Phallic Urethra: Prelaminated Buccal Mucosa Graft
Prelaminated buccal mucosa graft (BMG) phallic urethral construction is a staged strategy in which mucosa is grafted onto the future phalloplasty flap before transfer, allowed to vascularize in situ, and later tubularized as the pars pendulans when the flap is raised. The concept is biologically attractive, but reported urethral outcomes differ across series using different graft materials, flaps, and staging.[1][2] In the largest single-center ALT phalloplasty comparison, skin-graft prelamination had the highest urethral complication rate of the pars pendulans methods compared.[1][2][3]
For the reference tube-in-tube pathway, see Phallic Urethra: Tube-in-Tube and Pars Pendulans Construction. For oral graft biology and harvest principles, see Buccal Mucosa Graft.
Concept
Prelamination places a free graft into a flap before transfer so it can vascularize as part of the flap; prefabrication introduces a vascular pedicle into tissue before transfer.[22] The central problem is that a circumferential free graft placed into a marginal bed contracts and strictures. Prelamination attempts to avoid this by giving the graft time to inosculate, revascularize, and stabilize before tubularization.[3][4]
| Stage | Goal |
|---|---|
| Stage 1: graft placement | Harvest mucosa or skin and inset it onto the planned flap bed, such as forearm fascia or ALT undersurface |
| Maturation interval | Allow vascular ingrowth and inflammatory settling, often over months rather than weeks |
| Stage 2: flap transfer | Raise the composite flap, tubularize the grafted strip as the pars pendulans, and wrap remaining flap tissue as shaft |
| Urethral continuity | Anastomose the pars pendulans to the pars fixa at the phallus base |
The term "prelaminated BMG" should be used carefully. Much of the high-complication clinical phalloplasty literature involves skin-graft prelamination, not buccal mucosa specifically. A 21-patient retrospective RFFF series used vaginal and/or buccal mucosa and reported fistula in 6/21 (3/21 needing surgery) and stricture in 4/21, without graft-specific outcomes or postoperative follow-up duration.[20] BMG is hairless and used in urethroplasty, but whether primary BMG prelamination improves phalloplasty outcomes over skin-graft prelamination has not been established.[1][2][5][6]
Why Buccal Mucosa Is Attractive
BMG is the dominant graft material for urethroplasty because it is hairless, pliable, wet-environment tolerant, and supported by a vascular lamina propria. In a 2022 survey of 134 responding GURS members, 99% preferred buccal mucosa as their primary graft harvest site, and the AUA urethral stricture guideline states that surgeons should use oral mucosa as the first choice when using grafts for urethroplasty .[5][6]
| Feature | Relevance to Phallic Urethra |
|---|---|
| Hairless mucosa | Avoids intraurethral hair, stone, infection, and obstruction risk |
| Thick nonkeratinized epithelium | Better suited to a urinary channel than hair-bearing skin |
| Vascular lamina propria | Supports graft take by imbibition and inosculation |
| Low contracture tendency relative to skin | Theoretically reduces circumferential narrowing |
| Donor availability | Cheek, lip, and lingual mucosa can extend graft length |
The 2026 narrative review of buccal mucosa emphasizes that BMG biology remains more nuanced than "good graft material": its regenerative behavior, epithelial thickness, elastin-rich lamina propria, inflammatory profile, and future tissue-engineering directions are still active research areas.[7]
Technique
Stage 1: Prelamination
| Step | Technical Point |
|---|---|
| Mucosa harvest | Harvest buccal mucosa from one or both cheeks depending on desired urethral length |
| Flap-bed preparation | Expose the deep surface of the future phalloplasty flap, such as volar forearm fascia or ALT undersurface |
| Graft inset | Secure and quilt a flat graft to the flap bed without shear, preserving its orientation and a smooth future lumen; in a described mixed-mucosal RFFF protocol, mucosa is formed into a tube around a catheter during prelamination.[20] |
| Maturation | Allow graft vascular ingrowth and inflammatory settling, and confirm graft take before flap transfer. A mixed-mucosal RFFF series transferred at a mean 60.3 days (range 37–126); a separate vaginal-mucosa protocol used six months. Neither establishes a BMG-specific interval.[20][2] |
| Monitoring | Assess graft take, contraction, scarring, and donor-site suitability before committing to flap transfer |
Stage 2: Phalloplasty
| Step | Technical Point |
|---|---|
| Composite flap elevation | Raise the flap with the prelaminated mucosa incorporated |
| Tubularization | Roll a flat grafted strip around a catheter at transfer if that is the selected technique; if mucosa was tubularized around a catheter during prelamination, preserve that tube during flap elevation and transfer.[20] |
| Outer shaft construction | Wrap the remaining flap tissue around the urethral tube |
| Transfer | Perform pedicled or free flap transfer according to donor site and center practice |
| Anastomosis | Connect to the pars fixa without tension and protect the junction with vascularized tissue when possible |
The biologic weak point is the graft-flap interface. Even if the graft appears mature, elevation, shear, tubularization, and transfer can compromise perfusion or provoke contraction.
Clinical Outcomes
D'Arpa and colleagues retrospectively compared urethral techniques in 93 ALT phalloplasties, including 79 performed for gender affirmation. Urethral fistula or stricture occurred in 7/8 skin-graft prelaminations (87.5%), compared with 11/29 RFFF urethral flaps (37.9%), 10/38 SCIP urethral flaps (26.3%), and 1/5 tube-in-tube ALT urethras (20%).[1] The authors described flap prelamination as a second choice that gives high stricture rates.[1]
Hu and colleagues' 2022 meta-analysis (21 studies, 1,566 patients) found prelaminated flaps associated with a significantly higher urethral stricture or stenosis rate than tube-in-tube techniques. It found no difference between prelaminated and second-flap techniques.[3]
| Technique / Material | Series Context | Urethral Signal |
|---|---|---|
| Prelaminated ALT with skin graft | D'Arpa 2019, 8 patients | 87.5% fistula-or-stricture rate[1] |
| Prelaminated flap, meta-analysis | Hu 2022, pooled phalloplasty literature | Higher stricture / stenosis rate than tube-in-tube; no difference from second-flap techniques[3] |
| Tube-in-tube RFFF | Largest evidence base | Commonly used option with substantial fistula and stricture burden; no urethral technique is established as a standard of care[3][8] |
| Second-flap urethra | ALT shaft with RFFF urethral flap | Intermediate outcomes; D'Arpa reported 37.9% urethral complications[1][9] |
| SCIP urethral flap | ALT urethral-reconstruction series | 26.3% urethral complications in D'Arpa (38 patients), the lowest rate among the larger second-flap groups[1] |
| Prelaminated vaginal mucosa on a phalloplasty flap | Zhang 2015, 22 patients | 31.8% fistula, 4.5% stricture; single-center, retrospective and not BMG[2] |
Vaginal Mucosa Variant
Zhang and colleagues described vaginal mucosal graft prelamination for female-to-male urethral reconstruction. Vaginal mucosa was grafted onto the flap and matured for 6 months before phalloplasty. Histology showed similarity to buccal mucosa and urethral epithelium, and the series reported a low 4.5% stricture rate but a 31.8% fistula rate.[2]
Why Prelamination Fails
| Failure Mechanism | Practical Consequence |
|---|---|
| Incomplete graft take | Tubularization converts marginal take into circumferential stricture |
| Graft contraction | Even mature grafts can contract after being rolled into a tube |
| Shear during flap elevation | Separates graft from its induced vascular bed |
| Thick flap substrate | ALT bulk and hair pattern make tube formation less forgiving |
| Skin graft biology | Keratinization, hair, and contracture are worse than mucosal substitutes |
| Uncertain maturation interval | Too little time risks poor take; too much time may allow fibrosis |
Preclinical Direction
Guo and colleagues tested capsule-based BMG prefabrication in rabbit models. A tissue expander capsule was used as an induced vascular bed, then BMG was placed onto the capsule and later used for tubularized urethral reconstruction.[4][10] The prefabricated capsule-BMG construct maintained wider urethral caliber than free BMG alone.[4][10]
Lauer and colleagues used tissue-engineered mucosa to prelaminate fascial radial forearm flaps for oral reconstruction, demonstrating the broader reconstructive principle of building a mucosal-lined composite flap before transfer.[11]
BMG for Secondary Stricture Repair
Small series have reported BMG for secondary urethral reconstruction after phalloplasty. This is a separate indication from primary prelamination.
| Repair Context | Technique | Reported Signal |
|---|---|---|
| Neophallus anastomotic stricture | Single-stage double-face BMG urethroplasty with dorsal inlay and ventral onlay | Schardein 2020: 75% without stricture recurrence among 8 patients with follow-up (2 recurrences); 9 underwent repair; mean follow-up was 31 months[12] |
| Post-phalloplasty anastomotic stricture | One- or two-stage BMG-augmented urethroplasty | Beamer 2021: 14 patients with ≥1 year follow-up; recurrence in 2/9 single-stage and 0/5 staged repairs; staged repair used for poor tissue or prior failed augmented urethroplasty[13] |
| Long complex pendulous strictures | Two-stage urethroplasty with BMG augmentation and later tubularization | Schardein 2022: 12% failure in 17 patients; many had prior BMG used during phalloplasty prelamination[14] |
Revision of strictures after the initial urethral strategy has failed is the setting with published BMG series in post-phalloplasty care. All three are retrospective series of 8 to 17 patients.
A simultaneous dorsal inlay plus ventral onlay BMG repair has been described as a preferred configuration when feasible, avoiding circumferential mobilization of the neourethra because it may compromise phallic blood supply. Neoscrotal fat has been used as a Martius-like ventral graft bed; when a gracilis flap from the original phalloplasty is present, it has been split into two tails, one for vaginal-cavity obliteration and the other as the ventral BMG bed.[17]
Excision and primary anastomosis has also been evaluated for post-phalloplasty anastomotic stricture, restricted to isolated, short (<3 cm) strictures. In 44 selected patients, estimated freedom from further urethral manipulation was 47% at 5 years (median follow-up, 40 months).[16]
Current Role
| Scenario | Recommendation |
|---|---|
| RFFF candidate accepts forearm scar and UL risk | Prefer tube-in-tube RFFF or discuss a center-specific staged urethral plan. In a single-surgeon two-stage Big Ben series, 73 first-stage patients had at least 6 months of follow-up, and 71 proceeded to second-stage urethral creation; the authors reported 8% stricture and 16.4% fistula after stage 2.[19] |
| ALT shaft desired | Discuss dedicated RFFF urethral flap or staged skin-graft urethroplasty as center-specific options. Although SCIP urethras appeared favorable in an earlier Ghent series, that center later moved away from ALT-plus-SCIP after complete urethral flap losses.[1][15][18] |
| Prelaminated skin-graft ALT under consideration | Counsel that published complication rates are high and the method is a fallback, not first-line |
| Vaginal mucosa available | Consider as a center-specific option; a later retrospective cohort reported fistula in 8/31 and stricture in 4/31 after vaginal-mucosal prelamination (median follow-up five years), versus 1/10 and 1/10 with an added modified anastomosis (median follow-up two years).[2][23] |
| Failed phalloplasty urethra | BMG has been used for secondary single-stage or staged stricture repair in small series |
| Future tissue-engineered mucosa | — |
Operative Pearls
- Distinguish graft material from technique: skin-graft prelamination, vaginal mucosa prelamination, and BMG prelamination are not interchangeable.
- If prelamination is used, protect the graft-flap interface from shear during both maturation and flap elevation.
- Treat ALT prelamination as a high-risk salvage strategy unless local outcomes prove otherwise.
- EAU 2026 strongly recommends against endoscopic incision or urethroplasty within six months of neophalloplasty; during healing, suprapubic drainage is first-line for retention, recurrent UTI, or obstruction severely affecting quality of life. For neophallic urethral strictures needing open repair, EAU weakly recommends staged urethroplasty; BMG is a graft option when tissue quality and patient goals support urethral salvage.[21]
- For oral harvest biology, donor morbidity and non-GAS urethroplasty use, see the BMG foundations page.
References
1. D'Arpa S, Claes K, Lumen N, et al. Urethral reconstruction in anterolateral thigh flap phalloplasty: a 93-case experience. Plast Reconstr Surg. 2019;143(2):382e-392e. doi:10.1097/PRS.0000000000005278
2. Zhang YF, Liu CY, Qu CY, et al. Is vaginal mucosal graft the excellent substitute material for urethral reconstruction in female-to-male transsexuals? World J Urol. 2015;33(12):2115-2123. doi:10.1007/s00345-015-1562-z
3. 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
4. Guo HL, Jia ZM, Wang L, et al. Tubularized urethral reconstruction using a prevascularized capsular tissue prelaminated with buccal mucosa graft in a rabbit model. Asian J Androl. 2019;21(4):381-386. doi:10.4103/aja.aja_43_19
5. Berg C, Singh A, Hu P, et al. Current trends in the use of buccal grafts during urethroplasty among Society of Genitourinary Reconstructive Surgeons. Urology. 2024;191:139-143. doi:10.1016/j.urology.2024.06.019
6. Wessells H, Morey A, Souter L, Rahimi L, Vanni A. Urethral stricture disease guideline amendment (2023). J Urol. 2023;210(1):64-71. doi:10.1097/JU.0000000000003482
7. Sterling J, Hecksher D, Hayden C, et al. Buccal mucosa a narrative review: how does it work, how is it used, what is coming next. Urology. 2026. doi:10.1016/j.urology.2026.03.015
8. 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
9. van der Sluis WB, Smit JM, Pigot GLS, et al. Double flap phalloplasty in transgender men: surgical technique and outcome of pedicled anterolateral thigh flap phalloplasty combined with radial forearm free flap urethral reconstruction. Microsurgery. 2017;37(8):917-923. doi:10.1002/micr.30190
10. Guo HL, Wang L, Jia ZM, et al. Tissue expander capsule as an induced vascular bed to prefabricate an axial vascularized buccal mucosa-lined flap for tubularized posterior urethral reconstruction: preliminary results in an animal model. Asian J Androl. 2020;22(5):459-464. doi:10.4103/aja.aja_133_19
11. Lauer G, Schimming R, Gellrich NC, Schmelzeisen R. Prelaminating the fascial radial forearm flap by using tissue-engineered mucosa: improvement of donor and recipient sites. Plast Reconstr Surg. 2001;108(6):1564-1572. doi:10.1097/00006534-200111000-00019
12. Schardein J, Beamer M, Hughes M, Nikolavsky D. Single-stage double-face buccal mucosal graft urethroplasty for neophallus anastomotic strictures. Urology. 2020;143:257. doi:10.1016/j.urology.2020.06.010
13. Beamer MR, Schardein J, Shakir N, et al. One or two stage buccal augmented urethroplasty has a high success rate in treating post phalloplasty anastomotic urethral stricture. Urology. 2021;156:271-278. doi:10.1016/j.urology.2021.05.045
14. Schardein J, Beamer M, Kittleman MA, Nikolavsky D. Staged urethroplasty for reconstruction of long complex pendulous strictures of a neophallic urethra. Urology. 2022;164:e309-e311. doi:10.1016/j.urology.2021.12.029
15. Robinson I, Chao BW, Blasdel G, et al. Anterolateral thigh phalloplasty with staged skin graft urethroplasty: technique and outcomes. Urology. 2023;177:204-212. doi:10.1016/j.urology.2023.03.038
16. Verla W, Hoebeke P, Spinoit AF, Waterloos M, Monstrey S, Lumen N. Excision and primary anastomosis for isolated, short, anastomotic strictures in transmen. Plast Reconstr Surg Glob Open. 2020;8(2):e2641. doi:10.1097/GOX.0000000000002641
17. Schardein J, Blakely S, Nikolavsky D. Management of urologic complications following metoidioplasty and phalloplasty. In: Nikolavsky D, Blakely SA, eds. Urological Care for the Transgender Patient: A Comprehensive Guide. Springer; 2021:141–164. doi:10.1007/978-3-030-18533-6_11
18. De Gelder A, Young-Afat D, Claes K, et al. "Use of the superficial circumflex iliac artery perforator flap for urethra and/or shaft reconstruction in gender-diverse persons: 10-year single-center experience." Plast Reconstr Surg. 2025;155(6):1036e-1044e. doi:10.1097/PRS.0000000000011830
19. Berli JU, Ferrin PC, Buuck C, et al. "Long-term urologic outcomes using the Big Ben method for phalloplasty." Plast Reconstr Surg. 2025;156(2):279e-290e. doi:10.1097/PRS.0000000000012010
20. Salgado CJ, Nugent A, Hadeed J, Lalama M, Rey J, Medina C. "Two-stage prelaminated mucosal neourethra radial forearm flap phalloplasty for transgender men." Glob J Med Res. 2021;21(I1):1-6. doi:10.34257/GJMRIVOL21IS1PG1
21. European Association of Urology. "EAU Guidelines on Urethral Strictures: Disease Management in Transgender Patients." EAU Guidelines. 2026. Guideline chapter
22. Pribaz JJ, Fine NA. "Prelamination: defining the prefabricated flap--a case report and review." Microsurgery. 1994;15(9):618-623. doi:10.1002/micr.1920150903
23. Gao H, Wu D, Kong X, et al. "A novel technique of urethroplasty could reduce urethra-related complications in phalloplasty with urethral lengthening." Sex Med. 2022;10(6):100571. doi:10.1016/j.esxm.2022.100571