Urethral Plate Flap vs. Tunica Vaginalis Flap for Residual Severe Ventral Curvature in Hypospadias

Urethral Plate Flap Versus Tunica Vaginalis Flap Corporoplasty for the Correction of Residual Severe Ventral Curvature After Urethral Plate Transection in Hypospadias Repair: A Single-Center, Randomized, Controlled, Non-Inferiority Study

The correction of ventral curvature in hypospadias follows a stepwise principle. Clinically, in some cases of hypospadias, residual severe ventral curvature (VC ≥ 30°) persists even after thorough skin degloving and transection of the urethral plate, due to the unbalanced development of the ventral and dorsal tunica albuginea of the corpus cavernosum. In such cases, ventral tunica albuginea incision and corporoplasty with a graft are mandatory.

Although the currently commonly used pedicled Tunica Vaginalis Flap (TVF) corporoplasty can effectively correct the curvature, it requires additional dissection of the scrotum and tunica vaginalis sac. This prolongs the operative time and poses risks of donor-site complications, such as testicular retraction and scrotal hematoma.

The novel Urethral Plate Flap (UPF) corporoplasty utilizes local pedicled urethral plate tissue for homologous repair. This study adopts a prospective, single-center, randomized, controlled, double-blind, non-inferiority trial design, enrolling 90 subjects. The aim is to verify that the therapeutic efficacy of the UPF technique in correcting such residual severe ventral curvature is non-inferior to that of TVF, while demonstrating significant advantages in surgical efficiency and donor-site safety.

This study aims, through a single-center, double-blind, RCT design, and under the strict indication of "residual severe ventral curvature after urethral plate transection," to verify efficacy via a "non-inferiority" hypothesis, and to verify safety and efficiency via a "superiority" hypothesis. The goal is to provide Level I evidence for the update of hypospadias guidelines, while simultaneously exploring the establishment of postoperative imaging evaluation standards.

Study Overview

• Status: Not yet recruiting
• Conditions: Hypospadias; Residual Severe Ventral Curvature; Transection of the Urethral Plate; Corporoplasty; Pedicled Tunica Vaginalis Flap (TVF); Novel Urethral Plate Flap (UPF)
• Intervention / Treatment: Procedure: Urethral Plate Flap Corporoplasty; Procedure: Tunica Vaginalis Flap Corporoplasty

• Study Type: Interventional
• Enrollment (Estimated): 90
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Wei Ru Associate Chief Physician, MD; Phone Number: +86 13588064041; Email: ruwei@zju.edu.cn

Study Locations

• China
  • Zhejiang
    • Hangzhou, Zhejiang, China, 310052
      • Children's Hospital, Zhejiang University School of Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age: 6 months to 14 years.
• Diagnosis: Primary hypospadias (no history of prior hypospadias repair).
• Intraoperative Condition: Residual ventral curvature ≥ 30° confirmed by artificial erection test after transection of the urethral plate.
• Consent: Signed informed consent provided by the participant's legal guardian.

Exclusion Criteria:

① Glans diameter < 1 cm; ② Combined with cryptorchidism; ③ Combined with severe bleeding disorders or coagulation dysfunction.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Urethral Plate Flap Corporoplasty; After degloving and transecting the urethral plate, mobilize the urethral plate.; Transect the tunica albuginea at the point of maximal curvature to fully correct the ventral curvature.; Mobilize and open the tunica vaginalis sac, and harvest a pedicled Tunica Vaginalis Flap (TVF).; Transfer the TVF to the ventral side to repair the tunica albuginea defect, and suture with 6-0 absorbable sutures.; Mobilize the space between the scrotal skin and dartos fascia. Place 2 interrupted sutures between the external spermatic fascia near the testis and the dartos fascia at the scrotal base to fix the testis within the sub-dartos space.	Procedure: Urethral Plate Flap Corporoplasty; 1.After degloving and transecting the urethral plate, mobilize the urethral plate. 2.Transect the tunica albuginea at the point of maximal curvature to fully correct the ventral curvature. 3.Mobilize and open the tunica vaginalis sac, and harvest a pedicled Tunica Vaginalis Flap (TVF). 4.Transfer the TVF to the ventral side to repair the tunica albuginea defect, and suture with 6-0 absorbable sutures. 5.Mobilize the space between the scrotal skin and dartos fascia. Place 2 interrupted sutures between the external spermatic fascia near the testis and the dartos fascia at the scrotal base to fix the testis within the sub-dartos space.
Active Comparator: Tunica Vaginalis Flap Corporoplasty; After degloving and transecting the urethral plate, mobilize the urethral plate.; Transect the tunica albuginea at the point of maximal curvature to fully correct the ventral curvature.; Mobilize and open the tunica vaginalis sac, and harvest a pedicled Tunica Vaginalis Flap (TVF).; Transfer the TVF to the ventral side to repair the tunica albuginea defect, and suture with 6-0 absorbable sutures.; Mobilize the space between the scrotal skin and dartos fascia. Place 2 interrupted sutures between the external spermatic fascia near the testis and the dartos fascia at the scrotal base to fix the testis within the sub-dartos space.	Procedure: Tunica Vaginalis Flap Corporoplasty; 1.After degloving and transecting the urethral plate, mobilize the urethral plate. 2.Transect the tunica albuginea at the point of maximal curvature to fully correct the ventral curvature. 3.Mobilize and open the tunica vaginalis sac, and harvest a pedicled Tunica Vaginalis Flap (TVF). 4.Transfer the TVF to the ventral side to repair the tunica albuginea defect, and suture with 6-0 absorbable sutures. 5.Mobilize the space between the scrotal skin and dartos fascia. Place 2 interrupted sutures between the external spermatic fascia near the testis and the dartos fascia at the scrotal base to fix the testis within the sub-dartos space.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Recurrence Rate of Ventral Curvature at 12 Months Postoperatively	Recurrence of ventral curvature is defined as residual ventral curvature ≥ 10° on lateral photographs during artificial erection.	12 Months Postoperatively

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Operative Time for Curvature Correction	Recorded as the time from the "incision of the tunica albuginea" to the "completion of tunica albuginea repair and confirmation of a straight penis" (in minutes). This metric specifically excludes the time taken for urethroplasty and penile skin reconstruction to minimize confounding factors.	Intraoperative
Incidence of Donor-Site Complications	Assessment of complications related to the graft harvest site, including: Testicular events: Postoperative testicular retraction/ascent (defined as the testis position being higher than the middle of the scrotum). Scrotal events: Scrotal hematoma, edema, and secondary infections caused by these conditions.	From enrollment to the end of treatment at 12 months
Continuity of the tunica albuginea	Evaluation is performed by a sonographer blinded to group allocation using High-Frequency Penile Ultrasound Evaluation Evaluation Parameters: Continuity of the tunica albuginea (Categorized as: Continuous / Interrupted).	12 months postoperatively
Echogenicity of the corpus cavernosum beneath the graft	Evaluation is performed by a sonographer blinded to group allocation using High-Frequency Penile Ultrasound Evaluation Evaluation Parameters: Echogenicity of the corpus cavernosum beneath the graft (Assessed for consistency with the host cavernous tissue)	12 month postoperatively

Collaborators and Investigators

• Sponsor: The Children's Hospital of Zhejiang University School of Medicine

Study record dates

Study Major Dates

• Study Start (Estimated): February 23, 2026
• Primary Completion (Estimated): November 30, 2027
• Study Completion (Estimated): February 22, 2029

Study Registration Dates

• First Submitted: December 9, 2025
• First Submitted That Met QC Criteria: February 8, 2026
• First Posted (Actual): February 11, 2026

Study Record Updates

• Last Update Posted (Actual): February 11, 2026
• Last Update Submitted That Met QC Criteria: February 8, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urogenital Diseases; Genital Diseases; Genital Diseases, Male; Male Urogenital Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Congenital Abnormalities; Urogenital Abnormalities; Penile Diseases; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Hypospadias
• Other Study ID Numbers: 2025-IRB-0555-P-01

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No