Fistulae of the urinary tract: Vesicovaginal, ureterovaginal, and rectourethral

A fistula is an epithelialized or endothelialized connection between two or more organs. Frequently, it will be named after the organs or systems affected. Some fistulae can be made intentionally to treat a condition, others develop as a consequence of a noxious event, most of the time in the treatment of a condition.

Urogenital fistulae are among the most common throughout the literature. Different levels of pressure between the urinary, digestive, and genital system make this type of fistula easy to develop. The World Health Organization estimates 130,000 new cases per year worldwide.

Having a fistula represents a distressing condition that will reduce a person’s quality of life. All the efforts to improve this condition must be made, and a successful index repair is the desired goal.

Minimally invasive approaches have led us to improve historically morbid surgical procedures. Early experience with laparoscopic surgery improved the outcomes. However, highly complex surgical maneuvers had to be performed, and the learning curve was difficult to reach. Robotic-assisted laparoscopic surgery improved upon many of the advances already made, and this technology gives us the best chances for a successful index/primary repair. Several characteristics such as improved intracorporeal suturing, a magnified view, tremor reduction, and a high degree of mobility make this possible.

In this chapter, we will be reviewing the most important aspects of the vesicovaginal, ureterovaginal, and rectourethral fistula and discuss the robotic repair of each condition.

Vesicovaginal fistula

Vesicovaginal fistula (VVF) is an abnormal communication between the bladder and the vaginal epithelium. It is considered a devastating condition characterized by involuntary and continuous urine leakage per vagina, and recurrent urinary tract infections, resulting in significant psychosocial distress, isolation, and hygiene problems. ^,

Incidence

The exact incidence of VVF is not known, but it is believed to affect up to 2% of women worldwide. The cases are geographically distributed disproportionally, depending on the country’s development.

In developing countries, the incidence is around 1%. Of these, 98% occur due to obstetric causes, where obstructed or prolonged labor leads to vaginal ischemia and subsequent fistula formation. Iatrogenic bladder injury during cesarean section (C-section) also has a higher incidence compared to developed countries (2.4% vs. <1%, respectively). In addition, inadequate access to obstetric healthcare, poor nutrition, and early age at first childbirth are frequent clinical scenarios that may predispose to fistula formation.

In contrast to developed countries, where the incidence is around 0.3%, the most common etiologies are iatrogenic injuries during pelvic surgery, such as hysterectomy, occurring in 1 of every 1800 procedures, sequelae of malignant diseases, pelvic radiation, infections, foreign bodies, and trauma. Obstetric procedures as a cause of VVF encompass only about 20%, with twin delivery and labor dystocia being the most common causes. ^,

Classification

VVF can be classified by complexity. Complex fistulae include:

Size equal to or greater than 2.5 cm
Failed repair attempts
Postradiotherapy
Localized in the trigone or near the ureteral orifices (UO)
Multiple tracts
Associated with ureteric strictures, ureterovaginal or rectovaginal fistula

Simple fistulae are those that do not comply with the above.

Diagnosis

Digital vaginal examination and the use of speculum can provide invaluable information about vaginal anatomy and tissue characteristics, while enabling fistula identification. Methylene blue instillation into the bladder in a retrograde fashion and tampon placement in the vaginal vault may confirm the diagnosis by staining the tampon after ambulation.

Cystoscopy is the gold standard for diagnosis, providing information about size, location, tissue quality, fistula proximity to the UO, and if there are any other fistulae associated. Upper urinary tract evaluation should be mandatory, since 12% of the cases may have a concomitant ureteral injury, which can be evaluated with computed tomography (CT) urogram or magnetic resonance imaging (MRI).

Conservative treatment

Conservative treatment should be used as the first intervention in any patient presenting with VVF unless the fistula has clear indications for surgical repair. This includes continuous bladder drainage for up to 12 weeks, allowing tissue healing. If no beneficial change has occurred within this timeframe, resolution by conservative methods is unlikely to occur due to epithelization of the fistulous tract.

Spontaneous closure happens in only 7% to 12.5% of the cases, and it has been described only in patients with a simple fistula.

If conservative management is unsuccessful, transvaginal or transabdominal surgical repair can be done, with reported success rates of 93% and 91%, respectively.

Timing of surgical repair

As the best chance of success is with the first repair, appropriate timing of surgical repair is essential. In cases where the fistula presents immediately after a surgical procedure, a prompt surgical repair is recommended, as delaying it may result in loss of tissue planes and fibrosis. However, in cases of VVFs caused by other etiologies, it is preferable to perform the surgical repair at least 3 to 6 months after the initial diagnosis to allow the tissue inflammation to settle. Routine follow-up with cystoscopy and vaginoscopy to exclude inflammation, cystitis, or encrustation is critical.

Surgical treatment

Currently, there is no consensus about the best surgical approach. The fundamental principles of fistula repair must be followed to ensure a successful outcome; these include adequate exposure of the fistulous tract, excision of nonviable tissue from fistula edges, use of well-vascularized healthy tissue for repairs, watertight and tension-free closure, nonoverlapping suture lines, flap interposition, and adequate bladder drainage following the repair. ^,

Transvaginal approach

The initial repair is usually attempted transvaginally, due to the anatomic familiarity to gynecological surgeons who are often the first to encounter this clinical scenario. ^, Proponents of this repair noted advantages in terms of a better approach for low-lying fistulae, lower patient morbidity, blood loss, and postoperative bladder irritability. Moreover, the procedure may be done in an outpatient setting, postoperative pain is minimal, and success rates are nearly equal to those achieved by the abdominal approach. However, vaginal exposure has its limitations, especially when the VVF is high-lying and the vagina is severely scarred.

Transabdominal approach

The transabdominal approach has enjoyed reproducible and durable success. Indications include fistulae greater than 2.5 cm, high-lying or retracted fistula in a narrow vagina, close proximity to the UO, concomitant ureterovaginal or rectovaginal fistula, multiple tracts, after radiotherapy, morbid obesity, or associated intra-abdominal pathology that requires simultaneous care as this will permit better exposure of the tissue for repair. ^,

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