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McAninch Transverse Circular Penile Fasciocutaneous Flap

The McAninch transverse circular penile fasciocutaneous skin flap is a single-stage, pedicled flap technique for reconstruction of complex, long-segment anterior urethral strictures, first described by Jack W. McAninch at San Francisco General Hospital / UCSF in 1993. It uses Buck's fascia as the primary vascular pedicle and provides up to 15 cm of hairless tissue, making it one of the most versatile flaps in reconstructive urology. Long-term data from the UCSF series (124 patients, median 7.3 years follow-up) demonstrate stricture-free survival of 84% at 5 years and 79% at 10 years.[1][2][3]

For graft alternatives, see Dorsal Onlay OMG Urethroplasty and Ventral Onlay OMG Urethroplasty. For the underlying penile / preputial skin flap anatomy and other variants, see Pedicled Penile / Preputial Skin Flap. For graft material, see Buccal Mucosa Graft.

Historical Context and Evolution​

Predecessors

  • Orandi (1968) — first longitudinal ventral penile skin island flap based on the dartos fascia pedicle; established the principle of using pedicled penile skin for urethral reconstruction.
  • Quartey (1983) — introduced the transverse distal penile / preputial cutaneous island flap supplied by the superficial external pudendal vessels, demonstrating that a transversely oriented flap could reach from the meatus to the prostatic urethra.[6]
  • McAninch (1993) — refined and popularized the circular fasciocutaneous flap concept, using Buck's fascia (rather than dartos alone) as the major vascular conduit, providing a more robust and reliable blood supply.[1]

McAninch's innovation. The key insight was that the distal penile skin, when harvested circumferentially with its underlying Buck's fascia, creates a flap with:

  • Dual blood supply — both the dorsal penile artery branches within Buck's fascia and the subdermal plexus
  • Exceptional length — up to 15 cm, sufficient to reconstruct the entire anterior urethra from meatus to membranous urethra
  • Hairless tissue — distal penile skin is naturally hairless, avoiding intraurethral hair growth complications
  • Versatility — can be used as onlay (augmentation) or tubularized (substitution), and combined with other tissue transfer techniques[1][4]

Anatomy and Vascular Basis​

Penile vascular anatomy relevant to the flap. Buck's fascia is the deep fascial layer of the penis, lying between the dartos fascia (superficial) and the tunica albuginea (deep). Within Buck's fascia run the dorsal arteries of the penis (paired), the deep dorsal vein, and the dorsal nerves — collectively forming the dorsal neurovascular bundle. The circumflex arteries branch from the dorsal arteries and course circumferentially around the corpora within Buck's fascia, providing blood supply to the ventral and lateral penile skin.

Flap blood supply. The circular fasciocutaneous flap derives its blood supply from Buck's fascia, which serves as the vascular pedicle. The flap is based on retrograde flow through the circumflex branches of the dorsal penile arteries. When the flap is raised from the distal penis and rotated proximally, the intact Buck's fascia pedicle maintains perfusion through these vessels.[1][4]

This is fundamentally different from the Orandi flap, which relies on dartos fascia as its pedicle. Buck's fascia provides a more robust, well-defined vascular conduit, which is why the McAninch flap can achieve greater length and reliability.

Surgical Technique​

The technique as described by McAninch and Carney.[1][2][4]

Patient positioning​

  • Lithotomy position (exaggerated lithotomy for bulbar access)
  • Limit time in exaggerated lithotomy to prevent neurovascular lower-extremity complications (4 cases in the original 66-patient series).[2]

Urethral exposure​

  • A perineal incision for bulbar access, and / or a penile degloving incision for penile urethral access
  • The strictured urethra is identified and opened longitudinally (ventral or dorsal urethrotomy)
  • Stricture length and extent of spongiofibrosis assessed

Flap design and harvest​

  • The flap is designed on the distal penile shaft, oriented transversely (circumferentially) around the penis
  • Uncircumcised patients — inner preputial skin provides ample hairless tissue
  • Circumcised patients — remaining distal penile shaft skin is used; the flap can still be raised though available tissue may be somewhat less[1][8][17]
  • Skin island typically 2–3 cm wide, extending circumferentially around the penis (up to 15 cm length when full circumference is utilized)
  • Dissection proceeds deep to the skin but superficial to Buck's fascia, preserving Buck's fascia as the pedicle
  • The flap is raised as a fasciocutaneous unit — skin + subcutaneous tissue + Buck's fascia

Pedicle development​

  • The Buck's fascia pedicle is dissected off the underlying tunica albuginea, maintaining the vascular connections within the fascia
  • Pedicle developed proximally for sufficient length to reach the strictured segment
  • Pedicle must be wide enough for adequate blood supply but narrow enough to allow rotation without kinking

Flap transfer and configuration​

ConfigurationIndicationNotes
Ventral onlay (most common)Augmentation of a strictured urethra with intact dorsal plateFlap rotated and laid over the ventral urethrotomy as an onlay; sutured with absorbable sutures (5-0 / 6-0 PDS / Vicryl)
Dorsal onlayStrictures where dorsal mobilization is feasibleUrethra mobilized circumferentially; flap placed dorsally against the corpora; urethra rotated back over the flap. May reduce sacculation risk vs ventral.[7]
Tubularized substitutionObliterative strictures with no remaining urethral plateFlap tubularized around a catheter to create a neo-urethra. Significantly higher failure rates (58% recurrence) vs onlay (13%).[2]
Combined with graftsVery long strictures (>15 cm)Flap combined with free grafts (BMG, penile skin graft) to bridge the entire defect in a single stage.[1][14][18]

Closure​

  • Penile skin closed over the flap pedicle
  • Urethral catheter (16–18 Fr) placed
  • Suprapubic catheter may be placed for diversion
  • Drains as needed

Postoperative care​

  • Catheter removal at 2–3 weeks after VCUG confirms no extravasation
  • Follow-up with uroflowmetry, RUG, and / or cystoscopy

Clinical Outcomes — UCSF / SFGH Series​

StudynMean stricture lengthConfigurationPrimary successLong-term successFollow-upKey Findings
McAninch 1993 (original)[1]108–21 cm9 onlay, 1 tubularized100%100%14.4 moMean Qmax 21.7 mL/s; all normal erectile function; 2 combined with supplemental grafts for 18 and 21 cm strictures
McAninch / Morey 1998 (expanded)[2]669.08 cm54 onlay, 12 tubularized79% overall (87% onlay, 42% tubularized)95% including secondary procedures41 mo (1–7 yr)Onlay significantly better than tubularized (p < 0.05); 4 neurovascular extremity complications from prolonged lithotomy
Whitson 2008 (long-term)[3]124median 8.2 cmonlay (majority)95% at 1 yr; 89% at 3 yr; 84% at 5 yr; 79% at 10 yr—median 7.3 yr (range 1 mo–19.5 yr)Predictors of failure: smoking (HR 4.0), hypospadias history (HR 4.4), stricture 7–10 cm (HR 7.0); excluded LS patients

Key observations​

  • Onlay is superior to tubularization — McAninch / Morey 1998 demonstrated 87% onlay vs 42% tubularized. Replicated across all flap urethroplasty literature; now a fundamental principle of reconstructive urology.[2]
  • Long-term durability — Whitson 2008 remains the longest follow-up series for any penile skin flap technique, with median 7.3 yr and maximum 19.5 yr. 79% stricture-free at 10 yr demonstrates good long-term durability with gradual decline over time.[3]
  • Independent multivariate predictors of failure:[3]
    • Smoking (HR 4.0, 95% CI 1.2–12.9, p = 0.02)
    • History of hypospadias repair (HR 4.4, 95% CI 1.3–14.6, p = 0.01)
    • Stricture length 7–10 cm (HR 7.0, 95% CI 1.4–34.7, p = 0.02)
  • Secondary procedures salvage most failures — most recurrences in McAninch / Morey 1998 were managed with a single subsequent procedure (repeat urethroplasty in 5, optical urethrotomy / dilation in 6), bringing overall long-term success to 95%.[2]

Modified circular flap (Zhao 2026)​

A recent modification splits the circular fasciocutaneous flap longitudinally on the dorsal side of the penis and transfers it to the ventral side, rather than rotating the intact circular flap.[8]

In 54 patients at 15-month mean follow-up:

  • 0% stricture recurrence (54/54)
  • 0% penile skin necrosis or fistula
  • 24.1% post-micturition dribbling
  • 14.8% mild penile torsion
  • Successfully performed in 6 circumcised patients without skin shortage

Promising but requires longer follow-up.

Complications​

ComplicationIncidenceNotes
Stricture recurrence (onlay)13% (UCSF 1998); 16–21% at 10 yr (UCSF 2008)Most manageable with single secondary procedure[2][3]
Stricture recurrence (tubularized)58% (UCSF 1998)Significantly worse than onlay; avoid when possible[2]
Postvoid dribbling24–34%Sacculation / pseudodiverticulum at the flap site; more common with ventral onlay[9][10]
Superficial penile skin necrosis6–21% (flap arms in RCTs)Usually managed conservatively; 1 case required skin grafting[9][10]
Penile torsion7–15% (mild, < 30°)Asymmetric skin closure after flap harvest[8][9]
Urethrocutaneous fistula0–5%Usually distal anastomosis[10][11]
Neurovascular extremity complications6% (4/66 in UCSF 1998)Prolonged exaggerated lithotomy; prevented by limiting positioning time[2]
Erectile dysfunctionRare (0% in original series)Preserved in all UCSF patients; IIEF unchanged in modified technique[3][8]
Penile shortening / cosmetic deformityRareMore concern in circumcised patients with limited remaining skin[8][17]

Comparison with Buccal Mucosal Graft Urethroplasty​

Three RCTs and one comparative trial define the contemporary BMG-vs-flap evidence base.

StudynDesignSuccess: Flap vs BMGOR TimeKey Differences
Dubey 2007 RCT[9]55Dorsal onlay PSF (28) vs dorsal onlay BMG (27)85.6% vs 89.9% (p > 0.05, NS)224 vs 162 min (p = 0.001)Flap: more skin necrosis (25%), penile torsion (7%), postvoid dribbling (34% vs 15%, p = 0.001); BMG: 89% vs 65% would recommend (p = 0.001)
Tyagi 2022 PeeBuSt RCT[13]100PSG (50) vs BMG (50)89% vs 91% (p = 0.70, NS)—No difference in IIEF, MSHQ-EJD, IPSS, USS-PROM, or Qmax; comparable Clavien I complications (12.7% vs 16.7%)
Alrefaey 2025 RCT[12]98PSG (44) vs BMG (48)93.2% vs 97.9% (p = 0.346, NS)—No difference in any functional parameter; comparable satisfaction (90.9% vs 93.8%); Kaplan-Meier HR 1.19 (p = 0.275)
Hussein 2011 RCT[10]37Circular skin graft (18) vs circular skin flap (19)72.3% vs 79% (p = 0.249, NS)203 vs 282 min (p = 0.000)Graft: shorter OR; Flap: 3 cases skin necrosis, 1 fistula; similar postvoid dribbling

Summary of flap vs BMG evidence​

  • Success rates are comparable between penile skin flap and BMG urethroplasty across all RCTs (no statistically significant difference in any trial).[9][12][13]
  • BMG is technically simpler — shorter operative time, less technically demanding dissection.[9][10]
  • BMG has lower morbidity — less penile skin necrosis, less penile torsion, less postvoid dribbling.[9]
  • BMG is preferred by patients — 89% vs 65% would recommend the procedure (p = 0.001).[9]
  • The flap's unique advantage — it carries its own blood supply (pedicled), making it suitable for scarred, poorly vascularized urethral beds where a free graft might not take.[4]

The AUA Urethral Stricture Disease Guideline (2023) states that success rates of single-stage urethroplasty using penile fasciocutaneous flaps and oral mucosal grafts appear similar regardless of technique used, and recommends that surgeons may reconstruct long multi-segment strictures with one-stage or multi-stage techniques using oral mucosal grafts, penile fasciocutaneous flaps, or a combination (Moderate Recommendation; Grade C).[20]

Indications and Patient Selection​

Ideal indications[1][2][3]​

  1. Long, complex anterior urethral strictures (>5 cm, especially 8–15 cm) — the flap's greatest advantage is its length.
  2. Panurethral strictures — can reach from the meatus to the membranous urethra.
  3. Strictures with a compromised urethral bed — where spongiofibrosis is severe and a free graft may not take due to poor vascularity.
  4. Failed prior urethroplasty — well-vascularized flap can overcome the scarred, poorly vascularized tissue bed that contributed to prior graft failure.
  5. Patients with limited oral mucosa — when BMG donor sites are depleted or when oral pathology (e.g., submucous fibrosis) precludes BMG harvest.
  6. Combined with BMG — for very long strictures, the flap can be combined with BMG to achieve single-stage reconstruction of the entire anterior urethra.[14][18]

Contraindications / limitations​

  • Lichen sclerosus — genital skin (including penile skin) is susceptible to LS and should not be used in patients with LS-related strictures. Oral mucosa is the preferred substitute.[15][16][20]
  • Unhealthy penile skin — prior radiation, extensive scarring, or dermatologic conditions affecting the penile skin preclude flap use.
  • Insufficient penile skin — severely circumcised patients with very limited remaining penile skin may not have adequate tissue, though the technique can be performed in circumcised men with sufficient remaining skin.[1][8][17]
  • Hair-bearing skin — the AUA guideline states that surgeons should not use hair-bearing skin for substitution urethroplasty (Clinical Principle). The distal penile skin used in the McAninch flap is hairless, but care must be taken not to incorporate proximal hair-bearing penile shaft skin.[20]

Comparison of Penile Skin Flap Configurations​

Flap TypeOrientationPedicleMax LengthKey Feature
McAninch circular fasciocutaneous[1][2]Transverse / circumferentialBuck's fascia15 cmLongest reach; most versatile; gold standard flap
Orandi longitudinal[5]Longitudinal (ventral)Dartos fascia6–8 cmSimpler; shorter reach; good for penile strictures
Quartey transverse preputial island[6]TransverseSuperficial external pudendal vessels12–15 cmRequires intact prepuce; similar reach to McAninch
Circumpenile (Srivastava)[17]Circumferential (shaft skin)Dartos fasciavariableFor circumcised patients; uses remaining shaft skin
Modified circular (Zhao 2026)[8]Circular, dorsally splitBuck's fasciasimilar to McAninchDorsal split avoids rotation; 0% recurrence at 15 mo

Combination Techniques — Flap + Graft​

For the most complex strictures — particularly long penile strictures with a damaged urethral plate — combining a dorsal BMG with a ventral penile skin flap has emerged as a powerful single-stage alternative to staged urethroplasty.[14][18]

Karapanos 2024 described a technique preserving the native urethral plate and corpus spongiosum, combining a dorsal onlay BMG quilted to the corpora cavernosa with a longitudinal ventral penile skin flap (Orandi-type), achieving 91.7% success at 38 months in 12 patients with narrow penile strictures (median 5 cm). The preserved corpus spongiosum was wrapped around the flap ventrally for reinforcement. No sacculation or diverticula formed, though 41.7% reported postvoid dribbling.[18]

The AUA guideline explicitly endorses this combined approach: surgeons may reconstruct long multi-segment strictures with oral mucosal grafts, penile fasciocutaneous flaps, or a combination of these techniques (Moderate Recommendation; Grade C).[20]

Preputial Spiral Graft — A Modern Alternative​

The preputial spiral graft urethroplasty (PSGU) described by Bandini, Joshi, Kulkarni 2025 for panurethral strictures uses the prepuce as a free graft (not a flap) harvested in a spiral configuration to maximize length, achieving 90.4% success at 16 months in 114 patients with median stricture length 16 cm. Limitations include the requirement for an intact prepuce and absence of active lichen sclerosus.[19]

Key Takeaways​

The McAninch transverse circular penile fasciocutaneous flap remains one of the most important techniques in the reconstructive urologist's armamentarium for complex, long-segment anterior urethral strictures. Its key strengths are exceptional length (up to 15 cm), reliable Buck's fascia-based blood supply, versatility (onlay, tubularized, or combined with grafts), and proven long-term durability (79% at 10 yr).[1][2][3] While BMG urethroplasty has become the first-line substitution material for most strictures due to its technical simplicity and lower morbidity, the circular flap retains a critical role in scenarios where a pedicled, well-vascularized tissue transfer is needed — long strictures, scarred urethral beds, failed prior grafts, and patients with depleted oral mucosa donor sites.[2][3][9] The technique is contraindicated in lichen sclerosus, where oral mucosa should be used instead.[15][20]

Videos​

McAninch Fasciocutaneous Penile Flap for Urethral Stricture
Dr Venkatanaidu V (2023)

References​

  1. McAninch JW. Reconstruction of extensive urethral strictures: circular fasciocutaneous penile flap. J Urol. 1993;149(3):488-91. doi:10.1016/s0022-5347(17)36125-6.
  2. McAninch JW, Morey AF. Penile circular fasciocutaneous skin flap in 1-stage reconstruction of complex anterior urethral strictures. J Urol. 1998;159(4):1209-13.
  3. Whitson JM, McAninch JW, Elliott SP, Alsikafi NF. Long-term efficacy of distal penile circular fasciocutaneous flaps for single stage reconstruction of complex anterior urethral stricture disease. J Urol. 2008;179(6):2259-64. doi:10.1016/j.juro.2008.01.087.
  4. Carney KJ, McAninch JW. Penile circular fasciocutaneous flaps to reconstruct complex anterior urethral strictures. Urol Clin North Am. 2002;29(2):397-409. doi:10.1016/s0094-0143(02)00046-0.
  5. Barbagli G, Joshi PM, Kulkarni SB, et al. Penile urethroplasty using Orandi's dorsal skin flap: a new technique. BJU Int. 2019;124(5):892-896. doi:10.1111/bju.14881.
  6. Quartey JK. One-stage penile / preputial cutaneous island flap urethroplasty for urethral stricture: a preliminary report. J Urol. 1983;129(2):284-7. doi:10.1016/s0022-5347(17)52051-0.
  7. Bhandari M, Dubey D, Verma BS. Dorsal or ventral placement of the preputial / penile skin onlay flap for anterior urethral strictures: does it make a difference? BJU Int. 2001;88(1):39-43. doi:10.1046/j.1464-410x.2001.02257.x.
  8. Zhao T, Ji F, Liu Y, Wang L, Lyu X. Preliminary experience and outcomes of modified distal penile circular fasciocutaneous flap for the treatment of anterior urethral strictures. World J Urol. 2026;44(1):191. doi:10.1007/s00345-026-06289-1.
  9. Dubey D, Vijjan V, Kapoor R, et al. Dorsal onlay buccal mucosa versus penile skin flap urethroplasty for anterior urethral strictures: results from a randomized prospective trial. J Urol. 2007;178(6):2466-9. doi:10.1016/j.juro.2007.08.010.
  10. Hussein MM, Moursy E, Gamal W, et al. The use of penile skin graft versus penile skin flap in the repair of long bulbo-penile urethral stricture: a prospective randomized study. Urology. 2011;77(5):1232-7. doi:10.1016/j.urology.2010.08.064.
  11. Tijani KH, Adesanya AA, Ogo CN, Osegbe DN. Penile fasciocutaneous flap urethroplasty: recent experience and challenges in a sub-Saharan African teaching hospital. Urology. 2009;74(4):920-3. doi:10.1016/j.urology.2009.05.041.
  12. Alrefaey A, Anwar MA, Abdelmagid ME, et al. Comparative outcomes of penile skin grafts versus buccal mucosal grafts in urethroplasty for the treatment of extensive anterior urethral strictures. Sci Rep. 2025;15(1):29508. doi:10.1038/s41598-025-14191-w.
  13. Tyagi S, Parmar KM, Singh SK, et al. 'Pee'BuSt trial: a single-centre prospective randomized study comparing functional and anatomic outcomes after augmentation urethroplasty with penile skin graft versus buccal mucosa graft for anterior urethral stricture disease. World J Urol. 2022;40(2):475-481. doi:10.1007/s00345-021-03843-x.
  14. Anadani A, Obaidin A, Badawi B, Lutfi MY. One-stage urethroplasty using a combination of buccal mucosa graft and penile skin flap for a complicated urethral stricture: a challenging case report. Medicine. 2025;104(12):e41888. doi:10.1097/MD.0000000000041888.
  15. Stewart L, McCammon K, Metro M, Virasoro R. SIU/ICUD consultation on urethral strictures: anterior urethra — lichen sclerosus. Urology. 2014;83(3 Suppl):S27-30. doi:10.1016/j.urology.2013.09.013.
  16. Kulkarni S, Barbagli G, Kirpekar D, Mirri F, Lazzeri M. Lichen sclerosus of the male genitalia and urethra: surgical options and results in a multicenter international experience with 215 patients. Eur Urol. 2009;55(4):945-54. doi:10.1016/j.eururo.2008.07.046.
  17. Srivastava A, Vashishtha S, Singh UP, et al. Preputial / penile skin flap, as a dorsal onlay or tubularized flap: a versatile substitute for complex anterior urethral stricture. BJU Int. 2012;110(11 Pt C):E1101-8. doi:10.1111/j.1464-410X.2012.11296.x.
  18. Karapanos L, Halbe L, Storz E, et al. Preservation of the native urethral plate and corpus spongiosum combined with buccal mucosa graft plus Orandi's penile skin flap as an alternative to staged urethroplasty for narrow penile strictures. Int J Urol. 2024;31(10):1095-1101. doi:10.1111/iju.15521.
  19. Bandini M, Joshi P, Bafna S, et al. Establishing the role of single-stage preputial spiral graft urethroplasty for panurethral stricture. BJU Int. 2025. doi:10.1111/bju.16796.
  20. Wessells H, Morey A, Souter L, Rahimi L, Vanni A. Urethral stricture disease guideline amendment (2023). J Urol. 2023;210(1):64-71. doi:10.1097/JU.0000000000003482.