Colovesical Fistula

A rectovaginal fistula is an abnormal epithelial communication between rectum and vagina.

Major causes include obstetric injury, Crohn disease, colorectal or gynaecological surgery, radiation, malignancy and pelvic sepsis.

Management depends on fistula height, size, aetiology, sphincter integrity, tissue quality and previous repairs.

A simple low obstetric fistula is fundamentally different from a high irradiated or Crohn related fistula.

Patients report vaginal passage of flatus, stool or mucus, recurrent vaginal infection and significant continence related distress.

Assess anal sphincter function because an unrecognised obstetric sphincter defect can be the dominant functional problem.

Pain, fever or purulent drainage suggests unresolved pelvic or perineal sepsis.

Diagnosis is usually clinical with vaginal and rectal examination.

Examination under anaesthesia is useful when the tract is difficult to define or repair is being planned.

Pelvic MRI: useful for complex, recurrent or Crohn related fistulas and associated abscesses.

Endoscopy is appropriate when inflammatory bowel disease or malignancy is suspected.

Control sepsis before attempting definitive closure. Drain abscesses and use a loose seton when continuing drainage is required.

Allow acute obstetric inflammation and tissue trauma to settle before elective reconstruction.

For a simple low fistula with healthy tissue, local repair can be performed using an endorectal or vaginal advancement flap.

When an obstetric anal sphincter defect coexists, sphincteroplasty combined with fistula repair may provide better functional correction than closing the fistula alone.

Crohn related fistulas require control of active luminal and perianal inflammation before definitive repair. Attempting closure through actively inflamed Crohn tissue carries a high failure rate.

High fistulas related to colorectal anastomotic failure may require abdominal resection and reconstruction rather than a local flap.

Radiation associated and multiply recurrent fistulas are particularly difficult because tissue vascularity is poor. Tissue interposition, diversion or definitive resection may be required.

Faecal diversion is not automatically necessary for every fistula. Use selectively for severe sepsis, complex reconstruction, major tissue damage or repeated repair failure.