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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, avoiding the need for multiple separate grafts or two-stage procedures.[1][2]

For the canonical free-graft framework, see Penile / Preputial Skin Graft and Buccal Mucosa Graft. For the related pedicled flap, see Quartey 'Q' 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] The technique eliminates graft junctions and their associated recurrence risk, and avoids oral donor-site morbidity entirely.

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]
  • Active lichen sclerosus (BXO) is a contraindication; preputial skin quality is unreliable in this setting and graft failure rates are high.[2]
  • Diabetes mellitus (RR 5.21) and smoking (RR 4.19) are significant predictors of failure for preputial-skin grafts in general.[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)30% (mostly Clavien-Dindo I–II)
Bandini 2025 (multicenter)[2]11416 cm16 mo4.5 → 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).
  • Single-stage procedure avoids the morbidity and prolonged treatment timeline of two-stage repairs.
  • 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] However, a recent prospective randomized trial comparing penile-skin grafts to BMG for long anterior strictures (mean 6–8 cm) found comparable success rates (93.2% vs 97.9%, p = 0.346), equivalent functional outcomes, and similar complication rates.[7] PSGU extends this principle to panurethral strictures, where the spiral harvest method overcomes the length limitation of conventional flat preputial grafts. Among GURS members surveyed, 90% still preferred multiple BMGs for panurethral strictures, though that survey predated publication of 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 dorsal, ventral, or inlay onlays. 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 53 patients followed for 48 months, DLIPG achieved 87% stricture-free survival with no oral donor-site morbidity.[5]

RCT Evidence: Penile Skin vs BMG​

Three prospective randomised trials demonstrate functional and anatomic equivalence between penile-skin grafts and BMG for anterior urethral strictures:

TrialDesignStricture LengthSuccess
Dubey 2007[9]RCT, penile skin vs BMGLong anteriorEquivalent
Tyagi 2022 PeeBuSt[10]Single-centre RCTAnteriorEquivalent (93.2% vs 97.9%, p = 0.346)
Alrefaey 2025[7]RCT, extensive anteriorMean 6–8 cmEquivalent

Despite this equivalence data, a 2024 SGUR survey found ~99% of contemporary reconstructive urologists prefer BMG for substitution urethroplasty, citing superior graft biology, thicker lamina propria, and absence of hair-bearing risk.[8]

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] Diabetes mellitus (RR 5.21) and smoking (RR 4.19) are significant predictors of failure for preputial-skin grafts in general.[5]

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.