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Muscle-Sparing Urethroplasty

Muscle-sparing urethroplasty encompasses two related but distinct concepts: (1) the Barbagli muscle- and nerve-sparing bulbar urethroplasty (preserving the bulbospongiosus muscle during standard bulbar urethroplasty) and (2) the Kulkarni one-sided dorsolateral dissection technique (preserving the contralateral bulbospongiosus muscle, neurovascular bundle, and central tendon). Evidence on whether bulbospongiosus muscle sparing improves functional outcomes is conflicting; some studies show significant reductions in postvoid dribbling and ejaculatory dysfunction, while a matched multicenter study and a later single-center comparative study with alternating allocation found no significant benefit.[1][2][3][4]

For non-transecting anastomotic alternatives that also preserve corporal vascular supply, see Non-Transecting Bulbar Urethroplasty and Jordan Vessel-Sparing EPA. For augmented variants, see Augmented Anastomotic Urethroplasty. For graft details, see Buccal Mucosa Graft.

Anatomy and Rationale​

The bulbospongiosus (BS) muscle is a paired, striated muscle that envelops the ventral surface of the bulbar urethra and corpus spongiosum. It is innervated by the perineal branch of the pudendal nerve and plays a role in:[4][5]

  • Urinary expulsion. Compresses the bulbar urethra during the final phase of micturition to expel residual urine
  • Ejaculation. Rhythmic contraction propels semen through the urethra
  • Erection support. Contributes to penile rigidity by compressing the bulb of the penis

In standard bulbar urethroplasty, the BS muscle is divided in the midline raphe to expose the underlying corpus spongiosum. The concern is that midline division damages the muscle's innervation and vascularization, leading to postoperative postvoid dribbling (PVD) and ejaculatory dysfunction (EjD).[3][4]

Technique 1 — Barbagli Muscle- and Nerve-Sparing Bulbar Urethroplasty (2008)​

First described by Barbagli et al. in 2008 in European Urology, this technique avoids dissection of the BS muscle from the corpus spongiosum entirely.[4]

Surgical steps​

  1. Perineal incision. Standard midline perineal incision.
  2. Muscle preservation. Instead of splitting the BS muscle in the midline, access the bulbar urethra by dissecting between the BS muscle and the ischiocavernosus muscle on one side, leaving the BS muscle attached to the corpus spongiosum and the central tendon of the perineum intact.
  3. Urethral exposure. Expose the dorsal or ventral urethral surface for the selected oral-mucosal onlay while keeping the BS attached to the corpus spongiosum and the central tendon intact.[4]
  4. Urethrotomy and graft placement. A dorsal or ventral urethrotomy is performed, and an oral mucosal graft is placed as an onlay.
  5. Closure. The graft is sutured in place and the wound is closed without disrupting the BS muscle.[4]

Original series (Barbagli 2008)​

  • 12 patients, mean age 43.6 yr, mean stricture length 4.47 cm
  • 6 ventral onlay + 6 dorsal onlay BMG
  • 0% postvoid dribbling and 0% semen sequestration at 6 and 12 months
  • 0% stricture recurrence at mean 15.25 mo
  • No urethral sacculation on voiding cystourethrography[4]

Technique 2 — Kulkarni One-Sided Dorsolateral Onlay Urethroplasty​

Kulkarni et al. described one-sided dorsal oral-mucosa grafting for both bulbar and panurethral strictures; their original series included mean lengths of 4.2 cm and 10 cm, respectively.[20] Later long-segment cohorts selected strictures >8 cm.[8] It inherently spares the contralateral BS muscle and neurovascular bundle through one-sided dissection.[6][7][8]

Surgical steps​

  1. Perineal approach. Make a midline perineal incision; invaginate the penis through it when the repair extends into the penile urethra.[20]
  2. One-sided urethral mobilization. The urethra is mobilized from the corpora cavernosa on one side only (typically the left), preserving the contralateral lateral vascular supply, BS muscle attachment, and perineal nerve branches.
  3. Dorsal urethrotomy after one-sided rotation. Partially rotate the urethra on the dissected side, identify the distal extent of stenosis, and extend the midline dorsal urethrotomy proximally and distally through the full stricture. Measure the remaining urethral plate before sizing the graft.[20]
  4. Graft placement. An oral mucosal graft (selected non-LS cases may use hairless penile skin) is placed as a dorsolateral onlay and fixed to the corporal tunica albuginea; its apices and one margin are sutured to the urethrotomy. For panurethral strictures extending to the meatus, Kulkarni et al. describe a wide dorsal meatotomy through the glans, a distal oral graft sutured to the dorsal meatal edge, and a second graft opposite the bulbar urethra. Quilting sutures secure the grafts to the corporal bed, and continuous upward traction on the inverted penis during penile graft placement is used to prevent chordee.[20] The 2026 EAU guideline weakly recommends penile skin when buccal or lingual mucosa is unavailable, unsuitable, or declined, and strongly recommends against genital skin grafts in lichen sclerosus.[21] The cited penile-skin series excluded LS-related disease, unavailable penile skin, and obliterative strictures.[14]
  5. Closure. In the original Kulkarni technique, insert a 16 Fr grooved silicone catheter.[20] Rotate the urethra back to its anatomic position over the graft.[6][7][8][20] Fix the free urethral margin to the corpora cavernosa with interrupted sutures so the urethra and intact BS cover the graft.[20]

Outcomes of the Kulkarni technique​

StudynMean Stricture LengthSuccessFollow-upKey Findings
Kulkarni 2012 (panurethral)[22]11714 cm (mean)83.7% overall; 86.5% primary vs 61.5% after prior failed urethroplasty59 mo (median)Success meant no further instrumentation; most recurrences were at the proximal graft end
Spencer 2018 (multi-institutional)[8]7313.6 cm88%44 moIPSS improved 23 → 10 (p < 0.001); PVD 45%; chordee 25% (described as transient in the abstract)
Kartal 2020 (vs Barbagli)[7]31 vs 37Mean not reported; enrolled strictures >8 cm87.1% vs 70.3%~60 moShorter OR time, less blood loss, fewer complications with Kulkarni
Zumrutbas 2020[15]3513.6 cm82.9%≥6 mo88.6% satisfaction; recurrence 35.7% in age >65 vs 4.8% in ≤65
Takekawa 2025[6]3944 mm (median)89.7%12 mo (median)SHIM unchanged; OMG 80% vs PSG 95.8% success; grade 2 donor-site complications in 2/39 (5.2%)
Palminteri 2016 (penile skin)[14]375 cm (median)34/37 (92%)21 mo (median)Penile-skin variant; 81% had prior treatment. The BS was split for mid/proximal bulbar involvement, so muscle preservation was not uniform. Contrast leakage occurred in 7/37 (19%) at first VCUG and required 3–4 extra catheter weeks; ejaculatory function was not measured

Kulkarni vs. conventional Barbagli dorsal onlay​

In the retrospective comparison by Kartal et al. (2020) of strictures >8 cm (31 Kulkarni versus 37 conventional Barbagli dorsal onlay), the Kulkarni technique had lower operative time, blood loss, hospital stay and perioperative complications:[7]

  • Shorter operative time: 179.5 versus 195.5 min (p = 0.037)
  • Less blood loss: 164.3 versus 202.4 mL (p = 0.033)[7]
  • Shorter hospital stay: 3.5 versus 4.4 days (p = 0.002)
  • Fewer perioperative complications: 16.1% versus 37.8% (p = 0.046)[7]
  • Success: 87.1% versus 70.3% at a mean follow-up of about 60 months (the abstract gives no p value)[7]

Technique 3 — Proximal Dorsal, Two-Sleeve-Preserving Approach (Bandini / Joshi)​

For proximal bulbar strictures below the bulbocavernosus sleeves, Bandini and Joshi describe a dorsal approach that preserves both bulbospongiosus sleeves rather than dividing the midline sleeve or incising a single side: the perineal dissection begins below the sleeves, the dorsal urethra is exposed, a 12-o'clock urethrotomy is performed, a buccal graft is placed over the corpora cavernosa, and the urethra is closed over a 14 Fr silicone catheter. The bulbospongiosus muscle itself is not reconstructed. The preliminary chapter report describes 17 positive outcomes among 19 patients and no associated complications, without outcome definitions, follow-up duration, a comparator or a complication denominator for comparison with the Barbagli or Kulkarni approaches above.[18]

The Controversy — Does BS Muscle Sparing Actually Matter?​

This is the central debate. The evidence is conflicting.

StudyDesignnTechniquePVD (sparing vs non-sparing)EjD (sparing vs non-sparing)Conclusion
Barbagli 2008[4]Case series12Dorsal or ventral onlay0/12 (PVD)0/12 (semen sequestration)Feasibility series; symptoms assessed with a nonvalidated questionnaire at 6 and 12 months
Fredrick / Vanni 2017[3]Matched case-control50Mixed EPA / augmentationNo significant difference reportedMSHQ p = 0.90No difference detected
Elkady 2019[2]Randomized trial50Ventral onlay BMG1/25 vs 9/25 (PVD)2/25 vs 10/25 (semen sequestration)Less PVD and semen sequestration at the reported follow-up
Farias / Martins 2025[1]Prospective, alternating allocation70EPA; BS released from bulbar urethra, retracted and sutured back in sparing arm2.9% vs 5.7% (p = 0.64)No difference (p = 0.72)No statistically significant benefit detected for PVD or MSHQ-EjD-SF score change at 3–15 mo
Theisen 2021[5]Prospective cohort728All anterior——EjD/PVD occur equally after penile repairs (no BS muscle involved)

Studies supporting muscle sparing​

  • Elkady 2019. Prospective RCT, 50 patients (ventral onlay BMG): PVD in 1/25 (4%) muscle-sparing versus 9/25 (36%) non-sparing; semen sequestration in 2/25 (8%) versus 10/25 (40%). Both differences statistically significant.[2]
  • Barbagli 2008. 0% PVD and 0% semen sequestration in all 12 muscle-sparing patients.[4]

Studies without a detected benefit​

  • Fredrick / Vanni 2017. Multi-institutional matched case-control, 50 patients (25 versus 25), with postoperative assessment at 3 to 12 months: MSHQ scores were similar between groups (15.24 versus 15.40, p = 0.90). PVD rates and perceived ejaculatory function were also similar.[3]
  • Farias / Martins 2025. Prospective comparative study with alternating allocation, 70 patients (35 versus 35, EPA): MSHQ-EjD-SF decrease was 0.59 versus 0.67 (p = 0.72). PVD: 1 versus 2 patients (p = 0.64). The results did not show an advantage for the muscle-sparing group. Although the abstract calls assignment random, the Methods describe alternating consecutive patients; this predictable allocation limits causal inference.[1]

Evidence suggesting more than one mechanism​

  • Theisen 2021. 728 patients: EjD and PVD occurred at similar rates after penile and bulbar urethroplasty. The authors found a significant association between EjD and PVD (p < 0.05).[5]

Postvoid Dribbling and Ejaculatory Dysfunction — The Bigger Picture​

Questionnaire studies report substantial postoperative PVD and EjD.[5][16]

  • PVD: 8–70% depending on series, technique and definition.[5][16] In the Theisen cohort it was more common after bulbar augmentation than after anastomotic repair (70% versus 52%, p = 0.0001).[5]
  • EjD: 67% overall in a 728-patient series, where the single questionnaire item assessed ejaculatory force.[5]
  • Among survey respondents (32 dorsal buccal onlay; 96 anastomotic; 71.5% of the eligible cohort), PVD most or all of the time was reported by 28.1% versus 8.3%, respectively (p < 0.001).[16]
  • Among postoperative questionnaire respondents (71.5% of the 179 eligible patients), tethering with erections was reported more often after anastomotic repair (23.4%) than dorsal buccal onlay (3.1%, p = 0.008).[16]

A prospective cohort of 384 men found PVD in 46.9% before and 39.8% six months after urethroplasty; 18.0% reported de novo PVD. Anastomotic repair was associated with lower odds of de novo PVD (adjusted OR 0.33, 95% CI 0.13–0.83), but the study did not compare BS-sparing techniques.[23]

EjD and PVD occur at similar rates after penile repairs, where the BS muscle is not involved, and after anastomotic repairs. Theisen and colleagues read this as evidence against BS muscle damage as the sole cause; they found EjD and PVD associated with each other and conclude that the cause remains unknown.[5]

Persistent, bothersome or delayed-onset dribbling after urethroplasty should prompt reassessment rather than an assumption of a benign muscle-related symptom: pooling can be mistaken for urinary incontinence, and new or delayed dribbling can also signal stricture recurrence or a urethral sacculation, which urethrography can distinguish. Perineal compression after voiding is a possible conservative measure once pooling is confirmed and recurrence or sacculation have been excluded, not a first response to a new symptom.[19]

For the broader non-transecting evidence base on sexual dysfunction after bulbar urethroplasty, see Chapman 2019 (multi-institutional NT versus T comparative analysis), Oszczudlowski 2023 meta-analysis, Virasoro / DeLong 2020 review, the Andrich / Mundy 2012 preliminary NT report, and Verla 2019 vessel-sparing operative video.[9][10][11][12][13]

Practical Considerations​

When to consider muscle sparing​

  • The Kulkarni approach permits reconstruction of long anterior strictures through a perineal incision. Lower blood loss and shorter operative time were observed in a small comparative series; universal superiority has not been established.[6][7] For panurethral strictures, the 2026 EAU guideline weakly recommends repair in specialized centers because more than one technique or graft material may be required.[17]
  • For standard bulbar urethroplasty, the evidence does not strongly support routine muscle sparing as a standalone modification, given the conflicting data.[1][3]

Technical limitations​

  • In the Farias / Martins EPA series, BS preservation made exposure more difficult for the most proximal bulbar strictures. The authors would divide BS if preservation prevented adequate exposure and anastomosis.[1]
  • Penile invagination is used when distal or penile access is required; it is not necessary for every isolated bulbar one-sided repair.
  • Extent of mobilization must be tailored to scar, graft position and safe exposure.

Key Takeaways​

  • Barbagli's muscle- and nerve-sparing technique (2008) avoids midline BS muscle splitting by accessing the urethra between the BS and ischiocavernosus muscles, preserving the central tendon.
  • Kulkarni's one-sided dorsolateral technique inherently spares the contralateral BS muscle and is used for long anterior strictures; reported success and functional outcomes come from heterogeneous, mostly retrospective cohorts.
  • Evidence on whether BS muscle sparing improves PVD and ejaculatory outcomes is conflicting: the Elkady randomized trial reported less PVD and semen sequestration after ventral onlay grafting, whereas the matched comparison by Fredrick and colleagues and the alternating-allocation EPA study by Farias and Martins did not detect statistically significant differences in PVD or ejaculatory questionnaire outcomes at 3–12 and 3–15 months, respectively.[1][2][3]
  • In a 728-patient cohort (Theisen), EjD and PVD occurred at similar rates after penile repairs, where the BS muscle is not involved.
  • The evidence is insufficient to recommend routine muscle or nerve sparing solely to prevent dribbling or ejaculatory change. [17]

Videos​

Bulbospongiosus Muscle-Sparing Buccal Mucosa Urethroplasty
TURNS (Trauma and Urologic Reconstruction Network of Surgeons)

References​

  1. Farias RB, Martins FE. Comparison of postoperative outcomes related to ejaculatory function and post-micturition dribbling between bulbospongiosus muscle sparing and non-sparing anastomotic urethroplasty techniques. Sci Rep. 2025;15(1):37558. doi:10.1038/s41598-025-23625-4.

  2. Elkady E, Dawod T, Teleb M, Shabana W. Bulbospongiosus muscle sparing urethroplasty versus standard urethroplasty: a comparative study. Urology. 2019;126:217-221. doi:10.1016/j.urology.2018.12.028.

  3. Fredrick A, Erickson BA, Stensland K, Vanni AJ. Functional effects of bulbospongiosus muscle sparing on ejaculatory function and post-void dribbling after bulbar urethroplasty. J Urol. 2017;197(3 Pt 1):738-743. doi:10.1016/j.juro.2016.09.083.

  4. Barbagli G, De Stefani S, Annino F, De Carne C, Bianchi G. Muscle- and nerve-sparing bulbar urethroplasty: a new technique. Eur Urol. 2008;54(2):335-43. doi:10.1016/j.eururo.2008.03.018.

  5. Theisen KM, Soubra A, Grove S, et al. Association between ejaculatory dysfunction and post-void dribbling after urethroplasty. Urology. 2021;153:320-326. doi:10.1016/j.urology.2021.04.016.

  6. 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.

  7. 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.

  8. 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.

  9. Chapman DW, Cotter K, Johnsen NV, et al. Nontransecting techniques reduce sexual dysfunction after anastomotic bulbar urethroplasty: results of a multi-institutional comparative analysis. J Urol. 2019;201(2):364-370. doi:10.1016/j.juro.2018.09.051.

  10. Oszczudlowski M, Yepes C, Dobruch J, Martins FE. Outcomes of transecting versus non-transecting urethroplasty for bulbar urethral stricture: a meta-analysis. BJU Int. 2023;132(3):252-261. doi:10.1111/bju.16108.

  11. Virasoro R, DeLong JM. Non-transecting bulbar urethroplasty is favored over transecting techniques. World J Urol. 2020;38(12):3013-3018. doi:10.1007/s00345-019-02867-8.

  12. Andrich DE, Mundy AR. Non-transecting anastomotic bulbar urethroplasty: a preliminary report. BJU Int. 2012;109(7):1090-4. doi:10.1111/j.1464-410X.2011.10508.x.

  13. Verla W, Oosterlinck W, Waterloos M, Lumen N. Vessel-sparing excision and primary anastomosis. J Vis Exp. 2019;(143). doi:10.3791/58214.

  14. Palminteri E, Berdondini E, Lumen N, et al. Kulkarni dorsolateral graft urethroplasty using penile skin. Urology. 2016;90:179-83. doi:10.1016/j.urology.2015.12.014.

  15. Zumrutbas AE, Ozlulerden Y, Celen S, Kucuker K, Aybek Z. The outcomes of Kulkarni's one-stage oral mucosa graft urethroplasty in patients with panurethral stricture: a single centre experience. World J Urol. 2020;38(1):175-181. doi:10.1007/s00345-019-02758-y.

  16. Furr JR, Wisenbaugh ES, Gelman J. Urinary and sexual outcomes following bulbar urethroplasty — an analysis of 2 common approaches. Urology. 2019;130:162-166. doi:10.1016/j.urology.2019.02.042.

  17. European Association of Urology. EAU Guidelines on Urethral Strictures: disease management in males. 2026. Current guideline.

  18. Bandini M, Joshi PM. Novel Dorsal Approach to Proximal Bulbar Strictures. In: Joshi PM, Aubé-Peterkin M, Kulkarni SB, Datar G, eds. Surgical Atlas of Urethroplasty. Springer; 2024:99-104. doi:10.1007/978-981-97-5196-9_13

  19. Shenfeld O. Complications of Urethroplasty. In: Brandes SB, Morey AF, eds. Advanced Male Urethral and Genital Reconstructive Surgery. 2nd ed. Humana Press; 2014:310-312.

  20. Kulkarni S, Barbagli G, Sansalone S, Lazzeri M. "One-sided anterior urethroplasty: a new dorsal onlay graft technique." BJU Int. 2009;104(8):1150-1155. doi:10.1111/j.1464-410X.2009.08590.x

  21. Lumen N, Campos-Juanatey F, Dimitropoulos K, et al. EAU Guidelines on Urethral Strictures: Limited Update 2026. European Association of Urology; 2026:65 (§9.3). Full guideline.

  22. Kulkarni SB, Joshi PM, Venkatesan K. "Management of panurethral stricture disease in India." J Urol. 2012;188(3):824-830. doi:10.1016/j.juro.2012.05.020

  23. Calvo CI, Bekkema J, Rourke KF. "Prospective assessment of the incidence and associations of postvoid dribbling after urethroplasty: Impact of surgical technique." Can Urol Assoc J. 2023;17(10):341-345. doi:10.5489/cuaj.8360