Longitudinal Dorsal Dartos Flap for Prevention of Fistula after a Snodgrass Hypospadias Procedure

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european urology 50 (2006) 53–57

available at www.sciencedirect.com journal homepage: www.europeanurology.com

Surgery in Motion

Longitudinal Dorsal Dartos Flap for Prevention of Fistula after a Snodgrass Hypospadias Procedure Miroslav L. Djordjevic a,*, Sava V. Perovic a, Zoran Slavkovic b, Nenad Djakovic c a

Department of Urology, University Children’s Hospital, Belgrade, Serbia Military Medical Academy, Belgrade, Serbia c Department of Urology, Heidelberg University, Heidelberg, Germany b

Article info

Abstract

Article history: Accepted April 20, 2006 Published online ahead of print on May 3, 2006

Objectives: The Snodgrass technique presents the procedure of choice for distal hypospadias. Fistula formation is the most common complication with various rates. We evaluated the importance of a urethral covering using vascularized dorsal subcutaneous tissue for fistula prevention. Methods: Our study included 126 patients, aged 10 months to 16 years, who underwent hypospadias repair from April 1998 through June 2005. Of the patients, 89 had distal, 30 had midshaft and 7 had penoscrotal hypospadias. All patients underwent standard tubularized incised plate urethroplasty, which was followed by reconstruction of new surrounding urethral tissue. A longitudinal dorsal dartos flap was harvested and transposed to the ventral side by the buttonhole manoeuvre. The flap was sutured to the glans and the corpora cavernosa to completely cover the neourethra with well-vascularized subcutaneous tissue. Results: Mean follow-up was 32 (6–87) months. A successful result without fistula was achieved in all 126 patients. In six patients, temporary stenosis of the glandular urethra occurred and was solved by dilation. Conclusions: A urethral covering should be performed as part of the Snodgrass procedure. A dorsal well-vascularized dartos flap that is buttonholed ventrally represents a good choice for fistula prevention. Redundancy of the flap and its excellent vascularization depend on the harvesting technique.

Keywords: Hypospadias Tubularized incised plate urethroplasty Fistula Dartos flap

# 2006 European Association of Urology. Published by Elsevier B.V. All rights reserved. * Corresponding author. Department of Urology, University Children’s Hospital, Tirsova 10, 11000 Belgrade, Serbia and Montenegro. Tel. +381 11 685 200; Fax: +381 11 301 6380. E-mail address: [email protected] (M.L. Djordjevic).

1.

Introduction

Use of the Snodgrass technique has gained wide acceptance among pediatric urologists for the

correction of hypospadias because of its good cosmetics, low complication rate, and reliability in creating a vertically oriented meatus as in a normal

0302-2838/$ – see back matter # 2006 European Association of Urology. Published by Elsevier B.V. All rights reserved.

doi:10.1016/j.eururo.2006.04.014

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european urology 50 (2006) 53–57

Fig. 1 – Transversal skin incision is done proximal to the corona below the hypospadiac preputial and penile skin.

circumcised penis [1]. Fistula formation presents the most common complication with various rates [2–5]. There are several procedures for preventing this complication [6–9]. We evaluated our experience using the longitudinal dorsal dartos flap for decreasing the rate of urethrocutaneous fistulas. 2.

Fig. 2 – Harvesting of the dorsal dartos flap is started proximally and continued distally up to the border between outer and inner preputial layer. Dissection follows the axial course of blood vessels in the best possible way.

curvature is mandatory. Orthoplasty is performed, if needed, by dorsal tunica albuginea plication (2-0, 3-0 or 4-0 monofilic polydioxanone, according to patient’s age). The urethral plate is separated from the glans wings with two parallel long-

Materials and methods

We reviewed 126 patients aged 10 months to 16 years, who underwent hypospadias repair from April 1998 through June 2005. The hypospadiac meatus was classified as distal in 89 (70.6%), midshaft in 30 (23.8%) and penoscrotal in 7 (5.6%) patients. All patients had a well-developed urethral plate. Dihydrotestosterone as a topical gel was applied locally 3 weeks in cases with underdeveloped penis/glans. Our technique included standard tubularized incised plate urethroplasty, which was followed by reconstruction of new surrounding urethral tissue. A stay suture is placed through the glans for traction. Penile degloving includes creation of the well-vascularized subcutaneous dartos tissue flap. A longitudinal flap is harvested from excessive dorsal preputial and penile hypospadiac skin. Transversal skin incision is done proximal to the corona at the level of the normal penile skin (Fig. 1). At this region, subcutaneous tissue is well developed, and its dissection is simple and safe. De-epithelialization of the flap is continued and finished distally, including all dorsal dartos tissue (Figs. 2 and 3). Performance of an artificial erection to check penile

Fig. 3 – Redundant dorsal dartos flap is created. Vascularization is completely preserved. Hole is made at the base of the flap.

european urology 50 (2006) 53–57

Fig. 4 – Flap is transposed ventrally by buttonhole maneuver. Standard tubularized incised plate urethroplasty is performed.

itudinal incisions. These incisions are made very deep, up to the tips of the corpora cavernosa to enable better mobility of the wings. The urethral plate is incised in midline from the tip of the penis to the hypospadiac meatus and tubularized. The tubularization is performed over a 6–8 Fr stent without tension with a one-layer running suture (5-0 or 6-0 monofilic polyglecaprone 25, Monocryl; Ethicon). A long dartos flap with a completely preserved blood supply is then transposed to the

Fig. 6 – Reconstruction of the glans and penile body skin.

ventral side by the buttonhole manoeuvre (Fig. 4). The flap is then sutured to the glans wings around the neomeatus and to the corpora cavernosa up to the normally developed urethra with laterally based sutures. The neomeatus is fashioned widely and everted to prevent subsequent meatal stenosis. This method allows all sutured lines to be covered with a wellvascularized onlay dartos flap, which supports the neourethra like spongiosal tissue (Fig. 5). The glans wings are approximated in one or two layers without tension with several interrupted sutures (6-0 or 7-0 Monocryl; Ethicon). Caution should be used during penile skin reconstruction to prevent damage of the blood supply of the dartos flap (Fig. 6). Coban dressing (3M Inc, USA) is applied around the penis in a stretched position. A suprapubic catheter is placed for bladder drainage and removed between 7–12 days after surgery, depending on the patient’s age. Oral antibiotics and oxybutynin were used to prevent postoperative infection and bladder irritation.

3.

Fig. 5 – Flap is fixed to the glans wings around the neomeatus as well as to the corporeal bodies up to the normally developed urethra. Well-vascularized tissue completely covers the neourethra.

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Results

Mean follow-up was 32 (6–87) months. Successful results without a fistula and with a vertical slit meatus were achieved in all 126 patients. The patients had a cosmetically normal-looking circumcised penis. The neourethra was calibrated at 1, 2 and 3 months postoperatively. Meatal stenosis occurred in three patients, while urethral stenosis at the junction between the native and the new urethra was apparent in three other patients (two after midshaft and one after penoscrotal hypospadias repair) 2–3 months postoperatively. These cases were treated successfully by periodic urethral dilation during a 2-month period. Neither infection nor permanent urethral stricture occurred. Correction of curvature was done in 39 (31%) patients. Recurvation did not occur in this group.

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4.

european urology 50 (2006) 53–57

Discussion

A tubularized incised plate urethroplasty described by Snodgrass presents the method of choice in the treatment of distal/midshaft hypospadias with minimal complication rate [1]. Urethrocutaneous fistula is the most common complication, and interposition of well-vascularized tissue between the penile skin and the neourethra is essential for its prevention. Different tissues and techniques have been described to solve this problem. Retik and Borer [6] described covering the neourethra with an asymmetrical, rotational, subcutaneous dartos tissue flap harvested from the dorsal preputial and shaft skin. Yerkes et al. [7] have used a Y-to-I wrap of spongiosum for neourethral reinforcement. Shanberg et al. [8] reported results experienced in using the tubularized incised plate urethroplasty with a lateral-based de-epithelialized flap in previous hypospadias failures. Ventral-based dorsal flaps also can be used for the urethral covering. Asymmetrical flaps harvested from dorsal subcutaneous tissue and rotated over the neourethra do not provide ideal support and can cause penile rotation in some cases. The spongiosal tissue provides good anatomic coverage of the neourethra, but its usage is limited, especially in midshaft hypospadias. Ventral skin can be poorly developed, so it is not available for creating sufficient ventral dartos flaps. Snodgrass [10] also uses a dorsal dartos pedicle flap obtained from the dorsal prepuce, but buttonholed and transposed to the ventrum for additional covering of the neourethra. However, he reported complications in 14% of his patients, mainly related to urethroplasty. Independently from Snodgrass, we started to create a longitudinal dorsal dartos flap to minimize the urethrocutaneous fistula rate after tubularized incised plate urethroplasty. The dorsal hypospadiac skin is always well developed and vascularized. Flaps, harvested from dorsal skin, are abundant, well vascularized and follow the axial course of blood vessels in the best possible way. Our experiences confirm the use of a longitudinal island preputial and/or penile skin flap for onlay or tubularized urethroplasty [11]. The crucial point in the technique involves harvesting of the dorsal dartos flap. De-epithelialization starts proximally at the normal penile skin just below the hypospadiac prepuce. Dissection of subcutaneous tissue is easy at this site and continues distally up to the border between the outer and the inner preputial layer. In this method, a redundant dorsal dartos flap with completely preserved vascularization is

created. De-epithelialization in the opposite direction, distal to proximal, is more difficult because of frequent preputial deformities (eg, dorsal hump, dog eyes) and could result in a thin and reduced flap with a damaged blood supply. A transposed flap completely covers the neourethra, giving additional support in fistula prevention. The flap’s redundancy, vascularization and always sufficient length makes it very useful for distal, midshaft, and penoscrotal hypospadias repairs with a well-developed urethral plate. Also, penile rotation is avoided because of the longitudinal orientation of the flap. Use of this flap achieved very good outcomes in our patients, compared with other studies [6–10]. Deep dissection of the glans wings is recommended to obtain their good mobility for later closure. Incisions should be directly vertically to prevent injury of the penile arteries, which run into the glans lateroventrally. Glans closure usually was performed in two layers. However, in cases with smaller glans, approximation of the glans wings was done in one layer without tension. There was no case in which covering of the urethra and glans closure was not possible.

5.

Conclusion

Our results suggest that the neourethral covering should be performed as part of a Snodgrass procedure. A longitudinal, well-vascularized dartos flap, harvested dorsally and buttonholed ventrally, represents a good choice for fistula prevention. The flap’s redundancy and excellent vascularization is essential and depends on the harvesting technique.

Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at doi:10.1016/ j.eururo.2006.04.014 and via www.europeanurology.com. Subscribers to the printed journal will find the supplementary data attached (DVD).

References [1] Snodgrass W. Tubularized, incised plate urethroplasty for distal hypospadias. J Urol 1994;151:464–5. [2] Snodgrass WT. Snodgrass technique for hypospadias repair. BJU Int 2005;95:683–93. [3] Holland AJA, Smith GHH. Effect of the depth and width of the urethral plate on tubularized incised plate urethroplasty. J Urol 2000;164:489–91.

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[4] Borer JG, Bauer SB, Peters CA, et al. Tubularized incised plate urethroplasty: expanded use in primary and repeated surgery for hypospadias. J Urol 2001;165:581–5. [5] Chen SC, Yang SSD, Hsieh CH, Chen YT. Tubularized incised plate urethroplasty for proximal hypospadias. BJU Int 2000;86:1050–3. [6] Retik AB, Borer JG. Primary and reoperative hypospadias repair with the Snodgrass technique. World J Urol 1998; 16:186–91. [7] Yerkes EB, Adams MC, Miller DA, Pope IV JC, Rink RC, Brock III JW. Y-to-I wrap: use of distal spongiosum for hypospadias repair. J Urol 2000;163:1536–9.

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[8] Shanberg AM, Sanderson K, Duel B. Re-operative hypospadias repair using Snodgrass incised plate urethroplasty. BJU Int 2000;87:544–7. [9] Soygur T, Arikan N, Zumrutbas AE, Gulpinar O. Snodgrass hypospadias repair with ventral based dartos flap in combination with mucosal collars. Eur Urol 2005;47:879–84. [10] Sozibur S, Snodgrass W. A new algorithm for primary hypospadias repair based on TIP urethroplasty. J Pediatr Surg 2003;38:1157–61. [11] Perovic S, Vukadinovic V. Onlay island flap urethroplasty for severe hypospadias. A variant of the technique. J Urol 1994;151:711–4.

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