Abstract: Objective To investigate the clinical effect of modified Koyanagi technique for the repair of severe hypospadias. Methods We retrospectively analyzed 35 patients with severe hypospadias treated by modified Koyanagi technique. And for comparison,34 cases of severe hypospadias treated with one-stage Duckett+Duplay technique in the same term were collected. Results The operation time of modified Koyanagi technique was much shorter than one-stage Duckett+Duplay technique,the result had statistically significance ( P < 0 . 05 ). The successful rate and complication in two groups had no statistically significance( P>0 . 05 ). The patients with urethral fistula were treated successfully with the repair of urethral fistula 6 months after the first surgery. And the cases of stenosis were cured by urethral dilatation within 1 to 3 months. All patients of the two group were followed up 6 to 24 months( mean 15 months). The correction of chordee and the micturition were very well,and did not need urethral dilation in 6 months at least. Conclusion Modified Koyanagi technique for the repair of severe hypospadias is relatively simple,has similar effect of surgery compared with Duckett+Duplay technique.

Key words: hypospadias, urogenital surgical procedures, treatment outcome