# Is dorsal inlay graft (DIG) with TIP repair superior to TIP alone for primary hypospadias? A randomized clinical trial

## TL;DR

This study compares two surgical techniques for hypospadias repair and finds that adding a graft improves outcomes in some cases.

## Contribution

The study provides evidence on the effectiveness of adding a dorsal inlay graft to TIP repair in different urethral plate types.

## Key findings

- DIG with TIP improved neourethral and meatal function in patients with narrow urethral plates.
- Meatal stenosis occurred in 8.62% of TIP-only patients.
- DIGTIP resulted in better cosmetic outcomes at the glans tip.

## Abstract

Tubularized incised plate urethroplasty (TIP) is a widely practiced technique for hypospadias repair; however, it remains associated with complications, particularly meatal and/or neourethral stenosis. Grafting the incised plate with a dorsal inlay graft (DIG) during TIP has been proposed as a preferred modification to address these complications. Although several studies have investigated DIG in cases with a narrow urethral plate (UP), no current consensus exists regarding its use as an adjunct to TIP repair in different types of UP.

The current study aimed to investigate whether DIG with TIP repair is superior to TIP in different types of UPs regarding surgical and cosmetic outcomes.

In a comparative, randomized study conducted from January 2023 to December 2024, patients with primary hypospadias without chordee were randomly assigned to two groups: Group 1 underwent repair using TIP, and Group 2 underwent repair using the DIG with TIP technique. Short- and mid-term outcomes were compared between the two groups.

During the study period, 579 primary hypospadias cases met the inclusion criteria (290 in Group 1 and 289 in Group 2). The median age in both groups was 22 months (IQR, 13–36.25 months). Operative time was significantly longer in Group 2 (P = 0.001). Among patients with a narrow UP, surgical outcomes were better in Group 2, with statistically significant improvement in neourethral and meatal function (P = 0.001). In Group 1, meatal stenosis developed in 25 patients (8.62%); 14 cases presented early and improved with regular dilation, whereas 11 cases presented after 6 months and required meatoplasty. In patients with a wide UP (> 8 mm), better results were observed in Group 2, although the difference was not statistically significant. Regarding the final position of the meatus at the glans tip, significance was noted in Group 2 (P = 0.008). The follow-up period ranged from 6 to 23 months (mean ± SD: 13.76 ± 5.68). The hypospadias objective scoring evaluation (HOSE) score at the 6th month demonstrated statistical significance in Group 2.

Adding a DIG to TIP repair potentially reduces the risk of neourethral and meatal complications in patients with a narrow UP (4–8 mm). However, in wide UP (> 8 mm), comparable outcomes were observed in both groups. The dorsal inlay graft with tubularized incised plate (DIGTIP) is associated with longer operative times and greater technical demands; therefore, it should be applied only in selected patients and according to the surgeon's preference.

[NCT07086963] "Retrospectively registered" Date of registration [Jul 17 2025] https://clinicaltrials.gov/study/NCT07086963 and Unique identifying number [SVU/MED/SUR011/4/22/12/519].