Skip to main content

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. Asopa et al. first described it in 2001 in 12 men with long or multiple anterior strictures, using inner preputial skin in 10 and buccal mucosa in 2.[16] It combines dorsal graft placement against the corpora cavernosa with ventral access. One small alternate-allocation comparison reported shorter operating time than the 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 innovation is that 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 is intended to preserve the lateral and dorsal urethral blood supply while providing corporal backing for the graft.[1][3]

The technique has been used 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 or penile incision for penile strictures.[1][2]
  2. Exposure of the urethra. Corpus spongiosum exposed ventrally. 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, incise the dorsal urethral wall in the midline and extend the cut into healthy urethra at both ends. Sharply separate the incised dorsal edges from the tunica albuginea without lifting the urethra from its bed, creating an elliptical raw graft bed up to 1.5–2 cm wide.[1][2][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. Close the ventral urethrotomy over a urethral catheter and reinforce the continuous ventral suture line with interrupted sutures. Pisapati and Aldaqadossi used a 16 Fr silicone catheter. Close the corpus spongiosum and overlying tissues in layers.[1][2] In Aldaqadossi et al.'s series, pericatheter urethrography at 3 weeks guided catheter removal; one leak prompted 2 further weeks of catheterization.[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. The urethra remains in its bed, which is intended to preserve lateral and dorsal blood supply.
  • Shorter operative time. In the alternate-allocation study, 128 ± 5 min (Asopa) versus 205 ± 20 min (Barbagli), p < 0.0001.[2]
  • Less blood loss. In the same trial, 105 ± 12 mL (Asopa) versus 228 ± 5 mL (Barbagli), p < 0.0001.[2]
  • Technically easier. Pisapati considered the ventral approach easier than the dorsal urethrotomy approach, and it avoids circumferential dissection and urethral rotation.[1][2]
  • Dorsal graft position maintained. Despite the ventral access, the graft is placed against the tunica albuginea, as in the Barbagli technique.[1][3]

Outcomes​

StudynStricture LocationSuccessFollow-upKey Findings
Pisapati 2009[1]45 evaluated of 58 operatedRecurrent anterior strictures, including complex cases39/45 (87%)mean 42 mo5 fistulas and 7 wound infections; no concurrent comparator
Aldaqadossi 2014 alternate-allocation trial[2]22 (Asopa) vs 25 (Barbagli)Long anterior19/22 (86.4%) vs 22/25 (88%); no retreatment and Qmax >15 mL/smean 24.2 vs 22.6 moNo significant success difference
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]89Mixed anterior sites and grafts86.7%mean 28.9 moSeparate series; equivalence to bulbar dorsal or ventral onlay is unproven
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​

Mangera et al.'s review reported 86.7% success among 89 bulbar Asopa repairs at mean 28.9 months, versus 88.4% among 934 dorsal-onlay repairs at 42.2 months and 88.8% among 563 ventral-onlay repairs at 34.4 months.[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] The series included complex etiologies (38% iatrogenic, 24% hypospadias-related, 9% inflammatory).[4] 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).[5] For LS-related strictures, EAU 2026 recommends single-stage oral mucosa graft urethroplasty in the absence of adverse local conditions and advises against genital skin for augmentation penile urethroplasty .[12] It suggests staged urethroplasty for complex anterior strictures not suitable for a single stage .[12] In a 2025 nine-center observational cohort of selected penile LS strictures, five-year stricture-free estimates were 82% after single-stage oral mucosal graft repair, 76% after staged repair, and 75% after perineal urethrostomy (127, 44, and 60 patients; P = .6).[17]

Asopa vs. Barbagli — Direct Comparative Evidence​

Aldaqadossi et al. assigned 47 men by alternation to dorsal inlay (22) or dorsal onlay (25), without reported allocation concealment. 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]

Complications​

  • Stricture recurrence. Pisapati reported 6/45 (13%) recurrences among 45 evaluated of 58 men with recurrent anterior strictures over 12–60 months; Zumstein reported 70% overall success in a separate cohort of 125 men with penile strictures at median 36 months.[1][4]
  • Urethrocutaneous fistula. 5/45 evaluated patients in the Pisapati cohort.[1]
  • Wound infection. Seven minor wound infections among 45 evaluated of 58 operated patients in Pisapati’s cohort (7/45, approximately 16%).[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 has been described after penile Asopa repair: one man with pre-existing curvature in Asopa’s original 12-patient mixed-graft series developed significant postoperative chordee requiring dorsal plication.[4][16]

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.[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. It is used for tight or near-obliterative strictures with a salvageable plate where a single graft may not provide adequate luminal augmentation. Reported success was 88% (64/73, mean follow-up 48.9 mo) among Palminteri’s 73 analyzed cases selected from 105 operated men (buccal graft and at least 1 year of follow-up), and 90.1% (n = 53, mean 21.9 mo) in the systematic review.[5][10] A later retrospective single-center, single-surgeon cohort reported 188/216 (87%) without postoperative instrumentation, with median follow-up of 98 months; it likely overlaps the earlier series and reports two-sided grafting rather than Asopa-only outcomes.[15]

Indications and Patient Selection​

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

  • Bulbar urethral strictures not amenable to EPA; dorsal inlay is an option, but comparative evidence is insufficient to rank it against dorsal or ventral onlay.[14]
  • Penile urethral strictures as a one-stage option, with counseling about 70% study-defined success at median 36 months in one complex cohort and the alternative of staged repair.[4] EAU 2026 recommends counseling that adverse intraoperative findings may require conversion from a planned single-stage repair to a staged one .[12]
  • 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. AUA 2023 advises against genital skin for reconstruction in LS-proven strictures[13]; EAU 2026 advises against genital skin for augmentation penile urethroplasty in LS-related strictures.[12]
  • Reconstructive expertise. Access may be simpler, but patient selection, graft handling and ventral closure still require appropriate training.

Relative contraindications​

  • A narrow residual urethral plate may not accommodate an adequate dorsal inlay; Horiguchi describes a plate >1 cm as favorable and notes that an inlay graft is typically narrower than an onlay. For 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]

In a multi-institutional database of 2,098 anterior urethroplasties (2010 to 2017, 10 surgeons), single-stage dorsal repairs in the penile urethra increased by 280% and fasciocutaneous flaps declined by 86%. The study did not separate Asopa from other dorsal techniques.[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.

13. 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. Unabridged guideline.

14. 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

15. Palminteri E, Preto M, Clementi MC, et al. "Long-term follow-up of two-sided dorsal plus ventral oral graft bulbar urethroplasty: single center experience on 216 patients." Minerva Urol Nephrol. 2023;75(1):99-105. doi:10.23736/S2724-6051.21.04258-0

16. Asopa HS, Garg M, Singhal GG, Singh L, Asopa J, Nischal A. "Dorsal free graft urethroplasty for urethral stricture by ventral sagittal urethrotomy approach." Urology. 2001;58(5):657-659. doi:10.1016/S0090-4295(01)01377-2

17. Hengel R, Vanni A, Erickson B, et al. "Multi-Institutional Analysis of Surgery for Lichen Sclerosus-Induced Penile Urethral Stricture: Establishing Single-Stage Urethroplasty as a Primary Treatment Option." J Urol. 2025;213(5):628-637. doi:10.1097/JU.0000000000004434