Dissociated urethral plate Onlay and standard Onlay urethroplasty for mid-distal hypospadias: A comparative study

Urethral plate (UP) reserved Onlay urethroplasty is currently used widely in mid-distal hypospadias. However, for children with 15-30° residual curvature after degloving, only dorsal tunica albuginea plication is performed to correct penile ventral curvature (VC), and long-term follow-up showed a high recurrence rate of penile curvature. We developed a modified Onlay urethroplasty, which dissociates the UP and completely removes the tissue beneath the UP to fully correct penile curvature. Furthermore, we compared it with the standard Onlay urethroplasty to explore its rationality and feasibility.

We prospectively collected clinical data from 68 children with hypospadias who underwent standard or modified Onlay urethroplasty between September 2019 and June 2021, and evaluated the interim outcomes to identify the complications between the two groups. Additionally, we conducted histological examination of the tissue beneath the UP.

A total of 32 patients underwent modified Onlay urethroplasty. Intraoperative curvature measurements showed that 37.5% (12/32) of the patients had completely straightened their penis after UP dissection and removal of the fibrous tissue beneath it. A total of 36 patients underwent standard Onlay urethroplasty. Totally, five fistulas each were reported in the first and second groups, and the complication rates were 15.6% and 13.9%, respectively (P > 0.05). The histological results showed that the tissue below the UP contains a large amount of collagen, mainly type I collagen.

The dissociated UP Onlay urethroplasty can maximally remove factors limiting penis growth and completely correct penile curvature, without increasing the incidence of postoperative complications. Therefore, we recommend the application of the improved Onlay urethroplasty in children with mid-distal hypospadias.