[Uroflowmetry values among asymptomatic children who underwent tubularized incised plate urethroplasty]

Tubularized incised plate uretroplasty (TIPU) technique for hypospadias repair or Snodgrass procedure has become increasingly popular since its description in 1994. The elasticity of the neouretra is reduced and several studies have pointed out that flow parameters of the patients operated on this procedure show some grade of asymptomatic functional obstruction, although there are reports on the improvement of these parameters on the mid term. We evaluated the functional outcome in the form of urinary flow in asymptomatic children following uncomplicated TIPU.

We reviewed the urine flow rate of asymptomatic toilet trained children who underwent TIPU at our institution between 2005 and 2012. Uroflowmetries were performed in a serial fashion, during the follow up visits at the first months after the repair and yearly afterwards. Unfavourable values were plateau or interrupted curves and peak flow below the 5th percentile of a validated Nomogram for children (Gutiérrez-Segura). Statistical work up: SPSS 15.0.

85 patients were eligible. The mean age at surgery was 2.7 years. Median follow up was 29 months (6-82 months). Hypospadias was distal penile in 76 (89.5%) and mid penile in 9 (10.6%). We obtained 131 uroflowmetries (1.54 per patient) at a mean age of 5.1 years (2.5-8). 66.7% of the peak flow values and 55% of the average flow values were below the 5th percentile of the Nomogram. Flow curve was normal (bell- shaped) in 35 charts (26.5%), irregular in 38 (28.8%) and plateau in 56 (42.4%). Peak flow values improved in the second year after surgery (compared to the first year values): 7 ml/sgvs 8.09 ml/sg (p=0.07). The difference was significative in low volumes (<100 ml) (6.3 vs 7.8 ml/sg, p=0.04). Bell-shaped curve rate also grew: 21% (6/29) vs 28% (29/74), p> 0.05. We constructed a specific Nomogram for this population.

Our data confirm that many asymptomatic patients who undergo TIPU repair present altered flow patterns. Spontaneous partial improvement is the norm after the first year of surgery.