A method to assess posterior urethral valve ablation

There are few published reports addressing the assessment of posterior urethral valve ablation. This study was performed to provide a ratio to measure successful treatment of posterior urethral valves.

A total of 35 patients with posterior urethral valves were treated by a single surgeon between 1995 and 2004. Of these patients 23 were younger than 1 year at diagnosis and were selected for this study. A urethral ratio was calculated by dividing the posterior urethral diameter by the anterior urethral diameter. A total of 31 males undergoing cystography for urinary tract infections were evaluated as normative controls. The urethral ratio was also measured and calculated for these patients.

Median patient age was 1.5 months. In 13 patients preoperative cystograms were available and in 20 patients postoperative cystograms were available for review. Measurements were made of the posterior urethral and anterior urethral diameters. Median preoperative ratio in 13 patients was 8.6. This ratio decreased postoperatively to 3.1 in 15 patients who only required 1 ablation and 8.0 in 5 patients who required a second ablation. After a second ablation the ratio decreased to 3.1. The 5 cases requiring a second ablation were initially managed by cystoscopy and a flexible electrode. None of the patients treated initially with a resectoscope required a second ablation. Urethral ratio was 2.6 in 31 normal males undergoing cystogram for investigation of a urinary tract infection.

Calculating urethral ratio in patients with posterior urethral valves allows objective measurement of the technical success of valve ablation.