Endorectal Advancement Flap (ERAF) for Rectovaginal Fistula
The endorectal advancement flap (ERAF) is the procedure of choice for most rectovaginal fistulae (RVFs) per the ASCRS Clinical Practice Guidelines (Recommendation 14, Grade 1C), with reported success of 41–78% depending on etiology, technique, and definition of healing.[1] The defining principle is that the repair is performed from the high-pressure (rectal) side — intraluminal pressure helps press the flap onto the closed internal opening rather than pushing it open. When a concurrent sphincter defect is present, adding sphincteroplasty ± levatorplasty improves healing to >80% and is strongly recommended.[1][2]
For broader context see Rectovaginal Fistula and the Female Fistula treatment atlas.
Indications and Prerequisites
ERAF is appropriate for low and mid-level RVF of obstetric, cryptoglandular, postoperative, and select Crohn's etiology when the rectal mucosa has healed.[1][3][4]
Prerequisites:
- No active proctitis — absolute contraindication[3][4]
- No anorectal stricture[3]
- No malignancy at the fistula site[1]
- Adequate tissue quality — prior radiation markedly reduces success[1]
Preoperative Optimization
| Step | Rationale |
|---|---|
| Draining seton weeks-to-months before definitive repair | Resolves edema, infection, and inflammation in the rectovaginal septum; prior seton independently associated with success (P = 0.025)[1][5] |
| Abscess drainage | Prior I&D associated with improved healing (P = 0.010)[5] |
| Crohn's optimization | Anti-TNF ± immunomodulator with endoscopic mucosal healing of the rectosigmoid confirmed before flap repair[3] |
| Endoanal US / pelvic MRI | Drives the ERAF-alone vs ERAF + sphincteroplasty decision[1] |
| Mechanical bowel prep | Day before surgery |
Surgical Technique
Positioning and exposure
- Prone jackknife position is preferred for anterior fistulas; lithotomy is acceptable.
- A Lone Star (or equivalent self-retaining) anal retractor for circumferential exposure of the anal canal and distal rectum.
- The internal opening is typically on the anterior rectal wall at or just above the dentate line.
Step 1 — Tract curettage
- Curette the tract to remove granulation tissue and the epithelialized lining.[1]
- Hydrogen peroxide or methylene blue instilled through the vaginal opening confirms the tract and complete debridement.
Step 2 — Closure of the internal opening
- Close the rectal (high-pressure) side with absorbable suture (2-0 or 3-0 Vicryl) — figure-of-eight or interrupted.[1][6]
Step 3 — Optional muscular plication (modified de Parades technique)
- Plication of the anorectal muscular layer (internal sphincter + rectal-wall musculature) over the closed internal opening adds a reinforcing layer between the rectal and vaginal suture lines.[6]
- de Parades 2011 (n = 23): 65% success with no continence deterioration (mean Wexner 1.3 → 0.6).[6]
Step 4 — Flap design and elevation
- Broad-based, trapezoid flap: base proximal (cephalad), apex at or just distal to the internal opening.[4]
- Base width ≥ 2× apex width to preserve perfusion.
- Elevate 4–6 cm proximal to the internal opening.
Flap thickness:
| Variant | Composition | Trade-off |
|---|---|---|
| Full-thickness | Mucosa + submucosa + internal sphincter / rectal-wall musculature | More robust blood supply; higher continence-disturbance risk |
| Partial-thickness | Mucosa + submucosa only | Less sphincter disruption; potentially higher failure |
ASCRS permits inclusion of internal-sphincter fibers to preserve perfusion; the full- vs partial-thickness debate is unresolved.[1]
Step 5 — Flap advancement
- Advance the flap distally to cover the closed internal opening.
- Suture lines must not overlap — flap suture line is offset from the internal-opening closure.
- Interrupted absorbable sutures to surrounding anoderm/mucosa.
- The donor site proximal to the flap heals by secondary intention or is loosely approximated.
Step 6 — Vaginal side
- Leave the vaginal opening open for drainage and to prevent septal abscess.
- Some surgeons debride but do not close the vaginal side.
Key Technical Principles
- Repair is performed from the high-pressure side (rectal) — intraluminal pressure presses the flap onto the closure rather than driving it apart.
- Flap must have a broad base with reliable blood supply.
- Tension-free advancement.
- No overlapping suture lines between the internal-opening closure and the flap suture line.
- For very low RVF with the internal opening at or below the dentate line, a standard rectal mucosal flap risks mucosal ectropion; switch to an anoderm / perianal-skin flap.[1]
Adding Sphincteroplasty
When to add it
ERAF alone with a known sphincter defect yields only 41% healing; ERAF + sphincteroplasty ± levatorplasty yields >80%.[1]
| Indication | Rationale |
|---|---|
| Anterior sphincter defect on endoanal US | Combined repair restores function and continence[1] |
| Coexisting fecal incontinence (~48% of obstetric RVF) | Combined repair is the only durable solution[1] |
| Fistula diameter >1 cm | Independent ERAF-failure predictor; sphincteroplasty preferred[7] |
Combined ERAF + sphincteroplasty technique
- Complete the ERAF.
- Curvilinear perineal incision.
- Identify and mobilize the external anal sphincter ends, dissecting from surrounding scar.
- Overlapping sphincter repair with mattress sutures of delayed-absorbable material (2-0 PDS or Vicryl).
- ± Levatorplasty — plication of levator ani muscles anterior to the rectum reinforces the rectovaginal septum.
- Reconstruct the perineal body.
Outcomes of combined repair
Khanduja 1999 — landmark obstetric-RVF + sphincter-disruption series (n = 20):[2]
- 100% elimination of vaginal stool / flatus discharge
- 70% restored to perfect anal continence (14/20)
- 30% improved but not eliminated (4 incontinent to liquid, 2 to flatus)
- 95% rated result as excellent or good
- No complications
Outcomes of ERAF Alone
| Series | n | Etiology | First-repair success | Overall success | Key findings |
|---|---|---|---|---|---|
| Sonoda 2002 | 37 RVF (99 total) | CD 44%, cryptoglandular 48% | 63.6% (all fistulae) | — | CD (P = 0.027) and RVF (P = 0.002) independently reduced healing[5] |
| Jones 1987 | 23 RVF (39 total) | CD 49%, obstetric / surgical 51% | 69.2% (all fistulae) | — | CD 57.9% vs other 80%; active proctitis is contraindication[4] |
| de Parades 2011 | 23 | CD 30%, cryptoglandular 48%, obstetric 22% | 65% | — | Modified ERAF + muscular plication; no continence deterioration[6] |
| Corte 2015 | 79 (286 procedures) | CD 43%, postop 32%, obstetric 9% | — | 72% (all techniques) | Major procedure (OR 6.4), stoma (OR 3.5), early surgery (OR 2.3) predict success[8] |
| Li 2025 | 57 | Congenital 33%, obstetric 33% | 66.7% | 70.2% | Diameter > 1 cm independent risk factor (P < 0.05); sphincteroplasty rescued 2 failures[7] |
Risk Factors for Failure
Patient-level:
- Crohn's disease (P = 0.027)[5]
- Active proctitis — absolute contraindication[1][4]
- Smoking[1]
- Obesity[1]
- High-dose prednisone (> 20 mg/day) — no patients on high-dose steroid achieved long-term healing[5]
Fistula-level:
- Diameter > 1 cm — independent risk factor (P < 0.05)[7]
- RVF vs anorectal location (P = 0.002)[5]
- Recurrent fistula / prior failed repair[1]
- Sphincter defect without combined repair[1]
Factors associated with success:
- Prior seton (P = 0.025)[5]
- Prior abscess drainage (P = 0.010)[5]
- Short fistula duration before repair (P = 0.003)[5]
- Early surgery (within referenced window)[8]
- Increased age (P = 0.011)[5]
Functional Outcomes and Complications
- Inclusion of internal-sphincter fibers within the flap is permitted to preserve perfusion; reported continence outcomes are stable when the modified plication technique is used (Wexner 1.3 → 0.6).[6]
- The combined ERAF + sphincteroplasty series of Khanduja 1999 reported no perioperative complications.[2]
- Late complications include flap dehiscence, recurrence, septal abscess, and (rarely) mucosal ectropion when a true rectal-mucosal flap is misapplied to a very-low fistula.
References
1. Gaertner WB, Burgess PL, Davids JS, et al. "The American Society of Colon and Rectal Surgeons clinical practice guidelines for the management of anorectal abscess, fistula-in-ano, and rectovaginal fistula." Dis Colon Rectum. 2022;65(8):964–985. doi:10.1097/DCR.0000000000002473
2. Khanduja KS, Padmanabhan A, Kerner BA, Wise WE, Aguilar PS. "Reconstruction of rectovaginal fistula with sphincter disruption by combining rectal mucosal advancement flap and anal sphincteroplasty." Dis Colon Rectum. 1999;42(11):1432–1437. doi:10.1007/BF02235043
3. American Gastroenterological Association. "Medical position statement: perianal Crohn's disease." Gastroenterology. 2003;125(5):1503–1507. doi:10.1016/j.gastro.2003.08.024
4. Jones IT, Fazio VW, Jagelman DG. "The use of transanal rectal advancement flaps in the management of fistulas involving the anorectum." Dis Colon Rectum. 1987;30(12):919–923. doi:10.1007/BF02554276
5. Sonoda T, Hull T, Piedmonte MR, Fazio VW. "Outcomes of primary repair of anorectal and rectovaginal fistulas using the endorectal advancement flap." Dis Colon Rectum. 2002;45(12):1622–1628. doi:10.1007/s10350-004-7249-y
6. de Parades V, Dahmani Z, Blanchard P, et al. "Endorectal advancement flap with muscular plication: a modified technique for rectovaginal fistula repair." Colorectal Dis. 2011;13(8):921–925. doi:10.1111/j.1463-1318.2010.02338.x
7. Li X, Shao W, Sun G. "A single-center retrospective analysis of endorectal advancement flaps used for the treatment of simple rectovaginal fistulas." Scand J Gastroenterol. 2025;60(4):307–311. doi:10.1080/00365521.2025.2468493
8. Corte H, Maggiori L, Treton X, et al. "Rectovaginal fistula: what is the optimal strategy? An analysis of 79 patients undergoing 286 procedures." Ann Surg. 2015;262(5):855–860; discussion 860–861. doi:10.1097/SLA.0000000000001461