How do asymptomatic toilet-trained children void following tubularized incised-plate hypospadias repair?

PURPOSE: : To evaluate the functional outcome in the form of urinary flow rates in asymptomatic children following uncomplicated tubularized incised plate urethroplasty (TIPU) hypospadias repair.

METHODS: : We reviewed the records of children who underwent TIPU at our institution between April 1997 and September 2007 and included only asymptomatic toilet-trained children who had an uncomplicated postoperative course and had undergone uroflometry not less than 1 year postoperatively. Unfavourable voiding parameters were either a plateau curve, a peak flow below the 5th percentile range in nomogram or a post-void residual (PVR) more than 20% of the total functional capacity of the bladder. Uroflowmetry findings were analyzed against variables, including the surgeon, the severity of hypospadias, the presence of a hypoplastic urethra, the use of double layer closure, the performance of a spongioplasty and the use of a stent. Serial uroflowmetries, when available, were compared with respect to the initial flow study.

RESULTS: : In total, 59 patients were eligible for the study. The mean age at surgery was 2.4 years. Hypospadias was distal penile in 50 (85%) and mid and proximal penile in 9 (15%). Mean follow-up was 3.3±2 (1-9.5) years. The uroflow curve was bell-shaped in 18 (30%), interrupted in 8 (14%), slightly flattened in 27 (46%) and plateau in 6 (10%). Flow rate nomograms revealed that 40 (68%) were above the 20th percentile, 10 (17%) were below the 5th percentile and 9 (15%) were between these ranges. PVR was >20% of the pre-void volume in 9 children (15%). No patient demonstrated all three unfavourable parameters together. The groups of children with unfavourable functional voiding parameters were compared to the children with favourable parameters specifically with respect to the possible predictors of outcome. Follow-up uroflometry in 17 patients showed improvement in the flow curve, flow rate and PVR with significant improvement of maximum urinary flow rate (Qmax) and PVR values.

CONCLUSIONS: : Asymptomatic, urodynamic abnormalities were observed in our study following uncomplicated TIPU repair. These abnormalities were not related to the variation of the technique among surgeons. Spontaneous improvement has been noted on serial flow studies.