Editing Functional: Urinary Fistulae (section)

==== 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)'''