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Preputial Spiral Graft Urethroplasty (PSGU)

Preputial spiral graft urethroplasty (PSGU) is a novel single-stage technique developed by Kulkarni, Joshi, Basile, and Bandini for the management of panurethral strictures — anterior urethral strictures exceeding 10 cm. The technique uses a helicoidal (spiral) harvest from the inner prepuce to generate a single continuous graft of up to 20 cm in length, providing one continuous graft for selected single-stage augmentation.[1][2]

For the canonical free-graft framework, see Penile / Preputial Skin Graft and Buccal Mucosa Graft. For the related pedicled flap, see Quartey Flap and Pedicled Preputial Tube. For the alternative panurethral free-graft strategy, see Kulkarni One-Sided Dorsolateral BMG. For conventional flat inner-preputial and penile-skin free grafts, see the Flat Penile Skin / Inner Preputial Free Grafts section below.

Concept and Rationale​

Traditional approaches to panurethral strictures often require either two-stage procedures or multiple buccal mucosa grafts (BMGs) harvested from both cheeks (and sometimes lingual mucosa), which can lead to graft-junction recurrence at the sites where separate grafts meet. The spiral harvest addresses this by creating a single, seamless graft from a 5 cm-wide preputial mucocutaneous strip, cut in a helicoidal pattern to maximize length from a limited donor area.[1][2] A single graft avoids inter-graft joins and oral harvest, but whether this reduces recurrence compared with multiple oral grafts has not been demonstrated.

Surgical Technique​

Based on the description by Kulkarni 2023:[1]

  1. Preoperative assessment — retrograde and voiding cystourethrography and uroflowmetry (Qmax) to characterize stricture length and severity. Intraoperative urethroscopy confirms stricture extent.[2]
  2. Graft harvest — a 5 cm-wide strip of preputial mucocutaneous tissue is marked and harvested in a helicoidal (spiral) pattern, yielding a continuous graft up to 20 cm long.
  3. Urethral exposure — typically the Kulkarni one-sided dorsal onlay technique — perineal approach with penile invagination and one-sided urethral mobilization to preserve the lateral blood supply and minimize erectile-function impact.[3]
  4. Stricturotomy — the strictured urethra is opened dorsally along its full length.
  5. Graft placement — the spiral preputial graft is laid as a dorsal onlay over the entire length of the opened stricture and sutured to the urethral plate edges.
  6. Closure — standard layered closure over a urethral catheter.

Indications​

  • Panurethral strictures (anterior urethral stricture > 10 cm).[1][2]
  • Patients with an intact prepuce (uncircumcised).[2]
  • Patients in whom buccal mucosa is unsuitable — e.g., oral dyskeratotic changes from tobacco / gutkha use, or limited oral mucosa from prior bilateral harvest.[4]

Prerequisites and Contraindications​

  • Intact foreskin is mandatory — circumcised patients are excluded.[2][4]
  • LS-related urethral stricture is a contraindication to genital skin grafts, even if the foreskin appears uninvolved or LS is not currently active.[6]
  • Assess smoking, diabetes, tissue perfusion and previous reconstruction, but the cited Mathur risk ratios come from preputial skin flaps, not spiral free grafts, and should not be transferred to PSGU.[4]
  • Other risk factors for failure include severe periurethral fibrosis, prior failed urethroplasty, and post-infective etiology.[4]

Outcomes​

StudyNMedian Stricture LengthFollow-UpQmax ImprovementRecurrence RateComplications
Kulkarni 2023 (initial series)[1]20Not specified12 mo6.5 → 15.1 mL/s5% (1/20)6/20 complications, including one grade IIIa
Bandini 2025 (multicenter)[2]11416 cmmedian 16 mo (IQR 7–24)4.5 → 24 mL/s (p < 0.001)9.6% (11/114)23% (mostly Clavien-Dindo I)

Key findings from the largest multicenter series (114 patients across India, Colombia, Egypt, and Italy):[2]

  • Median operative time 134 minutes (IQR 123–142).
  • Median Qmax improved from 4.5 to 24 mL/s (p < 0.001).
  • Success required Qmax >10 mL/s without obstructive symptoms; this is not the same endpoint as routine cystoscopic patency or freedom from every intervention.
  • No oral donor-site morbidity (pain, numbness, restricted mouth opening) associated with bilateral buccal mucosa harvest.[4][5]
  • Graft tissue is in the surgical field, easily harvested, and the procedure can be performed under regional anesthesia.[5]
  • Particularly valuable in populations where buccal mucosa quality is compromised by tobacco / betel-nut use.[4]

Comparison With Buccal Mucosa Graft​

The AUA 2023 guideline amendment recommends oral mucosa as the first-choice graft for substitution urethroplasty.[6] Conventional penile-skin versus BMG trials do not establish equivalence or validate the spiral harvest itself; the comparisons and limitations appear below. PSGU remains supported by observational cohorts. Among GURS members surveyed, 90% preferred multiple BMGs for panurethral strictures, though that survey predated the multicenter PSGU data.[8]

Limitations and Current Evidence Gaps​

  • Long-term data beyond 2 years are lacking — the largest series has a median follow-up of only 16 months.[2]
  • Requires an intact prepuce, limiting applicability in circumcised populations.
  • Contraindicated in lichen sclerosus.[2]
  • No head-to-head randomized comparison with BMG urethroplasty (single- or staged) for panurethral strictures exists.
  • The technique is relatively new (first described in 2023) and experience remains concentrated in a few high-volume centers.

Flat Penile Skin / Inner Preputial Free Grafts​

Conventional flat penile skin and inner preputial free grafts are non-pedicled substitutes for the urethral plate, harvested as full-thickness strips and placed as onlay or inlay augmentation grafts. Although superseded in routine use by Buccal Mucosa Graft, penile skin remains a useful free-graft option in selected scenarios — particularly when oral harvest is unavailable, refused, or already exhausted from prior surgery.

Dorsolateral Inner Preputial Graft (DLIPG)​

The DLIPG technique described by Tyagi 2021 harvests a strip of non-hair-bearing inner preputial skin and places it as a dorsolateral onlay along the Kulkarni one-sided dissection platform. In a series of 80 patients followed for a median 48 months, DLIPG achieved success in 69/80 with no oral donor-site morbidity.[5]

RCT Evidence: Penile Skin vs BMG​

Two randomized studies compared free penile skin grafts with BMG; neither tested a spiral graft in a panurethral population.

TrialDesignSuccess
Tyagi 2022 PeeBuSt[10]100 randomized; 95 analyzedPSG 42/47 versus BMG 44/48 at 18 months (p = 0.70); powered for a large difference, not equivalence
Alrefaey 2025[7]Superiority trial; 98 randomized, 92 analyzedPSG 41/44 versus BMG 47/48 at 12 months (p = 0.346); important baseline stricture imbalances

Absence of a significant difference is not proof of equivalence. Dubey 2007 instead compared a penile skin flap with BMG and must not be cited as a free-graft trial.[9] Oral mucosa remains the AUA first-choice graft.[6]

Contraindications​

Lichen sclerosus is an absolute contraindication to penile or preputial skin grafts — the AUA 2023 guideline amendment states with Strong Recommendation that genital skin must not be used in LS strictures due to high recurrence rates from LS extension into graft material.[6] The available spiral-graft series do not provide validated patient-specific risk estimates for diabetes or smoking.

Videos​

Preputial Spiral Graft Urethroplasty
Operative technique

References​

1. Kulkarni SB, Joshi PM, Basile G, Bandini M. Novel single-stage preputial spiral graft for panurethral stricture: a step-by-step description of the technique. World J Urol. 2023;41(9):2459-2463. doi:10.1007/s00345-023-04514-9.

2. Bandini M, Joshi P, Bafna S, et al. Establishing the role of single-stage preputial spiral graft urethroplasty for panurethral stricture. BJU Int. 2025. doi:10.1111/bju.16796.

3. 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.

4. Mathur RK, Nagar M, Mathur R, et al. Single-stage preputial skin flap urethroplasty for long-segment urethral strictures: evaluation and determinants of success. BJU Int. 2014;113(1):120-126. doi:10.1111/bju.12361.

5. Tyagi S, Parmar K, Sharma A, et al. Dorsolateral inner preputial graft urethroplasty for anterior urethral strictures: long-term outcomes from a single tertiary care centre. World J Urol. 2021;39(9):3549-3554. doi:10.1007/s00345-021-03613-9.

6. 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.

7. Alrefaey A, Anwar MA, Abdelmagid ME, et al. Comparative outcomes of penile skin grafts versus buccal mucosal grafts in urethroplasty for the treatment of extensive anterior urethral strictures. Sci Rep. 2025;15(1):29508. doi:10.1038/s41598-025-14191-w.

8. 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.

9. Dubey D, Vijjan V, Kapoor R, et al. Dorsal onlay buccal mucosa versus penile skin flap urethroplasty for anterior urethral strictures: results from a randomized prospective trial. J Urol. 2007;178(6):2466-9. doi:10.1016/j.juro.2007.08.010.

10. Tyagi S, Parmar KM, Singh SK, et al. 'Pee'BuSt Trial: a single-centre prospective randomized study comparing functional and anatomic outcomes after augmentation urethroplasty with penile skin graft versus buccal mucosa graft for anterior urethral stricture disease. World J Urol. 2022;40(2):475-481. doi:10.1007/s00345-021-03843-x.