Surgical Management of Lower Urinary Tract Fistulas
WHEC Practice Bulletin and Clinical Management Guidelines for healthcare providers. Educational grant provided by Women's Health and Education Center (WHEC).
The nineteenth century was the dawn of a new era in the surgical treatment of vesicovaginal fistula. In 1834, Jobert de Lamballe successfully repaired a small number of fistulas using pedicled skin flaps. A second technique later enabled him to close a greater number of fistulas. This technique involved dissecting the bladder from cervix and vagina with the additional use of curved releasing incisions in the vagina to facilitate mobilization and closure without tension. In a letter of the Boston Medical and Surgical Journal in August 1838, John Peter Mettauer of Virginia stated that he had repaired a vesicovaginal fistula about the size of a half dollar using lead wire, with good results. This was the first successful repair in the United States. The discovery of antibiotics and the development of general and regional anesthesia contributed significantly to the surgical treatment of vesicovaginal fistulas in the 20th century. Obstructed labor remains the most important cause of vesicovaginal fistulas in developing countries. Absent or untrained birth attendants, reduced pelvic dimensions (caused by early childbearing, chronic disease, malnutrition, and rickets), uncorrected inefficient uterine action, malpresentation, hydrocephalus, and introital stenosis secondary to tribal circumcision all contribute to obstructed labor.
The purpose of this document is to explore various surgical techniques for surgical repairs of lower urinary tract fistulas. Obstetric fistulas are characterized by considerable necrosis, sloughing, tissue loss, and cicatrisation. Vesicovaginal fistulas commonly occur in the setting of wide range of other immediate problems, such as stillbirth, ruptured uterus, third- or fourth-degree perineal lacerations with resultant rectovaginal fistulas and anal incontinence, and pelvic infection. In modern obstetrics, most of these conditions do not exist. Generalists should be trained to repair simple fistulas, with referral of complex cases to specialized fistula hospitals.
Epidemiology and Etiology:
Demographic characteristic of women affected by vesicovaginal fistulas speak of the sociocultural climate in which they occur and to the terrible consequences. The social consequences of ostracism take an enormous toll on affected women; divorce is common, and depression and suicide may follow. This devastating condition affects more than 2 million women worldwide. There are estimated 50,000 to 100,000 additional cases each year, a figure some believe to be an underestimate. Most are young women or adolescents. Fistulas occur in areas where access to care at childbirth is limited, or of poor quality, mainly in sub-Saharan Africa and parts of southern Asia (1). In 2003, the United Nations Population Fund along with World Health Organization and other partners launched a Global Campaign for the Elimination of Fistula.
To understand the cause of fistula one must understand wound healing because it is a defect of vulnerability in this process that results in fistula development. Wounded tissue undergoes four phases of healing: coagulation, inflammation, fibroplasia, and remodeling (2). These phases do not occur independently but overlap each other like runners in a baton relay. During fibroplastic phase collagen is laid down, reaching its peak on the seventh day after injury and continuing for 3 weeks. Between the first and third weeks healing is most vulnerable to hypoxia, ischemia, malnutrition, radiation, and chemotherapy, so this is the time when most fistulas present. Conditions known to interfere with wound healing are associated with increased risk of fistula formation, including diabetes mellitus, smoking, infection, peripheral vascular disease, chronic steroid use, malignancy, HIV, or previous tissue injury.
Patients awaiting surgical repair need considerable psychologic support. Because most of the suffering endured by fistula victims is the result of social isolation and abandonment and the subsequent loss of self-esteem and economic deprivation that results from this social isolation, the evaluation of women with obstetric fistulas should include information on these social "co-morbidities". The fistula problem in the developing countries is inextricably intertwined with its social milieu, and this must be openly acknowledged (3). Leakage from small fistulas can be controlled by frequent voiding and the use of tampons, perineal pads, or silica-impregnated incontinence pants. Ammoniacal dermatitis is treated with sitz baths and zinc oxide barrier ointment. Before surgical repair, oral or vaginal estrogen should be given to women who are surgically or naturally postmenopausal to improve urogenital tissue integrity. In malnourished patients, a high-protein diet, vitamin and trace element supplements and correction of anemia are essential before surgical repair. Surgery should not be performed during menstruation because of the increased tissue vascularity at that time.
Principles of Surgical Repair for Fistula Closure:
The best chance for successful fistula closure is at the first operation. In practiced hands, skilled fistula surgeons routinely achieve fistula closure rates of 80% or better. Successful closure of about 65% can be achieved in those patients who require two or more operations (4). Suitable methods of anesthesia include epidural, low spinal, and general. Small fistulas can be repaired under local anesthesia without sedation. For proximal urethral or bladder neck fistulas, Lawson's position may be used. The patient placed in prone position on the operating table with her knees apart and her ankles raised and supported in stirrups, with the table in reversed Trendelenburg position. For higher fistulas, an exaggerated lithotomy position with standard Trendelenburg provides optimal access for vaginal approaches. Labial retraction sutures and if necessary , an episiotomy or Schuchardt incision may improve exposure. For abdominal repairs, steep Trendelenburg position may be helpful.
Adequate light and appropriate instruments and materials are mandatory. Although no single suture material has proven superiority, the use of No. 2-0 and 3-0 polyglycolic acid on CT-2 needles is favored by many for closure of all layers. The use of fine monofilament nylon for vaginal closure (with delayed removal at 3 to 4 weeks) also remains popular. The fistula should be widely mobilized from the surrounding tissues at the time of repair, so that fistula closure can be achieved without tension on the site of repair. The repair should be "water-tight" at the time of closure. If it is not, failure is virtually certain. The integrity of the repair may be tested by the instillation of methylene blue or indigo carmine into the bladder, but care must be taken to avoid over-distension. The traditional teaching has been that the fistula should be closed in multiple layers, avoiding overlapping suture lines, whenever this can be achieved; however, in some cases there is simply not enough tissue present to achieve a multi-layered closure. If vaginal relaxing incisions are used, a vaginal pack may be inserted for 24 hours postoperatively.
After vesicovaginal fistula repair, the bladder should be drained for 10 to 14 days, depending on the fistula size. If some leakage persists at 14 days, further drainage for 7 more days may occasionally result in fistula closure. Placing patient in prone position for 24-48 hours after surgery may prevent pressure from the catheter on the suture line before bladder mucosal integrity is restored. Fixation of the transurethral catheter externally is important, especially in sub-urethral fistulas, to avoid undue tension from the Foley balloon against the bladder neck. While catheterized patient is maintained on prophylactic antibiotics. Extreme efforts to hydrate the patient are important postoperatively to auto-irrigate the bladder, which avoids clot formation, catheter obstruction, bladder distension, and repair disruption.
Vesicovaginal Fistulas (VVF):
The first prerequisite for successful fistula repair is meticulous attention to detail. Adequate exposure is of utmost importance. Small VVF, less than 1 cm and is unrelated to malignancy or radiation, if diagnosed within 7 days of occurrence can be treated with bladder drainage alone for up to 4 weeks. Spontaneous healing has been reported in 12% to 80% of cases. Cystoscopic cauterization of small lesions may also be successful. Standard management of VVF dictates an interval from injury to repair of 3 to 6 months in surgical and obstetric fistulas and up to 1 year in radiation-induced fistulas to allow for resolution of necrosis and inflammation. If there is associated rectovaginal fistula, a transverse colostomy performed 2 to 3 months before fistula repair may be helpful (5). The time of repair should be individualized based on endoscopic evidence of healing. When the fistula site and adjacent tissues are pliable, non-inflamed, epithelialized, and free of granulation tissue and necrosis, little is gained by waiting longer. Corticosteroids and non-steroidal anti-inflammatory drugs have been used by some to facilitate early surgery but their efficacy has not been proven. It is generally preferable to identify and catheterize the ureters in most operations so that they are readily identifiable throughout the course of the operation. This can usually be done by passing catheters or stents through fistula into the ureters under direct vision or with the cystoscope. The purpose of ureteral catheterization is to ensure that the ureters are not inadvertently ligated during the fistula repair, with subsequent renal damage or death. Once the ureters have been catheterized, the ureteral catheters can be brought out of the bladder through the urethra, keeping them away from the operative field. Although some fistula surgeons prefer to leave ureteral catheters in place for up to 14 days after surgery, current Western urological practice would suggest that such catheters can be removed immediately at the end of the case, or within a day or two after surgery at most.
Procedure -- most of vesicovaginal fistulas can be approached via the vaginal route. With adequate exposure the fistula tract can be excised with a scalpel. The incision is carried around the circumference of the fistula. The margin of the fistula tract is elevated with thumb forceps and excised with Metzenbaum scissors. The entire tract is dissected. Frequently, when dense scar tissue has been released, the fistula will be 2-3 times larger than noted preoperatively. The layers of bladder wall and vagina should be adequately delineated, and each of these layers should be mobilized to allow the layers to be drawn together with fine sutures without tension. The bladder mucosa is identified and closed with interrupted 4-0 synthetic absorbable suture. An attempt should be made to keep the suture in the submucosal layer. We do not perform running locking sutures or continuous suture, since we feel this reduces the blood supply that is vital to proper closure. A second layer, the bladder muscle, is closed with 2-0 synthetic absorbable suture. The bladder muscle is completely closed over the fistula area with interrupted 2-0 synthetic absorbable suture. In high-risk cases, at this point use of a bulbocavernosus muscle-fat pad (Martius) graft is used to increase an external blood supply for the fistula site (6). This can be the bulbocavernosus muscle from beneath the labia majora, or in cases where a large fistula exists or where the fistula is high in the vaginal canal, the gracilis muscle from the leg or the rectus abdominis muscle can be brought in to cover the fistula site.
If the bulbocavernosus is selected, two incision sites are acceptable. One is on the inside of the labia minora and the other is down the body of bulbocavernosus muscle must be tunneled under the labia minora into the episiotomy wound. Allis clamps are used for retraction of the labia, and a scalpel is used for dissection down to the bulbocavernosus muscle. It is important to enlarge the incision so that the entire muscle can be visualized. The bulbocavernosus muscle is identified and mobilized. Frequently, the branches of the pudendal artery and vein enter the muscle and may have to be clamped and ligated for hemostasis. The bulbocavernosus muscle should be mobilized by blunt and sharp dissection up to the level of the clitoris and transected at its insertion in the perineal body. If the initial incision has been made on the inside of the labia minor, no tunneling of the bulbocavernosus muscle is needed, and the muscle is swung into position, covering the fistula site (7). It is sutured to the perivesical tissue with interrupted 3-0 synthetic absorbable sutures. If the initial incision has been carried over the labia majora, a tunnel is created with a Kelly clamp under the labia minora into the episiotomy incision. The bulbocavernosus muscle is pulled through this tunnel, applied to the fistula site, and sutured into place with interrupted 3-0 synthetic absorbable suture. The vaginal mucosa must be mobilized for closure without tension. Generally, the wound is closed with interrupted 0 synthetic absorbable sutures. The vaginal incision, the episiotomy incision, and the incision for the bulbocavernosus muscle transplant are closed. The Foley catheter is inserted through urethra. In addition to the transurethral Foley catheter, a suprapubic Foley is recommended by many fistula surgeons.
Vesicovaginal Fistula Repair
Abdominal Approach for Vesicovaginal fistula (VVF) Repair -- although most repairs are done vaginally (more than 80%), specific indications for an abdominal repair are the presence of a large vesicovaginal fistula in proximity to the ureter and difficulty obtaining adequate exposure with the vaginal route, even with the use of Schuchardt incision. When an abdominal approach is chosen, we prefer the transperitoneal approach, which permits mobilization of the base of the bladder and ureter (usually with an indwelling ureteral catheter) such that an accurate and safe repair can be accomplished under excellent visibility. In more complex fistulas, it occasionally may be advantageous to mobilize the omentum from the left side of the transverse colon and to fix the omentum into posterior cul-de-sac. It is sutured to the anterior wall of vagina or the posterior wall of bladder to thus give additional blood supply and a tissue barrier between the suture lines. Catheter drainage may be accomplished with a urethral or suprapubic approach (or both), depending on the circumstances of the repair.
The Fistula Complicated by Urethral Damage -- "Circumferential" fistulas, which involve a destruction of the bladder neck not only on the vaginal side but, in many instances, on the pubic side as well, can have great difficulty in achieving post-operative continence (8). Fistulas involving this level of destruction are daunting, and are rarely seen in developed countries. The three major problems in dealing with this type of fistula are: 1) extremely difficult exposure; 2) technical difficulty in dissecting the tissue remnants from the pubic bone; and 3) difficulty in joining in the bladder neck to the uretheral remnant or stump, if indeed any portion of the urethra is still intact. The basic principles of technique needed to deal with this type of injury are complete mobilization of the bladder so that it can be drawn down low enough to create a tension-free anastomosis with the urethral remnant. Freeing the urethral remnants from their adherence to the pubic bone may require a suprapubic incision with dissection from above in order to accomplish this. Reinforcement of the bladder neck with buttressing sutures, and Martius graft for better support is generally helpful for better blood supply and support. Various authors have described neourethral reconstruction using bladder flaps. All of these operations are based upon transabdominal techniques; however, a transvaginal approach to neourethral reconstruction using an anterior bladder flap which is rolled into a tube around a 16 Fr. Foley catheter to create a tube, is described (9). Patients usually have severe stress incontinence post-operatively. Recently Browning described a technique for urethral buttressing that could be carried out at the time of initial fistula repair, particularly in patients with urethrovaginal or bladder neck fistulas who are at high risk for persistent post-operative stress incontinence (10). The operation involves mobilization of a small strip of the ischiocavernosus muscles (or their fibrotic remnants) along each side of the urethra, then suturing them together in the midline under the repaired/reconstructed urethra. A Martius fat graft is then created and sewn over the sling and site of the repair to improve vascularization and healing of the repair.
Once the diagnosis of ureterovaginal fistula is confirmed, recommended initial management is ureteral stenting. It is more successful when performed sooner than later; in one study, 82% of attempts in patients whose fistulas were less than 1 month old were successful, compared to 33% with older fistulas (11). High success rates of stenting and complete resolution of fistulas have been reported when both antegrade and retrograde techniques were used together. Stents are usually made of silastic, with length measured in centimeters and diameter in French units, with single-J or double-J ends. Double-J ends are preferred because there is less risk of migration out of the renal pelvis and the distal J tip in the bladder is atraumatic. If a stent is placed successfully, it should be left in for 6 to 8 weeks. The risk of infection, stone formation, and ureteral occlusion increases with time. After 4 to 6 weeks, intravenous or retrograde pyelogram should be performed to evaluate for persistence of the fistula. If the fistula has healed, stent may be removed via cystoscopy and intravenous pyelograms should be performed at 3, 6, 12 and 24 months to rule out subsequent stricture formation. If the fistula has not healed at 6 weeks, a repeat examination may be performed at 8 weeks, with preparation to proceed with surgical repair if the fistula still has not healed.
Surgical management of ureteroneocystostomy should be reserved for those whose fistulas have been diagnosed within the first 2 or after 12 postoperative weeks. Interval management with percutaneous nephrostomy should be used when fistulas are diagnosed between 2 and 12 weeks postoperatively and also in patients who are poor surgical candidates or in the presence of previous radiation therapy, radical pelvic surgery, or pelvic malignancy. If the fistula has failed to heal after 12 weeks of percutaneous nephrostomy drainage, then surgery should be considered.
Although there is a general consensus in the literature that some fistulas simply cannot be repaired with restoration of full continence, there is no general agreement as to which fistulas should be treated initially by primary urinary diversion rather than an attempt at fistula closure. Similarly, there are no accepted criteria in failed cases to dictate when further attempts at closure should be abandoned and the patient should be offered some form of urinary diversion as a treatment (12). The role of urinary diversion for the "incurable" fistula, usually involves some form of uretero-sigmoidostomy. Urinary conduits can be constructed from small or large bowel; they may be continent or incontinent. The major continent conduits are the Koch pouch and the Miami pouch. The Koch pouch uses ileum with intussusception techniques, and the Miami pouch uses right hemicolon and a tapered terminal ileum. Both continent conduits have similar continence rates of 93% to 94%. Patients must be able and motivated to catheterize the stoma every 4 to 8 hours. Complications include stone formation, conduit leak and reflux, and metabolic disturbances. Early and late complications in continent diversions occur in 13% to 15%; re-operation is necessary in 1% to 4%.
Intestinal Loop Urinary Diversion
Complications of Fistula Repair:
The surgical repair of genitourinary fistulas may be complicated by risks common to all surgeries, such as hemorrhage, infection, and thromboembolism. If tissue breakdown occurs at the vaginal or bladder suture lines, the fistula may persist or recur. Other delayed surgical complications include vaginal stenosis and small-bladder syndrome, osteitis pubis, and urinary incontinence (stress and urge). Dyspareunia caused by tenderness over the site of Martius grafts has been reported. Metabolic disturbances and recurrent pyelonephritis may develop after uretero-sigmoidostomy. After successful fistula repair, elective cesarean delivery is strongly recommended for all subsequent births.
Although current surgical techniques consistently result in fistula closure rates of 80%-95% of cases, there has been almost no scientifically rigorous research carried out on most of the persistent technical surgical questions raised by fistulas. Urgent work is needed in this area. Among the issues that should be addressed are: problem of persistent stress incontinence after successful fistula closure; management of dramatically reduced bladder capacity in patients with large fistulas who have undergone successful closure; the role of urinary diversion for the "incurable" fistulas; the role of vaginoplasty in patients with vaginal atresia from obstructed labor; and future reproductive function in patients who have sustained an obstetric fistulas. Because obstetric fistulas are tied closely to overall maternal mortality, the best way to reduce fistula formation is to provide essential obstetric services at the community level with prompt access to emergency obstetric services at the first referral level.
Epidemiologic research is urgently needed to identify communities with a high prevalence of fistulas and to determine the characteristics of women at high risk for bladder or urethral injury during childbirth. Preventive strategies must be directed at several levels to achieve meaningful reduction in the occurrence of genitourinary fistulas caused by neglected obstructed labor. Sociocultural changes are necessary to delay childbearing until pelvic maturity. Increased availability of prenatal care and establishment of maternity centers would improve care during pregnancy and identify conditions such as abnormal fetal presentation before labor. Trained birth attendants could perform bladder drainage in labor and identify abnormal labor patterns using partographs. Emergency transport for women in prolonged labor to health-centers staffed by skilled personnel could enable abdominal delivery when vaginal delivery is impossible. Until all these goals and more can be realized, genitourinary fistulas will continue to occur and women will need advanced care for surgical management.