Perioperative management - Rectovaginal fistula: Anterior levatorplasty with simultaneous sphincter reconstruction

Since spontaneous healing of rectovaginal fistulas is rare even after the creation of a stoma, and conservative measures almost never lead to healing, the only sufficient therapy is surgical fistula repair.

Surprisingly, many patients present with fistulas that have existed for many years, which seems to be due to a minor or nonexistent level of distress and, naturally, also to shame. It is not uncommon for the presentation for fistula repair to occur at the urging of the partner or family, and occasionally the diagnosis is made incidentally, for example, during the diagnosis and treatment of other diseases.

Decisive for the indication for surgical fistula repair are a corresponding level of distress, recurrent infections, and possibly existing continence disorders. If there is no significant distress and/or the fistula is asymptomatic, the indication for surgery should be made with caution.

When is the ideal time for fistula correction?

With corresponding distress, rectovaginal fistulas should be repaired as quickly as possible. However, the condition of the affected tissue areas plays a crucial role in choosing the timing of the operation.

Before starting surgical measures, any existing inflammatory processes such as induration or inflammation must have largely subsided. If a fistula becomes symptomatic in the context of an abscess formation, one initially limits to an abscess incision and marking of the fistula with a vessel loop before aiming for fistula repair in a further step. The subsiding of inflammatory reactions can be supported by regular sitz baths, irrigation, possibly also debridement, 10-14 days of oral broad-spectrum antibiotics, and a low-fiber diet.

If the fistula is causally due to perineal trauma, for example, as a complication of the primary reconstruction of a higher-grade perineal tear during vaginal delivery, at least 10-12 weeks should be waited after the triggering event.

When is the placement of a protective, temporary stoma indicated?

The placement of a protective stoma is advisable for all fistula types with pronounced local inflammatory and scar changes, wide tissue defects, and anorectal incontinence requiring complex sphincter reconstruction. The so-called "complicated fistula disease" includes:

• Multiple fistula openings present
• Horseshoe-shaped or suprasphincteric fistula forms
• Wide fistula openings, which usually entail a difficult closure technique (e.g., gracilis interposition)
• Pronounced inflammatory perineal and perianal changes
• Crohn's fistulas
• Radiogenic fistula
• Severe obstetric injuries such as perineal loss

If a protective stoma is required, detailed counseling of the affected patient is mandatory not only by the surgeon but also by a stoma therapist, as well as the referral to self-help groups.

The reversal of a protective stoma should occur no earlier than 3 months after successful fistula repair.

Special case: Rectovaginal fistula and Crohn's disease

Fistulas that arise in the context of Crohn's disease have an extremely poor prognosis with a recurrence rate of over 50%. Fistula repairs during an acute flare should be avoided regardless of the location of the affected intestinal segment. Surgical measures must be postponed until the flare subsides, and the indication for the placement of a protective stoma should be made generously.

Absolute Contraindication

• The general condition of the patient no longer permits surgical intervention.
• Acute Crohn's flare-up

Relative Contraindication

• Lack of distress
• Asymptomatic fistulas

The diagnosis of a rectovaginal fistula is primarily based on the medical history and clinical examination.

Medical History

• Passage of intestinal gas or stool through the vagina (possibly only during diarrhea)
• Fecal incontinence: duration, type, frequency, impact of symptoms on daily and social life
• Recurrent infections of the vagina and lower urinary tract
• Foul-smelling vaginal discharge
• Vaginal deliveries
• Birth injuries: perineal tear, episiotomy;
  (Note: during an apparently "uncomplicated" delivery, sphincter lesions can also occur unnoticed!)
• Previous surgeries: gynecological, urological, colorectal
• Psychosocial burdens (subjective perception, partner, family, profession, leisure)

Clinical Diagnostics
The clinical diagnostics in the assessment of rectovaginal fistulas must include the entire sphincter complex to exclude possibly simultaneously existing causes of incontinence. Both the rectum and the vagina must be inspected. The rectovaginal examination includes:

• Inspection
  Fistula opening, scars (see Fig. No. 1), stool contamination or inflammatory changes in the vagina, vaginal discharge; in fistulas after birth trauma with sphincter defect, the perineum is often narrow (see Fig. No. 2), the anal mucosa is often tented towards the introitus, the perianal skin has lost its typical rosette-like form (see Fig. No. 3)

• Palpation
  A fistula opening at the introitus vaginae or in the rectum can especially be felt during a bimanual examination and possibly probed.

• Fistula probing
• Proctosigmoidoscopy, Colonoscopy

Tricks for detecting small-caliber and high fistulas, which are sometimes difficult to discover:

• Rectoscopic insufflation of air → exit through the vagina
• Rectal application of a blue solution diluted with physiological saline using a bladder syringe (or H2O2, which avoids skin discoloration) → exit through the vagina
• Oral intake of poppy seeds, which can be detected in the vagina with the help of a tampon (also suitable for detecting colovesical fistulas)

Imaging Techniques
Especially in complicated fistula tracts, e.g., in the context of Crohn's disease, or unclear cases, imaging techniques are used that provide important additional information.

Endo-Sonography
Transanal/endoanal sonography is to be performed as a standard method in every patient. In real-time, both the internal and external anal sphincter and the levator sling can be assessed. At the same time, it is possible to uncover other pelvic floor defects.

Typically, three regions are assessed in endoanal sonography:

• Distal region → external anal sphincter
• Middle of the anal canal → internal and external anal sphincter
• Proximal section → additionally the levator ani or the pubococcygeus muscle

Magnetic Resonance Imaging (contrast-enhanced)

• Detection of fistulas, abscesses, and sphincter lesions

Computed Tomography

• Less for fistula representation and more for excluding accompanying pathological processes (especially malignancies)

Obsolete: radiological fistula representation using contrast medium

Special Case Crohn's Disease
Crohn's patients should undergo staging before fistula repair to assess the activity of the underlying disease, which is crucial for the timing of surgery:

• Careful medical history
• Abdominal sonography
• Colonoscopy
• Possibly examination under short anesthesia for fistula probing, insertion of vessel loops
• Possibly also gastroscopy and small intestine double contrast

In principle, fecal contamination of the wound area should be avoided during and after the procedure:

• Liquid diet 24 hours preoperatively
• Bowel preparation as for colonoscopy or bowel resection, e.g., with oral saline solution

Additionally:

• Perioperative antibiotics: Cephalosporin + Metronidazole i.v.
• Possibly preoperative creation of a protective stoma, see chapter Indications

• Postoperative bleeding
• Local infections, abscesses
• Incontinence disorders (increases with the number of previous surgeries/previous damage)
• Fistula recurrence
• Suture dehiscence
• Dyspareunia
• Subsequent interventions
• Positioning injuries (soft tissues, nerves)
• Skin damage (due to the use of electric current, disinfectants)