Flaps in Genitourinary Reconstruction
A flap is a unit of tissue transferred with its native blood supply preserved, distinguishing it from a graft which is transferred without one. Flaps are selected when the recipient site is inadequately vascularized for graft take, when bulk or structural support is required, or when the defect is too large or complex for simpler reconstruction.
This page is the index to the flap library — overview of classification, the geometric plasty techniques, the flap-by-flap navigation table, and the by-indication selection principles. Each flap has its own dedicated page with full anatomy, harvest technique, outcomes, and limitations; click the flap names in the table to go there.
Flap Classification Overview
Flaps are classified along several intersecting axes:
| Axis | Categories |
|---|---|
| Blood supply | Random (subdermal plexus, no named vessel) · Axial (named artery along flap axis) · Perforator (named perforating vessel through muscle/fascia) |
| Tissue composition | Cutaneous · Fasciocutaneous · Myocutaneous · Adipofascial · Omental |
| Movement | Advancement · Rotation · Transposition · Interpolation |
| Transfer method | Pedicled (continuous vascular connection) · Free (microvascular anastomosis at recipient site) |
In GU reconstruction, fasciocutaneous and myocutaneous flaps predominate. Most pedicled flaps used in perineal and pelvic reconstruction are axial, based on named vessels with reliable anatomy.
Geometric Plasty Techniques
Several reconstructive maneuvers rearrange local tissue through defined geometric patterns rather than moving tissue from a distant donor. These are part of the flap toolkit and appear repeatedly in GU reconstructive practice:
| Technique | Principle | Primary GU role |
|---|---|---|
| Y-V plasty | Y-shaped incision → V-shaped closure; advances triangular flap into contracted segment to lengthen perimeter | Refractory bladder neck contracture, VUAS after radical prostatectomy |
| V-Y advancement | V-shaped incision → Y-shaped closure; advances triangular flap to cover a defect | Buried penis / penile lengthening (suprapubic V-Y); vulvar reconstruction (pubolabial, medial thigh, gluteal V-Y); scrotal and perineal coverage; perineoplasty for lichen-sclerosus introital stenosis; episiotomy-dehiscence repair |
| Z-plasty | Two transposed triangular flaps; reorients scar by up to 90°, lengthens by 50–70%, and breaks linear contractures | Pediatric genital reconstruction (hypospadias / chordee / penoscrotal webbing / bifid scrotum); foreskin Z-plasty for phimosis; frenuloplasty; transverse vaginal septum (Garcia / Grünberger); iatrogenic vaginal constriction; posterior-fourchette dyspareunia (Plymouth Procedure) |
| Rhomboid (Limberg) flap | Rhombic transposition flap (60° / 120°); 1:1 length-to-width ratio; random vascularization; flap chosen along the line of maximal extensibility | Small posterior / commissure vulvar defects (bilateral Limberg); epispadias-exstrophy penile elongation; scrotal SCC / EMPD reconstruction |
| Bilobed flap | Double-transposition flap with two sequential lobes around a shared pivot (Zitelli 90–100° arc); distributes tension across two donors | Vulvoperineal defects spanning urogenital + anal triangles (bilobed PAP flap); deep pelvic / perineal defects after APR / exenteration / Fournier's (bilobed gracilis); perineal-body reconstruction after fourth-degree obstetric injury |
| Propeller flap | Island flap rotated 90–180° around a single perforator (Tokyo Consensus); freestyle design | Aesthetic penoscrotal resurfacing (IPAP gluteal-fold propeller); vulvar reconstruction (IPAP, gull-wing, lotus petal, perineal-perforator switch); extensive perineal defects after Fournier's / ELAPE / exenteration (PMTP, vPMT, DEPAP, SCIP, EPAP); perineal urethrostomy revision |
| Lotus petal flap | Gluteal-fold IPA-perforator fasciocutaneous flap (Yii-Niranjan 1996); landmark-based harvest, hidden donor scar, sensate, 0% reported total flap loss | Vulvar reconstruction after oncologic resection (Negosanti algorithm Type IA / IB); ELAPE pelvic-floor reconstruction with optional neovagina; posterior perineal cavity filling; scrotal reconstruction after Fournier's; presacral and IPAT perineal reconstruction in males |
Key insight: The Y-V plasty is frequently forgotten as a "flap" because the tissue doesn't travel — but it is the operation of choice for refractory bladder neck contracture and deserves the same attention as any distant-tissue flap.
Flap Index
Each flap below has a dedicated page with detailed anatomy, harvest technique, GU applications, outcomes, and limitations. The table is the navigation entry point — click through to the dedicated page for full detail.
| Flap | Type | Vascular Pedicle | Composition | Primary GU Applications |
|---|---|---|---|---|
| Pedicled penile/preputial skin | Pedicled; fasciocutaneous; axial | Dartos fascia (superficial external pudendal a.) | Skin + dartos fascia | Anterior urethroplasty, hypospadias, penile shaft coverage |
| Radial Forearm Free Flap (RFFF) | Free; fasciocutaneous | Radial artery + venae comitantes / cephalic v. | Thin skin + deep fascia (± LACN nerve) | Phalloplasty (tube-in-tube), neourethroplasty |
| Gracilis | Pedicled or free; myocutaneous | Medial circumflex femoral a. (branch of profunda femoris) | Gracilis muscle ± skin paddle | Perineal/vaginal reconstruction, neovagina, scrotal reconstruction, sphincter reinnervation |
| Anterolateral Thigh (ALT) | Free or pedicled; perforator/fasciocutaneous | Descending branch lateral circumflex femoral a. | Skin + fat ± fascia ± VL muscle | Large perineal/vaginal defects, phalloplasty (select centers), pelvic reconstruction |
| VRAM | Pedicled; myocutaneous | Inferior epigastric a. | Rectus abdominis muscle + vertical skin paddle | Pelvic floor, perineal/vaginal defects post-cystectomy/exenteration |
| Omental flap | Pedicled or free | Right or left gastroepiploic a. | Omentum (adipose + vascular) | BMG ureteroplasty, urethrovaginal fistula, pelvic dead space obliteration |
| Peritoneal flap | Pedicled | Peritoneal perforators | Peritoneum | Ureteral onlay/wrap, Mitrofanoff adjunct |
| Vastus lateralis | Pedicled or free; myocutaneous | Descending branch lateral circumflex femoral a. | Vastus lateralis muscle ± skin | Perineal/gluteal defects, pelvic dead space, failed gracilis territory |
| Superficial Circumflex Iliac Artery Perforator (SCIP) | Free or pedicled; perforator | Superficial circumflex iliac a. (branch of femoral a.) | Thin skin + subcutaneous fat ± fascia / iliac bone / lymph nodes (chimeric) | Urethral reconstruction in ALT phalloplasty (preferred pedicled adjunct); penile shaft; perineo-scrotal coverage after Fournier's; vulvar reconstruction; vesicocutaneous fistula; vascularized lymph node transfer |
| Blandy flap | Pedicled; fasciocutaneous | Dartos fascia (pudendal perforators) | Penile or scrotal skin + dartos | Perineal urethrostomy, anterior urethral reconstruction |
| Martius flap | Pedicled; adipofascial | Posterior labial a. (internal pudendal a.) or anterior labial a. | Labial fat pad (bulbocavernosus) | Urethrovaginal/vesicovaginal fistula repair, female urethral reconstruction |
| Labia majora fasciocutaneous | Pedicled; fasciocutaneous | Posterior or anterior labial a. | Full-thickness labial skin + fat + fascia | Complex VVF / UVF with vaginal-wall deficit; vaginal wall reconstruction |
| Medial thigh flap | Pedicled; fasciocutaneous | Upper medial thigh vascular plexus (obturator, external pudendal, medial circumflex femoral) | Skin + fat ± fascia | Fournier's gangrene coverage (most common regional flap); perineal/scrotal resurfacing |
| Singapore / pudendal thigh | Pedicled; fasciocutaneous | Posterior labial a. (internal pudendal a.) | Medial thigh skin + adductor fascia | Vaginal reconstruction (bilateral for neovagina); posterior perineum |
| PMTP propeller | Pedicled; perforator propeller (180° rotation) | Deep femoral a. perforator | Skin + fat (island) | Extensive perineal / perineoscrotal defects (256 cm² mean) |
| Bladder flap | Pedicled; full- or partial-thickness bladder wall | Superior / inferior / middle vesical aa. | Urothelium-lined bladder wall ± detrusor | Boari flap + psoas hitch for distal-and-mid ureteral defects (≤ 15 cm); spiral / laparoscopic variants for full-length defects (> 20 cm) without intestinal substitution; rotational bladder flap for complex / recurrent VVF (88–94%); bladder-wall flaps for female urethral / bladder-neck reconstruction (82% socially dry) |
| Y-V plasty | Local tissue rearrangement | Native bladder vasculature | Bladder wall (triangular advancement flap) | Refractory bladder neck contracture; VUAS after radical prostatectomy |
Flap Selection Principles by Indication
Urethral strictures (anterior urethra)
- Vascularization is paramount — all penile flaps depend on dartos vascularity[1]
- Onlay is superior to tubularized — penile circular fasciocutaneous flap: 13% recurrence (onlay) vs. 58% recurrence (tubularized) in the McAninch-Morey series[2]
- Failed urethroplasties and obliterative strictures — vascularized flaps preferred over grafts because the recipient bed is inadequate for graft take
- Preserve erectile function — IIEF-5 maintained at 23.5–23.9 in contemporary penile flap series[1]
Bladder neck contracture / VUAS
- ≥2 failed endoscopic treatments define the threshold for open or robotic Y-V plasty
- Robotic/laparoscopic approaches offer reduced invasiveness with similar success to open (90–100%)[3]
- Firefly (ICG) fluorescence is useful for localizing the contracture in the scarred post-prostatectomy field
- Novel transurethral endoscopic Y-V variant described with 89% first-pass success[4]
Vesicovaginal and urethrovaginal fistula
- Simple VVF: direct repair without flap interposition
- Complex / radiation-induced VVF: Martius flap interposition is standard; omental flap as alternative for transabdominal repairs
- VVF with vaginal wall deficit: labia majora fasciocutaneous flap — the flap provides both fistula interposition and vaginal wall tissue[5]
- Recurrent VVF after failed Martius: escalate to labia majora fasciocutaneous, gracilis myocutaneous, or peritoneal/omental adjunct
- Single-layer annular vaginal flap — modified transvaginal technique offering shorter operative time, less blood loss, and no cystostomy; 82.3% first-time success[6]
Perineal / genital coverage (Fournier's, extensive defects)
- Exposed vital structures (testes, urethra, vessels) require immediate flap coverage — delay risks desiccation and secondary infection
- Regional flaps overwhelmingly preferred — systematic review of Fournier's reconstruction shows overall flap loss of only 1.6%[7]
- Medial thigh flap is the most commonly used regional option — proximity, tissue match, redundant vascular plexus
- Singapore / pudendal thigh flap is the most common posterior-perineal / vaginal reconstruction option
- Perforator propeller flaps (PMTP, DEPAP, SCIP, EPAP) increasingly favored for extensive defects — large coverage without microvascular anastomosis
- VRAM / ALT reserved for defects too large or deep for regional coverage
- Primary indications for flap coverage (per Fournier's systematic review): exposed structures 52%, functional restoration 39%, cosmesis 4%[7]
Penile shaft coverage
- Modified bilateral scrotal flap ("butterfly" design) — restores penile skin length from bilateral scrotal donors[8]
- External Pudendal Artery Perforator (EPAP) hemi-scrotal flap — sensate, thin, pigmented coverage of circumferential penile shaft defects with wider rotation arc than conventional scrotal flaps[9]
- SCIP flap — thin free flap alternative with inguinal donor concealment
Vulvovaginal reconstruction (oncologic)
- Small defects: rhomboid (Limberg) flap or V-Y advancement
- Moderate defects: lotus petal or superficial external pudendal artery flaps based on distinct vascular territories
- Large defects / full vaginal reconstruction: bilateral Singapore / pudendal thigh flaps or VRAM or gracilis myocutaneous
- Compound perineal + vulvar defects: bilobed pudendal artery perforator flap preserves distinct tissue character of urogenital and anal triangles[10]
References
1. Joshi PM, Bandini M, Kulkarni SB. Common flaps in genitourinary reconstruction. Urol Clin North Am. 2022;49(3):361–369. doi:10.1016/j.ucl.2022.04.001
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. Granieri MA, Weinberg AC, Sun JY, Stifelman MD, Zhao LC. Robotic Y-V plasty for recalcitrant bladder neck contracture. Urology. 2018;117:163–165. doi:10.1016/j.urology.2018.04.017
4. Abramowitz DJ, Balzano FL, Ruel NH, Chan KG, Warner JN. Transurethral incision with transverse mucosal realignment for the management of bladder neck contracture and vesicourethral anastomotic stenosis. Urology. 2021;152:102–108. doi:10.1016/j.urology.2021.02.035
5. Gupta P, Kalra S, Dorairajan LN, et al. Labia majora fasciocutaneous flap reconstruction in complex urogynecological fistulas with vaginal deficit — a versatile approach. Urology. 2022;167:241–246. doi:10.1016/j.urology.2022.05.017
6. Tang M, Li P, Wang C, Zhang Q, Meng X. Clinical application of single-layer annular vaginal flap in transvaginal repair for vesicovaginal fistula. World J Urol. 2023;41(1):249–255. doi:10.1007/s00345-022-04222-w
7. Alammar A, Laing K, Somasundaram J, Wallace DL, Rogers AD. Flap reconstruction following Fournier's gangrene: a systematic review of techniques and outcomes. Burns. 2026;52(3):107888. doi:10.1016/j.burns.2026.107888
8. Yao H, Zheng D, Xie M, et al. A modified bilateral scrotal flap for penile skin defect repair. J Vis Exp. 2022;(189). doi:10.3791/64017
9. 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
10. Yun IS, Lee JH, Rah DK, Lee WJ. Perineal reconstruction using a bilobed pudendal artery perforator flap. Gynecol Oncol. 2010;118(3):313–6. doi:10.1016/j.ygyno.2010.05.007