The Modified Multilayer Coverage of Urethroplasty for Distal Hypospadias.

PURPOSE: Our purpose is to present the modified multilayer coverage to prevent fistula and to present also the glans dissection respecting the continuity between glans and corpus spongiosum. We think an important factor for glans vascularization that prevents glans disruption for patients with distal hypospadias and report the follow-up.
INTRODUCTION: Fistula and glans disruption are still the most frequent complications of hypospadias surgery. Neourethral coverage is a mandatory step in this challenging surgery; it reduces the rate of fistula.
MATERIALS AND METHODS: Between September 2013 and December 2015, the modified multilayer coverage using two or three intermediate layers was performed in 110 patients with distal and midshaft hypospadias. Follow-up based on local examination, visual assessment of urine stream, and parent satisfaction was recorded at 1, 3, 6 months, 1 year, and yearly thereafter. Patients lost for the follow-up and the circumcised patients with a bad quality remaining dorsal dartos are excluded from the study.
RESULTS: Intraoperatively, the decision whether two or three intermediate layers should be performed depending on the type of the hypospadias and the presence of hypoplastic urethra. Among the 88 patients retained for the study, 86 patients presented satisfactory results, but one patient had a fistula that healed spontaneously and the second patient had a glans disruption.
CONCLUSIONS: The modified multilayer coverage with a wings glans dissection respecting the continuity of spongiosum and glans is a reliable procedure to reduce the rate of fistula and glans disruption in anterior and midshaft hypospadias.

INTRODUCTION

Despite the development of a number of techniques for hypospadias surgery, fistula and glans dehiscence are potential pitfall. This makes hypospadias surgery challenging. Advantages of intermediate layer are well known. It is now recognized as practical meaningful procedure that can reduce fistula rate. We describe a multilayer coverage with two or three intermediate layers, using a split dorsal dartos and spongiosum with a wing glans dissection respecting the continuity of the corpus spongiosum making this procedure as synergic techniques to prevent both fistula and glans disruption. The prototypes from which we performed the modification are four techniques of intermediate layers: the transposition of the dartos flap to the ventral aspect of the penis over a buttonhole technique as reported by Snodgrass, the laterally twisted dartos flap, the divided in two wings, and laterally twisted dartos flap and spongioplasty.

MATERIALS AND METHODS

A retrospective chart review study was conducted to evaluate the results of patients with distal and midshaft hypospadias operated on using the modified multilayer coverage from September 2013 to December 2015. One hundred and ten children operated on by one single surgeon were recorded. They are followed and evaluated by the same surgeon. Sixteen patients lost for the follow-up were excluded from the study. Four circumcised children and two reoperated patients who have lost the foreskin were also excluded from the study because of the bad quality of the remaining dorsal dartos we have used for coverage. Among the remaining 88 patients, two twins were recorded. Patient age ranged from 6 to 24 months (mean age 14 months). Clinical examination revealed 41 patients with coronal, 35 with subcoronal, 8 with midshaft, and 4 with glandular hypospadias. Twenty-seven patients had a mild chordee. One patient had a penile torsion. Four reoperative patients in whom the foreskin had not been used were recorded. Three patients with small size of the penis and glans had a preoperative testosterone therapy; one of them was diagnosed with Robinow syndrome. One patient with bilateral cryptorchidism with a normal karyotype was operated before urethroplasty, and a second patient with a right nonpalpable testis was diagnosed as a vanishing testis after laparoscopy. The indication to perform double or triple intermediate layers depends on the location of the meatus after the dissection and the quality of the distal urethra. For subcoronal hypospadias with a distal hypoplastic urethra and midshaft hypospadias, three intermediate layers with split dartos and spongiosum are performed. For coronal, subcoronal without hypoplastic urethra and glandular hypospadias, two intermediate layers with split dorsal dartos are performed. The indwelling catheter is used for 48 h, but in 4 patients (1 midshaft, 1 redo, and 2 dorsal inlay graft urethroplasties), it was used for 96 h.

Technique

A 4/0 nylon stay suture was placed through the glans [Figure 1a].

Figure 1

First step of coverage preparation. (a) Subcoronal hypospadias and a distal hypoplastic urethra with stay suture. (b) Degloving. (c) Harvesting and split of the dorsal dartos

Two parallel superficial incisions draw the borders between urethral plate and wings glans. We perform a circular incision at 3–5 mm from the coronal sulcus joining the superficial U-shaped incision surrounding the hypospadiac meatus.

A degloving is performed by sharp dissection between dartos and Buck's fascia until the root of the penis [Figure 1b].

A transverse incision is made below the hypospadiac preputial penile skin remaining sufficient proximal skin for penile couverture.

A sharp dissection was performed between dorsal dartos and skin creating a well-vascularized dorsal dartos and well-vascularized skin.

Deepithelialization of the outer and inner faces of the prepuce is easy from proximal to distal.

The dorsal dartos flap obtained is split in the midline with care to prevent vessel injury to not damage blood supply [Figure 1c].

An erection test is performed in some cases to assess any residual chordee.

Just behind the balanopenile furrow in each side of the penis at 9 and 3 o'clock, by a perpendicular dissection to the penis, a hole is performed cross the dartos and Buck's fascia until the area beneath this fascia [Figure 2a], and the direction of the dissection is changed toward the glans tip of the penis [Figure 2b]; in the glans, the direction of the scissors is changed toward the parallel superficial incisions made at the beginning, and we push the scissors to separate the urethral plate from the wings glans [Figure 2c]. Also carefully, we separate the meatus and 5 mm of the distal normal urethra from the spongiosum [Figure 2d]. Hence, we preserve the continuity between wings glans and corpus spongiosum that we think it is one important factor among others for glans vascularization to prevent glans disruption [Figure 3a].

Figure 2

Glans wings and corpus spongiosum dissection. (a) At 9 o'clock dissection cross the dartos and Buck's fascia until tunica albuginea. (b) Dissection toward the glans tip. (c) Dissection toward the incision separating the urethral plate and wing glans. (d) Dissection of wings glans and corpus spongiosum from the urethral plate, meatus, and 5 mm of distal urethra from the spongiosum

Figure 3

First and second layer coverage preparation. (a) The continuity of wings glans and spongiosum is preserved. (b) Passage of the right dorsal dartos flap through the tunnel at 9 o'clock, creating one intermediate layer. (c) Passage of the left dorsal dartos flap through the tunnel at 3 o'clock, creating a double intermediate layers. (d) Spongiosum dissected and wings glans approximated. (e) Spongioplasty is performed to complete triple intermediate layers. (f) Final result

Urethroplasty could be performed by different techniques (Duplay, Tubularized incised plate urethroplasty, inlay or meatal based-flap technique) over an 8- or 10-Fr stent using interrupted 7.0 subcuticular sutures.

The right dorsal dartos flap is transferred thorough the tunnel at 9 o'clock and then under the right wing glans to the neourethra with care to avoid twist of the flap and sutured over the neourethra [Figure 3b].

The left dartos flap is transferred through the tunnel at 3 o'clock and then under the left wing glans without twist to cover both the neourethra and the right dorsal dartos flap. We stitched the left flap over the right flap [Figure 3c].

Wings glans can be approximated [Figure 3d].

In some cases, especially midshaft hypospadias and subcoronal hypospadias with hypoplastic urethra, we performed a spongioplasty when the corpus spongiosum has been widely dissected and approximated in the midline to cover the previous double dartos flap [Figure 3e].

Skin cover ends the procedure [Figure 3f].

The indwelling catheter is removed with the dressing at 48 h after surgery.

Follow-up was recorded at 1, 3, 6 months, 1 year, and yearly thereafter. Cosmetic evaluation included meatal location and shape, glans, genital appearance, and visual assessment of the urine stream.

RESULTS

The coverage of urethroplasty was double intermediate layers in 52 patients and triple intermediate layers in 36 patients. The procedure was TIP in 60 patients, Duplay in 23 patients, dorsal inlay graft TIP in 4 patients, and meatal-based flap technique (Mathieu urethroplasty) in 1 patient. After a median follow-up of 1 year (ranged from 10 to 32 months), local examination and visual assessment of the urine stream revealed that 3 patients had a meatal stenosis and two of them had TIP urethroplasty with double layer coverage. They were treated by regular meatal dilatation, but in one patient, a meatotomy was performed. A rounded glandular meatus was witnessed in the patient with a Mathieu urethroplasty. A fistula that healed spontaneously was diagnosed in one reoperative patient with double layer coverage. One patient with a midshaft hypospadias had a glans disruption 2 months after surgery. Good cosmetic results, with a vertically oriented meatus, were reported in 86 patients.

DISCUSSION

Neourethral coverage with a well-vascularized tissue using subcutaneous flap, tunica vaginalis, or corpus spongiosum reduces the rate of fistula.[1] Coverage with a vascularized pedicle of subcutaneous tissue reduces significantly the rate of fistula over the use of adjacent local tissue.[2] Dorsal preputial dartos flap used for two layer covering can significantly reduce the incidence of urinary fistula[345] and penile torsion[6] as we reported only one fistula witnessed 1 month after surgery in one reoperative patient with double dartos flap that healed spontaneously. Even double dartos flap is more effective against fistula development than a single flap,[78] some authors argue against using dartos flap and more over double dartos flap because it may reduce the tension-free closure of the glans.[9] Glans dehiscence in double dartos flap can be avoided by a generous glans dissection.[810] The glans dehiscence occurred in 4% of distal hypospadias, and this complication was linked to the size of the glans, but it seems that deep incision and extended dissection of wings glans help to better and easy approximation reducing the rate of glans disruption.[11] The glans dissection we used at 3 and 9 o'clock leads to a generous dissection. Beside the extended dissection of wings glans, we think that preserving the continuity of the corpus spongiosum and the glans results in a well-vascularized glans which is an important factor to prevent glans disruption after the recommended generous and extended glans dissection. As the corpus spongiosum helps for good anatomical coverage,[12] the previous dissected corpus spongiosum provides a third covering layer in defined cases. In the subcoronal hypospadias associated to a hypoplastic urethra, the dissection of wings glans followed by the dissection of the hypoplastic urethra form the corpus spongiosum allowed to perform the double dartos flap coverage and furthermore a spongioplasty as the coverage layer number 3. In this modified coverage, the way wings glans are dissected and how the distal ends of the two halves of the double dartos flap passed through the tunnels helps to keep the continuity of wings glans and corpus spongiosum, to fann out the flaps under the wing glans and corpus spongiosum, and to result in a tension-free well-vascularized wings glans. The successful completion of wing glans dissection and passage of double flaps are intimately dependent on the good tunnel preparation because the successful completion of one is intimately dependent on the other.

CONCLUSION

Hypospadias must be taken as whole which is a number of procedures llinked to one another by facilitating each other and depending one on the other by renforcing each other. The modified multilayer coverage associated with the glans dissection respecting the continuity of spongiosum and glans is a reliable procedure to improve the outcome of distal and midshaft hypospadias and reduce the rate of fistula and glans disruption as well.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.