What is the management of a rectovestibular fistula with a patent anus?

Management of Rectovestibular Fistula with Patent Anus

For rectovestibular fistula with a patent anus, perform a primary perineal repair without colostomy using either a transanal approach or perineal fistula division, as these acquired fistulas do not require the extensive dissection used for congenital anorectal malformations. 1, 2, 3

Clinical Recognition and Diagnosis

Key Presenting Features

• Passage of stool per vagina is the hallmark symptom, reported in 75% of cases 1
• Vulvar or labial abscess in infancy is highly suspicious for this condition, particularly when parents report vaginal stool passage 1, 4
• Additional presentations include constipation, recurrent urinary tract infections, and history of vulvar inflammation within 3 months after birth (86% of cases) 1, 3

Diagnostic Approach

• Direct visual inspection under anesthesia is the key diagnostic method, as endoscopy frequently misses these fistulas 1
• The fistula typically opens in the vestibule, vagina, or labia on the vaginal side, with the internal orifice consistently located above the dentate line on the rectal side 1, 3
• Check for associated anal stenosis (present in 16% of cases) and presacral masses, as these require additional management 1
• Probing with a catheter under anesthesia confirms the fistula tract 2, 3

Surgical Management Algorithm

Primary Repair Without Colostomy (Preferred Approach)

Most patients can be managed with primary repair without diverting colostomy, as these are typically acquired fistulas from perineal infection rather than complex congenital malformations 2, 3

Surgical Technique Options

Option 1: Transanal Approach (Most Conservative)

• Perform transanal mobilization of the anterior rectal wall, leaving the perineal body intact 1
• This approach avoids disruption of the perineal body and external sphincter complex 1
• Mobilize healthy anterior rectal wall to cover the area of fistula on the posterior vagina 1

Option 2: Perineal Fistula Division

• Place patient in lithotomy position after appropriate bowel preparation 2
• Make a transverse perineal skin incision at the midpoint between the posterior commissure and anus 2
• Divide the fistula and close both ends with interrupted sutures 2
• Mobilize and interpose the external sphincter muscle between the vestibular and rectal stumps to prevent recurrence 2

Option 3: Posterior Sagittal Approach (For Complex Cases)

• Reserved for cases with previous failed repairs or complex anatomy 1
• Place sutures circumferentially around the fistulous opening on the rectal side 1
• Ligate the fistula and pull down normal rectal segment to be placed in front of the repaired vaginal wall 1

When to Consider More Extensive Dissection

• Large external opening (>5 mm diameter) with abnormal perineal appearance may require more extensive perineal dissection 3
• Previous failed repairs (recurrence rate 7-12%) may necessitate posterior sagittal approach 1, 3

Postoperative Management

Immediate Care

• Begin oral feeding on postoperative day 6 2
• Daily sitz baths with 3% boric acid solution 3
• Monitor for fistula reopening, which typically occurs 5-10 days postoperatively if it happens 3

Management of Recurrence

• Minor recurrences (occurring in 11-12% of cases) may heal spontaneously with daily sitz baths 3
• Persistent recurrence (7% of cases) requires reoperation using the same or alternative approach 2, 3

Critical Technical Points

Essential Surgical Principles

• The key technical point is obtaining healthy anterior rectal wall to cover the area of fistula on the posterior vagina 1
• Avoid extensive perineal dissection in most cases, as these are typically acquired rather than congenital malformations 3
• Ensure complete division and closure of both fistula ends to prevent recurrence 2

When Colostomy Is Indicated

• Diverting colostomy is unnecessary in most cases and should be reserved for: 2, 3
  • Early postoperative fistula reopening that fails conservative management 2
  • Multiple previous failed repairs 1
  • Severe associated anomalies requiring staged repair 1

Common Pitfalls to Avoid

• Do not rely on endoscopy alone for diagnosis, as it frequently misses these fistulas; direct inspection under anesthesia is essential 1
• Do not perform extensive perineal dissection routinely, as most cases are acquired and do not require the complex reconstruction used for congenital anorectal malformations 3
• Do not miss associated anal stenosis or presacral masses, which require concurrent management 1
• Do not dismiss vulvar abscess in infancy as simple infection; always investigate for underlying rectovestibular fistula, especially with history of vaginal stool passage 1, 4

Long-Term Outcomes

• All patients achieve normal bowel habits and continence with appropriate repair 1, 2, 3
• Follow-up ranging from 3 months to 17 years demonstrates excellent functional outcomes 1, 2, 3
• Zero recurrence rate is achievable with proper technique ensuring healthy rectal wall coverage of the vaginal repair 1