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Ventral Onlay Oral Mucosal Graft Urethroplasty

Ventral onlay oral mucosal graft (OMG) urethroplasty is a well-established substitution urethroplasty technique in which a free buccal (or lingual) mucosal graft is placed on the ventral surface of the opened urethra, supported by the underlying corpus spongiosum. It is the second most commonly used graft placement approach among reconstructive urologists (34% ventral vs 66% dorsal for bulbar strictures) and offers equivalent success rates to dorsal onlay with a potential advantage in preserving erectile function.[1][2]

For the dorsal alternative, see Dorsal Onlay OMG Urethroplasty. For graft material, see Buccal Mucosa Graft. For the focal-obliterative-segment hybrid, see Augmented Anastomotic Urethroplasty.

Indications​

  • Proximal bulbar urethral strictures — where the thick corpus spongiosum provides excellent mechanical and vascular support to the graft[3][4]
  • Bulbar strictures too long for excision and primary anastomosis (generally >2 cm)[4][5]
  • Bulbomembranous strictures post-TURP or post-prostatectomy[6]
  • Non-traumatic strictures of various etiologies (idiopathic, iatrogenic, inflammatory)[3]
  • Female urethral strictures — ventral onlay is the preferred approach in women, with the graft supported by periurethral fascia[7]

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.[8]

Rationale for ventral placement​

The ventral approach is particularly suited to the proximal bulbar urethra because:[3][4][10]

  • The corpus spongiosum is thickest in the proximal bulb, providing a robust vascularized bed for graft take via imbibition and inosculation.
  • The technique requires less urethral mobilization than the classic dorsal onlay (Barbagli) — the urethra does not need to be rotated 180°.
  • There is no dissection of the intercrural space, which may reduce the risk of injury to the cavernosal neurovascular bundles.[10]
  • The ventral surface is more directly accessible through a perineal approach.

Surgical Technique​

Positioning and exposure​

  • Patient in high lithotomy; perineal midline incision.
  • The bulbospongiosus muscle is divided in the midline to expose the corpus spongiosum.[3][4]

Key steps​

  1. Ventral urethrotomy — the corpus spongiosum is incised ventrally in the midline through the strictured segment. The urethrotomy extends into healthy urethra proximally and distally.[3][4]
  2. Stricture assessment — the urethral lumen is inspected; the length and severity of the stricture confirmed. The urethra is not mobilized circumferentially from the corpora cavernosa — a critical distinction from the dorsal onlay technique.[4][10]
  3. Graft harvest — buccal mucosa from the inner cheek (or lingual mucosa from the undersurface of the tongue). The graft is defatted and tailored, typically matching the length and width of the urethrotomy.[3][8]
  4. Graft placement — the oral mucosal graft is placed on the ventral urethral surface with the epithelial side facing the lumen. Sutured to the urethrotomy edges with interrupted or running absorbable sutures (typically 5-0 or 6-0 polyglycolic acid).[3][4]
  5. Spongioplasty — the corpus spongiosum is closed over the graft in the midline, providing a vascularized tissue bed that supports graft take and prevents graft sacculation or diverticulum formation. This is a critical step unique to the ventral approach.[11]
  6. Closure — bulbospongiosus muscle and perineal tissues closed in layers. Urethral catheter (typically 16–18 Fr) left in place.[3]

Spongioplasty and pseudospongioplasty​

Spongioplasty — closure of the corpus spongiosum over the ventral graft — is essential for graft stabilization and vascularization. However, in the pendulous and distal bulbar urethra, the spongiosum is often too thin for adequate coverage. In these cases, pseudospongioplasty can be performed: periurethral vascularized tissue flaps are mobilized bilaterally and sutured together in the midline to cover the graft. This achieves equivalent success to conventional spongioplasty (80% vs 84%, p = 0.645).[11]

Outcomes​

StudynSuccessFollow-upKey Findings
Barbagli 2013 — single center[3]21485.5%median 54 moPreoperative Qmax is the only significant predictor of outcome (OR 1.35, p = 0.001)
Vasudeva 2015 — RCT ventral vs dorsal[12]80 (40 / arm)90% ventral vs 92.5% dorsal12 moNo significant difference in IPSS, Qmax, or success
Shalkamy 2023 — retrospective[13]16587.1% ventral vs 88.3% dorsalmean 52 moComparable ED and voiding outcomes
Mousa 2025 — proximal bulbar in sexually active men[10]13391.7% ventral vs 90.4% dorsal12 moVentral had significantly better IIEF and lower ED rates
Hassan 2025 — meta-analysis[1]655RR 1.00 (no difference)variableTransient ED significantly lower with ventral (RR 0.24, p = 0.006)
Mousa 2024 — post-TURP bulbomembranous[6]3090% (3 recurrences)12 moExcellent functional outcomes; 2 patients with incontinence
Cordon 2014 — pseudospongioplasty[11]10280–84%39–41 moPseudospongioplasty equivalent to conventional spongioplasty

The European Urology systematic review of 41 studies (3,683 patients) concluded that no single technique appears superior for bulbar free-graft urethroplasty, with both dorsal and ventral onlay achieving ≤20% recurrence over medium-term follow-up.[5]

Advantages​

  • Less urethral mobilization — the urethra is not circumferentially mobilized or rotated, potentially preserving dorsal blood supply and reducing operative complexity.[4][10]
  • No intercrural-space dissection — may explain lower transient-ED rates.[3][10]
  • Lower transient ED — Hassan 2025 meta-analysis: RR 0.24 (95% CI 0.08–0.67, p = 0.006) vs dorsal.[1]
  • Technically straightforward access — ventral surface directly accessible through a standard perineal incision without urethral rotation.[4]
  • Excellent graft bed in the proximal bulb — thick spongiosum provides robust vascular support.[3]
  • Applicable to female urethral strictures — ventral onlay with periurethral fascia support achieves 98% success in women.[7]

Disadvantages and Limitations​

  • Risk of graft sacculation / diverticulum — without the rigid support of the corpora cavernosa (as in dorsal onlay), the graft may sacculate ventrally, particularly if spongioplasty is inadequate. This is the most commonly cited theoretical disadvantage.[9]
  • Dependent on adequate spongiosum — in the pendulous urethra and distal bulbar urethra, the thin spongiosum may not provide sufficient graft coverage, necessitating pseudospongioplasty.[11]
  • Not ideal for penile strictures — ventral onlay of buccal mucosa in the penile urethra is associated with higher recurrence; dorsal onlay or staged procedures are preferred for penile strictures.[9][14]
  • More technique-dependent — dorsal onlay is considered possibly less dependent on surgical expertise because the graft is supported by the rigid corpora cavernosa, making it potentially more suitable for surgeons newer to urethroplasty.[9]
  • Complications with longer follow-up — in series with longer follow-up, complications tend to be more prevalent with ventral onlay than dorsal onlay.[9]

Complications​

  • Stricture recurrence — 10–20% over medium-term follow-up; rates increase with longer follow-up.[3][5]
  • Transient ED — 1.6–5% — significantly lower than dorsal onlay in meta-analysis.[1][10][13]
  • Permanent ED — 1.7–3.2%; similar between ventral and dorsal.[1][13]
  • Graft sacculation / diverticulum — rare but unique to ventral placement; minimized by adequate spongioplasty.[9]
  • Wound complications — Clavien-Dindo I–II in ~15–19%.[13]
  • Urinary incontinence — rare (~6.7% in post-TURP bulbomembranous strictures).[6]
  • Fistula — rare.[5]
  • Donor-site morbidity — similar to dorsal onlay (transient oral pain, numbness, mouth-opening difficulty), generally self-limited.[8]

Ventral vs. Dorsal Onlay — Head-to-Head​

ParameterVentral OnlayDorsal Onlay
Success rate85–92%83–94%
Meta-analysis RR (success)1.00 (no difference)—
Transient ED1.6–5%3.9–25%
Permanent ED1.7–3.2%1.9–13.7%
Qmax at 12 monthscomparable (MD −0.57, p = 0.43)—
Urethral mobilizationminimal (no rotation)full circumferential + 180° rotation
Graft bedcorpus spongiosumtunica albuginea of corpora cavernosa
Risk of sacculationhigher (theoretical)lower (rigid corporal support)
Best locationproximal bulbarany bulbar; penile
Surgeon preference (GURS)34%66%
[1][2][10][12][13]

The data on erectile function are conflicting across studies. While the Hassan 2025 meta-analysis and Mousa 2025 found significantly lower transient ED with ventral onlay, Shalkamy 2023 found no significant difference in IIEF scores or ED rates between the two techniques (transient ED 1.6% ventral vs 3.9% dorsal, p = 0.41).[1][10][13] This discrepancy may reflect differences in patient populations, stricture locations (proximal vs distal bulbar), and the extent of urethral mobilization performed.

Combined Dorsal + Ventral Onlay (Gelman / Palminteri Technique)​

For obliterative or near-obliterative strictures not amenable to EPA, a combined approach using both dorsal and ventral buccal grafts can be employed. Gelman and Siegel described a technique where the corpus spongiosum is incised dorsally without transection, buccal mucosa is quilted to the corporal bodies dorsally, and additional buccal mucosa is placed ventrally on the non-transected spongiosum — achieving a 94% success rate (100% after one DVIU) at mean follow-up 50 months.[15]

Special Considerations​

  • Proximal bulbar strictures in sexually active men — ventral onlay may be the preferred approach given significantly better erectile function outcomes in this subgroup (IIEF 28.2 vs 22.1 at 3 months, p < 0.05).[10]
  • Post-TURP bulbomembranous strictures — ventral onlay BMG urethroplasty offers excellent functional outcomes with 90% success and minimal incontinence risk.[6]
  • Female urethral strictures — ventral onlay BMG with periurethral fascia support achieves 98% success at 38 months, with no incontinence.[7]
  • Penile strictures — ventral onlay should generally be avoided in the penile urethra due to higher recurrence; dorsal onlay or staged procedures are preferred.[9][14]
  • Preoperative Qmax as a predictor — in Barbagli's landmark series, preoperative Qmax was the only significant predictor of surgical outcome (OR 1.352, p = 0.001), while age, stricture length, type of stenosis, and previous treatment were not significant predictors.[3]

Videos​

Ventral Onlay BMG Urethroplasty
Operative technique
Ventral Onlay BMG Urethroplasty
Operative technique
Ventral Onlay BMG Urethroplasty
Operative technique

References​

  1. 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.
  2. 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.
  3. Barbagli G, Montorsi F, Guazzoni G, et al. Ventral oral mucosal onlay graft urethroplasty in nontraumatic bulbar urethral strictures: surgical technique and multivariable analysis of results in 214 patients. Eur Urol. 2013;64(3):440-7. doi:10.1016/j.eururo.2013.05.046.
  4. 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.
  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. Mousa A, Eissa A, Rawal AY, Zoeir A. Outcomes of ventral onlay buccal mucosal graft urethroplasty in bulbomembranous urethral strictures post-transurethral resection of the prostate. Urology. 2024;186:9-14. doi:10.1016/j.urology.2024.01.018.
  7. Berdondini E, Eissa A, Margara A, et al. Ventral onlay buccal mucosa graft urethroplasty for female urethral stricture: medium-term results in a single surgeon experience. Urology. 2024;193:194-200. doi:10.1016/j.urology.2024.06.045.
  8. 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.
  9. 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.
  10. Mousa A, Eissa A, Raheem AA, Zoeir A. Ventral versus dorsal onlay buccal mucosal graft urethroplasty for non-traumatic proximal bulbar urethral strictures in sexually active men: erectile and urinary functions. World J Urol. 2025;43(1):87. doi:10.1007/s00345-025-05441-7.
  11. Cordon BH, Zhao LC, Scott JF, Armenakas NA, Morey AF. Pseudospongioplasty using periurethral vascularized tissue to support ventral buccal mucosa grafts in the distal urethra. J Urol. 2014;192(3):804-7. doi:10.1016/j.juro.2014.03.003.
  12. Vasudeva P, Nanda B, Kumar A, et al. Dorsal versus ventral onlay buccal mucosal graft urethroplasty for long-segment bulbar urethral stricture: a prospective randomized study. Int J Urol. 2015;22(10):967-71. doi:10.1111/iju.12859.
  13. 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.
  14. 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.
  15. Gelman J, Siegel JA. Ventral and dorsal buccal grafting for 1-stage repair of complex anterior urethral strictures. Urology. 2014;83(6):1418-22. doi:10.1016/j.urology.2014.01.024.