Fibula Osteocutaneous Free Flap Phalloplasty
Fibula osteocutaneous free flap phalloplasty creates a neophallus from lateral lower-leg skin and vascularized fibula bone based on the peroneal artery system. Its defining feature is intrinsic bone rigidity, which can permit penetrative intercourse without a delayed erectile prosthesis. RFFF, ALT, and SCIP soft-tissue flaps do not provide intrinsic bone rigidity. The tradeoffs include microsurgery, lower-leg donor morbidity, persistent rigidity, and preoperative vascular mapping.[1][2][3][5] When urethral lengthening is planned, the Munich skin-graft prelamination protocol adds stages and carries stricture and fistula risk.[4][7]
For cohort-level pathway selection, see Masculinizing Gender-Affirming Surgery. For the major soft-tissue alternatives, see RFFF Phalloplasty, ALT Phalloplasty, and SCIP Phalloplasty.
Concept
The fibula flap is a bone-bearing phalloplasty flap. The skin island forms the visible phallus, the peroneal artery and venae comitantes provide free-flap inflow or outflow, the lateral sural cutaneous nerve can be coapted for sensation, and the fibular segment is fixed to the pubic symphysis or residual penile structures for structural support.[1][2][4]
| Component | Role |
|---|---|
| Lateral lower-leg skin island | External shaft skin |
| Fibula segment | Permanent intrinsic rigidity for penetration |
| Peroneal artery | Arterial pedicle; usually long enough for femoral recipient anastomosis |
| Venae comitantes | Venous drainage, often to saphenous branches |
| Lateral sural cutaneous nerve | Sensate flap nerve for neurorrhaphy |
| Prelaminated urethral tube | Staged phallic urethra in the Munich-style protocol |
Indications
Fibula phalloplasty is a niche operation for patients who place unusually high value on avoiding penile prosthesis implantation and who accept the donor-leg tradeoffs.
| Scenario | Fit for Fibula Phalloplasty |
|---|---|
| Penetrative intercourse without erectile prosthesis is the dominant goal | Strongest fit; intrinsic rigidity is the central advantage |
| Refuses forearm donor scar | Reasonable fit if lower-leg scar and functional risks are acceptable |
| Cisgender penile loss with residual recipient structures | Historical strong indication; bone can be fixed to residual tunica / pubic support |
| Accepts permanent rigidity | Required; the neophallus cannot deflate like an implant-based reconstruction |
| Adequate remaining foot perfusion after peroneal sacrifice | Confirm sufficient non-peroneal runoff with preoperative vascular mapping.[5][6] |
| Limited access to high-volume fibula-phalloplasty center | Poor fit; technique is uncommon and center-dependent |
Contraindications and Caution Zones
| Scenario | Counseling Point |
|---|---|
| Dominant peroneal artery / peronea arteria magna | Avoid standard harvest from that leg: peroneal sacrifice can cause limb ischemia. Modified harvest has been reported only in selected mapped cases.[5][6] |
| Peripheral arterial disease / diabetes with vascular disease | Avoid or obtain detailed vascular evaluation; foot perfusion must be preserved |
| High athletic lower-leg demands | Donor morbidity may matter more than concealed scar |
| Cannot tolerate permanent rigidity | Choose RFFF / ALT / SCIP / abdominal pathway with delayed prosthesis instead |
| Needs simplest urethral pathway | Fibula protocols commonly rely on staged prelamination, which has stricture risk |
| Poor candidate for microsurgery | Fibula is a free flap and requires microvascular anastomosis |
Historical Context
Sadove, Sengezer, McRoberts, and Wells described one-stage total penile reconstruction with a free sensate osteocutaneous fibula flap in 1993.[2] Sengezer later published long-term follow-up in 18 biologic male patients, documenting preserved bone viability, neural integrity, marriage / fertility outcomes, and patient-reported pleasurable intercourse without penile prosthesis implantation.[3]
The Munich group then adapted the fibula flap to gender-affirming phalloplasty with a prelaminated neourethra and a multistage protocol. Papadopulos, Schaff, and Biemer reported 32 prelaminated sensate osteofasciocutaneous fibula phalloplasties, and Schaff and Papadopulos later described a three-stage complete phalloplasty protocol that used fibula in 31 patients and RFFF in 6 patients.[4][7] Hage and Winters proposed design modifications including longitudinal flap orientation, nerve-territory mapping, and secondary urethral anastomosis.[8] Dabernig, Chan, and Schaff later described the sine fibula variant: a peroneal perforator skin flap harvested without bone, preserving the lateral-leg scar advantage while abandoning intrinsic rigidity.[9]
Vascular Anatomy and Preoperative Imaging
The flap is based on the peroneal artery, a branch of the tibioperoneal trunk that runs along the posterior interosseous membrane and supplies both the fibula and overlying lateral-leg skin through septocutaneous and musculocutaneous perforators.[1][10]
| Vascular Point | Practical Relevance |
|---|---|
| Peroneal artery | Must be safely expendable; cannot be sacrificed if it is dominant foot supply |
| Septocutaneous perforators | More common distally; useful for skin paddle design |
| Musculocutaneous / septomusculocutaneous perforators | More common proximally; harvest may require more dissection |
| Pedicle length | Plan recipient-vessel reach and graft need; a 2026 review of published cases reported an interpositional arterial vein graft in 33 of 83 fibula phalloplasties.[24] |
| Venae comitantes | Typically anastomosed to saphenous-system branches |
Lower-leg vascular imaging is recommended[5] before fibula harvest. A systematic review reported dominant peroneal artery variants in about 5.2% of limbs and peronea arteria magna in about 0.4%.[5] Two reported patients developed acute limb ischemia after fibula harvest when peronea arteria magna was not recognized preoperatively.[5][6]
| Imaging Question | Why It Matters |
|---|---|
| Are anterior and posterior tibial arteries adequate? | Foot perfusion must not depend on the peroneal artery |
| Is the peroneal artery dominant? | Dominant peroneal anatomy should redirect flap choice or side |
| Are variants bilateral? | Bilateral variants occur; image both legs if one side is abnormal |
| Are perforators suitable? | Skin paddle viability depends on perforator location and quality |
Neural Anatomy and Sensory Strategy
The flap can include the lateral sural cutaneous nerve (LSCN), which supplies the lateral calf skin island. In gender-affirming phalloplasty, the LSCN can be coapted to the dorsal clitoral nerve or another recipient sensory nerve; in cisgender penile loss, it can be coapted to a dorsal penile nerve stump when available.[1][3][8]
| Sensory Issue | Practical Point |
|---|---|
| Nerve mapping | Hage and Winters recommended local anesthetic mapping of the cutaneous nerve territory before flap design[8] |
| Erogenous sensation | Depends on recipient nerve strategy and preserved clitoral / penile sensory pathways |
| Protective sensation | LSCN neurorrhaphy can provide tactile recovery, but outcomes are heterogeneous |
| Comparison with RFFF | RFFF generally has stronger sensory literature; fibula may trade some sensibility for better penetrative rigidity[7][11] |
Sengezer documented neural integrity in a subset of patients using bulbocavernous reflex and penile somatosensory evoked potential testing.[3]
Technique
Munich-Style Three-Stage Osteocutaneous Fibula Protocol
| Stage | Operation | Timing / Notes |
|---|---|---|
| Stage I | Hysterectomy / oophorectomy if indicated, vaginectomy / colpocleisis, pars fixa urethral lengthening, and neourethral prelamination on the lateral lower leg | In the Munich protocol, a split-thickness skin graft is wrapped around a catheter and implanted at the planned donor site; maturation interval about 6 months.[4][7] A technical review describes selecting hairless donor skin for fibula urethral prelamination.[20] |
| Stage II | Free sensate osteofasciocutaneous fibula transfer | Harvest skin island, fibula segment, peroneal vessels, LSCN, and prelaminated urethra; perform microvascular and neural anastomoses; fix bone to pubic symphysis / residual penile support |
| Stage III | Urethral connection, scrotoplasty, and testicular implants | Usually 3-6 months after transfer, once flap and urethral tube have matured |
Flap Harvest and Transfer
| Step | Technical Goal |
|---|---|
| Confirm vascular anatomy | Review CTA / angiography before incision; choose side with safe tibial runoff |
| Design skin island | Center over perforators and LSCN territory; Hage and Winters recommended a longitudinal design for aesthetics.[8] For a proximal paddle 10–20 cm from the fibular head, Cho et al. recommended retaining a soleus and flexor hallucis longus cuff to preserve musculocutaneous perforators.[10] |
| Harvest fibula segment | Preserve ankle / knee stability with adequate proximal and distal residual fibula |
| Include prelaminated urethra | Bring the matured epithelialized tube with the flap |
| Transfer to perineum | Position bone and skin for shaft length, base stability, and urethral alignment |
| Arterial anastomosis | Peroneal artery to femoral artery or local recipient artery, depending on center practice |
| Venous anastomosis | Venae comitantes to saphenous-system branches |
| Neurorrhaphy | LSCN to dorsal clitoral / dorsal penile nerve target |
| Bone fixation | Fix fibular segment to pubic symphysis periosteum, tunica remnant, or stable pubic support |
Sine Fibula Variant
The sine fibula variant harvests the lateral-leg skin and peroneal septocutaneous perforator system without taking the fibular bone. Dabernig, Chan, and Schaff reported five patients with no flap loss, standing voiding, acceptable aesthetics, and no ambulation disturbance.[9]
| Feature | Osteocutaneous Fibula | Sine Fibula |
|---|---|---|
| Bone included | Yes | No |
| Intrinsic rigidity | Yes | No |
| Prosthesis compatibility | Usually unnecessary; permanent rigidity already present | Compatible with later hydraulic prosthesis |
| Donor-leg morbidity | Higher because bone is harvested | Lower; fibular continuity preserved |
| Core tradeoff | Penetration without implant, but always rigid | Less rigid / thinner, but loses defining fibula advantage |
Outcomes
Flap Survival
| Series | N | Flap Survival Signal |
|---|---|---|
| Papadopulos 2008 | 32 transgender patients | 2 total and 4 partial necroses during early protocol experience[4] |
| Schaff / Papadopulos 2009 | 37 complete phalloplasties; 31 fibula, 6 RFFF | 6 partial flap necroses in the overall cohort[7] |
| Pototschnig 2013 | 104 osteofasciocutaneous fibula flaps; 66 for neophallus | No total flap necrosis; skin-island edge necrosis was the most frequent complication[12] |
| Dabernig 2006 sine fibula | 5 transgender patients (mean follow-up 25 months) | No flap loss[9] |
Urethral Complications
Urethral morbidity remains substantial despite the bone advantage. A separate retrospective fibula protocol used vaginal mucosa to prelaminate the neourethra in 24 patients and connected it to the native urethra during flap transfer.[22] The prelaminated urethral strategy avoids a single-stage tube-in-tube skin fold but adds time and can carry stricture risk.[4][7][13]
| Study | Stricture / Stenosis | Fistula | Notes |
|---|---|---|---|
| Papadopulos 2008 | 10 / 32 (31.3%) | 7 / 32 (21.9%) | 6 stricture dilations and 5 fistula closures[4] |
| Schaff / Papadopulos 2009 | 12 / 37 (32.4%) | 6 / 37 (16.2%) | Mixed fibula / RFFF cohort, mostly fibula[7] |
| Hu 2022 meta-analysis | Technique-dependent | Technique-dependent | Prelaminated urethra associated with higher stricture / stenosis than tube-in-tube in pooled analysis[13] |
Intrinsic Rigidity and Sexual Function
Fibula is chosen for bone-supported penetration without a penile prosthesis.[23] A 2026 systematic review of 45 gender-affirming phalloplasty studies (2,586 patients, mostly RFFF) found inconsistent functional-outcome reporting.[23] In a retrospective series of 101 patients who completed three-stage phalloplasty (mean follow-up 12.1 months), the fibula group using vaginal mucosa for urethral prelamination had the lowest numerical overall complication rate (8/24, 33.3%). Its rate did not differ significantly from the two other groups using vaginal-mucosa prelamination; the tube-in-tube forearm group used a different urethral method.[22]
| Evidence | Finding |
|---|---|
| Sengezer 2004 | In 18 biologically male patients (mean follow-up 5.4 years, range 1 to 9), bone viability was assessed by radiographs, MRI and DEXA; no resorption or fracture was reported[3] |
| Papadopulos 2002 | In 18 of 46 patients who agreed to follow-up (12 forearm and 6 fibula flaps; follow-up 5 to 112 months), clinical examination showed maintained shape and rigidity of the neophallus bone, MRI showed bone vitality, and histology showed subperiosteal fibrous bone formation with predominantly avital lamellar cortical bone[14] |
| Sengezer 2004 | 6 of 18 patients married; 5 had children; most patients and partners reported pleasurable intercourse and orgasm without penile prosthesis[3] |
| Schaff / Papadopulos 2009 | In a 37-patient mixed-flap series (31 fibula, 6 RFFF), fibula recipients reported better intercourse despite lower neophallus sensibility.[7] |
The bony component can remain viable long-term, but it also creates the operation's most awkward daily-life limitation: the neophallus is permanently rigid. Concealment, clothing, sports, sitting, and patient comfort must be discussed explicitly before surgery.
Donor-Site Morbidity
The lateral lower-leg scar is more concealable than a forearm graft, but bone harvest has a real functional price. General fibula-flap morbidity literature reports wound, sensory, gait, ankle, strength, and pain issues; phalloplasty-specific series describe low-to-moderate donor morbidity but are smaller and center-specific.[12][15][16]
| Morbidity Domain | Evidence Signal |
|---|---|
| Delayed wound healing | Commonest donor-site issue in systematic reviews[15] |
| Gait change | Objective gait analysis can show lower walking speed, stride length, and cadence despite modest patient-perceived limitation[17][18] |
| Ankle instability / range of motion | Reported but uncommon when harvest preserves adequate proximal / distal fibula[15] |
| Sensory deficit | Foot / ankle sensory symptoms can occur after harvest[15] |
| Neuropathic pain | In a multicenter free-fibula donor study outside phalloplasty, 21% of 82 respondents (from 150 eligible patients) reported neuropathic pain; affected respondents reported worse quality of life.[19] |
| Sine fibula | Avoids bone harvest and reported no ambulation disturbance in the five-patient series[9] |
Comparison With RFFF, ALT, and SCIP
| Feature | Fibula Osteocutaneous | RFFF | Pedicled ALT | SCIP |
|---|---|---|---|---|
| Intrinsic rigidity | Yes; defining feature | No | No | No |
| Penile prosthesis | Usually avoided | Usually required for penetration | Usually required | Usually required if shaft used |
| Microsurgery | Required | Required | Usually not for pedicled ALT | Often not if pedicled |
| Urethral strategy | Prelaminated / staged | Tube-in-tube or staged | Staged or adjunct flap | Often separate urethral flap |
| Sensation evidence | Sensate LSCN flap; less robust than RFFF | Strongest | Variable | Limited / evolving |
| Donor scar | Concealed by long sock | Visible forearm | Concealed thigh | Concealed groin / flank |
| Donor morbidity | Leg / ankle / gait / neuropathic pain risk | Forearm scar / graft morbidity | Thigh numbness / bulk | Low donor morbidity |
| Daily-life drawback | Permanent rigidity | Prosthesis revision risk | Debulking | Limited sensation / smaller evidence base |
Advantages
- The fibula flap provides intrinsic rigidity for penetration without an erectile prosthesis, which the soft-tissue flaps compared here do not.
- It avoids implant complications such as infection, erosion, mechanical failure, malposition and explant.
- The lateral-leg donor scar can be concealed.
- The long vascular pedicle can simplify recipient-vessel reach.
- The large skin island and bone segment permit a normal-sized phallus.
- LSCN neurorrhaphy makes a sensate flap possible.
- Bone viability has been documented radiographically and by MRI or DEXA in small long-term series.
Limitations
- Permanent rigidity can be socially and physically difficult to conceal.
- The flap requires free-flap microsurgery.
- Map lower-leg arteries before fibula harvest to identify dominant peroneal supply; CTA, MRA, and catheter angiography are planning options, while palpable pulses alone do not exclude a variant.[5][21]
- Bone harvest adds leg, ankle, gait, and sensory risks; comparative donor-morbidity estimates against soft-tissue phalloplasty flaps remain limited.[12][15]
- Urethral prelamination adds months and carries stricture risk.
- Comparative sensory outcomes against RFFF remain uncertain because sensory measures and neurorrhaphy strategies vary across studies.[7][11]
- The technique is uncommon and concentrated in specialized centers.
- Bone fracture is theoretically possible, although the major series did not report it.
Patient Selection
Fibula phalloplasty is best suited for patients who:
- Prioritize penetrative intercourse without a penile prosthesis.
- Accept a permanently rigid neophallus.
- Refuse or strongly wish to avoid a forearm donor site.
- Have lower-leg vascular mapping showing that the planned fibula harvest preserves foot perfusion; a dominant peroneal variant may require an alternative leg or a selected modified harvest.[5][6]
- Accept lower-leg donor morbidity risk.
- Are willing to undergo a staged pathway over roughly 12-18 months.
- Can access a center with specific fibula-phalloplasty experience.
The sine fibula variant is a lateral-leg perforator phalloplasty. It preserves donor-scar discretion and reduces bone morbidity but gives up intrinsic rigidity.
Operative Pearls
- Do not harvest fibula without vascular imaging of the lower leg.
- Explain permanent rigidity as both the main advantage and the main lifestyle drawback.
- Counsel on the urethral pathway separately, because bone rigidity does not lower urethral risk.
- Center the skin paddle over both perforator anatomy and LSCN sensory territory.
- Preserve enough proximal and distal fibula to maintain knee / ankle stability.
- Fix the bony component securely to stable pubic or residual penile support.
- Choose sine fibula only when the patient explicitly prefers implant-compatible softness over intrinsic rigidity.
- Use a soft-tissue flap instead when the patient cannot accept donor-leg morbidity or permanent stiffness.
See Also
- Masculinizing Gender-Affirming Surgery
- RFFF Phalloplasty
- ALT Phalloplasty
- SCIP Phalloplasty
- Penile Implants
- Buccal Mucosa Graft
References
1. Zaheer U, Granger A, Ortiz A, et al. The anatomy of free fibula osteoseptocutaneous flap in neophalloplasty in transgender surgery. Clin Anat. 2018;31(2):169-174. doi:10.1002/ca.23018
2. Sadove RC, Sengezer M, McRoberts JW, Wells MD. One-stage total penile reconstruction with a free sensate osteocutaneous fibula flap. Plast Reconstr Surg. 1993;92(7):1314-1323. PMID 8248407
3. Sengezer M, Ozturk S, Deveci M, Odabasi Z. Long-term follow-up of total penile reconstruction with sensate osteocutaneous free fibula flap in 18 biological male patients. Plast Reconstr Surg. 2004;114(2):439-450. doi:10.1097/01.prs.0000131883.27191.86
4. Papadopulos NA, Schaff J, Biemer E. The use of free prelaminated and sensate osteofasciocutaneous fibular flap in phalloplasty. Injury. 2008;39 Suppl 3:S62-S67. doi:10.1016/j.injury.2008.05.019
5. Abou-Foul AK, Borumandi F. Anatomical variants of lower limb vasculature and implications for free fibula flap: systematic review and critical analysis. Microsurgery. 2016;36(2):165-172. doi:10.1002/micr.30016
6. Abou-Foul AK, Fasanmade A, Prabhu S, Borumandi F. Anatomy of the vasculature of the lower leg and harvest of a fibular flap: a systematic review. Br J Oral Maxillofac Surg. 2017;55(9):904-910. doi:10.1016/j.bjoms.2017.08.363
7. Schaff J, Papadopulos NA. A new protocol for complete phalloplasty with free sensate and prelaminated osteofasciocutaneous flaps: experience in 37 patients. Microsurgery. 2009;29(5):413-419. doi:10.1002/micr.20647
8. Hage JJ, Winters HA, Van Lieshout J. Fibula free flap phalloplasty: modifications and recommendations. Microsurgery. 1996;17(7):358-365. doi:10.1002/(SICI)1098-2752(1996)17:7<358::AID-MICR3>3.0.CO;2-C
9. Dabernig J, Chan LK, Schaff J. Phalloplasty with free (septocutaneous) fibular flap sine fibula. J Urol. 2006;176(5):2085-2088. doi:10.1016/j.juro.2006.07.036
10. Cho BC, Kim SY, Park JW, Baik BS. Blood supply to osteocutaneous free fibula flap and peroneus longus muscle: prospective anatomic study and clinical applications. Plast Reconstr Surg. 2001;108(7):1963-1971. doi:10.1097/00006534-200112000-00019
11. Ferrin PC, Burghardt E, Xu J, Peters BR. Optimizing neurorrhaphy to improve sensation in phalloplasty: a systematic review. Int J Impot Res. 2026;38(4):324-332. doi:10.1038/s41443-025-01021-w
12. Pototschnig H, Schaff J, Kovacs L, Biemer E, Papadopulos NA. The free osteofasciocutaneous fibula flap: clinical applications and surgical considerations. Injury. 2013;44(3):366-369. doi:10.1016/j.injury.2013.01.007
13. 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
14. Papadopulos NA, Schaff J, Biemer E. Long-term fate of the bony component in neophallus construction with free osteofasciocutaneous forearm or fibula flap in 18 female-to-male transsexuals. Plast Reconstr Surg. 2002;109(3):1025-1030. doi:10.1097/00006534-200203000-00035
15. Ling XF, Peng X. What is the price to pay for a free fibula flap? A systematic review of donor-site morbidity following free fibula flap surgery. Plast Reconstr Surg. 2012;129(3):657-674. doi:10.1097/PRS.0b013e3182402d9a
16. Buyuktopcu O, Baysal O, Agirdil Y, et al. Midterm donor site morbidity after vascularized free fibula flap harvesting. Foot Ankle Int. 2024;45(4):364-372. doi:10.1177/10711007241226620
17. Feuvrier D, Sagawa Y, Beliard S, Pauchot J, Decavel P. Long-term donor-site morbidity after vascularized free fibula flap harvesting: clinical and gait analysis. J Plast Reconstr Aesthet Surg. 2016;69(2):262-269. doi:10.1016/j.bjps.2015.10.007
18. Di Giuli R, Zago M, Beltramini GA, et al. Donor-site morbidity after osteocutaneous free fibula transfer: longitudinal analysis of gait performance. J Oral Maxillofac Surg. 2019;77(3):648-657. doi:10.1016/j.joms.2018.10.016
19. de Lange JWD, Hundepool CA, Duraku LS, et al. Neuropathic pain at the donor-site following free fibula flap harvest: a multicenter study. J Plast Reconstr Aesthet Surg. 2025;102:396-403. doi:10.1016/j.bjps.2025.01.021
20. Falcone M, Preto M, Blecher G, Timpano M, Gontero P. "Total phallic construction techniques in transgender men: an updated narrative review." Transl Androl Urol. 2021;10(6):2583-2595. doi:10.21037/tau-20-1340
21. Klein S, Van Lienden KP, Van't Veer M, Smit JM, Werker PMN. "Evaluation of the lower limb vasculature before free fibula flap transfer. A prospective blinded comparison between magnetic resonance angiography and digital subtraction angiography." Microsurgery. 2013;33(7):539-544. doi:10.1002/micr.22146
22. Wu SH, Shen BH, Perng CK, et al. "Complications of free-flap procedures for phalloplasty in female-to-male transgender surgery: 25-year experience a single medical center." J Chin Med Assoc. 2022;85(3):341-345. doi:10.1097/JCMA.0000000000000677
23. Tinajero JD, Liang DGK, Wasay S, Djordjevic ML, Di Taranto G. "The evolution of phalloplasty for masculinizing gender affirming surgery: a systematic review of surgical techniques and complications over the past 25 years." Microsurgery. 2026;46(6):e70273. doi:10.1002/micr.70273
24. Gaston J, Fodor R, Rampazzo A, Fascelli M, Bassiri Gharb B. "Recipient Vessel Selection in Free Flap Phalloplasty: A Systematic Review and Single-Arm Meta-Analysis." Microsurgery. 2026;46(5):e70251. doi:10.1002/micr.70251