used flaps for VVF repaired:</span>'''
**** '''<span style="color:#ff0000">Transvaginal repair: Martius flap or peritoneum</span>'''
**** '''<span style="color:#ff0000">Transabdominal: omentum or peritoneum</span>'''
*** '''Other options for a flap include:'''
**** '''Gracilis muscle'''
**** '''Labial myocutaneous flaps'''
**** '''Seromuscular intestinal flaps'''
**** '''Rectum abdominis flaps'''
***** '''<span style="color:#ff0000">Martius flap</span>'''
****** Labial fat pad consisting of adipose tissue and connective tissue
****** '''<span style="color:#ff0000">Blood supply derives from (3):</span>'''
******# '''<span style="color:#ff0000">Superiorly from the external pudendal artery</span>'''
******# '''<span style="color:#ff0000">Laterally from the obturator artery</span>'''
******# '''<span style="color:#ff0000">Inferiorly from the posterior labial vessels (branch of the internal pudendal artery)</span>'''
****** '''Preferred for low or distal fistulae''' '''involving the trigone, bladder neck, and urethra'''
***** '''Peritoneal flap'''
****** '''Preferred for high-lying post-hysterectomy VVF'''
******* For post-hysterectomy fistulae, the distance from the labial harvesting site of the Martius flap to the fistula at the apex of the vagina may be considerable. Mobilizing and then tunneling the Martius flap to reach this location may compromise its blood supply and viability.
****** May also be used as an adjunctive measure during transabdominal repair of VVF, although the approach and technique are vastly different
***** '''Omental flap'''
****** Blood supply derives from right and left gastroepiploic arteries
******* '''Blood supply enters''' the omentum perpendicular to its origin off the greater curvature of the stomach, '''enabling vertical incisions''' and mobilization into the deep pelvis.
******* '''In many individuals the flap will reach into the deep pelvis without mobilization and without tension'''; however, wide mobilization may be necessary to permit the omentum to reach the deep pelvis in some cases; however, 
******Can be a useful adjunctive measure in the setting of infection or inflammation because of its rich blood supply and lymphatic properties
**Postoperative drainage 
***Can be maintained by single or dual catheters.
**** Most commonly, both urethral and suprapubic drainage catheters are left postoperatively; the disadvantage to single-catheter drainage is principally that the catheter will malfunction, clog, or kink, resulting in bladder filling, eventual overdistention, and disruption of the suture line.
** Timing of repair
***Timing of repair is somewhat controversial
*** Radiation-induced fistula should be repaired after the fistula has matured
* '''Complications'''
** '''Late post-operative (3):'''
**# '''Vaginal shortening'''
**# '''Vaginal stenosis'''
**# '''Recurrence of the fistula'''
* '''Follow-up'''
**'''A postoperative cystogram should include voiding or postvoiding images to ensure that the VVF has been adequately repaired'''
*** There is no standard filling volume for cystography.
*** Generally, 2 to 3 weeks from surgery is an adequate time period for postoperative imaging.
* The success rate reported for a simple VVF repair is >90%.
** Complicated VVFs, including those resulting from obstetric causes, larger fistulae, and those associated with radiation, generally have a lower success rate.
*** Radiation-induced fistulae can be repaired vaginally, and adjuvant flaps are used to bolster the repair
** In patients with obstetric fistulae associated with loss of the bladder neck and proximal urethra, relatively high rates of persistent severe sphincteric incontinence are noted despite successful repair of the VVF
*** Stress urinary incontinence may coexist with VVF; however, it is usually not related to the repair.
* '''In some patients, repair of VVF is not possible or multiple surgical attempts have failed. Urinary diversion can be considered.'''
* '''Fistulae in patients who are not candidates for surgical intervention may be managed by percutaneous ureteral occlusion and permanent nephrostomy.'''