Complex Obstetrical Fistula
Steven D. Arrowsmith
Introduction
In the realm of pelvic reconstructive surgery, perhaps the most daunting challenge could be that of the obstetric fistula. In its full-blown form, this entity has virtually and thankfully disappeared from wealthy nations. However, because fistulas do occur from after a variety of injuries (trauma, surgical misadventure, and radiation) in developed countries,1 it is useful to consider principles developed to deal with obstetric fistula, which can still be seen in high volume in endemic areas, and apply the lessons learned to injuries that might be less complex. The subject matter deserves an entire textbook of its own, and so this, overview can only hope to outline some of the challenges complex fistula presents.
One of the unfortunate realities of fistula care has been, because the vast majority of complex fistula care has been delivered in some of the most resourcechallenged areas on earth, quality clinical data collection is one victim of the impoverished context. Many of the assertions presented here would be widely agreed on within the fistula community, but a robust evidence base, although finally starting to accrue, is still essentially lacking.
Fistulas seen in wealthy nations tend to be iatrogenic, resulting from the unintentional, direct cutting of pelvic structures, or devascularization of pelvic structures via ischemia resulting from ligature, indiscrete clamping, or overexuberant cautery. In nonobstetric fistula, these insults are generally limited to an area a few millimeters in size. With untreated obstructed labor, wide areas of pelvic tissue are subject to unrelenting pressure from the presenting fetal part, resulting in the compromise of arterial inflow and finally the ischemic loss of regions, and not small foci, of pelvic tissue. The only equivalent in Western medicine may be fistulas resulting from radiation therapy, especially early in the development in this technology, which caused vascular compromise to wide areas in the pelvis. It is the etiology of obstetric fistula that renders these injuries so severe and so varied. In obstetric fistula, much of the bladder, all of the urethra, the anterior rectum, the cervix, and much of the vagina may simply be lost.
Thankfully, large strides have been made in the prevention of obstetric fistula through the push toward improved access to emergency obstetric services addressed by strategies like the Millennium Development Goals and Sustainable Development Goals.2 These efforts have significantly impacted rates of maternal mortality and morbidity, and after many millennia of despair, the number of obstetric fistula cases may finally be trending downward.
DEFINITION
Surgeons attempting fistula repair often refer to “simple,” “moderate,” and “complex” fistulas. Although there seems to be an unspoken understanding of what roughly comprises each category, there has never been an accepted definition to exactly delineate the boundaries between these categories. For example, some would argue that the size of the defect is an important distinctive of complex fistulas; yet, there are many difficult small fistulas and simple large ones. In 2013 to 2014, a large multicenter prospective clinical trial was organized to study the need for long-duration catheterization after fistula repair.3 It was agreed that, for the sake of consistency of data, the study would be limited to women with simple fistula. Several group exercises were carried out in which a range of fistula surgeons were presented with a series of drawings depicting a wide range of fistula cases and then surveyed as to the consistency that the labels of “simple,” “moderate,” and “complex” agreed across the group. It was apparent that although there was good agreement on the characteristics of a simple fistula, there was far less consistency reporting of injuries felt to be moderate versus complex.
The “classic” simple fistula is a case where the defect is small, the location of the fistula and caliber of the vagina are such that the defect can be easily approached during repair, and vital structures like the urethra and it’s continence mechanism or ureters are not involved. Conversely, a complex fistula might be associated with a scarred vagina making surgical exposure challenging. Involvement of the bladder neck and urethra make the functional repair of the damage far more challenging. In the most severe cases, enough bladder
can be lost to require augmentation or urinary diversion. The concomitant presence of rectovaginal fistula from ischemia directed posteriorly threatens successful repair because of the constant contamination with fecal flora. Involvement of the ureters might require an abdominal approach and formal ureteral reimplantation. The sad fact is that, in obstetric fistula at least, if the ischemia has been widespread enough in the pelvis to produce any one of the injuries, then some or all of the others may occur as well. So perhaps the most significant distinctive of complex fistula repair is the tendency of never-ending combinations of injury to present all at once.4 Complex cases may require a staged approach or multiple attempts at repair, and some would argue that a history of previous repair would move an individual case into a complex category.
can be lost to require augmentation or urinary diversion. The concomitant presence of rectovaginal fistula from ischemia directed posteriorly threatens successful repair because of the constant contamination with fecal flora. Involvement of the ureters might require an abdominal approach and formal ureteral reimplantation. The sad fact is that, in obstetric fistula at least, if the ischemia has been widespread enough in the pelvis to produce any one of the injuries, then some or all of the others may occur as well. So perhaps the most significant distinctive of complex fistula repair is the tendency of never-ending combinations of injury to present all at once.4 Complex cases may require a staged approach or multiple attempts at repair, and some would argue that a history of previous repair would move an individual case into a complex category.
HISTORY
Fistula can be documented back to more than 4,000 years ago, as an Egyptian mummy, thought to possibly be that of a wife of a Pharaoh, was noted to have a complex fistula.5 The basic techniques of fistula repair began to be published in the mid-1800s, and from beginning, it was necessary to address approaches to complex injuries. Indeed, a surgical text in 1846 describes the use of an island flap in fistula repair,6 perhaps one of the earliest examples of the use of this tool from the armamentarium of plastic surgery. Therefore, complex fistula might rightfully be thought of as a major driving force in modern surgical innovation.
PRESENTATION
In terms of the symptoms a patient may describe, vesicovaginal fistula presents with total urinary incontinence. Generally, there is no difference in the degree of urinary leakage between women with simple fistulas and those whose injuries are more complex. It is astounding to see that a tiny pinhole fistula can destroy quality of life just as effectively as a massive complex fistula.
Women with complex fistula are more likely to present with symptoms and quality of life impacts arising from the presence of comorbidities that are not so commonly seen in association with a simple fistula.4 In addition to urinary incontinence, women suffering complex fistula may present with fecal incontinence from concomitant rectovaginal fistula, impairment of sexual function because of vaginal stenosis, and foot drop resulting from peripheral nerve damage during prolonged labor. Other issues related to severe, complex fistula may not appear until after an initial procedure to close the fistula. Once the defect has been dealt with and continuity of the urinary tract restored, it is only then that the woman may display post-repair incontinence because of damage to the continence mechanism and urethra or debilitating urinary frequency from loss of bladder tissue resulting in reduced bladder capacity. The cause for these ongoing symptoms is present at presentation but not expressed until the patient resumes function of the lower urinary tract.
EVALUATION
The initial physical examination in women with fistula should be focused on delineating as completely as possible the extent of injury, all with the intent of planning the best approach to repair.
Factors to be evaluated include the following:
The condition of the vagina: Is there any compromise in vaginal depth or caliber from ischemic injury? In complex fistula, dense bands of scar may traverse the vagina, especially posteriorly at the junction of the proximal one-third and distal twothirds of the vagina.
The status of the urethra. Has it been spared injury? Partially damaged? Completely destroyed? The urethral length should be measured. This is most easily accomplished by inserting a bladder catheter and noting the distance between the inflated balloon and the urethral meatus. Is the urethra scarred and stiff? In complex fistula, it is not unusual to encounter urethral stricture while attempting passage of the catheter.
Status of the bladder: Does there appear to be significant loss of bladder storage capacity? By definition, the bladder is unable to store urine with a fistula present, so it is not possible to determine bladder capacity with bedside or formal urodynamic studies. Likewise, a cystoscopy is generally unfeasible as the bladder cannot retain any irrigating fluid.
In very large fistulas, it is not unusual for prolapse of the dome of the bladder to occur. This is not to be confused with classic prolapse of the bladder, where the anterior vaginal wall loses support and the bladder base and vesicourethral junction descend. Instead, the bladder can simply evert via the fistula defect. While distressing in appearance, this finding is generally associated with an abundance of bladder tissue which has survived the initial trauma.
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