Repair of Proximal Hypospadias





Proximal hypospadias repair remains a challenging reconstructive procedure for even the most seasoned pediatric urologist. Complication rates range between 20% and 60%. Although the basic steps are similar to those of a distal repair, there is a wide array of procedures to correct penile curvature associated with a proximal hypospadias as well as a need to make a decision to perform the surgery in 1 or 2 stages.


Preoperative Preparation and Planning


Depending on surgeon preference and experience, one may choose to administer preoperative testosterone to help increase glans size, although its usefulness is controversial. We prefer to administer 25 mg intramuscular testosterone enanthate at 4 and 2 weeks before surgery.




Operative Technique


Initial incisions are made as illustrated in Fig. 130.1 . The penis is then degloved down to the penopubic junction and proximal to the hypospadiac meatus. If the child has a bifid scrotum, then a longitudinal incision can be carried down the median raphe toward the perineal body in preparation for later repair. After the penis is degloved, an artificial erection is performed using a tourniquet and an 18-gauge butterfly needle with injectable saline. A detailed description can be found in Chapter 121 .




FIGURE 130.1


Initial incisions for repair of proximal hypospadias.

(From Wein AJ, ed. Campbell-Walsh urology , vol 4, 9th ed. Philadelphia: Elsevier; 2007:3736.)


Ventral Curvature (<30 Degrees)


Mild curvature can be managed with a midline dorsal plication into the tunica albuginea of the corpora cavernosum opposite the area of greatest curvature. This technique avoids the neurovascular bundles that lie on either side of the midline. Lateral curvature can be managed with either a tunica albuginea plication (TAP) procedure or Yachia procedure, both of which are described in detail in Chapter 121 .


Ventral Curvature (>30 Degrees)


Urethral Plate Mobilization


When more severe curvature is encountered, a variety of techniques can be used. This curvature highlights the disproportion between the ventral and dorsal aspects of the corpora cavernosa. Because of the extensive blood supply to the urethral plate from the proximal corpus spongiosum, one can reliably dissect alongside the urethral plate, elevating it completely from the underlying corporal bodies ( Fig. 130.2 ). This dissection is begun by making parallel incisions with scissors through Buck fascia down to the tunica albuginea just lateral to the urethral plate to avoid injury to the dorsal neurovascular bundles. It is important to release the Y -shaped pillars of corpus spongiosal tissue that are contributing to glanular tilt distally.




FIGURE 130.2


Urethral plate is completely elevated from corporeal bodies with or without the need for ventral graft.


Ventral Corporal Lengthening


If curvature persists despite complete elevation of the urethral plate, a ventral corporal lengthening procedure should be performed. We typically perform this with initial transection of the urethral plate followed by a full-thickness transverse incision from the 3 to 9 o’clock positions into the corpora cavernosum. Alternatively, if the urethral plate is deemed unhealthy, one can resect the plate before grafting the corporeal bodies ( Fig. 130.3 ). The choice of grafting material can vary but most commonly uses either a locally harvested dermal graft or single layer small intestinal submucosal (SIS) graft. This graft is then sutured to the edges of the corporotomy using 6-0 absorbable suture in addition to several quilting sutures ( Fig. 130.4 ). Alternatively, grafting can be performed under an intact urethral plate, or several partial-thickness corporotomy incisions can be made on the ventral lateral aspect of the corporal bodies in the area of maximal curvature. These incisions allow expansion of the corporal bodies without the need for grafting.




FIGURE 130.3


Dysplastic or scarred urethral plate resection.



FIGURE 130.4


Grafting of single-layer small intestinal submucosal.


Urethroplasty


The decision on the type of urethroplasty to be performed depends on whether or not the urethral plate was left intact or transected. If left intact, then one can perform a tubularized incised plate (TIP) urethroplasty or a flap-based repair . The TIP repair is briefly discussed below and is described in more detail in Chapter 129 . When the plate is transected, the most commonly performed procedure is that of a two-stage operation using Byars flaps. The use of buccal mucosa are discussed in a separate section.


Tubularized Incised Plate Urethroplasty


This technique was popularized by Snodgrass and involves a midline incision into the dorsal urethral plate before tubularization. The urethral plate is tubularized over a preplaced 6- or 8-Fr stent using either interrupted or continuous subcuticular 6-0 or 7-0 PDS (polydioxanone) stitches. The surrounding corpus spongiosal tissue is then wrapped around this first layer and brought together with a running 6-0 absorbable suture.


Onlay Preputial Transverse Island Flap


This technique, popularized by Duckett, involves making a rectangular-based inner preputial flap and rotating this down to create the ventral aspect of the urethra after it has been sutured to the urethral plate. This technique may be best used with the urethral plate that is thin and not amenable to the TIP technique. Initially, four traction sutures using 5-0 silk sutures are placed in the dorsal inner preputial skin. An inner preputial flap measuring approximately 8 to 10 mm wide with a length equal or just a bit longer than the urethral plate is used. The incisions are made with a scalpel and then deepened appropriately to preserve this flap of skin on its dark ptosis pedicle. The pedicle is carefully dissected down to the base of the penis dorsally area. This flap is then rotated ventrally and sutured to one edge of the urethral plate starting at the native meatus using a subepithelial 7-0 PDS. An 8-Fr catheter is placed, and the flap is trimmed appropriately before it is sutured to the opposite side of the urethral plate. The pedicle can be tacked to the tunica albuginea on either side of the urethra to cover the neourethral anastomotic lines, thus providing a second layer of coverage and decreasing the incidence of fistula formation ( Figs. 130.5 and 130.6 ).




FIGURE 130.5


Onlay preputial transverse island flap, extension of urethral plate incision.

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Jan 2, 2020 | Posted by in UROLOGY | Comments Off on Repair of Proximal Hypospadias
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