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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​

Every classification axis below descends directly from the layered, tiered-perfusion anatomy of the skin — see the Skin anatomy page for the layers, vascular plexuses, and biomechanics that the terms here refer to. Flaps are classified along several intersecting axes:

AxisCategories
Blood supplyRandom (subdermal plexus, no named vessel) · Axial (named artery along flap axis) · Perforator (named perforating vessel through muscle/fascia)
Tissue compositionCutaneous · Fasciocutaneous · Myocutaneous · Adipofascial · Omental
MovementAdvancement · Rotation · Transposition · Interpolation
Transfer methodPedicled (continuous vascular connection) · Free (microvascular anastomosis at recipient site)

By vascular pattern, Nakajima's classification splits cutaneous flaps into five types — cutaneous, fasciocutaneous, adipofascial, septocutaneous, and musculocutaneous — with the fasciocutaneous group further divided into six subtypes by their input to the fascial plexus.[11] 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.

Vascular Basis of Flap Design — Angiosome and Perforasome​

Two anatomic models predict how far a flap can reach beyond its named vessel before it outruns its blood supply.

The angiosome concept (Taylor & Palmer, 1987) partitioned the body into roughly 43 three-dimensional vascular territories, each supplied by a source artery and its accompanying veins and spanning from skin to bone.[12] Its operative corollary, validated experimentally, is that the safe clinical territory of a single perforator reliably extends to include the anatomical territory of the next adjacent perforator in any direction.[12][13] In practice a flap can safely "capture" one adjacent vascular territory beyond its own angiosome — and no more without delay or a supercharging anastomosis.

The perforasome theory (Saint-Cyr, 2009) refined this to the territory of an individual perforator and added the rules that govern flap axis:[14]

  • Each perforasome links to its neighbors through direct linking vessels (true parallel anastomoses) and indirect linking vessels (connections through the subdermal plexus).
  • The vascular axis of a flap follows the axiality of the linking vessels — orient the flap along them.
  • Perforators near a joint direct flow away from the joint; mid-trunk perforators have multidirectional flow.
  • Both the subdermal plexus and the deep fascia contribute to flap perfusion.

Clinical translation: main source arteries are fairly constant, but individual cutaneous perforators are variable in size, distribution, and location, which is why perforator-flap design demands preoperative mapping (handheld Doppler, CT angiography, or ICG angiography) and a flexible operative plan that can shift to an adjacent perforator intraoperatively.[15] These principles underwrite the propeller and perforator flaps used in perineal and genital reconstruction (PMTP, SCIP, IGAP / IPAP, EPAP).

Random Pattern Flap Design Principles​

Many of the local genital and perineal flaps in this library — penile/preputial and scrotal transposition flaps, and the rhomboid (Limberg), bilobed, rotation, and advancement flaps used for vulvar and perineal defects — are random pattern flaps: they carry no named axial vessel and survive entirely on the subdermal plexus, with blood entering from the pedicle base and perfusion decreasing linearly from base to tip.[16][17] The dominant mechanism of distal necrosis is venous microvascular obstruction → progressive hypoxia → oxidative stress and apoptosis.[16] The following principles maximize survival.

Length-to-width ratio​

Traditional teaching limits random flaps to a length-to-width ratio of 1:1 to 2:1 on the trunk and limbs, while the face tolerates 3:1 or higher because of its exceptionally rich subdermal plexus.[17] Random flaps should generally not exceed their base width in length, and probably not exceed ~12.5 cm.[17] Laser speckle contrast imaging in humans confirms perfusion pressure falls linearly with increasing length-to-width ratio across advancement, rotation, and transposition designs.[18]

Geometry — the arbor principle​

A large area can survive on a narrow base with a short pedicle, but not on a long narrow pedicle: blood flows radially from the base in a tree-foliage ("arbor") pattern. Small random flaps should therefore be broadened immediately adjacent to a short, narrow base rather than drawn as long rectangles.[19]

Orientation to relaxed skin tension lines​

Place closure lines parallel to RSTLs wherever possible — parallel wounds need less force to close, retract less, and benefit more from undermining.[20] Flap advancement perpendicular to RSTLs minimizes stress within the flap; advancement parallel to RSTLs raises stress at the distal flap. Incisions along cosmetic-unit junctions give the best scar quality. (See the Skin biomechanics section.)

Undermining — technique and extent​

Undermining lowers closure tension up to a point of diminishing returns:

  • Undermining out to ~3× the defect diameter captures most of the available tension reduction; beyond that adds little.[21]
  • On the scalp, 5 cm of subgaleal undermining achieves an ~83% reduction in closing tension; extending to 15 cm reaches ~92% — statistically significant but a clinically modest further gain.[22]
  • Undermine in the subcutaneous plane (above the deep fascia for most sites) to keep the subdermal plexus with the flap.

Tension and blood flow​

There is an inverse relationship between closing tension and flap blood flow; experimentally, closure tension above ~250 g produces a significant increase in necrosis.[23] Design generously, and offload tension with Burow's triangles, back-cuts, or base extensions. For the A-to-T advancement flap, an evidence-based geometry uses a vertical height twice the defect height, base extensions of one defect diameter each way, and undermining to 3× the defect diameter.[21]

Preserve the subdermal plexus​

The subdermal plexus is the lifeline of a random flap:

  • Do not thin the flap — removing subcutaneous fat disrupts the subdermal network and cut survival from 95.5% to 64.9% in 5×10 cm experimental flaps.[24]
  • When de-epithelializing a buried flap, preserve the dermis intact — dermal excision reduces perfusion by ~25.9%.[25]
  • Keep the flap full-thickness and avoid cautery on its undersurface.

The delay phenomenon​

When a needed flap exceeds safe dimensions, a surgical delay — partially incising or elevating the flap 5–14 days before transfer — markedly improves survival.[26][27] Delay works through ischemia-driven VEGF upregulation with vasodilation then angiogenesis: VEGF peaks at ~3 days, perfusion improves significantly by ~day 5, and the optimal interval is ~5–7 days; flow reroutes parallel to the incision until ~day 14.[27][28] Delay can rescue flaps even under unfavorable geometry (narrow base, awkward transposition angle).[26] Microneedling preconditioning for 7–14 days has achieved comparable survival in experimental models as a potential non-surgical alternative.[29]

Pharmacologic adjuncts​

In the McFarlane rat dorsal random-flap model, the agents most consistently reducing distal necrosis are pentoxifylline, sildenafil, chlorpromazine, phenoxybenzamine, and phentolamine — acting through hemorheologic improvement, nitric-oxide-mediated vasodilation, or blockade of sympathetic vasoconstriction.[30] Clinical translation remains limited, and surgical delay stays the most reliable method when dimensions are unfavorable.

Summary​

PrincipleBest practiceRationale
Length-to-width≤1:1–2:1 trunk/limb; up to 3:1 facePerfusion drops linearly from base to tip[17][18]
ShapeBroaden adjacent to a short, narrow base (arbor)Radial flow from base; long narrow pedicles fail[19]
OrientationAlign closure with RSTLs / cosmetic-unit junctionsLess tension and retraction; better scars[20]
UnderminingUp to ~3× defect diameter, subcutaneous planeDiminishing returns beyond; preserves plexus[21][22]
TensionMinimize; avoid >250 g closing forceInverse with blood flow; drives necrosis[23]
ThicknessFull-thickness; do not thinThinning disrupts subdermal plexus[24]
De-epithelializationPreserve dermis when buryingDermal excision cuts perfusion ~26%[25]
Delay~5–7 day interval for unfavorable flapsVEGF-driven angiogenesis and vasodilation[26][27]

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:

TechniquePrinciplePrimary GU role
Y-V plastyY-shaped incision → V-shaped closure; advances triangular flap into contracted segment to lengthen perimeterRefractory bladder neck contracture, VUAS after radical prostatectomy
V-Y advancementV-shaped incision → Y-shaped closure; advances triangular flap to cover a defectBuried 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-plastyTwo transposed triangular flaps; reorients scar by up to 90°, lengthens by 50–70%, and breaks linear contracturesPediatric 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) flapRhombic transposition flap (60° / 120°); 1:1 length-to-width ratio; random vascularization; flap chosen along the line of maximal extensibilitySmall posterior / commissure vulvar defects (bilateral Limberg); epispadias-exstrophy penile elongation; scrotal SCC / EMPD reconstruction
Bilobed flapDouble-transposition flap with two sequential lobes around a shared pivot (Zitelli 90–100° arc); distributes tension across two donorsVulvoperineal 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 flapIsland flap rotated 90–180° around a single perforator (Tokyo Consensus); freestyle designAesthetic 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 flapGluteal-fold IPA-perforator fasciocutaneous flap (Yii-Niranjan 1996); landmark-based harvest, hidden donor scar, sensate, 0% reported total flap lossVulvar 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.

FlapTypeVascular PedicleCompositionPrimary GU Applications
Pedicled penile/preputial skinPedicled; fasciocutaneous; axialDartos fascia (superficial external pudendal a.)Skin + dartos fasciaAnterior urethroplasty, hypospadias, penile shaft coverage
Radial Forearm Free Flap (RFFF)Free; fasciocutaneousRadial artery + venae comitantes / cephalic v.Thin skin + deep fascia (± LACN nerve)Phalloplasty (tube-in-tube), neourethroplasty
GracilisPedicled or free; myocutaneousMedial circumflex femoral a. (branch of profunda femoris)Gracilis muscle ± skin paddlePerineal/vaginal reconstruction, neovagina, scrotal reconstruction, sphincter reinnervation
Anterolateral Thigh (ALT)Free or pedicled; perforator/fasciocutaneousDescending branch lateral circumflex femoral a.Skin + fat ± fascia ± VL muscleLarge perineal/vaginal defects, phalloplasty (select centers), pelvic reconstruction
VRAMPedicled; myocutaneousInferior epigastric a.Rectus abdominis muscle + vertical skin paddlePelvic floor, perineal/vaginal defects post-cystectomy/exenteration
Omental flapPedicled or freeRight or left gastroepiploic a.Omentum (adipose + vascular)BMG ureteroplasty, urethrovaginal fistula, pelvic dead space obliteration
Peritoneal flapPedicledPeritoneal perforatorsPeritoneumUreteral onlay/wrap, Mitrofanoff adjunct
Vastus lateralisPedicled or free; myocutaneousDescending branch lateral circumflex femoral a.Vastus lateralis muscle ± skinPerineal/gluteal defects, pelvic dead space, failed gracilis territory
Superficial Circumflex Iliac Artery Perforator (SCIP)Free or pedicled; perforatorSuperficial 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 flapPedicled; fasciocutaneousDartos fascia (pudendal perforators)Penile or scrotal skin + dartosPerineal urethrostomy, anterior urethral reconstruction
Martius flapPedicled; adipofascialPosterior labial a. (internal pudendal a.) or anterior labial a.Labial fat pad (bulbocavernosus)Urethrovaginal/vesicovaginal fistula repair, female urethral reconstruction
Labia majora fasciocutaneousPedicled; fasciocutaneousPosterior or anterior labial a.Full-thickness labial skin + fat + fasciaComplex VVF / UVF with vaginal-wall deficit; vaginal wall reconstruction
Medial thigh flapPedicled; fasciocutaneousUpper medial thigh vascular plexus (obturator, external pudendal, medial circumflex femoral)Skin + fat ± fasciaFournier's gangrene coverage (most common regional flap); perineal/scrotal resurfacing
Singapore / pudendal thighPedicled; fasciocutaneousPosterior labial a. (internal pudendal a.)Medial thigh skin + adductor fasciaVaginal reconstruction (bilateral for neovagina); posterior perineum
PMTP propellerPedicled; perforator propeller (180° rotation)Deep femoral a. perforatorSkin + fat (island)Extensive perineal / perineoscrotal defects (256 cm² mean)
Island groin flapPedicled; axial fasciocutaneousSuperficial circumflex iliac a. (named axial vessel)Skin + subcutaneous fat ± fasciaSingle-stage scrotal-defect coverage (Sahai 30-yr experience); paired with bilateral thigh flaps for total scrotal loss
MCFAPPedicled; perforator (muscle-sparing alternative to gracilis MC)Musculocutaneous perforators of medial circumflex femoral a.Skin + fat (gracilis preserved)Moderate scrotal defects after Fournier's where bulk is not required (Coskunfirat 2011)
IGAP / gluteal-foldPedicled; perforator / propeller (90–180° rotation)IGA / SGA perforators ± IGA descending branch ± PFA perforatorsSkin + fat ± fascia (gluteus preserved)Combined perineal / pelvic + scrotal coverage; aesthetic penoscrotal resurfacing (IPAP gluteal-fold propeller, Han 2018); posterior perineal defects
Posterior thigh flapPedicled; fasciocutaneousDescending IGA branch + PFA perforatorsPosterior-thigh skin + fat ± fasciaComplex pelvic / perineal reconstruction when laparotomy avoided; pre-existing dual diversion; salvage when VRAM / gracilis unavailable
EPAP hemi-scrotalPedicled; perforator; sensateExternal pudendal a. perforatorHemi-scrotal skin + dartosCircumferential penile-shaft resurfacing (Tsukuura 2025); hemi-scrotal reconstruction; native-quality sensate penile cover
Bladder flapPedicled; full- or partial-thickness bladder wallSuperior / inferior / middle vesical aa.Urothelium-lined bladder wall ± detrusorBoari 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 plastyLocal tissue rearrangementNative bladder vasculatureBladder 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

11. Nakajima H, Fujino T, Adachi S. A new concept of vascular supply to the skin and classification of skin flaps according to their vascularization. Ann Plast Surg. 1986;16(1):1–19. doi:10.1097/00000637-198601000-00001

12. Taylor GI, Corlett RJ, Dhar SC, Ashton MW. The anatomical (angiosome) and clinical territories of cutaneous perforating arteries: development of the concept and designing safe flaps. Plast Reconstr Surg. 2011;127(4):1447–1459. doi:10.1097/PRS.0b013e318208d21b

13. Morris SF, Taylor GI. Predicting the survival of experimental skin flaps with a knowledge of the vascular architecture. Plast Reconstr Surg. 1993;92(7):1352–61.

14. Saint-Cyr M, Wong C, Schaverien M, Mojallal A, Rohrich RJ. The perforasome theory: vascular anatomy and clinical implications. Plast Reconstr Surg. 2009;124(5):1529–1544. doi:10.1097/PRS.0b013e3181b98a6c

15. Morris SF, Tang M, Almutairi K, Geddes C, Yang D. The anatomic basis of perforator flaps. Clin Plast Surg. 2010;37(4):553–70, xi. doi:10.1016/j.cps.2010.06.006

16. Chen H, Chen B, Li B, et al. Gastrodin promotes the survival of random-pattern skin flaps via autophagy flux stimulation. Oxid Med Cell Longev. 2021;2021:6611668. doi:10.1155/2021/6611668

17. Stell PM. The viability of skin flaps. Ann R Coll Surg Engl. 1977;59(3):236–41.

18. Carvalho Brinca AM, de Castro Pinho A, Costa Vieira RJD. Blood perfusion of random skin flaps in humans — in vivo assessment by laser speckle contrast imaging. Dermatol Surg. 2021;47(11):1421–1426. doi:10.1097/DSS.0000000000003164

19. Wexler MR. An arbor flap: the tree-pattern flap, or how narrow may the base of a skin flap be? An experimental study. Plast Reconstr Surg. 1981;68(2):185–94.

20. McGuire MF. Studies of the excisional wound: I. Biomechanical effects of undermining and wound orientation on closing tension and work. Plast Reconstr Surg. 1980;66(3):419–27.

21. Stevens CR, Tan L, Kassir R, Calhoun K. Biomechanics of A-to-T flap design. Laryngoscope. 1999;109(1):113–7. doi:10.1097/00005537-199901000-00022

22. Raposio E, Nordström RE, Santi PL. Undermining of the scalp: quantitative effects. Plast Reconstr Surg. 1998;101(5):1218–22. doi:10.1097/00006534-199804050-00007

23. Larrabee WF, Holloway GA, Sutton D. Wound tension and blood flow in skin flaps. Ann Otol Rhinol Laryngol. 1984;93(2 Pt 1):112–5. doi:10.1177/000348948409300202

24. Yazar S, Guzel MZ, Aydin Y, Arslan H, Demir M. Demonstration of circulation haemodynamics in random pattern thinned skin flap (an experimental study). J Plast Reconstr Aesthet Surg. 2008;61(11):1368–77. doi:10.1016/j.bjps.2007.11.045

25. Laungani AT, Van Alphen N, Christner JA, et al. Three-dimensional CT angiography assessment of the impact of the dermis and the subdermal plexus in DIEP flap perfusion. J Plast Reconstr Aesthet Surg. 2015;68(4):525–30. doi:10.1016/j.bjps.2014.12.004

26. Ha JH, Lee SY, Choi TH, Park SO. Surgical delay increases the survival of expanded random-pattern flap in pediatric patients. Sci Rep. 2023;13(1):19204. doi:10.1038/s41598-023-45852-3

27. Holzbach T, Neshkova I, Vlaskou D, et al. Searching for the right timing of surgical delay: angiogenesis, vascular endothelial growth factor and perfusion changes in a skin-flap model. J Plast Reconstr Aesthet Surg. 2009;62(11):1534–42. doi:10.1016/j.bjps.2008.05.036

28. Jonsson K, Hunt TK, Brennan SS, Mathes SJ. Tissue oxygen measurements in delayed skin flaps: a reconsideration of the mechanisms of the delay phenomenon. Plast Reconstr Surg. 1988;82(2):328–36. doi:10.1097/00006534-198808000-00020

29. Unverdi OF, Coruh A. Effects of microneedle length and duration of preconditioning on random pattern skin flaps in rats. J Plast Reconstr Aesthet Surg. 2020;73(9):1758–1767. doi:10.1016/j.bjps.2020.03.022

30. Üstün GG, Öztürk S, Koçer U. Standardization of the rat dorsal random pattern (McFarlane) flap model and evaluation of the pharmacological agents aiming to salvage partial flap necrosis: a systematic review and a meta-analysis. Ann Plast Surg. 2021;87(6):e145–e152. doi:10.1097/SAP.0000000000002919