The modified Koyanagi repair for severe proximal hypospadias

Abstract

Objective To report the method and results of a modi®ed one-stage Koyanagi repair (urethroplasty with a parameatal-based and fully extended circumferential foreskin¯ap) to preserve the vascularity to the peripheral portion of the neourethra, in the repair of severe hypospadias. Patients and methods Using a skin-incision line as in the original Koyanagi repair, a circumferential incision is made < 5 mm proximal to the corona and the urethral plate incised as for repair of chordee. A Ushaped skin incision is then made surrounding the meatus, extended to the dorsal prepuce for < 8 mm and parallel to the ®rst incision. The tissue between the prepuce and dartos is dissected on the dorsal side to ®x the prepuce as a neourethra to the dartos and to maintain blood supply. After mobilizing the loopshaped skin¯ap through the button-hole of the pedicle, the internal and external sides of the loop are sutured to construct a neourethra. Twenty patients (aged 10 months to 9 years) with severe proximal hypospadias underwent the one-stage modi®ed Koyanagi repair. Results The repair was successful after the initial procedure in 14 patients, but urethrocutaneous ®stulae developed in three and meatal stenosis in three. The overall success rate was thus 70%. Conclusions There were fewer complications than reported with the original Koyanagi repair, suggesting that the attempted vascular preservation of the neourethra was effective.

Original Koyanagi urethroplasty versus modified Hayashi technique: Outcome in 57 patients

“…In the armamentarium of techniques used to reconstruct proximal severe hypospadias, the Koyanagi procedure [4] and its variant e the Hayashi procedure [5] e are established alternatives for urethral reconstruction. The aim of this article is to compare the outcomes of these two techniques and discuss their place compared to other techniques.…”

Choosing a technique for severe hypospadias

“…[7] The glans is drawn dorsally through a button-hole in the dartos pedicle bringing the neourethra ventrally. These two modifications, the island flap and loop shape, are the modifications described later by Hayashi et al [9] In the report by Snow and Cartwright the neourethra is drawn through the tip of the glans whilst in the Hayashi description the glans is split. [20] In this regard the technique we use corresponds to the latter technique.…”

“…Different techniques were performed: The Koyanagimodified Hayashi procedure, [9] the tubularised transverse preputial island flap technique (Duckett), [10] the onlay preputial island flap urethroplasty, [11] the augmented Duckett (Duckett + Thiersch-Duplay), [12] and a simple tubularised plate urethroplasty without plate incision. The decision to transect the urethral plate was taken by the surgeon based on his preoperative judgment of the severity of the chordee.…”

“…Whilst some surgeons prefer a two-stage technique, [1][2][3] several one-stage repairs have been described with variable success rates. [4][5][6][7][8][9] Each technique, whether twostage or one-stage, has its advantages and drawbacks and not one technique has gained widespread popularity. Heralding one technique as the gold standard for posterior hypospadias is probably unrealistic and paediatric urologists have to master a variety of techniques because various patient-related specifics can favour one or another technique.…”

Two-stage repair for proximal hypospadias: A reappraisal

“…Some of their patients underwent third and fourth surgeries [30,31]. Complication rates have been as high as 30% and consist of meatal stenosis and fistulae [32][33][34]. Glassberg et al [35] modified the procedure and reported a fistula rate of 50%.…”