A Multicenter Randomized Controlled Trial Comparing Platelet-Rich Fibrin and Ventral Dartos Flap as Intermediate Layers in Tabularized Incised Plate (TIP) Urethroplasty for Distal Hypospadias With Mild Penile Curvature

This randomized controlled trial aims to compare the incidence of urethrocutaneous fistula at a minimum of 6 months postoperatively between two intermediate layers used in hypospadias repair: platelet-rich fibrin (PRF) membrane and ventral dartos flap. The study will also evaluate secondary outcomes, including rates of meatal stenosis, urethral stricture, other postoperative complications, and cosmetic outcomes assessed by standardized photographs and blinded expert scoring.

Study Design and Setting:

This prospective, multicenter, single-blinded randomized controlled trial will be conducted at centers in Tashkent, Uzbekistan, and Jakarta, Indonesia. A total of 140 patients (70 per group) will be enrolled, with randomization stratified by urethral plate score and center to ensure balanced groups.

Participants:

Children aged 6 months to 5 years with primary distal hypospadias (Grade 1, Abbas classification) or redo distal hypospadias (Grade 1, Abbas classification), with penile curvature less than 30° after degloving (measured as per Abbas, 2022), will be included. Exclusion criteria include previous hypospadias surgery, proximal hypospadias, penile curvature ≥30°, or syndromic anomalies/coagulopathies.

Interventions:

Participants will undergo tubularized incised plate (TIP) or glanuloplasty TIP (GTIP) urethroplasty performed by experienced pediatric urologists using standardized techniques.

Group A: Application of autologous platelet-rich fibrin membrane over the neourethra. PRF will be prepared intraoperatively by drawing 10 mL of peripheral blood, centrifuging at 3000 rpm for 10 minutes, extracting the PRF clot, compressing it into a membrane, and securing it over the neourethra with absorbable sutures.

Group B: Rotation of a ventral dartos flap over the neourethra.

Intraoperative PRF Preparation:

Blood will be collected into sterile glass tubes without anticoagulants, centrifuged immediately, and the PRF membrane prepared as described. The membrane will be placed over the neourethra before glans closure, secured laterally, and the skin closure completed in standard fashion.

Stratification:

Participants will be stratified based on urethral plate characteristics using a validated scoring system before randomization to ensure anatomical balance.

Follow-Up:

Patients will be assessed at 1, 3, and 6 months postoperatively for complications (fistula, stenosis, etc.), neomeatus function, and cosmetic appearance. Digital photographs will be evaluated by two blinded pediatric urologists, and cosmetic outcomes will be scored using the HOSE system.

Data Management and Analysis:

All data will be anonymized and stored securely. Statistical analysis will be performed using SPSS v22, applying appropriate tests for categorical and continuous variables, with multivariate regression if necessary.

Inclusion criteria

• Primary and complex distal hypospadias (Grade 1, Abbas classification)
• Penile curvature <30° after degloving (Methodology of curvature measurement: Abbas T. O. (2022).
• Children aged 6 months to 5 years

Exclusion criteria

• Previous hypospadias surgery
• Proximal hypospadias
• Penile curvature ≥30°
• Syndromic anomalies or coagulopathy