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Keywords:

  • urethra;
  • hypospadias;
  • urethroplasty

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. References
  8. Authors

Objective To report the method and results of a modified one-stage Koyanagi repair (urethroplasty with a parameatal-based and fully extended circumferential foreskin flap) 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 U-shaped skin incision is then made surrounding the meatus, extended to the dorsal prepuce for ≈ 8 mm and parallel to the first incision. The tissue between the prepuce and dartos is dissected on the dorsal side to fix the prepuce as a neourethra to the dartos and to maintain blood supply. After mobilizing the loop-shaped skin flap 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 modified Koyanagi repair.

Results The repair was successful after the initial procedure in 14 patients, but urethrocutaneous fistulae 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.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. References
  8. Authors

Severe hypospadias, one of the most challenging problems in paediatric urology, can be repaired using a variety of methods, e.g. adjacent skin flaps, vascularized skin flaps, free full-thickness skin grafts, bladder mucosal grafts and buccal mucosa grafts, in a staged repair or a one-stage repair. Although a staged repair remains indicated for reconstructing severe hypospadias, when the meatus is well proximal to the penoscrotal junction, various one-stage repairs have been attempted. The urethroplasty with a parameatal-based and fully extended circumferential foreskin flap, developed by Koyanagi et al.[1] (Koyanagi repair) has enabled the repair of severe hypospadias in one-stage. However, the incidence of complications, which seem to be caused by insufficient blood supply to a neourethra, was higher than expected. We also had some complications when using the Koyanagi repair and therefore, for severe hypospadias, we modified the method to preserve the vascularity to the peripheral portion of a neourethra [2], in a similar way to that reported by Snow and Cartwright [3]; herein, we report this modified Koyanagi repair and the results.

Patients and methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. References
  8. Authors

A skin-incision line is drawn with a marking pen, as in the original Koyanagi repair (Fig. 1a) and an appropriate sized silicone Foley catheter (usually 6 or 8 F) is placed. A circumferential incision is made ≈ 5 mm proximal to the corona after noradrenaline (1 : 200 000) is injected subcutaneously along the proposed line of incision. The portion between the dartos and Buck's fascia is dissected on the dorsal side (Fig. 1b). On the ventral side the urethral plate is incised as for chordee repair (Fig. 1c). A U-shaped skin incision is then made surrounding the meatus, to extend the skin along the marked line after injecting the diluted noradrenaline (Fig. 1d). This second incision is extended laterally and dorsally onto the dorsal prepuce, ≈ 8 mm parallel to the first incision. The incised line of the dorsal prepuce is joined at the 12 o'clock position.

image

Figure 1. The operative procedure of the modified Koyanagi repair for severe proximal hypospadias. a, The skin incision line is drawn according to the original Koyanagi repair. b, A circumferential incision is made ≈ 5 mm proximal to the corona and the portion between the dartos and Buck's fascia is dissected on the dorsal side. c, On the ventral side, the urethral plate is incised as for chordee repair. d, A U-shaped skin incision is made surrounding the meatus to extend the skin along the marked line. This second incision is extended laterally and dorsally onto the dorsal prepuce ≈ 8 mm parallel to the first incision. The incised line of the dorsal prepuce is joined at the 12 o'clock position. e, The portion between the prepuce and the dartos is dissected on the dorsal side, to fix the prepuce as a new urethra to the dartos and to maintain blood supply. f, A button-hole is made through the pedicle of dartos. While the glans is passed through this hole, the parameatal skin flap and the vascular pedicle are mobilized to the ventral side keeping the loop shape. g, The internal side of the loop is closed from the front wall with continuous full-thickness bites using 7/0 polyglactin sutures. h, The external side is sutured in a continuous subcuticular manner with the same sutures from the back wall of the neourethra. i, The meatus is created by splitting the glans and the divided dorsal Byar's flaps turned towards the ventral side, and sutured to cover the ventral skin defect. From [2] with permission.

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This loop-shaped skin flap is used to create a new urethra. Subsequently the portion between the prepuce and the dartos is dissected on the dorsal side, to fix the prepuce as a new urethra to the dartos and to maintain blood supply. The pedicle to the neourethra is sufficiently dissected down towards the penile base (Fig. 1e). On the ventral side, bands of fibrous tissue, which can be seen passing proximal to the hypospadiac meatus, should be excised until the corpus spongiosum proximal to the meatus is completely exposed inside the scrotum.

In the original Koyanagi repair, the skin flap is divided into two portions at the 12 o'clock position to form a Y-shape, whereas in the modified Koyanagi repair, a button-hole is made through the pedicle of the dartos (Fig. 1f). While the glans is passed through this hole, the parameatal skin flap and the vascular pedicle are mobilized to the ventral side, keeping the loop shape. The internal side of the loop is then closed from the front wall with continuous full-thickness bites using 7/0 polyglactin sutures (Fig. 1g). The external side is sutured as minutely as possible in a continuous subcuticular manner with the same sutures from the back wall of the neourethra (Fig. 1h), although the distal sutures are placed interrupted when excessive length is to be trimmed.

The meatus is created by splitting the glans. After the injecting diluted noradrenaline into the glans a single midline vertical incision is made extending to the tip of the glans, and sharp dissection is carried out bilaterally to define the plane between the glans cap and the corpora, mobilizing the wings. The neourethra is placed within the groove and anastomosed with the tip. When the glans wings are approximated, a haemostat should be placed between the neourethra and the glans, but not too close to the glans. The edge of the neourethra and the glans is sutured as for meatoplasty. Byar's flaps are created with the dorsal foreskin. The divided dorsal flaps are turned towards the ventral side and sutured to cover the ventral skin defect (Fig. 1i).

Twenty patients (aged 11 months to 9 years, mean age 2.5 years) with severe proximal hypospadias underwent the one-stage modified Koyanagi repair. After surgery the patients remained in bed for a few days and the catheter was removed 7 days after surgery. All patients were followed by monthly meatal calibration using an 8 F metal sound for 6 months after surgery.

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. References
  8. Authors

While the repair was successful at the initial procedure in 14 patients, urethrocutaneous fistulae developed in three and meatal stenosis in three; the overall success rate was therefore 70%.

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. References
  8. Authors

In patients with a meatus proximal to the penoscrotal junction in severe hypospadias, alternatives for reconstruction include a staged repair, one-stage repair involving a free graft, one-stage repair using a pedicled preputial tube, and a free graft or a pedicled tube added onto a proximal Thiersch-Duplay tube.

Staged repairs remain the preference for severe proximal hypospadias; Retik et al. [4] reported a complication rate of only 5% for a two-stage repair in 58 patients with severe proximal hypospadias. Greenfield et al.[5] reported that all children had an excellent cosmetic and functional outcome, although the complication rate was 41% in their series. They advocated that for the staged approach, testosterone could be administered twice to correct small phallic structures in many children with severe hypospadias or intersex abnormalities.

In contrast, several attempts have been made to repair severe proximal hypospadias in one stage. Woodard and Cleveland [6] used a full-thickness free skin graft tube to complete the urethral construction, after forming the proximal portion of the urethroplasty with a Thiersch-Duplay tube extending from the hypospadias meatus to the penoscrotal junction. However, this procedure has not become widely used.

Glassberg [7] applied the same principle using a transverse island pedicle distally (an augmented Duckett repair) in four patients with severe proximal hypospadias, with a urethrocutaneous fistula in one. Goepel et al.[8] also used a combination of Duckett's preputial tube and the Thiersch-Duplay procedure in six patients with severe hypospadias, with success in four.

Duckett [9] recommended a long transverse preputial tube urethroplasty, even with a very proximal meatus in the perineum or deep scrotum. He suggested that the inner-skin margin may be taken as a flap of up to 6–7 cm if the foreskin is considered as a ‘horseshoe’ going from the scrotum around the top of the penis and back to the scrotum, although the usual rectangle of skin from the dorsal inner prepuce may be too small. Even so, he commented that the technique used is critical to a good outcome. Thus, these one-stage repair methods have a disadvantage in that the anastomosis between the neourethra and the native urethra is necessary in addition to the anastomosis at the neomeatus.

The advantages of the Koyanagi repair are that only one anastomosis is necessary at the meatus, and neither torsion nor bulking of the penile shaft was apparent. This procedure is also applicable to any kind of proximal hypospadias, even those with a scrotal or perineal meatus. The original authors reported that among 70 patients treated with a parameatal based and fully extended circumferential foreskin flap, complications necessitated a secondary repair in 33 (47% complication rate). Glassberg et al.[10] used the Koyanagi repair in 14 patients with severe hypospadias, reporting complications in seven. However, they noted that the cosmetic results were generally better than with a planned two-stage repair, even if the procedure became a two-stage repair. They further noted that the procedure is technically easier than the previously reported augmented Duckett repair.

However, in the Koyanagi repair the blood supply to the neourethra is based completely on parameatal tissue rather than the blood supply to the dorsum of the penis. Belman [11] commented that the vascularity is not as good as Koyanagi et al. assumed it to be, as they had a high rate of complications, including meatal stenosis, which is a consequence of diminished vascularity. Rushton [12] also commented that the high complication rate associated with the Koyanagi repair was probably caused by failure to preserve the axial blood supply to the long parameatal ventral preputial skin flaps used to construct the neourethra. As no vascularized pedicle is used and the parameatal-based flaps are much too long and narrow to satisfy the principles of reliable flap survival, Snow and Cartwright [3] modified the Koyanagi repair using an island-flap technique, which preserved a reliable dual blood supply to a long neourethra.

We previously used a one-stage urethroplasty with the Koyanagi repair in 17 patients with proximal hypospadias and obtained success in nine, corresponding with the results of Koyanagi et al.[1] and Glassberg et al.[10]. Meatal stenosis occurred in three, meatal regression in two and urethrocutaneous fistula in three. Thus to avoid compromising the vascularity, we modified the Koyanagi repair as described; in the present series complications occurred in six of the 20 patients. This complication rate is still too high but lower than that reported for the original Koyanagi repair, implying that vascular preservation of the neourethra is effective. In conclusion, although the Koyanagi repair provides a one-stage urethral reconstruction for severe proximal hypospadias with good cosmetic and functional results, the success rate might be increased by using the present technique to preserve the blood supply to the entire neourethra.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. References
  8. Authors
  • 1
    Koyanagi T, Nonomura K, Kakizaki H, Takeuchi H & Yamashita T. Experience with one-stage repair of severe proximal hypospadias: Operative technique and results. Eur Urol 1993; 24: 235238
  • 2
    Hayashi Y, Kojima Y & Mizuno K. One-stage repair for severe hypospadias. Jap J Clin Urol 2000; 54: 1924
  • 3
    Snow BW & Cartwright PC. Yoke hypospadias repair. J Pediatr Surg 1994; 29: 55760
  • 4
    Retik AB, Bauer SB & Mandell J. Management of severe hypospadias with a 2-stage repair. J Urol 1994; 152: 74951
  • 5
    Greenfield SP, Sadler BT & Wan J. Two-stage repair for severe hypospadias. J Urol 1994; 152: 498501
  • 6
    Woodard JRJ & Cleveland R. Application of Horton-Devine principles to the repair of hypospadias. J Urol 1982; 127: 11558
  • 7
    Glassberg KI. Augmented Duckett repair for severe hypospadias. J Urol 1987; 138: 3801
  • 8
    Goepel M, Otto T, Kropfl D & Rubben H. Recent considerations for hypospadias repair: results of 252 operations from 1985 to 1990. Eur Urol 1996; 29: 636
  • 9
    Duckett JW. The current hype in hypospadiology. Br J Urol 1995; 76: 17
  • 10
    Glassberg KI, Hansbrough F & Horowits M. The Koyanagi-Nonomura 1-stage bucket repair of severe hypospadias with and without penoscrotal transposition. J Urol 1998; 160: 11047
  • 11
    Belman AB. Editorial comment. J Urol 1994; 152: 1237
  • 12
    Rushton HG. Editorial. Hypospadias. J Urol 1994; 152: 1241

Authors

  1. Top of page
  2. Abstract
  3. Introduction
  4. Patients and methods
  5. Results
  6. Discussion
  7. References
  8. Authors

Y. Hayashi MD, Assistant professor.

Y. Kojima MD, Instructor.

K. Mizuno MD, Resident.

A. Nakane MD, Resident.

K. Kohri MD, Professor.