Value of urinary flow patterns in the follow-up of children who underwent Snodgrass operation

The urinary flow patterns and the Toguri nomogram were compared in the intermediate functional results of the tubularized-incised plate urethroplasty (TIPU) to repair distal and midpenile hypospadias by using uroflowmetry. 28 children who were toilet trained, were able to void volitionally, and had no fistulas following hypospadias repair were eligible for the study. The study did not include children who had persistent fistula, meatal stenosis or urethral stricture, and did not return for follow-up. The mean age was 8.4 years and the mean follow-up period was 18 months. The urinary flow pattern, maximum (Q(max)) and average flow rate (Q(ave)) were measured; the results were expressed as percentiles and compared to the Toguri values from normal children. The Q(max) and Q(ave) were considered normal if they were in >25th percentile, equivocally obstructed in the 5-25th percentile and obstructed if <5th percentile. The flow pattern was classified as bell ring shape, plateau or intermittent. According to the Toguri nomogram, 22 of 28 patients (78.5%) were considered normal, 4 patients (14.2%) as equivocally obstructed, and 2 patients (7.1%) as obstructed group. A normal bell-shaped flow curve was obtained in 23 (82.1%) of the children. 4 patients (14.2%) had a plateau flow pattern. Only 1 of the patients had an intermittent shape flow curve. The flow pattern was normal bell-shaped for all of the patients, except 1, with Q(max) above the 25th percentile according to the Toguri nomogram. Of children with Q(max) below the 5th percentile, both of them had a plateau flow pattern and were found to have an asymptomatic meatal stenosis, which was improved with urethral dilatation. However, of the 4 patients with Q(max) between 5 and 25 percentiles, 2 had a plateau flow pattern and the others had a bell-shaped flow pattern. The flow patterns of the 2 patients determined as obstructive by the Toguri nomogram were plateau-shaped. TIPU provides satisfactory functional results for distal and midpenile hypospadias; uroflowmetry is an important noninvasive tool to evaluate this technique. There are no studies in the literature which only used flow patterns for the evaluation of urination for follow-up after the hypospadias repair. Our study showed that the evaluation of obstruction according to the Toguri nomogram may not be necessary in patients with a normal bell-shaped flow pattern in uroflowmetry.