Value of Urinary Flow Patterns in the Follow-Up of Children Who Underwent Snodgrass Operation

Abstract

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.

The Use of Uroflowmetry to Diagnose Recurrent Stricture After Urethral Reconstructive Surgery

“…What small studies have shown is that children with a flow rate of 2 SD below the mean or those with a flat voiding curve have a high likelihood of post-repair urethral stricture. 7,8 Children suspected of having postoperative pathology by UF parameters can then undergo urethral examination with a high likelihood of finding recurrence and of successfully managing recurrent obstruction at the same operative/anesthetic setting.…”

Prospective Randomized Comparison of Distal Extension of Midline Urethral plate Incision and Standard Tubularized Incised Plate Urethroplasty – Do Anatomical Penile Measurements Influence the Outcomes?

“…Functional outcome following TIP repair using uroflowmetry had been investigated in many studies signifying the importance of long-term follow-up of those boys and the obtained results were quite controversial. While some studies claimed that majority of patients exhibited normal flow pattern [14][15][16], others reported an obstructed flow in a significant proportion of cases [17,18]. In a systematic review addressing the importance of uroflowmetry studies after TIP repair, 11 studies reported obstructive flow in 24.6% of patients (93 / 378) [19].…”

Tubularized incised plate technique for recurrent hypospadias

“…The Q max and Q ave were considered normal if they were above 25th percentile, equivocally obstructed if in the 5-25th percentile, and obstructed if below 5th percentile. The flow pattern was classified as a bell ring shape, plateau, or intermittent [12].…”