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

Summary

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.

Conditions

• Residual Severe Ventral Curvature
• Transection of the Urethral Plate
• Corporoplasty
• Pedicled Tunica Vaginalis Flap (TVF)
• Novel Urethral Plate Flap (UPF)
• Hypospadias

Interventions

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.

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.

Sponsors & Collaborators

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

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

PARALLEL

Eligibility

Min Age

6 Months

Max Age

14 Years

Sex

MALE

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-02-23

Primary Completion

2027-11-30

Completion

2029-02-22

Countries

• China

Study Locations