What is the recommended surgical approach for a 1-month-old baby with a rectovestibular fistula and a patent anus?

Surgical Management of Rectovestibular Fistula with Patent Anus in a 1-Month-Old Infant

Primary Recommendation

Delay definitive surgical repair beyond the neonatal period (after 30 days of age) and perform single-stage posterior sagittal anorectoplasty (PSARP) without a diverting colostomy when the infant is older and larger, typically around 5-6 months of age and 6-7 kg body weight. 1

Rationale for Delayed Repair

• Delaying repair beyond the neonatal period is safe and associated with low complication rates (11% wound complications in delayed repairs), with satisfactory healing outcomes even when complications occur 1

• The median age at repair in successful series was 166 days (approximately 5.5 months) with median weight of 6.5 kg, demonstrating that waiting allows for better tissue handling and surgical outcomes 1

• No diverting colostomy is necessary in the vast majority of cases (74-95% of patients in published series), as this adds unnecessary morbidity without improving outcomes 1, 2

Surgical Approach Options

Posterior Sagittal Anorectoplasty (PSARP) - Preferred Method

• PSARP is the standard approach for rectovestibular fistula repair, providing excellent exposure and anatomic reconstruction through the sphincter complex 1

• This technique allows proper identification and division of the fistula tract, with closure of both rectal and vestibular ends, followed by pull-through of the rectum to the normal anal position 1

Alternative Approaches for Select Cases

• Anterior sagittal anorectoplasty can be performed in the lithotomy position, cutting through the anterior portion of sphincter muscles via median perineal incision, with satisfactory results in 12 reported patients 3

• Simple transanal or perineal approaches may be appropriate when the fistula has a small external opening (<5 mm diameter) and the internal orifice is just above the dentate line 2

• Vestibular-rectal pull-through or transanal procedures were successful in 74-95% of cases without extensive perineal dissection 2

Immediate Management (Birth to Surgery)

• Perform thorough perineal examination to confirm the presence of a patent, normally positioned anus separate from the rectovestibular fistula 4, 2

• Document the exact location of the fistula opening (vestibule) and confirm the internal opening is above the dentate line through gentle probing 2

• Counsel parents about vulvar hygiene and watch for signs of vulvar inflammation or abscess formation, which occurs in approximately 86% of cases within 3 months of birth 2

• If vulvar abscess develops (particularly left-sided), this strongly suggests rectovestibular fistula and may require drainage with fistulotomy and curettage as temporizing measure 5

Surgical Technique Details

• Position the patient in lithotomy for optimal exposure of the perineal anatomy 4, 3

• Perform appropriate bowel preparation prior to surgery 4

• Make a perineal transverse skin incision at the midpoint between the posterior commissure and the anus, or use a median perineal approach depending on the specific technique chosen 4, 3

• Identify and divide the fistula tract, closing both vestibular and rectal ends with interrupted sutures 4

• Mobilize the external sphincter muscle to interpose between the vestibular and rectal stumps, preventing fistula recurrence 4

• Delay oral feeding until postoperative day 6 to allow healing 4

Expected Outcomes and Complications

• Wound complications occur in approximately 11% of cases, including skin separation or wound dehiscence requiring local wound care 1

• Fistula recurrence occurs in 7-12% of patients within 5-10 days postoperatively 2

• Most recurrences (approximately 38% of those that recur) heal spontaneously with daily sitz baths using 3% boric acid 2

• Only 2-7% of patients require reoperation for persistent fistula or wound complications 1, 2

• Neo-anal stricture develops in a small percentage of patients and can be managed with dilation 1

• Long-term continence is excellent, with all patients in follow-up series (3-17 years) demonstrating normal bowel habits and continence 4, 2

Critical Pitfalls to Avoid

• Do not perform routine diverting colostomy unless extensive perineal dissection is required or the patient has failed previous repair 1, 2

• Avoid operating in the immediate neonatal period when tissue is fragile and the infant is small 1

• Do not perform extensive perineal dissection when simple fistula division is adequate (most cases with small external openings) 2

• Watch for associated VACTERL anomalies (present in approximately 2% of cases) and screen appropriately 2

• If wound complications occur, manage conservatively with local wound care and sitz baths before resorting to colostomy 1, 2