Radial Forearm Free Flap Phalloplasty
Radial forearm free flap (RFFF) phalloplasty is the benchmark microsurgical flap for total phallic construction in masculinizing genital gender-affirming surgery. It offers thin pliable tissue, reliable radial-artery vascular anatomy, tube-in-tube urethral construction, and strong potential for tactile and erogenous reinnervation, but it also carries high urethral complication rates and a conspicuous forearm donor-site scar.[1][2][3][4]
This is the atlas page for gender-affirming RFFF phalloplasty. For the cross-application donor-flap anatomy and non-GAS salvage uses, see Radial Forearm Free Flap. For cohort-level pathway selection, see Masculinizing Gender-Affirming Surgery.
Indications
RFFF phalloplasty is best suited for patients who prioritize phallic size, penetrative potential with a delayed prosthesis, sensory reinnervation, and standing micturition, and who accept microsurgical staging plus a visible forearm donor site.[2][3][5]
| Patient Priority | Fit for RFFF Phalloplasty |
|---|---|
| Penetrative intercourse | Strong fit after delayed erectile prosthesis |
| Standing micturition | Strong fit if urethral lengthening is included |
| Tactile / erogenous sensation | Strong fit; multiple forearm sensory nerves are available for coaptation |
| Thin, aesthetic shaft | Strong fit; forearm skin is thin and pliable |
| Avoiding visible donor-site scar | Poor fit; the forearm scar is the defining disadvantage |
| Avoiding urethral morbidity | Poor fit if tube-in-tube UL is performed |
| Avoiding microsurgery | Poor fit; choose pedicled ALT or abdominal options if microsurgery is not available |
Contraindications and Caution Zones
The key preoperative questions are whether the hand can tolerate radial-artery sacrifice, whether the forearm skin is suitable for a urethral tube, and whether the patient accepts the tradeoff between aesthetics / sensation and urethral morbidity.
| Scenario | Counseling Point |
|---|---|
| Abnormal ulnar collateral circulation | Avoid radial-artery harvest or obtain vascular imaging; Doppler Allen testing is more objective than clinical Allen testing[6][7] |
| Dense forearm hair in urethral segment | Preoperative laser / electrolysis is needed to avoid intraurethral hair, stones, infection, and obstructive symptoms |
| Active smoking / nicotine use | Stop before microsurgical phalloplasty; smoking is a risk factor for wound and flap complications[8] |
| High BMI / thick forearm adiposity | Adjust flap width and counsel about shaft bulk / debulking |
| Forearm-scar intolerance | Consider pedicled ALT, abdominal, or other flap pathways |
| Standing micturition not desired | Consider shaft-only phalloplasty without UL to reduce urethral complication burden |
Historical Context
Chang and Hwang introduced the radial-forearm tube-in-tube phalloplasty concept in 1984, and Gottlieb and Levine later modified the design to improve glans / meatal configuration and vascular reliability.[2][9] Contemporary practice still revolves around these design families, with refinements in venous drainage, nerve coaptation, urethral staging, glansplasty, donor-site closure, and prosthesis anchoring.
Preoperative Planning
| Planning Domain | Practical Point |
|---|---|
| Readiness criteria | Follow WPATH SOC8 and local multidisciplinary GAS criteria; many centers require at least 12 months of testosterone before genital surgery[10][11] |
| Vascular assessment | Perform Allen assessment; Doppler Allen testing better approximates intraoperative findings than bedside clinical testing in many series[6][7] |
| Hair removal | Clear hair from the planned urethral strip before transfer |
| Urethral plan | Decide tube-in-tube, prelaminated urethra, staged urethral lengthening, or no UL |
| Vaginectomy / pars fixa | Coordinate gynecology and reconstructive urology for hysterectomy / BSO, vaginectomy, and fixed urethral lengthening when planned |
| Donor-site closure | Plan full-thickness graft, split-thickness graft with dermal matrix, or free groin flap coverage based on local expertise[12][13] |
| Prosthesis expectations | Penetrative function usually requires delayed erectile prosthesis, with higher revision risk than anatomic-penis implantation[14][15] |
Technique
Flap Design
The classic RFFF phalloplasty uses a tube-in-tube design: the inner skin tube forms the phallic urethra and the outer skin tube forms the shaft. The flap is usually harvested from the non-dominant forearm and includes radial artery, venae comitantes, superficial veins, and sensory nerves.[2][16]
| Component | Operative Role |
|---|---|
| Radial artery | Primary arterial pedicle |
| Venae comitantes | Deep venous drainage |
| Cephalic / basilic system | Superficial venous outflow; using at least two veins reduces vascular risk[17] |
| Lateral antebrachial cutaneous nerve | Commonly coapted for tactile / protective sensation |
| Medial antebrachial cutaneous nerve | Commonly coapted to dorsal clitoral nerve for erogenous sensation |
| Posterior antebrachial cutaneous nerve | Additional / alternative shaft-sensation target in contemporary nerve planning[18] |
Chang-Hwang Versus Gottlieb-Levine
| Feature | Chang-Hwang | Gottlieb-Levine |
|---|---|---|
| Urethral / shaft relationship | De-epithelialized strip separates urethral and shaft skin | Urethral tube positioned at ulnar edge / modified neoglans continuity |
| Urethral complications | Lower in a comparative 45-patient series | Higher in that series |
| Partial flap necrosis | Higher | Lower |
| Practical interpretation | Urethral advantage | Vascular / necrosis advantage |
Spennato et al. found Chang-Hwang design associated with fewer urologic complications, while Gottlieb-Levine had significantly lower partial flap necrosis. This is a design tradeoff rather than a universal winner.[19]
Recipient-Site Reconstruction
| Step | Technical Goal |
|---|---|
| Pars fixa urethra | Connect native urethra to phallus base using anterior vaginal-wall / labial tissue, BMG, or staged approaches depending on center practice |
| Flap transfer | Tunnel / inset the neophallus and connect the phallic urethra to the fixed urethra |
| Arterial anastomosis | Radial artery to common femoral, inferior epigastric, or local recipient artery depending on approach |
| Venous anastomoses | Superficial and deep venous outflow to saphenous / femoral branches; dual drainage is protective |
| Nerve coaptation | Coapt forearm cutaneous nerves to dorsal clitoral nerve and ilioinguinal or other recipient sensory nerves |
| Clitoral management | Usually buried at the phallus base for erogenous stimulation |
| Scrotoplasty | Labia majora flaps create the neoscrotum; implants are usually delayed |
| Donor-site closure | Resurface forearm and immobilize / protect graft site |
Perfusion Modifications
ICG angiography and additional arterial inflow can be used when marginal perfusion is detected. De Wolf et al. described a bipedicled radial forearm / posterior interosseous artery perforator approach for perfusion support in selected phalloplasty flaps.[20]
Staging
RFFF phalloplasty is usually staged. Exact sequencing varies by center and by whether urethral lengthening is planned.
| Stage | Operation | Timing / Notes |
|---|---|---|
| Preliminary stage | Hysterectomy / BSO, vaginectomy, pars fixa urethral lengthening, or neourethral prelamination | Often 3-6 months before main phalloplasty when staged UL is used[21] |
| Main phalloplasty | RFFF harvest, tube-in-tube construction, microsurgical transfer, urethral anastomosis, clitoral burial, scrotoplasty | Multidisciplinary plastic surgery + reconstructive urology operation |
| Refinement stage | Glansplasty / coronoplasty, debulking, urethral revisions, scrotal refinements | Performed after flap maturation and wound stabilization |
| Prosthetic stage | Testicular implants and erectile prosthesis | Typically delayed at least 9-12 months after phalloplasty, after reliable voiding and flap vascularity are confirmed[14] |
Outcomes
Flap Survival
Flap survival is the most reliable part of RFFF phalloplasty. Large series and reviews generally report total flap loss in the low single digits, while partial necrosis and wound problems remain more common.[1][17]
| Study / Review | N | Key Flap Finding |
|---|---|---|
| Monstrey 2009 | 287 | RFFF remained the standard technique because of reliability, aesthetics, and sensation despite urethral morbidity[1] |
| Falcone 2020 single-center + SR | 25 local cases | Total flap loss uncommon; fewer than two venous outflow channels predicted vascular complications[17] |
| Netshiongolwe 2025 SR | 769 total; 614 RFFF | RFFF flap failure 1.9%; pedicled ALT 0.6%; satisfaction similar, RFFF still framed as most reliable when feasible[3] |
Urethral Complications
Urethral fistula and stricture are the dominant morbidity and the main driver of revisions. The rates vary because studies mix flap designs, urethral staging, prior vaginectomy, smoking status, follow-up duration, and definitions of complication.[22][23][24]
| Study / Review | N | Urethral Signal |
|---|---|---|
| Hu 2022 meta-analysis | 1,566 transgender men | Pooled fistula / stenosis complication burden about half of patients across phalloplasty techniques[22] |
| Veerman 2020 | 27 RFFF subset | High revision burden after UL; strictures and fistulas can present after early recovery[23] |
| Paganelli 2023 | 89 | Free-flap phallic urethra had high long-term urethral complication burden[24] |
| Wang 2026 | 25 RFFF subset | RFFF had higher overall and urologic complications than pedicled abdominal and ALT flaps in that series[25] |
Standing micturition is achievable for most patients after successful construction and revision, but patients should be counseled that "standing voiding" often requires staged correction of fistula, stricture, spraying, dribbling, or meatal problems.
Sensation and Sexual Function
Nerve coaptation is one of the major reasons RFFF remains favored. Innervated RFFF neophalli recover tactile and erogenous sensation more reliably than non-innervated reconstructions, though measurement methods vary.[26][27][28]
| Outcome Domain | Evidence Signal |
|---|---|
| Tactile sensation | Multimodal testing shows recovery of multiple sensory modalities in many patients after innervated RFFF[27] |
| Erogenous sensation | Coaptation to dorsal clitoral nerve supports erogenous sensation and orgasmic function |
| Posterior antebrachial cutaneous nerve | May innervate much of the shaft territory and should be considered during harvest planning[18] |
| Sexual health outcomes | 2025 systematic review found sexual health outcomes generally favorable but limited by heterogeneous, non-validated measures[28] |
Erectile Prosthesis
RFFF creates a sensate phallic shaft, but penetrative rigidity usually requires a delayed erectile prosthesis. Implant surgery in a neophallus is harder than in an anatomic penis because there are no corpora cavernosa, so cylinders require wrapping and fixation to the pubic bone or periosteal structures.[14][15][29]
| Prosthesis Issue | Counseling Point |
|---|---|
| Timing | Delay until flap vascularity, sensation, wound stability, and voiding are reliable |
| Device choice | Inflatable devices are common; malleable and transgender-specific devices may be used by selected centers |
| Fixation | Cylinder wrapping and pubic fixation are essential to prevent migration / erosion |
| Durability | Five-year retention is lower than in anatomic-penis implantation |
| Revisions | Infection, erosion, malposition, migration, and mechanical failure are common enough that revision should be expected over a lifetime |
Donor-Site Morbidity
The donor site is the main non-urologic drawback. Function is often acceptable, but scar visibility, sensory disturbance, cold intolerance, pain, and graft aesthetics matter to patients.[12][13][30][31]
| Domain | Evidence Signal |
|---|---|
| Motor function | Grip strength, wrist mobility, finger motion, and thumb opposition are usually preserved in modern series[30] |
| Nerve morbidity | Superficial radial nerve symptoms, hypoesthesia, and neuroma can occur[30] |
| Daily function | DASH / QuickDASH scores often show mild or minimal impairment, but individual occupational needs matter[31] |
| Closure innovation | Integra / dermal matrix plus split-thickness graft can improve graft take, healing time, operative time, and cosmetic satisfaction compared with full-thickness grafting in selected series[12] |
| Free groin flap coverage | Can improve donor-site aesthetics / function at the cost of additional microsurgical time[13] |
Comparison With ALT and Abdominal Flaps
| Feature | RFFF | Pedicled ALT | Pedicled Abdominal |
|---|---|---|---|
| Microsurgery | Required | Usually not required | Not required |
| Tissue thickness | Thin, pliable | Often bulky; may need debulking | Variable |
| Tube-in-tube urethra | Reliable single-flap option | Feasible only in selected thin thighs; often staged or separate-flap | Usually staged / separate urethral plan |
| Sensation potential | Excellent | Good, but less predictable | Limited |
| Aesthetic shaft | Usually best | Good after debulking | Variable |
| Donor site | Visible forearm scar | Concealed thigh scar | Concealed abdominal scar |
| Complication profile | High urethral burden | Bulk / debulking and urethral strategy issues | Lower urologic complications in some series, but less sensation |
RFFF remains favored when the patient accepts the forearm donor site and wants the best combination of aesthetics, tube-in-tube urethra, and sensation. ALT is attractive when forearm scarring is unacceptable or RFFF is contraindicated. Abdominal flaps may reduce microsurgical complexity and donor-site visibility but usually sacrifice sensory potential.[3][25]
Operative Pearls
- Plan the urethral strip first; hair-bearing skin in the urethra is a preventable lifelong problem.
- Use objective vascular testing when the Allen exam is equivocal or local protocol requires it.
- Take enough venous outflow; insufficient venous drainage is a major avoidable flap-risk point.
- Discuss forearm scar visibility as a core operation feature, not a minor donor-site detail.
- Counsel that standing micturition often requires revisions even when the flap survives perfectly.
- Delay erectile prosthesis until the flap, urethra, and perineal wounds have fully declared themselves.
- Coordinate urology, plastic surgery, and gynecology sequencing before committing to one-stage versus staged UL.
References
1. Monstrey S, Hoebeke P, Selvaggi G, et al. Penile reconstruction: is the radial forearm flap really the standard technique? Plast Reconstr Surg. 2009;124(2):510-518. doi:10.1097/PRS.0b013e3181aeeb06
2. Gottlieb L, Cripps C. An update on gender-affirming phallus construction using the radial forearm free-flap. Neurourol Urodyn. 2023;42(5):963-972. doi:10.1002/nau.25103
3. Netshiongolwe T, Mitchell S, Kathiravelupillai S, et al. Pedicled flaps versus free radial forearm flap for phalloplasty in female to male gender-confirming surgery: a systematic review. Ann Plast Surg. 2025;95(6):661-666. doi:10.1097/SAP.0000000000004502
4. Garaffa G, Christopher NA, Ralph DJ. Total phallic reconstruction in female-to-male transsexuals. Eur Urol. 2010;57(4):715-722. doi:10.1016/j.eururo.2009.05.018
5. Berli JU, Knudson G, Fraser L, et al. What surgeons need to know about gender confirmation surgery when providing care for transgender individuals: a review. JAMA Surg. 2017;152(4):394-400. doi:10.1001/jamasurg.2016.5549
6. Tousidonis M, Escobar JIS, Caicoya SO, et al. Preoperative Doppler ultrasonography Allen test for radial forearm free flap in oral cancer reconstruction: implications in clinical practice. J Clin Med. 2021;10(15):3328. doi:10.3390/jcm10153328
7. Nuckols DA, Tsue TT, Toby EB, Girod DA. Preoperative evaluation of the radial forearm free flap patient with the objective Allen's test. Otolaryngol Head Neck Surg. 2000;123(5):553-557. doi:10.1067/mhn.2000.110728
8. Spennato S, Burger AE, Schlosshauer T, et al. Microsurgical phalloplasty in nontranssexual patients - considerations after a retrospective single-center analysis of 23 cases. Urology. 2020;141:154-161. doi:10.1016/j.urology.2020.03.038
9. Kim S, Dennis M, Holland J, et al. The anatomy of forearm free flap phalloplasty for transgender surgery. Clin Anat. 2018;31(2):145-151. doi:10.1002/ca.23014
10. Coleman E, Radix AE, Bouman WP, et al. Standards of care for the health of transgender and gender diverse people, version 8. Int J Transgend Health. 2022;23(Suppl 1):S1-S259. doi:10.1080/26895269.2022.2100644
11. American College of Obstetricians and Gynecologists. Health care for transgender and gender diverse individuals: ACOG Committee Opinion, Number 823. Obstet Gynecol. 2021;137(3):e75-e88. doi:10.1097/AOG.0000000000004294
12. Falcone M, Preto M, Ciclamini D, et al. Bioengineered dermal matrix (Integra) reduces donor site morbidity in total phallic construction with radial artery forearm free-flap. Int J Impot Res. 2026;38(4):333-339. doi:10.1038/s41443-023-00775-5
13. Rieger UM, Majenka P, Wirthmann A, et al. Comparative study of the free microvascular groin flap: optimizing the donor site after free radial forearm flap phalloplasty. Urology. 2016;95:192-196. doi:10.1016/j.urology.2016.04.007
14. Kocjancic E, Jaunarena JH, Schechter L, Acar O. Inflatable penile prosthesis implantation after gender affirming phalloplasty with radial forearm free flap. Int J Impot Res. 2020;32(1):99-106. doi:10.1038/s41443-019-0153-8
15. Neuville P, Morel-Journel N, Maucourt-Boulch D, et al. Surgical outcomes of erectile implants after phalloplasty: retrospective analysis of 95 procedures. J Sex Med. 2016;13(11):1758-1764. doi:10.1016/j.jsxm.2016.09.013
16. Staud CJ, Zaussinger M, Duscher D, et al. A modified microvascular tube-in-tube concept for penile construction in female-to-male transsexuals: combined radial forearm free flap with anterolateral thigh flap. J Plast Reconstr Aesthet Surg. 2021;74(9):2364-2371. doi:10.1016/j.bjps.2021.01.016
17. Falcone M, Preto M, Timpano M, et al. The surgical outcomes of radial artery forearm free-flap phalloplasty in transgender men: single-centre experience and systematic review of the current literature. Int J Impot Res. 2021;33(7):737-745. doi:10.1038/s41443-021-00414-x
18. Peters BR, Richards HW, Berli JU. Optimizing innervation in radial forearm phalloplasty: consider the posterior antebrachial cutaneous nerve. Plast Reconstr Surg. 2023;151(1):202-206. doi:10.1097/PRS.0000000000009771
19. Spennato S, Ederer IA, Borisov K, et al. Radial forearm free flap phalloplasty in female-to-male transsexuals - a comparison between Gottlieb and Levine's and Chang and Hwang's technique. J Sex Med. 2022;19(4):661-668. doi:10.1016/j.jsxm.2022.01.004
20. De Wolf E, Claes K, Sommeling CE, et al. Free bipedicled radial forearm and posterior interosseous artery perforator flap phalloplasty. J Sex Med. 2019;16(7):1111-1117. doi:10.1016/j.jsxm.2019.03.270
21. Medina CA, Fein LA, Salgado CJ. Total vaginectomy and urethral lengthening at time of neourethral prelamination in transgender men. Int Urogynecol J. 2018;29(10):1463-1468. doi:10.1007/s00192-017-3517-y
22. Hu CH, Chang CJ, Wang SW, Chang KV. A systematic review and meta-analysis of urethral complications and outcomes in transgender men. J Plast Reconstr Aesthet Surg. 2022;75(1):10-24. doi:10.1016/j.bjps.2021.08.006
23. Veerman H, de Rooij FPW, Al-Tamimi M, et al. Functional outcomes and urological complications after genital gender-affirming surgery with urethral lengthening in transgender men. J Urol. 2020;204(1):104-109. doi:10.1097/JU.0000000000000795
24. Paganelli L, Morel-Journel N, Carnicelli D, et al. Determining the outcomes of urethral construction in phalloplasty. BJU Int. 2023;131(3):357-366. doi:10.1111/bju.15915
25. Wang E, Cleff B, Basta A, et al. Flap choice in gender-affirming phalloplasty affects postoperative complication rates. Microsurgery. 2026;46(1):e70154. doi:10.1002/micr.70154
26. Ma S, Cheng K, Liu Y. Sensibility following innervated free radial forearm flap for penile reconstruction. Plast Reconstr Surg. 2011;127(1):235-241. doi:10.1097/PRS.0b013e3181fad371
27. Kuenzlen L, Nasim S, van Neerven S, et al. Multimodal evaluation of functional nerve regeneration in transgender individuals after phalloplasty with a free radial forearm flap. J Sex Med. 2020;17(5):1012-1024. doi:10.1016/j.jsxm.2020.02.014
28. Goldstein B, Okamuro K, Lewis P, et al. Sexual health outcomes following gender-affirming phalloplasty: a systematic review. J Sex Med. 2025;22(9):1700-1706. doi:10.1093/jsxmed/qdaf166
29. van der Sluis WB, Pigot GLS, Al-Tamimi M, et al. A retrospective cohort study on surgical outcomes of penile prosthesis implantation surgery in transgender men after phalloplasty. Urology. 2019;132:195-201. doi:10.1016/j.urology.2019.06.010
30. Kuenzlen L, Nasim S, van Neerven S, et al. Multimodal evaluation of donor site morbidity in transgender individuals after phalloplasty with a free radial forearm flap: a case-control study. J Plast Reconstr Aesthet Surg. 2022;75(1):25-32. doi:10.1016/j.bjps.2021.05.068
31. Ozturk M, Wellenbrock S, Wiebringhaus P, et al. Functionality and scar evaluation of the donor site in extended radial forearm flap phalloplasty: how affected is the arm in day-to-day life? J Clin Med. 2024;13(19):6004. doi:10.3390/jcm13196004