Age-related changes in urinary flow following dorsal inlay graft urethroplasty for hypospadias in early childhood: Potential improvement over 11 years of age

Introduction: One of the goals of hypospadias repair is to create a neourethra with normal urinary stream and normal growth. Several studies have reported that dorsal inlay graft urethroplasty (DIG) has wide indications for various clinical phenotypes of hypospadias, with good short-term outcomes and few complications. However, there have been no reports that evaluated both short-term and long-term functional outcomes using uroflowmetry in patients with DIG.

Objective: The aim was to investigate whether uroflowmetry parameters change with time following DIG for hypospadias in early childhood.

Materials and methods: Uroflowmetry parameters after DIG for hypospadias in childhood were retrospectively evaluated and compared between two defined ages at follow-up: 4-6 years and 11-13 years. Maximum urinary flow (Q_max) under the 25th percentile on the Miskolc nomogram was defined as obstruction. To evaluate the shapes of uroflow quantitatively, the flow index (FI) was used. The FI cut-offs for the flow shapes were defined as tower >1.253, plateaus <0.659; bells were between these two values.

Results: Thirty-four patients met the inclusion criteria. The median operative age was 1.8 years (range 1.0-4.9 years). The median follow-up time was 10.3 years (range 7.2-12.3 years). The mean ± SD Q_max at the two follow-up times increased with time, from 9.2 ± 3.7 to 18.8 ± 7.8. The mean ± SD FI changed from 0.53 ± 0.19 to 0.85 ± 0.31. Both Q_max and the FI were significantly improved (p < 0.001, p < 0.001, respectively). There were significantly fewer patients with obstruction evaluated by the Miskolc nomogram at 11-13 years of age (n = 11, 32.4%) than at 4-6 years (n = 31, 91.2%) (p < 0.001). Plateau shapes assessed by the FI were seen in 24 (70.6%) patients at 4-6 years and 10 (29.4%) patients at 11-13 years (Table). The number of patients with plateau shapes was significantly decreased (p = 0.001).

Discussion: Only one report noted long-term outcomes and spontaneous uroflowmetry resolution after tubularized incised plate urethroplasty. The current report is the first to present the short-term and long-term uroflowmetry outcomes after DIG. In addition, the FI was used for the first time to evaluate uroflowmetry after hypospadias repair. It was found that the uroflowmetry parameters improved spontaneously over 11 years of age following DIG for hypospadias in early childhood.

Conclusion: Uroflowmetry parameters improved spontaneously over 11 years of age following DIG for hypospadias in early childhood.