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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] It is currently the preferred graft placement approach among reconstructive urologists (66% dorsal vs 34% ventral for bulbar strictures), with a clear trend toward increasing dorsal approaches over the past decade.[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]
  • Post-prostatectomy / post-radiation vesicourethral anastomotic stenosis[10]
  • All etiologies — idiopathic, iatrogenic, traumatic, inflammatory — though lichen sclerosus strictures may be better served by staged repair[11][1]

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]

  • Rapid re-epithelialization and a fetal-like "scarless healing" phenotype
  • Thick non-keratinized epithelium with thin lamina propria — facilitating graft take via imbibition and inosculation
  • Resistant to infection in a wet environment
  • Easily harvested with minimal donor-site morbidity
  • Tolerant of a moist urethral environment
  • 99% of contemporary reconstructive urologists prefer 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 then rotated back to its anatomic position, and the ventral urethral wall is closed over the graft.[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.
  • Advantages — shorter operative time, less blood loss, lower complication rates, and potentially better preservation of erectile function compared to classic Barbagli for long strictures.[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 — post-prostatectomy / radiation[10]84% (7/45 recurrences)median 21 moNo de novo incontinence; significant IPSS improvement
Dorsal vs ventral onlay — meta-analysis[19]RR 1.00 (no difference)variableEquivalent success; ventral may have less transient ED

A large single-center series of 507 bulbar urethroplasties with dorsal BMG reported an overall success rate of 93.9% at mean follow-up 79 months. Notably, pure dorsal onlay was superior to augmented anastomotic urethroplasty (HR 4.8 for recurrence with augmented anastomotic, p = 0.002).[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 permanent ED rates were similar.[19]

Complications​

  • Stricture recurrence — ≤20% at medium term; rates increase with longer follow-up.[5]
  • Transient ED — ~4–6% with dorsal onlay (may be higher than ventral); typically resolves by 12 months.[18][19][21]
  • Permanent ED — rare (~1–2%); similar between dorsal and ventral.[18][19]
  • 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]

The dorsal onlay technique is considered possibly less dependent on surgical expertise and therefore more suitable for surgeons newer to urethroplasty — the graft is supported by the rigid corpora cavernosa, reducing the risk of sacculation or diverticulum formation that can occur with ventral placement.[6]

Postoperative Management​

Perioperative practices vary, but consensus per the Hoare 2021 GURS survey includes:[22]

  • Intraoperative IV antibiotics (97.9%)
  • Urethral catheter for 2–3 weeks (58.5%) or 3–4 weeks (30.1%)
  • Oral antibiotics continued until catheter removal (70%)
  • VCUG or retrograde urethrogram at catheter removal (67.6%) — though some evidence suggests routine imaging may be omitted given low extravasation rates (~3%).[23]
  • Uroflowmetry + PVR at 2–6 months (82%)
  • Cystoscopy at follow-up (57.7%)
  • Sonourethrography combined with uroflowmetry and IPSS may serve as a reliable noninvasive surveillance alternative.[24]

Significant improvements in IPSS, quality of life, and voiding parameters are consistently reported. Patients with good baseline erectile function may experience a transient decline in IIEF-5 scores at first follow-up, with full recovery by 12–17 months.[21]

Special Considerations​

  • Lichen sclerosus — one-stage dorsal onlay has a higher recurrence rate (~50%) compared to staged repair (~80% success); multistage repair with complete excision of diseased urethra is preferred.[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.[25]
  • Post-radiation stenosis — viable option with no de novo incontinence and high patient satisfaction (86.6%).[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. Hoare DT, Doiron RC, Rourke KF. Determining perioperative practice patterns in urethroplasty: a survey of genitourinary reconstructive surgeons. Urology. 2021;156:263-270. doi:10.1016/j.urology.2021.05.067.
  23. Hoy NY, Wood HM, Angermeier KW. The role of postoperative imaging after ventral onlay buccal mucosal graft bulbar urethroplasty. J Urol. 2020;204(6):1270-1274. doi:10.1097/JU.0000000000001311.
  24. Seibold J, Werther M, Alloussi S, et al. Urethral ultrasound as a screening tool for stricture recurrence after oral mucosa graft urethroplasty. Urology. 2011;78(3):696-700. doi:10.1016/j.urology.2011.04.051.
  25. 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.