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Asopa Dorsal Inlay OMG Urethroplasty

Asopa urethroplasty — also called the dorsal inlay technique — is a single-stage substitution urethroplasty in which a buccal mucosal graft is placed into the dorsal urethral wall through a ventral sagittal urethrotomy, without circumferential mobilization of the urethra. First described by Asopa et al. in 2001, it combines the advantages of dorsal graft placement (rigid corporal support) with the simplicity of ventral access, avoiding circumferential mobilization; one small randomized comparison reported shorter operating time than classic Barbagli dorsal onlay.[1][2][3]

For the dorsal-onlay alternative, see Dorsal Onlay OMG Urethroplasty. For the ventral-onlay alternative, see Ventral Onlay OMG Urethroplasty. For graft material, see Buccal Mucosa Graft.

Concept and Rationale​

The Asopa technique was developed to address the technical complexity of the Barbagli dorsal onlay, which requires full circumferential urethral mobilization and 180° rotation. The key innovation: the graft is placed dorsally (against the tunica albuginea of the corpora cavernosa) but accessed ventrally — avoiding the need to mobilize the urethra from its bed. This preserves the lateral and dorsal urethral blood supply while still providing the rigid corporal backing that promotes graft take and provides mechanical support.[1][3]

Particularly well-suited for:

  • Penile urethral strictures — a one-stage option when tissue quality and the residual urethral plate permit augmentation[3][4]
  • Long anterior strictures — where circumferential mobilization would be extensive and potentially devascularizing[1]
  • Recurrent strictures — where prior surgery may have compromised the periurethral tissue planes[1]

Surgical Technique​

Step-by-step​

  1. Patient positioning — lithotomy; perineal midline incision for bulbar strictures, or circumcoronal / penile incision for penile strictures.[1][2]
  2. Exposure of the urethra — corpus spongiosum exposed ventrally. Critically, the urethra is not mobilized circumferentially from the corpora cavernosa — it remains in its anatomic bed.[1][3]
  3. Ventral sagittal urethrotomy — the urethra is incised ventrally through the strictured segment in the midline, opening the urethral lumen. The incision extends into healthy urethra proximally and distally.[1][2]
  4. Dorsal urethrotomy — through the ventral opening, the dorsal urethral wall is incised in the midline (a second sagittal incision), exposing the underlying tunica albuginea of the corpora cavernosa. This creates a raw, well-vascularized bed on the corporal surface.[1][3]
  5. Graft harvest and preparation — buccal mucosa harvested from the inner cheek, defatted, and tailored.[1]
  6. Graft inlay — the buccal mucosal graft is inlaid into the dorsal urethral defect with the epithelial surface facing the urethral lumen. Graft edges sutured to the edges of the dorsal urethrotomy with interrupted absorbable sutures (typically 5-0 or 6-0). The graft is quilted to the tunica albuginea of the corpora cavernosa with additional sutures to ensure close apposition and prevent graft displacement.[1][2][3]
  7. Retubularization — the ventral urethrotomy is closed over a urethral catheter (typically 16–18 Fr), reconstituting the tubular urethra. Corpus spongiosum and overlying tissues closed in layers.[1][2]

"Inlay" vs. "Onlay" — the key distinction​

The Asopa technique is a dorsal inlay — the graft is placed into the dorsal wall of the urethra through a window created by the dorsal urethrotomy. This contrasts with the Barbagli dorsal onlay, where the graft bridges a dorsal urethrotomy after mobilization and rotation; it is not placed over intact dorsal urethral mucosa. Both techniques achieve dorsal graft placement against the corpora cavernosa, but the surgical access and degree of urethral mobilization differ fundamentally.[2][3]

Advantages Over Barbagli Dorsal Onlay​

The Asopa technique offers several practical advantages:[1][2][3]

  • No circumferential urethral mobilization — urethra remains in its bed, preserving lateral and dorsal blood supply. This is the most significant advantage.
  • Significantly shorter operative time — RCT: 128 ± 5 min (Asopa) vs 205 ± 20 min (Barbagli), p < 0.0001.[2]
  • Significantly less blood loss — 105 ± 12 mL (Asopa) vs 228 ± 5 mL (Barbagli), p < 0.0001.[2]
  • Technically easier — ventral approach is more familiar to most urologists, and the technique avoids the challenging step of circumferential dissection and urethral rotation.[1][2]
  • Dorsal graft support maintained — despite the ventral access, the graft is still placed against the rigid tunica albuginea, providing the same mechanical support as Barbagli and reducing the risk of graft sacculation.[1][3]

Outcomes​

StudynStricture LocationSuccessFollow-upKey Findings
Pisapati 2009[1]45 evaluated of 58 operatedAnterior, including complex/recurrent cases39/45 (87%)mean 42 mo5 fistulas and 7 wound infections; no concurrent comparator
Aldaqadossi 2014 RCT[2]22 (Asopa) vs 25 (Barbagli)Long anterior86.4% vs 88%—No significant success difference; small trial, not proof of equivalence
Zumstein 2020[4]125Penile70%median 36 moLower than expected; complex etiologies (38% iatrogenic, 24% hypospadias)
Zumstein 2020 review[4]272 (9 studies)Mixed73–100%variableWide range reflects heterogeneous populations
Mangera 2011 SR[5]89Bulbar86.7%mean 28.9 moComparable to dorsal / ventral onlay for bulbar
Wan 2023 (LS strictures)[6]42 Asopa / 35 KulkarniLS; retrospective, lingual mucosa—median 18 moFewer meatal stenoses with Asopa; composite recurrence endpoint favors Asopa, but no adjusted technique effect

Bulbar strictures​

For bulbar urethral strictures, the Asopa technique achieves success rates of 86–87%, comparable to both the Barbagli dorsal onlay (88.4%) and ventral onlay (88.8%) techniques.[1][2][5]

Penile strictures​

Outcomes are more variable. The largest single-center series (Zumstein 2020, n = 125) reported a 70% success rate at median 36 mo, lower than previously reported smaller series (73–100%).[4] This likely reflects the inclusion of complex cases with challenging etiologies (38% iatrogenic, 24% hypospadias-related, 9% inflammatory / lichen sclerosus). Even after excluding hypospadias and LS cases, the success rate improved only marginally to 71%.[4] Patients with mid-penile strictures were significantly more satisfied than those with distal or proximal penile strictures.[4]

A 2011 review reported 90.5% success after staged penile repairs versus 75.7% after one-stage repairs, but these were heterogeneous, selected cohorts with different mean follow-up (22.2 versus 32.8 months); this does not demonstrate that staging itself is superior.[5] Current EAU guidance supports single-stage oral-mucosa repair for LS when local conditions are suitable, with staged reconstruction when they are not.[12]

Asopa vs. Barbagli — Direct Comparative Evidence​

Aldaqadossi randomized 47 men to dorsal inlay (22) or dorsal onlay (25). Success was 86.4% versus 88%, respectively, without a significant difference. Operating time was 128 ± 4.9 versus 205 ± 19.63 minutes and blood loss 105 ± 12.05 versus 228 ± 5.32 mL, favoring inlay in that trial. The study was too small to establish equivalence or reliable differences in uncommon complications.[2]

The 5/45 fistulas in Pisapati's separate cohort cannot be compared with a fistula percentage from an unrelated dorsal-onlay series to rank techniques.[1]

Complications​

  • Stricture recurrence — 13–30% depending on stricture location and etiology; higher in penile strictures and complex cases[1][4]
  • Urethrocutaneous fistula — 5/45 evaluated patients in the Pisapati cohort; a technique-wide or comparative rate is not established.[1]
  • Wound infection — ~15% (minor)[1]
  • Meatal stenosis — reported in penile stricture repairs, particularly distal penile[4][6]
  • Erectile dysfunction — postoperative changes should be assessed against baseline sexual function. Published anterior-urethroplasty cohorts differ in operation, population and definition; there is no reliable Asopa-specific risk reduction or guaranteed recovery interval.[7][8][9]
  • Chordee — possible with penile repairs[4]

Asopa vs. Kulkarni for Lichen Sclerosus Strictures​

Wan 2023 retrospectively compared Asopa (42 patients) with Kulkarni (35), using lingual mucosa for LS strictures. Overall complications were 8/42 versus 12/35 (p = 0.105); urethral restricture occurred in 4 versus 5 patients, and meatal stenosis in 1 versus 7. Three glans dehiscences occurred after Asopa.[6]

The recurrence-free analysis favored Asopa when urethral recurrence and meatal stenosis were combined, excluding glans dehiscence. Technique was not an independent predictor in the multivariable model. This small nonrandomized cohort therefore does not establish Asopa superiority or justify choosing an operation from the unadjusted curve alone.[6]

Role in the Palminteri (Combined Dorsal + Ventral) Technique​

The Asopa dorsal inlay concept forms the dorsal component of the Palminteri two-sided technique. In this approach, the urethra is opened ventrally, a dorsal inlay graft is placed (as in the Asopa technique), and then a second ventral onlay graft is added. Used for tight or near-obliterative strictures with a salvageable plate where a single graft may not provide adequate luminal augmentation. The Palminteri technique achieves 88–90% at mean follow-up 21–49 mo.[5][10]

Indications and Patient Selection​

Best suited for:[1][3][4][6]

  • Bulbar urethral strictures not amenable to EPA — comparable results to Barbagli and ventral onlay
  • Penile urethral strictures as a one-stage option — with counseling about the 30% recurrence observed in one complex cohort, rather than a universal risk and the alternative of staged repair
  • Long anterior strictures — where avoiding circumferential mobilization is advantageous
  • Recurrent strictures — where prior surgery may have compromised tissue planes
  • LS strictures — a single-stage oral-mucosa option when local tissue conditions are suitable; genital skin should not be used for LS-related reconstruction.[12]
  • Reconstructive expertise — access may be simpler, but patient selection, graft handling and ventral closure still require appropriate training.

Relative contraindications​

  • An unsalvageable plate or adverse local tissue conditions — consider staged repair; LS or prior hypospadias alone does not mandate staging[3][4]
  • Cases where the ventral urethral wall is severely compromised — increasing fistula risk[1]

Multi-institutional data show that single-stage dorsal repairs for penile strictures have increased by 280% over recent years, reflecting growing adoption of techniques like the Asopa and Kulkarni approaches, while fasciocutaneous flaps have declined by 86%.[11]

Videos​

Dorsal Inlay BMG (Asopa) Urethroplasty for Anterior Urethral Stricture
Operative video (2021)

References​

  1. Pisapati VL, Paturi S, Bethu S, et al. Dorsal buccal mucosal graft urethroplasty for anterior urethral stricture by Asopa technique. Eur Urol. 2009;56(1):201-5. doi:10.1016/j.eururo.2008.06.002.

  2. Aldaqadossi H, El Gamal S, El-Nadey M, et al. Dorsal onlay (Barbagli technique) versus dorsal inlay (Asopa technique) buccal mucosal graft urethroplasty for anterior urethral stricture: a prospective randomized study. Int J Urol. 2014;21(2):185-8. doi:10.1111/iju.12235.

  3. 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.

  4. Zumstein V, Dahlem R, Kluth LA, et al. A critical outcome analysis of Asopa single-stage dorsal inlay substitution urethroplasty for penile urethral stricture. World J Urol. 2020;38(5):1283-1294. doi:10.1007/s00345-019-02871-y.

  5. Mangera A, Patterson JM, Chapple CR. A systematic review of graft augmentation urethroplasty techniques for the treatment of anterior urethral strictures. Eur Urol. 2011;59(5):797-814. doi:10.1016/j.eururo.2011.02.010.

  6. Wan X, Yao HJ, Xie MK, et al. A comparative study of two single-stage oral mucosal substitution urethroplasty (Kulkarni and Asopa) in the surgical treatments of lichen sclerosus urethral strictures. Asian J Androl. 2023;25(6):719-724. doi:10.4103/aja20236.

  7. Erickson BA, Granieri MA, Meeks JJ, Cashy JP, Gonzalez CM. Prospective analysis of erectile dysfunction after anterior urethroplasty: incidence and recovery of function. J Urol. 2010;183(2):657-61. doi:10.1016/j.juro.2009.10.017.

  8. Feng C, Xu YM, Barbagli G, et al. The relationship between erectile dysfunction and open urethroplasty: a systematic review and meta-analysis. J Sex Med. 2013;10(8):2060-8. doi:10.1111/jsm.12181.

  9. Dogra PN, Saini AK, Seth A. Erectile dysfunction after anterior urethroplasty: a prospective analysis of incidence and probability of recovery — single-center experience. Urology. 2011;78(1):78-81. doi:10.1016/j.urology.2011.01.019.

  10. Palminteri E, Berdondini E, Shokeir AA, et al. Two-sided bulbar urethroplasty using dorsal plus ventral oral graft: urinary and sexual outcomes of a new technique. J Urol. 2011;185(5):1766-71. doi:10.1016/j.juro.2010.12.103.

  11. 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.

12. 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.