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Dorsal Onlay Oral Mucosal Graft Urethroplasty

Dorsal onlay oral mucosal graft (OMG) urethroplasty is the most widely used substitution urethroplasty technique for anterior urethral strictures not amenable to excision and primary anastomosis. First described by Barbagli in 1996, it places a free oral mucosal graft on the dorsal surface of the opened urethra, secured against the corpora cavernosa.[1][2] In a 2024 GURS survey, 66% of respondents preferred dorsal placement for bulbar grafting (134 responses from 350 invitees). This measures responding surgeons’ practice, not proof of superiority.[3][4]

For graft details, see Buccal Mucosa Graft. For the augmented anastomotic alternative, see Augmented Anastomotic Urethroplasty. For the muscle-sparing one-sided variant for long-segment / panurethral disease, see Muscle-Sparing Urethroplasty.

Indications​

  • Bulbar urethral strictures too long for EPA (generally >2 cm)[1][5]
  • Penile urethral strictures — one-stage dorsal onlay or staged procedures[6][7]
  • Panurethral / long-segment strictures — using the Kulkarni modification[8][9]
  • Selected nonobliterative anastomotic / bulbomembranous stenosis after both prostatectomy and radiation[10]
  • Etiology and tissue quality guide selection; single-stage oral mucosa remains an option in lichen sclerosus when local conditions are suitable.[23]

The AUA Urethral Stricture Disease Guideline (2023) recommends oral mucosa as the first-choice graft material for substitution urethroplasty, with buccal and lingual mucosal grafts considered equivalent alternatives.[12]

Why buccal / oral mucosa?​

Buccal mucosa possesses unique biological properties that make it an ideal graft material:[1][13]

  • Favorable mucosal wound-healing biology; clinical repairs can still scar or recur
  • Thick non-keratinized epithelium with thin lamina propria — facilitating graft take via imbibition and inosculation
  • Adapted to a moist environment; infection can still compromise reconstruction
  • Accessible donor site, with possible pain, numbness and restricted mouth opening
  • Tolerant of a moist urethral environment
  • 99% of respondents in the GURS survey selected buccal mucosa as the primary graft site[3]

Surgical Technique​

Three principal dorsal approaches exist, each with distinct technical features.

1. Barbagli technique (classic dorsal onlay)​

  • Lithotomy position; perineal midline incision.
  • The bulbar urethra is fully mobilized circumferentially from the corpora cavernosa.
  • The urethra is rotated 180° to expose the dorsal surface.
  • A dorsal urethrotomy is performed through the strictured segment.
  • The buccal mucosal graft (harvested from the inner cheek) is sutured to the edges of the urethrotomy and quilted to the tunica albuginea of the corpora cavernosa, providing a well-vascularized bed.
  • The urethra is rotated back and both margins of the dorsal urethrotomy are apposed to the graft edges, completing the augmented lumen. The ventral urethral wall remains intact in the classic dorsal-onlay operation.[2][14][15]

2. Kulkarni technique (dorsolateral onlay, one-sided dissection)​

  • Designed for long-segment and panurethral strictures.
  • The urethra is mobilized from one side only, preserving the contralateral blood supply and the central perineal tendon attachments.
  • Penile invagination through the perineal incision allows access to the entire anterior urethra without a separate penile incision.
  • The graft is placed in a dorsolateral position.
  • A retrospective comparison reported shorter operating time and less blood loss than circumferential dissection; preservation of contralateral attachments is the anatomical rationale, not proof that sexual complications are prevented.[8][9][16]

3. Asopa technique (dorsal inlay)​

  • A ventral sagittal urethrotomy is performed without mobilizing the urethra from the corpora.
  • Through this ventral opening, a dorsal urethrotomy is made, and the graft is inlaid into the dorsal wall and sutured to the corpora cavernosa.
  • Avoids circumferential urethral mobilization entirely.[1]

Graft harvest​

  • Buccal mucosa is harvested from the inner cheek (most common); grafts typically 2.5–13 cm in length.[2][14]
  • For long grafts, 56% of surgeons prefer harvesting from both cheeks.[3]
  • The donor site may be left open or closed — a randomized trial demonstrated non-closure is non-inferior to closure regarding oral pain and morbidity.[17]

Outcomes​

TechniqueSuccessFollow-upKey Findings
Dorsal onlay (Barbagli) — bulbar[1][2][5][14]83–97%21–79 moGold standard; ≤20% recurrence at medium term
Dorsal onlay — penile[6][7]67–87%variableBest results with staged approach for complex cases
Kulkarni (dorsolateral) — long / panurethral[8][9][16]87–90%12–60 moLess blood loss, shorter OR time vs classic Barbagli
Dorsal onlay — after both prostatectomy and radiation[10]84% (7/45 recurrences)median 21 mo among those without recurrence28/45 were already incontinent; no new incontinence observed
Dorsal vs ventral onlay — meta-analysis[19]RR 1.00 (no difference)variableNo significant success difference; imprecise sexual outcomes

A single-center retrospective study included 507 bulbar graft repairs: 221 augmented anastomotic and 286 pure dorsal onlay. The combined success was 93.9% at mean 78.9 months. Augmented anastomotic repair was associated with recurrence after adjustment (HR 4.8, p = 0.002), but treatment selection and an institutional technique change over time limit causal interpretation.[20]

A 2025 meta-analysis of 8 studies (655 patients) found no significant difference in success between dorsal and ventral onlay (RR 1.00, 95% CI 0.94–1.06), with comparable Qmax at 3 and 12 months. However, transient ED was significantly lower with the ventral technique (RR 0.24, p = 0.006), while the estimate for permanent ED was too imprecise to establish a difference or equivalence (RR 0.57, 95% CI 0.03–12.20).[19]

Complications​

  • Stricture recurrence — ≤20% at medium term; rates increase with longer follow-up.[5]

  • Sexual-function change — counsel and measure against baseline; transient and persistent ED estimates vary substantially between cohorts. The meta-analysis does not establish a universal dorsal-onlay ED rate or recovery deadline.[18][19][21]

  • Wound infection / hematoma — Clavien-Dindo I–II in ~15–18%.[18]

  • Postvoid dribbling — up to 45% with long-segment repairs.[9]

  • Chordee — ~25% (usually transient) with panurethral repairs.[9]

  • Fistula — rare (~2%).[11]

  • Donor-site morbidity — oral pain (median VAS 3/10 at first follow-up, resolving to 0 by 17 months), transient numbness (~9%), temporary difficulty with mouth opening — generally self-limited.[14][17][21]

Graft support against the corpora can limit sacculation, but it does not replace expertise in tissue handling and reconstruction. The EAU-panel systematic review found no clear best free-graft placement for all bulbar strictures.[5]

Postoperative Management​

Use culture-directed treatment of preoperative infection/bacteriuria and an intraoperative prophylactic regimen chosen for local resistance patterns. Current EAU guidance finds no evidence that routine prolonged antibiotics through catheter removal reduce infections.[24]

A urethral catheter commonly remains for two to three weeks, adjusted to repair complexity and healing. Assess for extravasation with validated urethrography before removal; maintain drainage and reassess significant leakage. Follow-up includes symptoms, uroflowmetry and PVR, with anatomical reassessment guided by the reconstruction and recurrence risk.[24]

Patient-reported voiding improvement is common, but sexual recovery is variable and should not be promised by a fixed postoperative date.[21]

Special Considerations​

  • Lichen sclerosus — EAU recommends single-stage oral mucosa when local conditions permit; staged reconstruction remains an option for adverse local conditions. Do not use genital skin. An older 13-patient LS subgroup cannot support a general claim that staged repair is superior.[23][11]
  • Pediatric — dorsal onlay BMG urethroplasty (Barbagli and Kulkarni techniques) is safe and feasible in children with long-segment non-hypospadias strictures, with success rates of 83–88% at median follow-up 90–96 months.[22]
  • After prostatectomy plus radiation — the 45-patient Sterling cohort supports feasibility in selected patients; 7 recurred, and 28 already had incontinence. Absence of new incontinence in this cohort is not a guarantee for all radiated stenoses.[10]

Videos​

Dorsal Onlay BMG Urethroplasty
Operative technique
Dorsal Onlay BMG Urethroplasty
Step-by-step demonstration
Dorsal Onlay BMG Urethroplasty
Operative technique

References​

  1. Horiguchi A. Substitution urethroplasty using oral mucosa graft for male anterior urethral stricture disease: current topics and reviews. Int J Urol. 2017;24(7):493-503. doi:10.1111/iju.13356.

  2. Barbagli G, Palminteri E, Rizzo M. Dorsal onlay graft urethroplasty using penile skin or buccal mucosa in adult bulbourethral strictures. J Urol. 1998;160(4):1307-9.

  3. 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.

  4. Cotter KJ, Hahn AE, Voelzke BB, et al. Trends in urethral stricture disease etiology and urethroplasty technique from a multi-institutional surgical outcomes research group. Urology. 2019;130:167-174. doi:10.1016/j.urology.2019.01.046.

  5. Barratt R, Chan G, La Rocca R, et al. Free graft augmentation urethroplasty for bulbar urethral strictures: which technique is best? A systematic review. Eur Urol. 2021;80(1):57-68. doi:10.1016/j.eururo.2021.03.026.

  6. Patterson JM, Chapple CR. Surgical techniques in substitution urethroplasty using buccal mucosa for the treatment of anterior urethral strictures. Eur Urol. 2008;53(6):1162-71. doi:10.1016/j.eururo.2007.10.011.

  7. Jasionowska S, Bochinski A, Shiatis V, et al. Anterior urethroplasty for the management of urethral strictures in males: a systematic review. Urology. 2022;159:222-234. doi:10.1016/j.urology.2021.09.003.

  8. Takekawa K, Horiguchi A, Shinchi M, et al. One-sided dorsal onlay urethroplasty with penile invagination (Kulkarni urethroplasty) for complex anterior urethral strictures: a single-center experience. Int J Urol. 2025;32(6):749-755. doi:10.1111/iju.70048.

  9. Spencer J, Blakely S, Daugherty M, et al. Clinical and patient-reported outcomes of 1-sided anterior urethroplasty for long-segment or panurethral strictures. Urology. 2018;111:208-213. doi:10.1016/j.urology.2017.08.029.

  10. Sterling J, Simhan J, Flynn BJ, et al. Multi-institutional outcomes of dorsal onlay buccal mucosal graft urethroplasty in patients with postprostatectomy, postradiation anastomotic stenosis. J Urol. 2024;211(4):596-604. doi:10.1097/JU.0000000000003848.

  11. Levine LA, Strom KH, Lux MM. Buccal mucosa graft urethroplasty for anterior urethral stricture repair: evaluation of the impact of stricture location and lichen sclerosus on surgical outcome. J Urol. 2007;178(5):2011-5. doi:10.1016/j.juro.2007.07.034.

  12. 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.

  13. 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:S0090-4295(26)00169-X. doi:10.1016/j.urology.2026.03.015.

  14. Pfalzgraf D, Kluth L, Isbarn H, et al. The Barbagli technique: 3-year experience with a modified approach. BJU Int. 2013;111(3 Pt B):E132-6. doi:10.1111/j.1464-410X.2012.11399.x.

  15. Pansadoro V, Emiliozzi P, Gaffi M, et al. Buccal mucosa urethroplasty in the treatment of bulbar urethral strictures. Urology. 2003;61(5):1008-10. doi:10.1016/s0090-4295(02)02585-2.

  16. Kartal I, Çimen S, Kokurcan A, et al. Comparison between dorsal onlay and one-sided dorsolateral onlay buccal mucosal graft urethroplasty in long anterior urethral strictures. Int J Urol. 2020;27(9):719-724. doi:10.1111/iju.14286.

  17. Soave A, Dahlem R, Pinnschmidt HO, et al. Substitution urethroplasty with closure versus nonclosure of the buccal mucosa graft harvest site: a randomized controlled trial with a detailed analysis of oral pain and morbidity. Eur Urol. 2018;73(6):910-922. doi:10.1016/j.eururo.2017.11.014.

  18. Shalkamy O, Elatreisy A, Salih E, et al. Erectile and voiding function outcomes after buccal mucosa graft urethroplasty for long-segment bulbar urethral stricture: ventral versus dorsal onlay technique. World J Urol. 2023;41(1):205-210. doi:10.1007/s00345-022-04220-y.

  19. Hassan AA, Soliman AM, Shouman HA, et al. Dorsal- vs ventral-onlay buccal mucosal graft urethroplasty for urethral strictures: a meta-analysis. BJU Int. 2025. doi:10.1111/bju.16811.

  20. Redmond EJ, Hoare DT, Rourke KF. Augmented anastomotic urethroplasty is independently associated with failure after reconstruction for long bulbar urethral strictures. J Urol. 2020;204(5):989-995. doi:10.1097/JU.0000000000001177.

  21. D'hulst P, Muilwijk T, Vander Eeckt K, Van der Aa F, Joniau S. Patient-reported outcomes after buccal mucosal graft urethroplasty for bulbar urethral strictures: results of a prospective single-centre cohort study. BJU Int. 2020;126(6):684-693. doi:10.1111/bju.15131.

  22. Patil N, Javali T. Paediatric buccal mucosal graft urethroplasty for non-hypospadias urethral strictures: a single centre experience with long term outcomes. Urology. 2021;158:174-179. doi:10.1016/j.urology.2021.06.029.

23. EAU Guidelines on Urethral Strictures, 2026: disease management in males. https://uroweb.org/guidelines/urethral-strictures/chapter/disease-management-in-males. Accessed September 12, 2026.

24. EAU Guidelines on Urethral Strictures, 2026: perioperative care. https://uroweb.org/guidelines/urethral-strictures/chapter/perioperative-care-of-urethral-surgery. Accessed September 12, 2026.