Comparative Analysis of Tubularized Incised Plate Versus Onlay Island Flap Urethroplasty for Penoscrotal Hypospadias

PURPOSE: Despite being the dominant technique for repair of distal hypospadias, application of the tubularized incised plate approach for penoscrotal hypospadias remains controversial. We report our experience with severe hypospadias, comparing tubularized incised plate to transverse island flap onlay urethroplasty. MATERIALS AND METHODS: We retrospectively reviewed consecutive patients with penoscrotal hypospadias presenting between 1998 and 2006. Based on surgeon preference 35 children underwent tubularized incised plate and 40 underwent onlay urethroplasty. Penoscrotal transposition and degree of ventral curvature, type of ventral curvature repair, complication rate, postoperative uroflowmetry pattern in toilet trained patients and number of reoperations were compared between the 2 groups. RESULTS: Mean patient age at surgery was 17 months (range 9 to 91) for tubularized incised plate urethroplasty and 17.8 months (10 to 58) for the onlay procedure. Urethroplasty was performed over an 8Fr catheter in all patients. With mean followups of 30 months (range 6 to 74) and 38.8 months (16 to 80) the overall complication rates were 60% and 45% for the tubularized incised plate and onlay procedures, respectively. Fistula occurred in 15 patients and repair breakdown in 3 patients (total 51.4%) treated with tubularized incised plate repair, compared to 8 and 2 patients, respectively (25%), treated with onlay repair (p = 0.01). Fistula location also differed significantly between the 2 groups, with proximal fistulas occurring in 11 of 15 tubularized incised plate repairs (73.3%) vs 2 of 8 onlay repairs (25%, p = 0.02). Recurrent ventral curvature was more frequent after onlay urethroplasty (5.7% vs 12.5%, not significant). At a mean age of 5.1 years a plateau uroflow curve (vs normal bell curve) was observed in 16 of 24 children (66.7%) who underwent tubularized incised plate repair and in 7 of 21 (33.3%) who underwent onlay repair (p <0.01). CONCLUSIONS: In this series the overall complication rate was similar for tubularized incised plate and onlay urethroplasty. Despite similar urethroplasty calibers, the uroflow curves and fistula positions in patients undergoing tubularized incised plate repair suggest that the neourethra distal to the fistula may be relatively narrow, creating flow resistance and leading to proximal fistula. Longer followup and close monitoring are needed before embracing one approach over the other.