Rectovaginal fistulas

rectovaginal fistula, complete perineal tear, obstetric fistula, obstetrics trauma, fecal incontinence, perineal body, deficient perineum, obstructed labour, instrumental delivery, malignant fistula

1. RECTOVAGINAL FISTULAS By Magdy Abdelrahman mohamed Lecturer of OB/GYN 2016

2. Definition and classifications Rectovaginal Fistula is an abnormal communication between the rectum and the vagina . RVFs are classified on the basis of location, size, and etiology, each of which affects the treatment plan and prognosis

3. Relevant Anatomy The rectovaginal septum is the thin septum separating the anterior rectal wall and the posterior vaginal wall. The caudal portion of the septum is the perineal body. The anal sphincters are located in the posterior portion of the perineal body.

4. A more precise definition is that a low RVF is between the lower third of the rectum and the lower half of the vagina, and a high fistula is between the middle third of the rectum and the posterior vaginal fornix. Low RVFs are closest to the anus and can be corrected with a perineal approach. High fistulas require a transabdominal approach for repair

5. RVFs may vary greatly in size, but most are less than 2 cm in diameter. Small-sized fistulas are less than 0.5 cm in diameter, medium-sized fistulas are 0.5-2.5 cm, and large-sized fistulas exceed 2.5 cm.

6. Etiology Traumatic: Obstetrical trauma.(commonest) Surgical trauma. Direct trauma. Inflammatory: Pelvic abscess. TB. crohn’s disease. Neoplastic post-irradiation.

7. Clinical: A few patients are asymptomatic. Most patients report passage of flatus or stool through the vagina. Patients may also experience vaginitis or cystitis. At times, a foul-smelling vaginal discharge develops, but frank stool per vagina usually occurs only when the patient has diarrhea.

8. The clinical picture may include fecal incontinence due to associated anal sphincter damage .

9. Physical examination is essential. This usually confirms the diagnosis and affords much information regarding the size and location of the fistula, the function of the sphincters, and the possibility of IBD ( Inflammatory Bowel Disease) or local neoplasm.

10. The suspicion of Crohn ’ s disease should be high if there is any other abnormality of the rectal mucosa or a previous or currently coexisting fistula. Failure to recognize Crohn disease can lead to inappropriate operative intervention and can worsen the patient's situation

11. Diagnostic Procedures: Flexible endoscopy ( sigmoidoscopy or colonoscopy) is used to fully evaluate the possibility of IBD or malignancy. When IBD is in the differential diagnosis, endoscopy with biopsies must precede any operative approach to the fistula because the treatment varies, depending upon the diagnosis.

12. Treatment: Indications: Because the symptoms of RVFs are so distressing, surgical therapy is almost always indicated. Exceptions include patients who unfit for surgery.

13. Medical therapy Treat acute fistulas of traumatic origin (including those caused by obstetric and operative trauma) and fistulas complicated by secondary infection or of infectious origin with local care, drainage of abscesses, and directed antibiotic therapy. Allow tissues to heal for 6-12 weeks.

14. Dietary modification and supplemental fiber can greatly diminish symptoms during this period. Many fistulas resulting from obstetric or operative trauma heal completely, requiring no further therapy.

15. RVFs of radiation origin are very difficult to treat surgically, and medical therapy is often initially recommended in this setting. Diet and fiber are the mainstays of therapy.

16. Surgical therapy: Preoperative details: Complete mechanical bowel preparation & intestinal antiseptics. Although used in the past, the majority of RVFs are now repaired without first performing a diverting colostomy

17. Surgical therapy: Local repair methods Transanal advancement flap repair: The best results have been reported with this type of repair. The fistula is identified using the operating anoscope . A flap is outlined, extending at least 4 cm superior to the fistula.

18. Conversion to complete perineal tear: with layer closure. Simple fistulotomy : This procedure works well for small anovaginal fistulas, in which no sphincter is involved in the tract.

19. Transabdominal approaches Transabdominal approaches are generally used for high RVFs when the fistula originates from a neoplasm, radiation, or, occasionally, IBD.

20. Fistula division and closure without bowel resection : This is the simplest abdominal approach. Interposition of healthy tissue, such as omentum , may be used to separate the suture lines.

21. Bowel resection: When tissues are abnormal because of radiation, inflammation, or neoplasm.