Inverted Urethral Flap (IUF) Glanuloplasty
The inverted urethral flap (IUF) is the most extensively studied flap-based neoglans reconstruction, with the largest published cohort (Chavarriaga n = 74, median follow-up 72 months) and the longest follow-up of any urethral-flap technique. It is a single-stage procedure performed simultaneously with partial penectomy, using the patient's own distal urethral tissue to create a moist mucosal neoglans without a separate donor site.[1][2]
For the comparative overview of all four flap-based glanuloplasty options (IUF, Gulino everted, Mazza scrotal, Shaeer rectus) see Glanuloplasty With Flaps. For the STSG-based standard, see Glansectomy With STSG. For the broader decision framework, see Penile Reconstruction.
Historical Development and Rationale
First described by Belinky, Cheliz, Graziano, and Rey (2011, n = 10) and validated at scale by Chavarriaga et al. at Instituto Nacional de Cancerología (Bogotá), Colombia in the landmark 2022 cohort of 74 patients.[1][2]
The fundamental rationale: after partial penectomy the urethra is typically transected at the same level as the corpora and the excess discarded. The IUF technique intentionally preserves the urethra 2–3 cm beyond the corporal transection line, then inverts that excess over the closed corporal tips to create a moist mucosal neoglans that closely mimics native glans epithelium — biologically more similar than keratinized skin grafts.
Anatomical Basis
- The corpus spongiosum surrounds the penile urethra and is supplied by the urethral / bulbar artery (branch of internal pudendal) — provides robust independent blood supply that maintains flap viability after separation from the corpora[3][4]
- Dorsal arteries principally perfuse glans and spongiosum with perforators to the distal corpora — additional collateral flow to the urethral flap
- The urethra has dual blood supply (proximal + distal) — enhances flap reliability
- Urethral mucosa is richly innervated with sensory nerve endings — accounts for the excellent thermal / tactile sensation preserved[5]
- Buck's fascia circumferentially envelops the corpora and spongiosum and helps maintain structural integrity of the flap
Indications
| Indication | Notes |
|---|---|
| Partial penectomy for penile SCC | Primary and most-studied indication[1][2] |
| Traumatic partial amputation | When distal urethra is preserved |
| Any partial penectomy with ≥ 2–3 cm urethral length preservable beyond the corporal transection without compromising oncologic margins | Defining technical prerequisite |
Contraindications
- Tumor involving or extending into the urethra (preserving longer stump → positive-margin risk)
- Proximal penectomy with insufficient residual urethra
- Total penectomy (no residual urethra)
Surgical Technique
Step 1 — Partial penectomy
- Penile-base tourniquet
- Circumferential skin incision at the planned amputation level
- Sharp transection of the corpora
- Frozen-section analysis of corporal margins and the urethral stump to confirm negative margins — the critical oncologic safety step[1][2][6]
Step 2 — Urethral preservation (defining step)
- Transect the urethra 2–3 cm distal to the corporal transection line — preserving a longer urethral segment than would be needed for voiding alone
- Send the urethral stump for frozen section to confirm negative margin at the true urethral transection
Step 3 — Corporal closure
- Close each corpus cavernosum tip individually with 3-0 / 4-0 absorbable interrupted suture
- Approximate tunica albuginea for hemostasis and a smooth rounded corporal tip surface
Step 4 — Urethral flap inversion
- The preserved distal urethral segment, still on its spongiosal blood supply, is inverted (folded back proximally) over the closed corporal tips
- Mucosal (luminal) surface faces outward — creates the moist pink glans-like surface
- Serosal / adventitial surface faces inward against the corpora
Step 5 — Neoglans shaping and fixation
- Suture the inverted flap circumferentially to the penile shaft skin at the level of the corporal transection with fine absorbable suture
- Junction creates a corona-like ridge simulating the coronal sulcus
- Sculpt / trim to approximate native-glans shape and contour
Step 6 — Neomeatus creation
- Fashion a new urethral meatus at the tip of the neoglans by creating a small opening in the inverted flap
- Evert the meatal edges and suture to prevent stenosis
- Position to allow directed urinary stream for standing voiding
Step 7 — Catheterization and dressing
- 14–16 Fr Foley through the neomeatus × 7–10 days
- Light compressive dressing
Published Series
Belinky 2011 — Original Description (n = 10)[1]
| Parameter | Value |
|---|---|
| Mean age | 61 y (18–71) |
| Indication | Penile SCC — all partial penectomy |
| Mean follow-up | 11 mo (5–17) |
| Flap necrosis | 0% |
| Neomeatal stenosis | 0% |
| Local tumor recurrence | 10% (1 / 10) |
| Ventral penile curvature | 10% (1 / 10) — no penetration difficulty |
Authors' conclusion: "simple, reproducible" with "satisfactory functional and cosmetic results, and an acceptable complication rate."
Chavarriaga 2022 — Landmark Cohort (n = 74)[2]
The largest published IUF cohort in the world literature.
Demographics
| Parameter | Value |
|---|---|
| n | 74 |
| Enrollment | May 2007 – December 2019 |
| Median age | 62 y (IQR 52–76) |
| Median follow-up | 72 mo (IQR 38–121) |
| DSNB | 83.8% (62 / 74) |
| ILND | 39.2% (29 / 74) |
Oncologic outcomes (6-year)
| Outcome | Estimate |
|---|---|
| Overall survival | 86.5% |
| Recurrence-free survival | 90.5% |
| Progression-free survival | 85.1% |
Functional outcomes (validated PROMs)
| Domain | Instrument | Result | Interpretation |
|---|---|---|---|
| Global health status | EQ-5D-3L-VAS | 84.6 ± 10.4 | Excellent HRQoL |
| Erectile function | IIEF-5 | 17.3 ± 7 | Mild-moderate ED (17–21 = mild) |
| Voiding symptoms | ICIQ-MLUTS | 1.7 ± 3.2 | Minimal symptoms |
IUF achieves a mean IIEF-5 of 17.3 — comparable to the 91.1% preserved erectile function from the Pang SR of glansectomy + STSG.[7] ICIQ-MLUTS 1.7 is substantially better than median IPSS 6 reported after total penectomy with perineal urethrostomy.[8]
Comparative IIEF-5 context:
| Cohort | IIEF-5 |
|---|---|
| Chavarriaga IUF (n = 74) | mean 17.3 |
| Pérez / Chavarriaga multicenter OSS (n = 57) | median 19 (IQR 10.75–25) |
| Croghan partial glansectomy[18b] | mean 14.9 |
| Croghan radical glansectomy[18b] | mean 15.8 |
The mean ICIQ-MLUTS voiding score of 1.7 is substantially better than the median 4 (IQR 1–15) reported across all organ-sparing techniques in the Pérez multicenter series.
Gulino 2007 — Related Eversion Variant (n = 14)[5]
A distinct variant using eversion rather than inversion of the urethral flap, sharing the same fundamental principle:
| Parameter | Value |
|---|---|
| Mean age | 54 y |
| Procedure | Glansectomy (8) or distal-shaft amputation (6) |
| Mean follow-up | 13 mo |
| Thermal / tactile sensation | 100% (14 / 14) |
| Rigid erections (spontaneous / induced) | 71% (10 / 14) |
| IIEF ejaculation change | Not significant |
| IIEF orgasm change | Not significant |
| Local recurrence | 0% |
| Penile retraction | 0% |
The 100% sensation preservation is a standout finding attributed to the rich sensory innervation of urethral mucosa.
Pérez / Chavarriaga 2020 — Multicenter OSS (n = 57 including IUF)[9]
| Parameter | Value |
|---|---|
| n | 57 (20 glans resurfacing, 23 partial penectomy, 14 glansectomy) |
| Median age | 55.1 y |
| Median follow-up | 55.7 mo |
| 5-year OS | 87.5% |
| 5-year PFS | 83% |
| Mean EQ-5D-3L | 82.5% |
| Median ICIQ-MLUTS | 4 (IQR 1–15) |
| Median IIEF-5 | 19 (IQR 10.75–25) |
The median IIEF-5 of 19 across all OSS techniques is consistent with the Chavarriaga IUF-specific cohort (17.3), supporting favorable sexual outcomes for reconstructive organ-sparing approaches.
Complications
| Complication | Belinky (n = 10) | Chavarriaga (n = 74) | Gulino (n = 14) |
|---|---|---|---|
| Flap necrosis | 0% | n/r (implied 0%) | 0% |
| Neomeatal stenosis | 0% | n/r specifically | 0% |
| Local tumor recurrence | 10% (1 / 10) | 9.5% (6-yr RFS 90.5%) | 0% |
| Ventral penile curvature | 10% (1 / 10) | n/r specifically | 0% |
| Penile retraction | n/r | n/r | 0% |
| Urethral fistula | 0% | n/r | 0% |
Ventral penile curvature (10% in Belinky) is attributed to differential tissue elasticity between the inverted urethral flap (ventral) and the penile shaft skin (dorsal); did not cause penetration difficulty.
Zero meatal stenosis across all IUF series is a notable advantage over STSG-based neoglans (pooled 8.1%, 0–14.3% in Pang SR)[7] — urethral mucosa is inherently resistant to contracture. Wang's spiral-embedded-flap urethroplasty for post-cancer meatal stenosis (n = 7, 100% success) would rarely be needed after IUF.[10]
Oncologic Safety
The central oncologic concern — whether preserving a longer urethral stump risks residual disease — is addressed by:[1][2][6][11][12]
- Mandatory frozen-section confirmation of the urethral stump margin before IUF is performed
- 6-year RFS 90.5% in Chavarriaga — favorable vs Parnham glansectomy + STSG (LR 9.3% at median 41.4 mo)
- Urethral involvement is rare in early-stage SCC — penile SCC typically arises from glans epithelium and invades the corpora before the urethra; in early-stage disease (most common at diagnosis) the urethra is usually uninvolved. In AJCC 8th edition staging, urethral invasion no longer differentiates T2 from T3 — T2 now includes invasion of the corpus spongiosum with or without urethral invasion[19b]
- EAU-ASCO 2023 — strong recommendation for organ-sparing surgery with reconstructive techniques; frozen section in cases of doubt
- NCCN — negative margins from frozen sections of cavernosal bed and urethral stump; reconstruction "in certain instances with an STSG or FTSG to create a neoglans" (IUF not specifically named but consistent with the principle)
Comparison With Other Reconstruction Techniques
| Parameter | IUF (Chavarriaga) | STSG neoglans (Parnham) | STSG SR (Pang) | Scrotal flap (Mazza) | No reconstruction |
|---|---|---|---|---|---|
| n | 74 | 177 | 327 | 34 | Variable |
| Follow-up | 72 mo median | 41.4 mo | 40.7 mo mean | 73.2 mo mean | — |
| Stages | 1 | 1 | 1 | 2 | 0 |
| Donor site | None | Thigh | Thigh | Scrotum | None |
| Local recurrence | 9.5% (6 y) | 9.3% | 9.1% | n/r | Variable |
| Meatal stenosis | 0% | 9% req intervention | 8.1% (0–14.3%) | 2.9% | Common |
| Flap / graft loss | 0% | 9% req intervention | 6.1% (0–17.6%) | 5.8% | n/a |
| Erectile function | IIEF-5 17.3 | n/r | 91.1% preserved | 20.5% potency | Reduced |
| Sensation | 100% (Gulino) | n/r | 83.7% (63.6–91.2%) | n/r | Absent |
| Voiding | ICIQ-MLUTS 1.7 | n/r | 75.6% standing | 100% unobstructed | Variable |
| Depilation needed | No | No | No | 17.6% | No |
| Curvature | 10% | n/r | n/r | n/r | n/a |
Comparison With Scrotal-Flap Glanuloplasty (Mazza)
| Parameter | IUF (Chavarriaga) | Mazza scrotal flap |
|---|---|---|
| n | 74 | 34 |
| Follow-up | 72 mo median | 73.2 mo mean |
| Stages | 1 | 2 |
| Donor site | None | Scrotum |
| Flap necrosis | 0% | 5.8% |
| Meatal stenosis | 0% | 2.9% |
| Erectile function | IIEF-5 17.3 | 20.5% potency |
| Depilation needed | No | 17.6% |
IUF is clearly superior in number of stages, erectile-function preservation, absence of hair growth, and complication rates.[17b]
Surveillance — NCCN vs EAU-ASCO
| Period | NCCN[6] | EAU-ASCO[12] |
|---|---|---|
| Years 1–2 | Clinical exam every 6 months | Clinical exam every 3 months |
| Years 3–5 | Clinical exam every 12 months (years 3–10) | Every 6 months |
| Self-examination | Encouraged | Encouraged |
| Imaging | US / CT / MRI of inguinal region if abnormal clinical exam, obesity, or prior inguinal surgery | n/a as routine |
| Strict-follow-up compliance | Recommended | Required prerequisite (Strong) |
Psychosexual Impact and Quality of Life
Partial penectomy has a substantial psychosexual impact that IUF aims to mitigate:[14][15][16][17][12]
- Whyte 2022 SR — partial penectomy decreases all IIEF domains; many patients still maintain satisfactory sex lives; greater residual penile length → higher postoperative function; older age and anxiety → lower function
- Roumieux 2025 qualitative study[20b] — penile-cancer diagnosis and treatment profoundly impact intimacy; patients describe a "voyage of sexual re-discovery"; emphasizes need for comprehensive pre-surgical information and post-surgical psychosexual support
- Yu 2016 (n = 43) — significant decreases in IIEF-15, increases in SAS / SDS; flaccid penile length positively associated with intercourse satisfaction; anxiety negatively associated with erectile, orgasmic, desire, and intercourse-satisfaction domains
- Romero 2005 (n = 18) — 55.6% had erectile function for intercourse after partial penectomy; 50% of sexually abstinent patients cited shame from small penis size and absence of the glans as the main reason for not resuming
- Kieffer 2014 (n = 90) — (partial) penectomy patients had significantly worse orgasm (effect size 0.54), appearance concerns (0.61), life interference (0.49), and urinary function vs penile-sparing surgery
- EAU-ASCO — partial penectomy is associated with poorer sexual outcomes vs organ-sparing
The IUF addresses these psychosexual concerns by:
- Natural-appearing neoglans reduces appearance-related shame and distress
- Moist mucosal surface mimicking native glans
- Excellent sensation (100% thermal / tactile in Gulino series)
- EQ-5D-3L global health 84.6% indicating excellent overall QoL
Advantages
- Single-stage — performed simultaneously with partial penectomy
- No separate donor site — eliminates thigh (STSG) or oral (BMG) donor morbidity
- Moist mucosal surface — closely mimics native glans
- Excellent sensation preservation — 100% thermal / tactile (Gulino)
- Zero meatal stenosis across all published series (vs 8.1% with STSG)
- Zero flap necrosis — robust spongiosal supply
- Preserved ejaculation and orgasm — IIEF ejaculation / orgasm domains unchanged
- Oncologically safe — 6-y RFS 90.5% with frozen-section margins
- Minimal voiding symptoms — mean ICIQ-MLUTS 1.7
- Excellent HRQoL — EQ-5D-3L 84.6%
Limitations
- Requires ≥ 2–3 cm preservable urethral length beyond the corporal transection — not feasible for proximal amputations or tumors involving urethra
- ~ 10% ventral penile curvature — differential tissue elasticity
- Limited published data — only two dedicated IUF series (Belinky n = 10, Chavarriaga n = 74) + Gulino n = 14 eversion variant; no RCT vs STSG
- Not specifically referenced in NCCN / EAU-ASCO guidelines — consistent with their reconstruction-after-negative-margins principle, but unnamed
- Single-center experience for the landmark series — external validation needed
- No standardized cosmetic-satisfaction data — unlike Pang STSG SR (86.3% satisfaction)
Postoperative Surveillance
- Clinical examination every 3 months × 2 years, then every 6 months × years 3–5
- Patient self-examination — neoglans and penile stump
- Biopsy of any suspicious lesion
- Salvage organ-sparing surgery for small recurrences not involving the corpora
- Strict-follow-up compliance is a prerequisite for organ-sparing surgery (strong recommendation)
Future Directions
- Multicenter validation across diverse institutions and populations
- Randomized comparison of IUF vs STSG neoglans for functional and oncologic outcomes
- Standardized functional-outcome reporting (per Pang SR call)
- Hybrid IUF + BMG meatoplasty combinations
- Long-term histologic studies of inverted urethral mucosa to characterize keratinization / metaplastic changes
Key Takeaways
- The most extensively studied flap-based neoglans technique — Chavarriaga n = 74 with 6-y OS 86.5%, RFS 90.5%, IIEF-5 17.3
- Defining technical innovation — preserve urethra 2–3 cm beyond corporal transection, invert mucosa-outward over closed corporal tips
- Single-stage, no donor site, moist mucosal surface, zero meatal stenosis, excellent sensation (Gulino 100%)
- Frozen-section confirmation of the urethral stump margin is the central oncologic safety step
- Ventral curvature (~ 10%) is the main technique-specific complication and does not affect penetrative function
- Reserved for partial penectomy with sufficient preservable urethral length; not for proximal amputations or urethra-involving tumors
Cross-references
- Glanuloplasty With Flaps — comparative overview of all four flap-based neoglans techniques
- Glansectomy With STSG — alternative graft-based neoglans
- Glans Resurfacing — superficial-disease organ-sparing alternative
- Penile Reconstruction — full decision framework
- Penile Skin Grafting
- Penile Replantation — for traumatic-amputation context
References
1. Belinky JJ, Cheliz GM, Graziano CA, Rey HM. "Glanuloplasty With Urethral Flap After Partial Penectomy." J Urol. 2011;185(1):204–6. doi:10.1016/j.juro.2010.09.010
2. Chavarriaga J, Becerra L, Camacho D, et al. "Inverted Urethral Flap Reconstruction After Partial Penectomy: Long-Term Oncological and Functional Outcomes." Urol Oncol. 2022;40(4):169.e13–169.e20. doi:10.1016/j.urolonc.2022.02.006
3. Lee JY, Spratt DE, Liss AL, McLaughlin PW. "Vessel-Sparing Radiation and Functional Anatomy-Based Preservation for Erectile Function After Prostate Radiotherapy." Lancet Oncol. 2016;17(5):e198–208. doi:10.1016/S1470-2045(16)00063-2
4. Yiee JH, Baskin LS. "Penile Embryology and Anatomy." ScientificWorldJournal. 2010;10:1174–9. doi:10.1100/tsw.2010.112
5. Gulino G, Sasso F, Falabella R, Bassi PF. "Distal Urethral Reconstruction of the Glans for Penile Carcinoma: Results of a Novel Technique at 1-Year of Followup." J Urol. 2007;178(3 Pt 1):941–4. doi:10.1016/j.juro.2007.05.059
6. National Comprehensive Cancer Network. Penile Cancer. Updated 2025-11-12.
7. Pang KH, Alnajjar HM, Muneer A. "Functional Outcomes of Glansectomy to Treat Localised Penile Cancer: A Systematic Review." Int J Impot Res. 2026;38(3):206–213. doi:10.1038/s41443-025-01062-1
8. Falcone M, Preto M, Ferro I, et al. "Surgical and Functional Outcomes of Penile Amputation and Perineal Urethrostomy Configuration in Invasive Penile Cancer." Urology. 2023;177:227. doi:10.1016/j.urology.2023.04.005
9. Pérez J, Chavarriaga J, Ortiz A, et al. "Oncological and Functional Outcomes After Organ-Sparing Plastic Reconstructive Surgery for Penile Cancer." Urology. 2020;142:161–165.e1. doi:10.1016/j.urology.2020.03.058
10. Wang Y, Liu M, Song LJ, et al. "Novel Strategy Using a Spiral Embedded Flap for Meatal Stenosis After Post-Penile Cancer Amputation Surgery: A Single-Center Experience." Asian J Androl. 2022;24(6):591–593. doi:10.4103/aja20227
11. Parnham AS, Albersen M, Sahdev V, et al. "Glansectomy and Split-Thickness Skin Graft for Penile Cancer." Eur Urol. 2018;73(2):284–289. doi:10.1016/j.eururo.2016.09.048
12. Brouwer OR, Albersen M, Parnham A, et al. "European Association of Urology-American Society of Clinical Oncology Collaborative Guideline on Penile Cancer: 2023 Update." Eur Urol. 2023;83(6):548–560. doi:10.1016/j.eururo.2023.02.027
13. Mazza ON, Cheliz GM. "Glanuloplasty With Scrotal Flap for Partial Penectomy." J Urol. 2001;166(3):887–9.
14. Whyte E, Sutcliffe A, Keegan P, et al. "Effects of Partial Penectomy for Penile Cancer on Sexual Function: A Systematic Review." PLoS One. 2022;17(9):e0274914. doi:10.1371/journal.pone.0274914
15. Yu C, Hequn C, Longfei L, et al. "Sexual Function After Partial Penectomy: A Prospective Study From China." Sci Rep. 2016;6:21862. doi:10.1038/srep21862
16. Romero FR, Romero KR, Mattos MA, et al. "Sexual Function After Partial Penectomy for Penile Cancer." Urology. 2005;66(6):1292–5. doi:10.1016/j.urology.2005.06.081
17. Kieffer JM, Djajadiningrat RS, van Muilekom EA, et al. "Quality of Life for Patients Treated for Penile Cancer." J Urol. 2014;192(4):1105–10. doi:10.1016/j.juro.2014.04.014
17b. Mazza ON, Cheliz GM. "Glanuloplasty With Scrotal Flap for Partial Penectomy." J Urol. 2001;166(3):887–9.
18b. Croghan SM, Compton N, Daniels AE, et al. "Phallus Preservation in Penile Cancer Surgery: Patient-Reported Aesthetic & Functional Outcomes." Urology. 2021;152:60–66. doi:10.1016/j.urology.2021.02.011
19b. Khalil MI, Kamel MH, Dhillon J, et al. "What You Need to Know: Updates in Penile Cancer Staging." World J Urol. 2021;39(5):1413–1419. doi:10.1007/s00345-020-03302-z
20b. Roumieux C, Royakkers L, Albersen M, Dancet E. "The Impact of Diagnosis and Treatment of Penile Cancer on Intimacy: A Qualitative Assessment." Int J Impot Res. 2025;37(9):759–765. doi:10.1038/s41443-024-00992-6