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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, making it technically easier and faster 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 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 prevents sacculation.[1][3]

Particularly well-suited for:

  • Penile urethral strictures — one of the two preferred one-stage approaches (along with the Kulkarni technique)[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 is placed on top of the dorsal urethral surface after the urethra has been mobilized and rotated. 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]45Anterior (recurrent)87%mean 42 mo13% recurrence; 11% fistula rate
Aldaqadossi 2014 RCT[2]22 (Asopa) vs 25 (Barbagli)Long anterior86.4% vs 88%—Equivalent success; Asopa shorter OR + less blood loss
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]42LS stricturesacceptablevariableLower meatal stenosis vs Kulkarni (p = 0.020); RFS favored Asopa (p = 0.016)

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 systematic review confirmed that for penile strictures, two-stage urethroplasty (90.5%) significantly outperforms one-stage techniques (75.7%), including the Asopa technique.[5] Staged urethroplasty should be discussed as an alternative, particularly for complex penile strictures.[3][4]

Asopa vs. Barbagli — Head-to-Head​

ParameterAsopa (Dorsal Inlay)Barbagli (Dorsal Onlay)
Success rate (bulbar)86–87%83–88%
Success rate (penile)70–100%67–87%
Operative time128 ± 5 min205 ± 20 min (p < 0.0001)
Blood loss105 ± 12 mL228 ± 5 mL (p < 0.0001)
Urethral mobilizationnone (urethra stays in bed)full circumferential + 180° rotation
Graft bedtunica albuginea (dorsal)tunica albuginea (dorsal)
Graft placementinlay (through ventral window)onlay (after rotation)
Technical difficultyeasiermore complex
Fistula risk~11%lower (~2%)
[1][2][3][4][5]

The higher fistula rate with Asopa (11% in the Pisapati series) is a notable concern, attributed to the ventral urethrotomy, which creates a ventral suture line that may be more vulnerable to breakdown — particularly in the penile urethra where the spongiosum is thin.[1]

Complications​

  • Stricture recurrence — 13–30% depending on stricture location and etiology; higher in penile strictures and complex cases[1][4]
  • Urethrocutaneous fistula — ~11% — higher than other techniques, attributed to the ventral suture line[1]
  • Wound infection — ~15% (minor)[1]
  • Meatal stenosis — reported in penile stricture repairs, particularly distal penile[4][6]
  • Erectile dysfunction — transient ED occurs in ~10–20% of anterior urethroplasty patients regardless of technique, with recovery in most by 6 months. The Asopa technique's avoidance of circumferential mobilization may theoretically reduce ED risk, though no comparative data specific to Asopa vs other techniques exist for this outcome.[7][8][9]
  • Chordee — possible with penile repairs[4]

Asopa vs. Kulkarni for Lichen Sclerosus Strictures​

A comparative study of 77 patients with LS urethral strictures (Wan 2023) found that both Asopa (n = 42) and Kulkarni (n = 35) techniques provided acceptable results, with important differences:[6]

  • Overall complication rate — 19.0% (Asopa) vs 34.2% (Kulkarni) (p = 0.105, NS)
  • Postoperative meatal stenosis — significantly lower with Asopa (p = 0.020)
  • Recurrence-free survival significantly favored Asopa (p = 0.016)
  • Risk factors for complications — antiplatelet / anticoagulant use (p = 0.020), diabetes (p = 0.003), smoking (p = 0.019), coronary heart disease (p < 0.05)

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 obliterative or near-obliterative strictures 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 — though patients must be counseled about the 30% recurrence 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 — as a one-stage option with potentially better RFS than Kulkarni, though staged repair remains preferred for complex LS cases
  • Surgeons with less experience in urethral mobilization — the ventral approach is more familiar and technically straightforward

Relative contraindications​

  • Complex penile strictures with extensive LS or failed hypospadias — staged repair preferred[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] However, the Asopa technique remains less commonly used than the Barbagli dorsal onlay for bulbar strictures, where the dorsal onlay approach predominates (66% of reconstructive urologists).[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.