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Endorectal Advancement Flap (ERAF) for Rectourethral Fistula

The endorectal advancement flap (ERAF) is a sphincter-preserving, transanal technique for rectourethral fistula (RUF) repair that achieves primary closure rates of 67–100% in selected patients, with a final success rate (including repeat flaps) of approximately 83–100%.[1][2][3] It is best suited for small, non-radiated, iatrogenic RUF and is among the simplest surgical options available, though at high-volume centers it has been largely supplanted by transperineal gracilis interposition for complex cases.[4][5]

For the gold-standard alternative see Transperineal Gracilis Interposition for RUF; for incisionless transanal alternatives see Transanal Minimally Invasive Repair (MITAR / TAMIS / TEM); for the analogous RVF technique see ERAF ± Sphincteroplasty for RVF.

Definition and Principle​

ERAF mobilizes a well-vascularized segment of rectal wall (mucosa, submucosa, often a portion of the internal sphincter / muscularis) to cover the internal (rectal) opening of the fistula after curettage and closure of the tract. The fundamental principle: close the fistula from the high-pressure side (rectum), allowing the urethral side to heal secondarily.[1][6]

Surgical Technique​

1. Transanal (pure endorectal) approach​

  1. Position lithotomy or prone jackknife.
  2. Exposure Parks' or Lone Star retractor; identify the fistula on the anterior rectal wall, typically 3–5 cm from the anal verge.[2][3]
  3. Tract curettage to remove granulation and epithelialized lining.[6]
  4. Flap design broad-based, trapezoidal or U-shaped flap; base proximal (cephalad). Mucosa + submucosa + variable muscularis (partial-thickness) or full-thickness rectal wall. Base width ~ 2× apex width to preserve perfusion.[3][6]
  5. Flap mobilization distal-to-proximal; mobilize enough for tension-free advancement.
  6. Internal-opening closure with interrupted absorbable suture at the muscularis / submucosa; some surgeons additionally close the urethral defect when accessible.[1][2]
  7. Flap advancement distally to cover the closed fistula; sutured with interrupted absorbable suture so flap and internal-opening suture lines are offset (non-overlapping).[3][6]
  8. No electrocoagulation near the repair (avoids thermal injury).[7]

2. Posterior transsphincteric approach with anterior rectal-wall advancement (al-Ali 1997)​

For posttraumatic RUF, combines a posterior midline transsphincteric incision (York-Mason type) with anterior rectal-wall advancement:[8]

  1. Prone jackknife.
  2. Posterior midline incision through the sphincter complex; open posterior rectal wall to expose the anterior rectal wall and fistula.
  3. Mobilize anterior rectal wall and advance over the fistula site.
  4. Meticulously re-approximate the sphincter complex in layers.

Provides superior visualization vs the purely transanal route. Original series: 100% (11/11), urethral stricture in 27%.[8]

Preoperative Considerations​

Fecal diversion — debated​

  • Dreznik 2003 — successful ERAF without fecal or urinary diversion in 2/3.[3]
  • Joshi 2011 — diversion less likely needed with localized (type 2) sepsis; required for severe intra-abdominal (type 1) sepsis.[2]
  • ASCRS 2022 — diverting stoma has not been shown to improve outcomes after ERAF and is not typically recommended.[6]
  • al-Ali 1997 — double diversion (colostomy + suprapubic cystostomy) considered a prerequisite for posttraumatic RUF reconstruction.[8]
  • Keller 2015 algorithm — 47% healed spontaneously (27% without diversion, 20% with diversion alone); only 43% required definitive surgery.[9]

Urinary drainage​

Urethral or suprapubic catheter for 2–4 weeks postoperatively.[1][2]

Outcomes​

Seriesn (ERAF)EtiologyPrimaryFinalFollow-upMorbidityNotes
Garofalo 2003 (Cleveland Clinic 20-yr)12Mixed (prostatic surgery, trauma, Crohn's)67% (8/12)83% (10/12)31 mo (mean)8%4 recurrences; 2 salvaged with repeat ERAF; CGQOL 0.82[1]
Joshi 20115Post-laparoscopic prostatectomy (non-radiated)80% (4/5)100% (5/5)11 mo (mean)Minimal1 patient required second flap; cystography confirmed closure in all[2]
Dreznik 20033Post-prostatic surgery100%100%NS0%2 without any diversion; normal continence in all[3]
al-Ali 1997 (transsphincteric)11Posttraumatic (missile wounds)100%100%NSUrethral stricture 27%All had double diversion preoperatively[8]
Keller 2015 (algorithm-based)13 (mixed transanal / transperineal)Prostate cancer treatment (97%)90% overall90% (0% recurrence)72 mo (mean)17% permanent stoma47% healed spontaneously; 37% long-term urinary incontinence[9]

Risk Factors for ERAF Failure (ASCRS 2022)​

Directly applicable to RUF repair:[6]

  • Prior pelvic radiation — most important predictor of failure
  • Active proctitis or sepsis
  • History of abscess drainage
  • Smoking
  • Malignancy
  • Obesity
  • > 1 previous attempted repair
  • Crohn's disease (less relevant for RUF)

Advantages​

  • Simplicity — most straightforward repair option; no external incisions, no muscle harvest, no specialized equipment[2][3]
  • Sphincter preservation — the purely transanal route avoids any sphincter division (vs York-Mason)[1][6]
  • Low morbidity — 0–8% complications; minimal blood loss; short OR time[1][3]
  • Short LOS — 1.5–4.5 days[1][2]
  • Diversion may be avoided — particularly in small non-radiated fistulas with localized sepsis[2][3]
  • Repeatable — failed ERAF can be redone with healing in 57–100% of second attempts[1][6]
  • Good functional outcomes — normal fecal and urinary continence in most series; CGQOL 0.82/1.0[1][3]
  • No donor-site morbidity (vs gracilis)[1]

Limitations​

  • Lower primary success than gracilis — ERAF 67–80% vs gracilis 84–100%; Park 2022 — recurrence with vs without flap 8% vs 50% (P = 0.009).[1][2][10][11]
  • No tissue interposition — no vascularized barrier between urethral and rectal suture lines, critical especially in irradiated / previously operated fields.[5][11]
  • Poor visualization — traditional transanal headlight + retractor exposes the anterior rectal wall poorly, particularly in men with deep buttocks. Cited as a major reason the technique has been "widely abandoned" by some reconstructive urologists in favor of transperineal repair.[5][6]
  • Inability to close the urethral defect reliably — unlike transperineal or MIS transanal techniques.[5]
  • Not suitable for radiated RUF — radiation-damaged tissue has poor vascularity and healing capacity; flap necrosis and recurrence likely.[6][12][13]
  • Not suitable for large fistulas — generally limited to fistulas < ~ 1.5 cm.[7]
  • Anterior position is technically demanding — particularly in obese men.[6]
  • Risk of incontinence — internal sphincter fibers may be included to maintain blood supply; mild-to-moderate incontinence reported in up to 35% with decreased manometric resting and squeeze pressures.[6]

Place in the RUF Algorithm​

  • Hechenbleikner 2013 SR (n = 416) — transanal approaches were only 5.9% of RUF repairs vs 65.9% transperineal; high-volume centers (≥ 25 patients) used transperineal repair with tissue flap in 100%.[4]
  • Harris 2017 multi-institutional (n = 201) — interposition flap or graft used in 91–92% of cases, overall success 92%.[14]
  • Keller 2015 algorithm-based — conservative management ± diversion first (47% spontaneous closure); definitive surgery in remainder, with transanal or transperineal flap (endorectal, dartos, or gracilis) achieving 90% healing.[9]

Current consensus:

  • First-line option for small (< 1.5 cm), non-radiated, iatrogenic RUF without active sepsis or prior failed repair, especially when patient prefers a less morbid approach[2][3][9]
  • Not recommended for radiation-induced, large, or complex RUF — transperineal gracilis remains standard[4][11][13]
  • Salvage after failed ERAF should proceed to transperineal repair with tissue interposition rather than repeat ERAF in most cases[4][11]

ERAF vs Transperineal Gracilis Interposition for RUF​

FeatureERAFTransperineal Gracilis
Primary success67–100%84–100%[1][2][3]
Tissue interpositionNoneVascularized muscle
Recurrence with vs without flap—8% vs 50% (P = 0.009)[11]
Suitable for radiated RUFNoYes (84%)[10]
Fecal diversionOften not requiredUsually yes
OR timeShortLonger (flap harvest)[1][7]
LOS1.5–4.5 d5–7 d[1][7]
Donor-site morbidityNoneMild (thigh numbness)[7]
Sphincter preservationYesYes
VisualizationLimited (transanal)Excellent (perineal)[8]
High-volume-center useRare (5.9%)Predominant (65.9%)[4]

Summary​

ERAF for RUF is a simple, low-morbidity, sphincter-preserving technique that delivers excellent results in carefully selected patients — small, non-radiated, iatrogenic fistulas without active sepsis or prior failed repair. Primary closure (67–80%) is lower than transperineal gracilis (84–100%), and the absence of tissue interposition is a meaningful disadvantage in irradiated or previously operated fields. ERAF remains a valid first-line option for simple RUF at centers with appropriate expertise; transperineal gracilis interposition is the dominant technique at high-volume referral centers for all complexities.

References​

1. Garofalo TE, Delaney CP, Jones SM, Remzi FH, Fazio VW. "Rectal advancement flap repair of rectourethral fistula: a 20-year experience." Dis Colon Rectum. 2003;46(6):762–769. doi:10.1007/s10350-004-6654-6

2. Joshi HM, Vimalachandran D, Heath RM, Rooney PS. "Management of iatrogenic recto-urethral fistula by transanal rectal flap advancement." Colorectal Dis. 2011;13(8):918–920. doi:10.1111/j.1463-1318.2010.02278.x

3. Dreznik Z, Alper D, Vishne TH, Ramadan E. "Rectal flap advancement — a simple and effective approach for the treatment of rectourethral fistula." Colorectal Dis. 2003;5(1):53–55. doi:10.1046/j.1463-1318.2003.00400.x

4. Hechenbleikner EM, Buckley JC, Wick EC. "Acquired rectourethral fistulas in adults: a systematic review of surgical repair techniques and outcomes." Dis Colon Rectum. 2013;56(3):374–383. doi:10.1097/DCR.0b013e318274dc87

5. Hebert KJ, Naik N, Allawi A, et al. "Rectourethral fistula repair using robotic transanal minimally invasive surgery (TAMIS) approach." Urology. 2021;154:338. doi:10.1016/j.urology.2021.05.027

6. 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

7. Nicita G, Villari D, Caroassai Grisanti S, et al. "Minimally invasive transanal repair of rectourethral fistulas." Eur Urol. 2017;71(1):133–138. doi:10.1016/j.eururo.2016.06.006

8. al-Ali M, Kashmoula D, Saoud IJ. "Experience with 30 posttraumatic rectourethral fistulas: presentation of posterior transsphincteric anterior rectal wall advancement." J Urol. 1997;158(2):421–424. doi:10.1016/s0022-5347(01)64493-8

9. Keller DS, Aboseif SR, Lesser T, et al. "Algorithm-based multidisciplinary treatment approach for rectourethral fistula." Int J Colorectal Dis. 2015;30(5):631–638. doi:10.1007/s00384-015-2183-0

10. Vanni AJ, Buckley JC, Zinman LN. "Management of surgical and radiation-induced rectourethral fistulas with an interposition muscle flap and selective buccal mucosal onlay graft." J Urol. 2010;184(6):2400–2404. doi:10.1016/j.juro.2010.08.004

11. Park KM, Rosli YY, Simms A, et al. "Preventing rectourethral fistula recurrence with gracilis flap." Ann Plast Surg. 2022;88(4 Suppl 4):S316–S319. doi:10.1097/SAP.0000000000003085

12. Hanna JM, Turley R, Castleberry A, et al. "Surgical management of complex rectourethral fistulas in irradiated and nonirradiated patients." Dis Colon Rectum. 2014;57(9):1105–1112. doi:10.1097/DCR.0000000000000175

13. Lo Re M, Pezzoli M, Garcia Rojo E, et al. "A systematic review on the surgical management of acquired rectourethral fistula." Int J Impot Res. 2026;38(3):214–225. doi:10.1038/s41443-025-01100-y

14. Harris CR, McAninch JW, Mundy AR, et al. "Rectourethral fistulas secondary to prostate cancer treatment: management and outcomes from a multi-institutional combined experience." J Urol. 2017;197(1):191–194. doi:10.1016/j.juro.2016.08.080