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Scrotal Flaps for UCF Repair

Scrotal flaps are a family of techniques that achieve the highest pooled success rate (94.6%) of any waterproofing layer for UCF repair — marginally exceeding tunica vaginalis flap (94.3%) — in the 2023 Choudhury meta-analysis of 2,886 patients.[1] The term encompasses several distinct scrotal tissue sources: the scrotal dartos flap (Churchill), the de-epithelialized scrotal skin flap (Lee), the de-epithelialized turnover dartos flap (Ahuja), and the scrotal septum flap (Sakai / Mokhless / Yachia / Gil-Vernet). All share the critical advantage of providing well-vascularized, unscarred tissue from outside the penile operative field.[2][3][4]

For alternative UCF approaches see Simple Closure + Skin Advancement Flap, Double Dartos Flap, and PATIO Repair; for broader context see the male fistula treatment atlas.

Scrotal Vascular Anatomy​

Carrera 2009 cadaveric microvascular study (15 cadavers) — scrotal skin is irrigated by two main vascular systems distributed across three cutaneous territories:[5]

  • Two lateral territories — each hemiscrotum receives an inferior external pudendal artery entering at the midpoint of the scrotal root and fanning out
  • One central territory — vascularized by branches of the perineal arteries (posterior scrotal arteries) running deeply on both sides of the scrotal septum
  • Wide inter-anastomoses — redundant blood supply enabling reliable flap harvest from multiple scrotal locations

Type 1 — Scrotal Dartos Flap (Churchill, 1996)​

Most commonly used scrotal flap for UCF repair.[2]

Anatomy: fibroadipose tissue between scrotal skin and tunica vaginalis, with vascular pedicle based at the penoscrotal angle; can reach the distal penile shaft without tension.[2]

Technique​

  1. Fistula excision and urethral closure — circumscribe and excise the tract; close the urethral defect with fine absorbable suture (6-0 or 7-0) in an inverting fashion
  2. Scrotal incision — transverse or oblique on the ipsilateral hemiscrotum, typically at the penoscrotal junction
  3. Dartos harvest — elevate scrotal skin off underlying dartos; raise a rectangular or tongue-shaped flap of scrotal dartos preserving the penoscrotal-angle pedicle[2]
  4. Transposition — superiorly to the penile shaft; lay over the urethral suture line. The penoscrotal pedicle naturally reaches the ventral shaft
  5. Fixation — secure over the urethral closure with fine absorbable suture; ensure complete coverage with offset suture lines
  6. Skin closure — scrotal and penile skin closed over the dartos flap
  7. Urinary diversion — urethral stent or catheter for 3–7 d[7]

Outcomes​

  • Churchill 1996 — repeat hypospadias surgery; 100% (6/6 with follow-up) at 1 yr; described as "easy to mobilize"[2]
  • Muruganandham 2010 (n = 21) — scrotal dartos wrapping of 2–4 mm fistulas: 90.5% at mean 3.5 yr; no scrotal, testicular, or penile complications[7]

Type 2 — De-Epithelialized Scrotal Skin Flap (Lee, 1990)​

Uses the scrotal skin itself (epithelium removed) as a vascularized reinforcement layer.[3]

Technique​

  1. Fistula closure — close the urethral defect primarily
  2. Flap design — adjacent scrotal skin large enough to cover the urethral repair site
  3. De-epithelialization — remove the epithelium by sharp dissection or dermatome, leaving dermis + dartos fascia intact with blood supply
  4. Transposition — rotate or advance over the urethral closure as a reinforcing layer
  5. Skin closure — advance remaining scrotal skin to close the donor site

Outcomes​

Lee 1990 (n = 8): 100% success for both complicated and uncomplicated fistulas; 3 of 8 procedures performed without urinary diversion or urethral stent.[3]

Advantages: thick, well-vascularized tissue layer; can be performed without diversion in selected cases; minimal donor-site morbidity.

Type 3 — De-Epithelialized Turnover Dartos Flap (Ahuja, 2009)​

Hybrid technique combining local penile dartos closure with scrotal skin coverage:[8]

  1. Circumscribing incision around the fistula; inner skin edges closed with inverting subcuticular stitch as the urethral layer
  2. Flap marked adjacent to the circumscribing incision and de-epithelialized
  3. De-epithelialized flap raised with underlying dartos fascia and turned over (hinged) onto the first layer of closure; vascular supply based on hinge of tissue around the defect
  4. Long skin flap from the shaft or scrotum approximated over this layer; alternatively "pants over vest" skin closure
  5. Indwelling catheter 3–4 d

Outcomes​

Ahuja 2009 (n = 10, ages 4–25 yr), including patients with multiple fistulas and long proximal-to-penoscrotal fistula: 9/10 healed without complications. The 1 patient with multiple shaft fistulas had a residual pinpoint fistula that closed spontaneously.[8]

Type 4 — Scrotal Septum Flap Variants​

Several use the midline scrotal septum as a tissue source, particularly for complex urethral reconstruction (panurethral):

Sakai septocutaneous island flap (1990)​

Supplied by vascular networks in the scrotal septum from both perineal and posterior scrotal arteries. Flap divided into two components — one for urethral lining and one for skin defect coverage. Hairless scrotal skin must be used for the urethral lining.[4]

Mokhless scrotal septum pedicled flap (1992)​

n = 7 complex hypospadias with inadequate preputial skin. The scrotal septum serves as the vascular pedicle. 5/7 satisfactory; 2 distal urethral stricture, 1 subcoronal UCF; minor hair growth in 1.[9]

Yachia pedicled scrotal flap (1986)​

One-stage procedure using the scrotal septum as a pedicle for bulbomembranous urethral reconstruction; the septum provides excellent mobility, applicable anywhere along the urethra.[10]

Gil-Vernet biaxial epilated scrotal flap (1997)​

Perineum-based scrotal flap with biaxial vascularization supplied by both superficial perineal arteries; lengths up to 20 cm for panurethral reconstruction. n = 37 men with complex urethral stenosis — 86% achieved normal voiding after one-stage urethroplasty at mean 39.5 mo.[11]

Outcomes Summary​

SeriesYearnFlap typeIndicationSuccessFollow-up
Lee19908De-epithelialized scrotal skinUCF repair100%NS[3]
Churchill19968Scrotal dartos (penoscrotal pedicle)Repeat hypospadias100% (6/6 f/u)1 yr[2]
Shankar20026Scrotal dartos or TVF≥ 3rd repair83% (5/6)7.5 yr[12]
Ahuja200910De-epithelialized turnover dartosUCF (various)100%NS[8]
Muruganandham201021Scrotal dartos wrapping2–4 mm UCF90.5%3.5 yr[7]
Choudhury 2023 pooled meta2023PooledAll scrotal flapsUCF repair94.6%Variable[1]

Scrotal Flaps vs Other Waterproofing Layers​

TechniquePooled successTissue sourceAdditional incisionTesticular risk
Scrotal flaps94.6%Scrotal wall / septumPenoscrotal / scrotalNone reported[1]
Tunica vaginalis flap94.3%Parietal tunica vaginalisScrotal incisionTesticular ascent 7.3%[1]
PATIO93.5%Fistula tract (inverted)NoneNone[1]
Biomaterials / dermal substitutes92%Acellular matrixNoneNone[1]
Double dartos flap81%Penile dartosNoneNone[1]
Single dartos flap78.8%Penile dartosNoneNone[1]
Simple closure73.2%NoneNoneNone[1]

Advantages​

  • Highest success rate — 94.6% pooled, best-performing waterproofing layer (Choudhury 2023)[1]
  • Unscarred tissue from outside the penile field — ideal for recurrent and multiply-operated patients[2][12]
  • Independent blood supply — scrotal vasculature (external pudendal + perineal arteries) is separate from penile vasculature and uncompromised by prior penile surgery[5]
  • No testicular complications — unlike TVF, scrotal dartos harvest does not require testicular delivery, tunica vaginalis incision, or orchidopexy. No testicular atrophy / torsion / ascent / ischemia reported[2][7]
  • Abundant tissue — large reservoir sufficient for extensive repairs or multiple fistulas[11]
  • Can be performed without urinary diversion — Lee 3/8 patients[3]
  • Easy to mobilize — Churchill described scrotal dartos as "easy to mobilize" with excellent coverage[2]
  • Unaffected by prior inguinal surgery — vs TVF which may be compromised by prior orchidopexy or inguinal hernia repair[2]

Limitations​

  • Hair-bearing tissue — if used for urethral lining (scrotal septum flaps for urethroplasty), hair can be imported into the urethra → hair-ball, stone formation, recurrent UTI. Mitigated by using hairless scrotal areas or epilation. Not a concern for UCF repair where scrotal tissue is a waterproofing layer, not urethral lining[14][15]
  • Cosmetic concerns — scrotal skin transposed to penile shaft may differ in color, texture, thickness. Churchill reported 84% excellent cosmesis[2]
  • Limited reach for distal fistulas — penoscrotal-based dartos can reach distal shaft but very distal (subcoronal / coronal) fistulas may be at the limit; TVF with subcutaneous tunneling may have better reach[2][16]
  • Diverticulum formation when scrotal skin is used for urethral lining (urethroplasty) — Jordan noted that when properly prepared, scrotal flaps are no more likely to create diverticula than other genital skin islands[14]
  • Limited comparative data — unlike TVF (RCT vs dartos), scrotal dartos data for UCF repair are case-series without randomized comparisons[1]
  • Testicular ascension — reported in 22.7% with bilateral scrotal flaps for penile shaft reconstruction (not UCF repair); not reported in the smaller UCF repair series[17]

Scrotal Dartos vs Tunica Vaginalis — Key Distinctions​

Both originate from the scrotum but are anatomically distinct:

FeatureScrotal dartos flapTunica vaginalis flap
Tissue layerFibroadipose between scrotal skin and tunica vaginalisParietal layer of tunica vaginalis (serous membrane)
Blood supplyExternal pudendal + perineal arteries via scrotal wallCremasteric vessels
Pedicle basePenoscrotal angleSuperior (toward external inguinal ring)
Testicular delivery requiredNoYes
Orchidopexy recommendedNoYes
Testicular ascent riskNot reported7.3%[1]
Tissue thicknessThicker (fibroadipose)Thinner (serous membrane)
Pooled UCF-repair success94.6%94.3%[1]
Prior inguinal surgery limitationNoYes (may compromise pedicle)

Where Scrotal Flaps Fit in the Algorithm​

  1. Medium-sized UCF (2–4 mm) — scrotal dartos wrapping excellent (Muruganandham 90.5%)[7]
  2. Recurrent UCF — scrotal dartos or TVF both first-choice (94–95% each); scrotal dartos preferred when prior inguinal surgery precludes TVF[1][12]
  3. Prior orchidopexy / inguinal hernia repair — scrotal dartos preferred over TVF[2]
  4. Penoscrotal and proximal fistulas — ideal location; pedicle immediately adjacent[2][7]
  5. Complex urethral reconstruction — scrotal septum flaps (Gil-Vernet, Yachia) provide up to 20 cm for panurethral reconstruction[10][11]
  6. Hypospadias cripples — unscarred, well-vascularized coverage when all penile tissue is fibrotic[2][12]

Technical Pearls​

  • Use hairless scrotal skin when the tissue will contact the urethral lumen; for waterproofing layers (dartos interposition), hair is not a concern[14][15]
  • Preserve the penoscrotal pedicle — lifeline of the scrotal dartos flap. Avoid cautery or excessive traction[2]
  • Adequate flap dimensions — extend at least 5 mm beyond the urethral suture line in all directions
  • Offset all suture lines — urethral, dartos, and skin closures should not overlap[16]
  • Exclude distal obstruction before repair[16]
  • Wait ≥ 6 months after the last surgery to allow tissue maturation
  • Consider scrotal dartos over TVF in patients with prior inguinal surgery, undescended testis history, or when avoiding testicular manipulation is preferred[2]

Key Takeaways​

  • Highest pooled UCF-repair success of any waterproofing layer (94.6%) — marginally above TVF (94.3%).
  • No testicular complications — major advantage over TVF.
  • Four technique variants — Churchill scrotal dartos (most common), Lee de-epithelialized scrotal skin, Ahuja turnover dartos, scrotal septum variants (Sakai / Mokhless / Yachia / Gil-Vernet for complex urethroplasty).
  • Penoscrotal pedicle reaches the distal penile shaft without tension.
  • Preferred over TVF when prior inguinal surgery precludes the cremasteric pedicle.
  • Hairless tissue required only when used for urethral lining; not a concern for waterproofing.

References​

1. 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

2. Churchill BM, van Savage JG, Khoury AE, McLorie GA. "The dartos flap as an adjunct in preventing urethrocutaneous fistulas in repeat hypospadias surgery." J Urol. 1996;156(6):2047–2049.

3. Lee SE, Kim KM, Kim YK. "De-epithelialized scrotal flap in repair of urethrocutaneous fistula and hypospadias." Urology. 1990;36(2):160–163. doi:10.1016/0090-4295(90)80217-b

4. Sakai S, Soeda S, Yoshii S. "Scrotal septocutaneous island flap for the reconstruction of the urethral fistula." Ann Plast Surg. 1990;24(1):49–52. doi:10.1097/00000637-199001000-00009

5. Carrera A, Gil-Vernet A, Forcada P, et al. "Arteries of the scrotum: a microvascular study and its application to urethral reconstruction with scrotal flaps." BJU Int. 2009;103(6):820–824. doi:10.1111/j.1464-410X.2008.08167.x

6. Tsukuura R, Engmann T, Miyazaki T, Yamamoto T. "The sensate external pudendal artery perforator (EPAP) hemi-scrotal flap for the circumferential skin defect of the penile shaft: a case report and literature review." Microsurgery. 2025;45(7):e70123. doi:10.1002/micr.70123

7. Muruganandham K, Ansari MS, Dubey D, et al. "Urethrocutaneous fistula after hypospadias repair: outcome of three types of closure techniques." Pediatr Surg Int. 2010;26(3):305–308. doi:10.1007/s00383-009-2490-z

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. Mokhless I. "Modified vascularized pedicled scrotal flap for complex hypospadias." J Urol. 1992;148(1):55–57. doi:10.1016/s0022-5347(17)36507-2

10. Yachia D. "A new, one-stage pedicled scrotal skin graft urethroplasty." J Urol. 1986;136(3):589–592. doi:10.1016/s0022-5347(17)44982-2

11. Gil-Vernet J, Arango O, Gil-Vernet A, Gil-Vernet J, Gelabert-Mas A. "A new biaxial epilated scrotal flap for reconstructive urethral surgery." J Urol. 1997;158(2):412–420.

12. Shankar KR, Losty PD, Hopper M, Wong L, Rickwood AM. "Outcome of hypospadias fistula repair." BJU Int. 2002;89(1):103–105.

13. Ramez M, Hashem A, Bazeed M, Dawaba MS, Helmy TE. "Tunica vaginalis or dartos as second layer coverage for distal and mid-shaft penile hypospadias, quo vadis?" World J Urol. 2025;43(1):78. doi:10.1007/s00345-024-05419-x

14. Jordan GH. "Scrotal and perineal flaps for anterior urethral reconstruction." Urol Clin North Am. 2002;29(2):411–416. doi:10.1016/s0094-0143(02)00030-7

15. Provet JA, Surya BV, Grunberger I, Johanson KE, Brown J. "Scrotal island flap urethroplasty in the management of bulbar urethral strictures." J Urol. 1989;142(6):1455–1457. doi:10.1016/s0022-5347(17)39124-3

16. Landau EH, Gofrit ON, Meretyk S, et al. "Outcome analysis of tunica vaginalis flap for the correction of recurrent urethrocutaneous fistula in children." J Urol. 2003;170(4 Pt 2):1596–1599. doi:10.1097/01.ju.0000084661.05347.58

17. Mendel L, Neuville P, Allepot K, et al. "Bilateral pedicled scrotal flaps as an alternative to skin graft in penile shaft defects repair." Urology. 2023;176:206–212. doi:10.1016/j.urology.2023.03.025

18. Fahmy O, Khairul-Asri MG, Schwentner C, et al. "Algorithm for optimal urethral coverage in hypospadias and fistula repair: a systematic review." Eur Urol. 2016;70(2):293–298. doi:10.1016/j.eururo.2015.12.047