Schematic model.

Operative animation, Gender-affirming masculinising urogenital reconstruction

Gender-affirming masculinising urogenital reconstruction: radial forearm phalloplasty

A staged reconstruction that creates a phallus, a lengthened urethra and a scrotum for a transgender man who has chosen genital surgery. The urologist builds the fixed part of the new urethra from local flaps and joins it to a urethra rolled inside the forearm flap.

The lesson is that join, where fistula and stricture begin, and a urethra that needs urological follow-up for life.

Advanced tier FRCS andrology and genital reconstruction, urethral reconstruction Interactive 3D
Schematic scene preview: Masculinising urogenital reconstruction
Preparing the 3D anatomy…

UrOops3D · UroRef · © Nity G

How to use this module. Play through the eight steps, or use Back and Next. Watch the pars fixa roll over the catheter, the forearm flap roll into a tube within a tube, and the join at the base in amber. The triggers show the four urethral and flap complications and the three later stages.

Click me next Section 2 of 8 Anatomy The structures this operation works between, and the one it must not cross.

The structures in the scene

Gender-affirming masculinising urogenital reconstruction: how the structures relateThe join of the new urethra at the base of the phallus, and what lies around it. Join: pars fixa to pars pendulans: its proximal side; tubed over the catheter Pars fixa, from labia minora flaps. Join: pars fixa to pars pendulans: its distal side, inside the shaft Pars pendulans, inner tube of the flap. Join: pars fixa to pars pendulans: upstream; joined at the meatus, never through it Native urethra and bladder neck (danger). Join: pars fixa to pars pendulans: beside it at the base; no tension or kink Pedicle to the groin vessels (danger). Join: pars fixa to pars pendulans: covered by it, with the pars fixa Scrotum from the labia majora. Join: pars fixa to pars pendulans: just above; where cylinders are anchored Pubic bone: later prosthesis anchor.Join: pars fixa to parspendulansPars fixa, fromlabia minora flapsPars pendulans,inner tube of theflap!Native urethra andbladder neck!Pedicle to the groinvesselsScrotum from thelabia majoraPubic bone: laterprosthesis anchorits proximal side;tubed over thecatheterits distal side,inside the shaftupstream; joined atthe meatus, neverthrough itbeside it at thebase; no tension orkinkcovered by it, withthe pars fixajust above; wherecylinders areanchoredTargetDangerLandmarkContext
The join of the new urethra at the base of the phallus, and what lies around it. Schematic, not to scale; relationships only.
  • From the foot of the table, the pars fixa runs up the midline from the native meatus to the base of the phallus on the mons.
  • The phallus stands forward from the pubis, its urethra on the side facing the scrotum.
  • The join lies at the base, under the front of the scrotum; the pedicle runs from the base to the groin.
  • ›Native urethra and bladder neck - the continence mechanism; the new urethra begins at the native meatus.
  • ›Vagina - its epithelium removed and its cavity obliterated where vaginectomy is part of the plan.
  • ›Bladder and rectum - in front of and behind the vaginectomy dissection.
  • ›Vestibule and labia minora - the flaps that are tubed to make the pars fixa.
  • ›Pars fixa - the fixed part of the new urethra, from the native meatus to the base of the phallus.
  • ›Pars pendulans - the urethra of the shaft: the inner tube of the forearm flap.
  • ›Radial forearm flap - skin, fat, the radial artery and its veins, and the forearm sensory nerves.
  • ›Recipient vessels and nerves in the groin - where the pedicle is joined under the microscope.
  • ›Labia majora - advanced as flaps to make the scrotum.
  • ›Pubic bone - where the cylinders of a later prosthesis are anchored.
Click me next Section 3 of 8 Steps The operation in order, with the landmark that guards each move.

Operative steps

  1. The native anatomy A transgender man who has chosen phalloplasty with urethral lengthening after assessment by the multidisciplinary team, and whose hysterectomy has been done. In lithotomy the genitalia, perineum, lower abdomen and the chosen forearm are prepared. A urethral catheter is passed along the native urethra into the bladder. The new urethra will begin at the native meatus.
    where it bites: the native urethra and bladder neck are the continence mechanism; they are joined to, never dissected or tunnelled through.
  2. Vaginectomy and closure Where vaginectomy is part of the plan, the vaginal epithelium is removed from within and the cavity is obliterated, working between the bladder in front and the rectum behind. The introitus is closed in the midline. Some units leave the vagina in place when the patient prefers it, and urethral lengthening is then planned differently.
    where it bites: the bladder base lies on the anterior wall and the rectum on the posterior wall; either can be opened in this dissection.
  3. Urethral lengthening: the pars fixa Flaps of vestibular and labia minora skin are marked on each side of a line from the native meatus to the planned base of the phallus. They are raised, rolled toward the midline over the catheter and closed in the midline as a tube. This is the pars fixa, the fixed part of the new urethra; its far end will meet the urethra of the shaft.
    where it bites: a flap raised thin or closed under tension narrows or breaks down at its far end, which becomes the join.
  4. The forearm flap: a tube within a tube The plastic surgical team raises the radial forearm flap on the radial artery and its venae comitantes, with a superficial vein and the forearm sensory nerves. A narrow ulnar strip is rolled skin side in to make the inner tube, the pars pendulans; hair on that skin is removed beforehand. The wide flap is rolled round it skin side out to make the shaft. The forearm is closed with a skin graft.
    where it bites: the donor site keeps its tendons, the radial nerve branches and the hand circulation covered and safe.
  5. Transfer and microvascular anastomosis The tube within a tube is carried to the pubis with its pedicle. In the groin the radial artery is joined to a recipient artery and a flap vein to a recipient vein under the microscope; a forearm sensory nerve is joined to a recipient nerve for sensation. The vessels are left without tension or kink.
    where it bites: the pedicle and the recipient vessels: a kinked, compressed or tight pedicle loses the flap.
  6. The join At the base of the phallus the pars pendulans is joined end to end to the far end of the pars fixa over the catheter, without tension and with well-vascularised tissue round it. The catheter passes through the whole new urethra to the tip. A suprapubic catheter drains the bladder while the urethra heals.
    where it bites: this join is the commonest site of fistula and stricture.
  7. Scrotoplasty The labia majora are raised as flaps, advanced toward the base of the phallus and joined in the midline to make the scrotum, which lies over the pars fixa. Testicular implants are left for a later stage.
    where it bites: the scrotal flaps cover the pars fixa; a tense closure over it compromises both.
  8. Healing and voiding The flap is watched closely in the first days. After healing, and once imaging round the catheter shows no leak, the urethral catheter is removed and then the suprapubic one. He voids standing through the meatus at the tip. Glansplasty, testicular implants and a penile prosthesis are later stages, after healing and the return of sensation.
    where it bites: fistula, stricture and voiding problems can appear years later; follow-up is lifelong.
Click me next Section 4 of 8 Danger zones Where this operation bites, and why it bites there.
Critical relationship

Danger zones

The spatial relationships the animation is built to make automatic. Before you read each one, ask yourself: at this point in the operation, what is about to go wrong, and what is my first move? The save for each sits in the Complications tab.

  • RiskThe join of pars fixa to pars pendulans - the commonest site of fistula and stricture; joined without tension over the catheter.
  • RiskMicrovascular pedicle and recipient vessels - no tension, kink or compression; flap loss follows a failed anastomosis.
  • RiskBladder and rectum in the vaginectomy - the bladder base in front and the rectum behind the dissection.
  • RiskNative urethra and bladder neck - the continence mechanism, kept intact; the new urethra is joined to the meatus.
  • RiskDonor-site nerves, tendons and vessels - the forearm keeps its tendons covered and its hand circulation.
  • RiskProsthetic implant pockets - a later prosthesis lies close to the new urethra and the skin; infection and erosion are common.
Practise it Take me into the scene Opens the animation at a danger moment and asks you to predict the mechanism and your first move before it reveals.
Click me next Section 5 of 8 Complications The save for each one: the first move, the escalation trigger, the op-note line.

Complications and immediate saves

Trigger each of these live in the Animation tab, then read the save: the first move, the escalation trigger, and the line that goes in the op note.

Urethral fistula at the join

  • urine leaks through the skin on voiding, most often at the join at the base; fistula is among the commonest complications of phalloplasty with urethral lengthening.
The save
  1. Divert the urine: catheter drainage, suprapubic where a urethral catheter cannot be passed safely. first move
  2. Define the fistula with imaging and endoscopy, and look for a stricture beyond it that drives it.
  3. Many early fistulae close with diversion alone; a persistent one is repaired once the tissues have settled.
  4. A distal stricture, a large fistula or repeated failure goes to a urologist who does this reconstruction regularly. escalation trigger
  5. Notes: the site, the size, any stricture beyond it, the diversion and the plan. document

Urethral stricture at the join

  • a poor stream, straining, infection or retention from narrowing of the new urethra, most often at the join.
The save
  1. Retention or a high residual: suprapubic catheter first. first move
  2. Define the length and site with urethrography and endoscopy.
  3. No endoscopic incision or urethroplasty in the first six months after the phalloplasty.
  4. Endoscopic incision only for a short stricture, and not more than twice; open repair of the shaft urethra is staged. escalation trigger
  5. Notes: the site and length, the diversion and the planned revision. document

Flap loss

  • partial or total loss of the phallus from failure of the microvascular anastomosis, usually in the first days.
The save
  1. A dusky, cold or congested phallus is reported at once to the operating team. first move
  2. Remove anything compressing the pedicle: dressings, position, a tight closure.
  3. Urgent return to theatre to explore the anastomosis; time decides whether the flap survives. escalation trigger
  4. Partial loss is debrided once demarcated, and the urethra protected by diversion.
  5. Notes: the times of the flap checks, the findings and what was done. document

Spraying and voiding dysfunction

  • spraying, dribbling after voiding as urine pools in the pars fixa, or difficulty emptying; these can appear years after the operation.
The save
  1. Measure the flow and the residual and image the urethra: look for a stricture or a diverticulum first. first move
  2. Post-void dribble from pooling: perineal massage after voiding, as taught.
  3. A stricture or diverticulum found is treated on its own terms.
  4. Recurrent infection or retention goes back to the reconstructive urologist. escalation trigger
  5. Notes: the symptoms, the flow and residual, the findings and the follow-up plan. document
Click me next Section 6 of 8 Troubleshooting When the case turns: the problem, then the next move.

Intra-operative troubleshooting

When the case turns: the problem, then the next move.

  • ActionHe wants a phallus without a forearm scar or flap surgery - metoidioplasty uses the hormone-enlarged clitoris to make a small sensate phallus, with or without urethral lengthening. It is usually too small for penetration and the urethral complications still occur.
  • ActionHe does not want to void standing - phalloplasty without urethral lengthening avoids the urethral complications; the native meatus stays where it is and vaginectomy may not be needed.
  • ActionAn anterolateral thigh flap instead of the forearm - the thigh avoids a visible forearm scar but is often bulkier, and its urethra may need a second flap or a staged build. The join is still the weak point.
  • ActionA leak on the imaging before the catheter comes out - leave the catheters, repeat the imaging later; many small leaks seal with longer drainage.
  • ActionHair in the new urethra - hair removal from the urethral skin before the flap is raised prevents it; hair found later causes stones and infection and needs removal.
  • ActionA request for an individually customised operation - WPATH asks surgeons to consult a comprehensive multidisciplinary team before an individually customised operation.
Click me next Section 7 of 8 FRCS viva Say it out loud, then mark yourself against the model answer.

FRCS viva questions

The examiner stems this scene prepares you for. Try to answer out loud first, then reveal, and learn the discriminator, the detail that turns a pass into a strong pass.

QA transgender man asks about genital surgery. How would you assess him, and who else is involved?reveal answer
  • I would see him within a multidisciplinary gender surgery team.
  • I would start with his own goals: whether he wants to void standing, penetrative function, sensation, appearance, and whether fertility has been discussed.
  • WPATH version 8 suggests that genital surgery is considered for an adult who is stable on his current treatment, which may include at least six months of hormone therapy unless that is not wanted or not possible.
  • It asks that reproductive options are discussed before gonadectomy, and that a hysterectomy accompanies a colpectomy.
  • I would assess his general health, smoking and body habitus, and the donor sites with the plastic surgeons.
  • I would explain that this is several operations over a year or more, that the urethral complications are common, and that WPATH suggests lifelong urological follow-up after metoidioplasty or phalloplasty.
  • Mental health support stays part of the team throughout.
Strong pass

Say all three

  • Starting from his goals
  • Quoting what WPATH actually says about eligibility
  • Describing a team rather than an operation
Examiner note
Starting from his goals, quoting what WPATH actually says about eligibility, and describing a team rather than an operation.
QCompare metoidioplasty and phalloplasty. What does urethral lengthening add?reveal answer
  • Metoidioplasty releases the hormone-enlarged clitoris to make a small, sensate phallus from native tissue;
  • phalloplasty builds a larger phallus from a flap, most often the radial forearm, and can take a prosthesis for penetration.
  • Both can be done with or without urethral lengthening, which is what allows voiding standing, and it is the lengthening that brings the urethral complications.
  • In the review of Jolly and colleagues, seven series with 403 patients, every metoidioplasty technique included lengthening, and fistula ranged from 5 to 37 per cent and stricture from 2 to 35 per cent depending on technique.
  • In the review of Wang and colleagues, 1731 patients across 39 studies, the radial forearm flap was used in 75.1 per cent, fistula was 34.1 per cent and stricture 25.4 per cent, and 92.2 per cent could void standing.
  • I would set those numbers against what he wants.
Strong pass

Say all three

  • Knowing that the urethral complications come with lengthening
  • Not with the phallus
  • Giving rates with their source
Examiner note
Knowing that the urethral complications come with lengthening, not with the phallus, and giving rates with their source.
QDraw the urethra after a radial forearm phalloplasty. Where does it go wrong?reveal answer
  • I would draw it from the bladder: the native urethra runs to the native meatus.
  • From there the pars fixa, made from vestibular and labia minora flaps, runs up the perineum under the scrotum to the base of the phallus.
  • There it is joined to the pars pendulans, the inner skin tube of the tube within a tube, which runs to the meatus at the tip.
  • The join between the fixed and the pendulous parts is where fistula and stricture most often occur, because two tissues with different blood supplies meet there.
  • Monstrey and colleagues, in 287 radial forearm phalloplasties, describe a high number of early fistulas and potential long-term urological complications as the main drawbacks, with voiding standing achieved.
  • In the meta-analysis of Hu and colleagues, 1566 patients, fistula or stenosis together reached 48.9 per cent, and a prelaminated urethra had more strictures than a tube within a tube.
Strong pass

Say all three

  • Naming pars fixa and pars pendulans
  • Putting the join at the base
  • Explaining why it fails there
Examiner note
Naming pars fixa and pars pendulans, putting the join at the base, and explaining why it fails there.
QSix weeks after his phalloplasty he has a poor stream and is straining. What do you do?reveal answer
  • I would assume a stricture until proven otherwise and protect the upper tract.
  • If he is in retention or has a high residual I would place a suprapubic catheter, which the EAU stricture guideline makes the first step for obstruction, infection or retention after neophallic reconstruction.
  • I would define the stricture by urethrography and endoscopy.
  • The guideline advises no endoscopic incision or urethroplasty within six months of the phalloplasty, so diversion carries him until the tissues settle.
  • After that, a short stricture at the join can have an endoscopic incision, but not more than two unless the intent is palliative, and an open repair of the shaft urethra is staged.
  • I would involve a reconstructive urologist who does this work regularly and record the site, length and plan.
Strong pass

Diverting first, respecting the six-month wait, and limiting repeated incisions.

QA year later he wants an erectile prosthesis. What do you tell him?reveal answer
  • I would wait until the phallus has healed and sensation has returned to the tip, which the Ghent overview puts at about a year.
  • The cylinders have no corpora to sit in, so their proximal ends are anchored to the pubic bone, with a pump in the scrotum and a reservoir behind the abdominal wall.
  • I would be frank about the risk.
  • In the Ghent series of Hoebeke and colleagues, 129 patients, 41.1 per cent needed removal or revision of the prosthesis, with infection in 11.9 per cent and protrusion in 8.1 per cent, and WPATH lists infection, malfunction, urethral erosion, skin extrusion and dislocation of the bone fixation.
  • A device that erodes into the new urethra is removed.
Strong pass

Say both

  • Explaining the anchoring to bone
  • Giving the revision rate before he consents
Examiner note
Explaining the anchoring to bone and giving the revision rate before he consents.
Click me next Section 8 of 8 Evidence The guidance each of these answers is built on.

Evidence and guidance

Operative Dictations in Urologic Surgery
Armenakas NA, Fracchia JA, Golan R. Operative Dictations in Urologic Surgery. Wiley, 2019
Searched for this operation and found to have no chapter on gender-affirming phalloplasty, metoidioplasty or urethral lengthening; nothing on this page is taken from it. The order of the steps follows the hub sequence for this procedure (define goals; plan donor tissue, lengthening and staging; create a perfused phallus and tension-aware urethral continuity; scrotal and prosthetic stages after healing; lifelong follow-up) and the sources below. The operative detail of the steps (the vaginectomy, the flaps of the pars fixa, the tube within a tube, the groin anastomosis, the suprapubic catheter, the imaging before catheter removal) is general practice in UK and European units, summarised from the Ghent overview and not from a single operative text. The scene is schematic: the forearm is drawn as a panel beside the field, the vaginectomy as the vagina fading and the introitus closing, and the phallus is not drawn to a measured size.
Open guideline
WPATH
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. Chapter 13, Surgery and postoperative care, read 19 October 2026
Statement 13.6: genital procedures considered in eligible adults stable on their current treatment, which may include at least 6 months of hormone treatment unless hormone therapy is not desired or is contraindicated. 13.4: reproductive options discussed before gonadectomy. 13.8: a comprehensive multidisciplinary team consulted for individually customised surgery. 13.9: surgeons caring for people who have had metoidioplasty or phalloplasty encourage lifelong urological follow-up. The text says urethral lengthening is an option for both metoidioplasty and phalloplasty; that if colpectomy is performed a hysterectomy must also be performed; reports urethral strictures of 35 to 58% and lists fistulae, diverticula and hair in the neourethra; lists prosthesis complications as infection (8 to 12%), malfunction, urethral erosion, skin extrusion and dislocation of the bone fixation; and describes follow-up for stricture with bladder ultrasound for residual, urethrography and endoscopy. Read through a fetch tool that returned short quotations.
Open guideline
European Association of Urology
EAU Guidelines on Urethral Strictures: disease management in transgender patients, read 19 October 2026
Do not perform endoscopic incision or urethroplasty within six months after neophalloplasty (strong). Do not perform more than two endoscopic incisions for strictures in trans men unless with palliative intent (strong). Perform staged urethroplasty for strictures at the neophallic urethra if open reconstruction is indicated. The text describes the anastomosis between the neophallic urethra and the fixed part of the urethra; a suprapubic catheter as first-line for obstructive symptoms, recurrent infection or retention, with perineostomy the alternative; a first endoscopic incision patency of 37 to 45.5%. The EAU Sexual and Reproductive Health guideline online had no chapter on this surgery when checked, and BAUS has no operation-specific guidance that was found; neither is quoted.
Open guideline
Plastic and Reconstructive Surgery
Monstrey S, Hoebeke P, Selvaggi G, et al. Penile reconstruction: is the radial forearm flap really the standard technique? Plast Reconstr Surg 2009;124:510-518
Abstract read 19 October 2026. 287 radial forearm phalloplasties by one team: a reliable technique, mostly in two stages, always allowing voiding standing and in most cases sexual satisfaction; the disadvantages are the high number of initial fistulas, the forearm scar and potential long-term urological complications; the authors hold a multidisciplinary approach between plastic surgeon and urologist to be essential. No rates are given in the abstract.
Open guideline
Seminars in Plastic Surgery
Monstrey SJ, Ceulemans P, Hoebeke P. Sex reassignment surgery in the female-to-male transsexual. Semin Plast Surg 2011;25:229-244
Abstract read 19 October 2026. The genital stage includes a vaginectomy, reconstruction of the horizontal part of the urethra, a scrotoplasty and a penile reconstruction, usually with a radial forearm flap; after about one year, when sensation has returned to the tip, erectile and testicular prostheses can be implanted. The source for the order of the stages on this page.
Open guideline
Sexual Medicine Reviews
Wang AMQ, Tsang V, Mankowski P, et al. Outcomes following gender affirming phalloplasty: a systematic review and meta-analysis. Sex Med Rev 2022;10:499-512
Abstract read 19 October 2026. 39 studies, 1731 patients; radial forearm free flap in 75.1%; overall complication rate 76.5%; urethral fistula 34.1% and urethral stricture 25.4%; tactile sensation 93.9% and voiding standing 92.2% where reported. The authors judge the evidence weak.
Open guideline
Journal of Plastic, Reconstructive and Aesthetic Surgery
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;75:10-24
Abstract read 19 October 2026. 21 studies, 1566 patients: tube in tube in 8 studies (1061 patients), prelaminated flap in 9, second flap in 6. The prelaminated flap had significantly more strictures than the tube in tube. Pooled urethral fistula or stenosis 48.9%; voiding standing 91.5%; prosthesis complications 27.9%; satisfaction 90.5%.
Open guideline
Sexual Medicine
Jolly D, Wu CA, Boskey ER, et al. Is clitoral release another term for metoidioplasty? A systematic review and meta-analysis of metoidioplasty surgical technique and outcomes. Sex Med 2021;9:100294
Abstract read 19 October 2026. 7 series, 403 patients; four techniques, all including urethral lengthening; most voided standing; fistula 5 to 37% and stricture 2 to 35% depending on technique, lowest with the Belgrade technique.
Open guideline
European Urology
Hoebeke PB, Decaestecker K, Beysens M, et al. Erectile implants in female-to-male transsexuals: our experience in 129 patients. Eur Urol 2010;57:334-340
Abstract read 19 October 2026. 129 patients with a neophallus and an erectile prosthesis, mean follow-up 30.2 months; 41.1% needed removal or revision for infection, erosion, dysfunction or leak; across 185 prostheses, infection 11.9%, protrusion 8.1%, leak 9.2%, dysfunction 13%, malposition 14.6%. The authors still regard a hydraulic prosthesis as the best option for intercourse.
Open guideline

Curriculum. Supports learning relevant to the ISCP Urology Curriculum syllabus topics Andrology and Urethral stricture disease. Not a workplace-based assessment and not evidence of competence.

Two minutes

Close the lap: recall it before you leave.

Say it aloud, then reveal. Reading is not remembering.

  1. 01 The relationship Say the critical spatial relationship out loud, then reveal. reveal
    Memory frame

    From the foot of the table, the pars fixa runs up the midline from the native meatus to the base of the phallus on the mons.

    Why?
    The phallus stands forward from the pubis, its urethra on the side facing the scrotum. The join lies at the base, under the front of the scrotum; the pedicle runs from the base to the groin.
  2. 02 The first move Urethral fistula at the join. Your first move? reveal
    First move

    Divert the urine: catheter drainage, suprapubic where a urethral catheter cannot be passed safely.

  3. 03 The escalation trigger Urethral fistula at the join. What makes you call for help? reveal
    Escalate when

    A distal stricture, a large fistula or repeated failure goes to a urologist who does this reconstruction regularly.

  4. 04 The discriminator What turns a pass into a strong pass? reveal
    Strong pass

    Say all three

    • Starting from his goals
    • Quoting what WPATH actually says about eligibility
    • Describing a team rather than an operation
    Examiner note
    Starting from his goals, quoting what WPATH actually says about eligibility, and describing a team rather than an operation.
  5. 05 The pitfall Where does this operation bite first? reveal
    Pitfall

    The join of pars fixa to pars pendulans

    Why?
    the commonest site of fistula and stricture; joined without tension over the catheter.

Revision practice with self-marked answers, not an assessment of clinical competence. Kept in this browser only; it does not sync between devices.