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Simple Closure with Skin Advancement Flap for Urethrocutaneous Fistula

The simple closure with skin advancement flap technique for urethrocutaneous fistula (UCF) repair achieves a 95.7% success rate for simple fistulas, significantly outperforming simple closure alone (71–79%).[1][2] The landmark series by Santangelo, Rushton, and Belman at Children's National Medical Center — spanning 99 patients and 94 repairs — remains the most comprehensive outcome analysis.[1]

For alternative UCF approaches see the male fistula treatment atlas.

Concept and Rationale​

Two-layer coverage: the urethral defect is closed first, then a second tissue layer (de-epithelialized or full-thickness skin advancement flap) is placed over the urethral closure to separate the suture lines and provide a vascularized waterproofing barrier.[1][3]

This addresses the primary cause of recurrence in simple closure — overlapping suture lines between urethral and skin closures, which create a direct pathway for fistula recurrence.[4][5]

Indications​

  • Small-to-moderate fistulas (typically ≤ 4 mm) at any penile location[1][2]
  • Coronal fistulas — particularly well-suited[2][6]
  • Midshaft fistulas — best suited for the de-epithelialized "pants over vest" variant[6]
  • Both first-time and recurrent fistulas, provided adequate local tissue is available[1]
  • Optimal for large (> 4 mm) and coronal fistulas, where simple closure alone has the highest recurrence — 78% of recurrences were coronal in one series[2]

Surgical Technique​

Variant 1 — De-Epithelialized "Pants Over Vest" Flap (preferred for midshaft)​

  1. Fistula excision — circumscribing incision; dissect tract to its base; excise completely[7][8]
  2. Urethral layer ("vest") closure — invert inner skin edges and close with fine absorbable suture (6-0 or 7-0) using an inverting subcuticular stitch[8]
  3. De-epithelialization — mark a flap of adjacent penile skin; remove epithelium while preserving underlying dermis and dartos fascia; keep base attached (hinged) to maintain vascular pedicle[3][8]
  4. Flap turnover ("pants") — turn the de-epithelialized flap over the urethral closure; secure with fine absorbable suture; completely covers the urethral suture line[6][8]
  5. Skin closure — advance remaining penile skin and close over the de-epithelialized flap as the third layer; final skin suture line offset from urethral closure[8]

Belman midshaft series: 100% success in 19 midshaft fistulas; 68% performed as nondiverted outpatient procedures.[6]

Variant 2 — Full-Thickness Skin Advancement Flap (preferred for coronal)​

  1. Fistula excision — circumscribe and excise tract to urethral base[1]
  2. Urethral closure — close defect with fine absorbable suture in a single layer[1]
  3. Skin advancement — mobilize a full-thickness skin flap from adjacent penile shaft; advance distally over the urethral closure; suture in place. Advancement ensures the skin suture line does not overlie the urethral closure[1][9]
  4. Tension-free closure — if tension is present, a longitudinal relaxing incision 0.5–1.5 cm from the wound edge heals secondarily in 7–21 d[4]

Belman coronal series: 10/11 (91%) success in coronal fistulas.[6]

Technical Pearls​

  • Exclude distal obstruction before any repair — calibrate the meatus ± cystoscopy. Unrecognized meatal stenosis or stricture is a major cause of recurrence[1][2]
  • Offset suture lines — the critical principle. The interposed de-epithelialized tissue or advancement flap achieves this separation[3][8]
  • Suture material — fine absorbable monofilament (6-0 or 7-0 polyglactin / polyglycolic acid)[7][8]
  • Minimize cautery — excessive electrocautery devascularizes tissue and promotes recurrence[4]
  • Adequate tissue mobilization — tension is the enemy; generous undermining of adjacent tissue is essential[4]
  • Tourniquet use — penile tourniquet improves visualization during dissection; release before final closure to assess hemostasis and perfusion

Postoperative Management​

A major advantage: stents and catheters generally not required for simple repairs.

  • Santangelo / Belman: stents not left postoperatively in simple cases; repairs routinely performed as outpatient procedures[1]
  • Geltzeiler & Belman: 68% midshaft and 91% coronal repairs as nondiverted outpatient procedures[6]
  • For large (> 4 mm) or multiple fistulas, suprapubic diversion is recommended — recurrence 16% with diversion vs 45% without[2]
  • When a catheter is used, indwelling urethral catheter for 3–4 d[8]
  • Prophylactic antibiotics commonly given perioperatively (limited evidence for benefit)
  • Anticholinergics (oxybutynin) to reduce bladder spasms if a catheter is in place

Outcomes​

TechniquenSuccessFistula location
De-epithelialized "pants over vest" (midshaft)19100%Midshaft[1][6]
Skin advancement flap (coronal)1191%Coronal[1][6]
De-epithelialized or full-thickness advancement (simple)6995.7%Mixed[2]
De-epithelialized or full-thickness advancement (all, incl. complex)9493.6%Mixed[2]
"Pants over vest" layered repair (Cimador 2003)3294% first attemptShaft[10]
Simple closure alone (comparator)39–4271–74%Mixed[10]

Layered repair (94%) vs simple closure (74%) — statistically significant.[10]

De-Epithelialized Turnover Dartos Flap — Related Variant​

Ahuja modification — combines de-epithelialization with a dartos-based turnover flap. Circumscribe fistula, close urethral layer with inverting sutures, raise a de-epithelialized flap with underlying dartos fascia on a hinged pedicle, turn over the closure. Long skin flap from shaft or scrotum is then approximated over this layer.[8]

100% success in 10 patients (ages 4–25). Particularly useful when local dartos tissue is available and well-vascularized.

Comparison with Other Waterproofing Techniques​

TechniquePooled successBest for
Skin-based flaps (heterogeneous)54.5% pooled across all studies (Choudhury 2023 meta)Heavily influenced by older series[5]
De-epithelialized advancement flap (refined Belman / Santangelo)> 90% with meticulous techniqueFirst-time, small-to-moderate fistulas[1][6]
Tunica vaginalis flap94.3%Recurrent or complex fistulas; scarred local tissue[5]
Scrotal dartos flap94.6%Mid-shaft / proximal fistulas with scarred local tissue[5]
PATIO repair~83%Coronal / subcoronal fistulas[11]

The refined de-epithelialized advancement flap technique (Belman / Santangelo) consistently achieves > 90% when performed with meticulous technique.

When to Choose This Technique vs Alternatives​

  • Simple closure + skin advancement flap — first-time, small-to-moderate fistulas with adequate local penile skin, particularly coronal and midshaft locations[1][2][6]
  • Tunica vaginalis flap — recurrent fistulas or fibrotic local penile tissue from prior surgery[5]
  • Scrotal dartos flap — mid-shaft and proximal fistulas with scarred local tissue[5]
  • PATIO repair — technically straightforward option for coronal / subcoronal fistulas (~83%)[11]

Key Takeaways​

  • 95.7% success for simple fistulas with meticulous technique (Santangelo / Belman).
  • Two technique variants: "pants over vest" de-epithelialized flap for midshaft (100% in Belman), full-thickness advancement flap for coronal (91% in Belman).
  • Stents / diversion not routinely required for simple repairs — most performed as outpatient procedures.
  • Exclude distal obstruction before any repair; offset suture lines; minimize cautery; mobilize generously for tension-free closure.
  • For large (> 4 mm) or multiple fistulas: suprapubic diversion reduces recurrence from 45% to 16%.

References​

1. Santangelo K, Rushton HG, Belman AB. "Outcome analysis of simple and complex urethrocutaneous fistula closure using a de-epithelialized or full thickness skin advancement flap for coverage." J Urol. 2003;170(4 Pt 2):1589–1592. doi:10.1097/01.ju.0000084624.17496.29

2. Elbakry A. "Management of urethrocutaneous fistula after hypospadias repair: 10 years' experience." BJU Int. 2001;88(6):590–595. doi:10.1046/j.1464-4096.2001.02390.x

3. Belman AB. "De-epithelialized skin flap coverage in hypospadias repair." J Urol. 1988;140(5 Pt 2):1273–1276. doi:10.1016/s0022-5347(17)42022-2

4. Chen W, Ma N, Wang W, Ju M. "The application of multilayer direct closure with a longitudinal relaxing incision in urethrocutaneous fistula repair." Ann Plast Surg. 2020;84(3):317–321. doi:10.1097/SAP.0000000000002056

5. Choudhury P, Saroya KK, Jain V, et al. "'Waterproofing layers' for urethrocutaneous fistula repair after hypospadias surgery: evidence synthesis with systematic review and meta-analysis." Pediatr Surg Int. 2023;39(1):165. doi:10.1007/s00383-023-05405-1

6. Geltzeiler J, Belman AB. "Results of closure of urethrocutaneous fistulas in children." J Urol. 1984;132(4):734–736. doi:10.1016/s0022-5347(17)49846-6

7. Dekalo S, Ben-David R, Bar-Yaakov N, et al. "In support of a simple urethrocutaneous fistula closure technique following hypospadias repair." Urology. 2020;143:212–215. doi:10.1016/j.urology.2020.06.015

8. Ahuja RB. "A de-epithelialised 'turnover dartos flap' in the repair of urethral fistula." J Plast Reconstr Aesthet Surg. 2009;62(3):374–379. doi:10.1016/j.bjps.2008.03.031

9. Zagula EM, Braren V. "Management of urethrocutaneous fistulas following hypospadias repair." J Urol. 1983;130(4):743–745. doi:10.1016/s0022-5347(17)51434-2

10. Cimador M, Castagnetti M, De Grazia E. "Urethrocutaneous fistula repair after hypospadias surgery." BJU Int. 2003;92(6):621–623. doi:10.1046/j.1464-410x.2003.04437.x

11. Rathod K, Loyal J, More B, Rajimwale A. "Modified PATIO repair for urethrocutaneous fistula post-hypospadias repair: operative technique and outcomes." Pediatr Surg Int. 2017;33(1):109–112. doi:10.1007/s00383-016-3983-1