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Outcomes of Onlay Island Flap Technique in Shallow Urethral Plate Hypospadias - a 3 Years’ Experience

Leily Mohajerzadeh, Ahmad Khaleghnejad, Naser Sadeghian, Alireza Mirshemirani, Mohsen Rozroukh, Alireza Mahdavi, Sareh Pourhassan

Pediatric Surgery Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran



Leily Mohajerzadeh

Pediatric Surgery Research Center

Shahid Beheshti University of Medical Sciences

Tehran, Iran

Tel/Fax: +98-2122924488

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Objective: This study aimed to evaluate the outcomes of using onlay island flap technique in the repair of hypospadias with shallow urethral plate.

Patients and methods: In this prospective study between June 2012 and June 2014, we performed onlay island flap procedure for the repair of hypospadias with shallow urethral plate - less than 6 millimeters. This technique was selected for all types of hypospadias except subcoronal type. Nesbit's dorsal plication procedure was performed for chordee. In cases with very small glans, urethroplasty was performed without glansoplasty.

Results: Twenty three patients with mean age of 30 months (range 10-60 months) underwent onlay island flap repair; all had a shallow urethral plate of less than 6 mm, 3 had a very small glans and 18 had chordee. Meatus was located in distal shaft in 5 cases, midshaft in 8, proximal in 6 and penoscrotal type in 4 patients. Chordee was corrected with Nesbit's dorsal plication in 16 cases. Complications were: meatal stenosis in 2 cases and urethrocutaneous fistula in 2 patients and all were repaired surgically. Mean follow up time was 13 months (range 3-20 months). All cases that had glansoplasty have excellent esthetic appearance.

Conclusion: This technique offers acceptable results regarding meatal stenosis, urethrocutaneous fistula and good esthetic outcome. 

Keywords: onlay island flap, hypospadias, urethroplasty



Hypospadias is one of the most common congenital genital anomalies in males with a current trend to be operated early in infancy (be tween 6 to 9 months old). In the same time, hypospadias repair is a challenging surgery for the pediatric urologist with multiple reconstruction techniques available. A perfect hypospadias repair should reconstruct the urethral continuity keeping sufficient caliber, correct phallus curvature and provide an acceptable appearance with low complications. Onlay preputial flap repair was first described by Duckett [1] in 1987. In this study we assessed objectively the feasibility of this technique. Complications such as fistula, wound dehiscence, recurrent ventral curvature, meatal stenosis, diverticulum and urethral stricture were analyzed.

Patients and methods

Between June 2012 and June 2014, onlay island flap hypospadias repair was performed in cases with shallow urethral plate (less than 6 millimeter). This surgical technique was selected in all types of hypospadias except subcoronal type. The island flap onlay urethroplasty was performed based on the unique explanations of Duckett [2]. In all cases, the glans was injected with 1:200.000 epinephrine solution at the incision site using 2.5 magnifying loupes for most cases. U-shaped incision of the ventral skin was performed with preservation of the urethral plate (Fig. 1). A circumferential incision, 5 mm proximal to the coronal margin was done next. Phallus was completely degloved to the corpus spongiosum to correct the mild ventral curvature. Subsequently, an artificial erection was obtained to assess the remaining ventral curvature, which if present, was corrected using Nesbit’s dorsal plication using 4.0 Prolen at the 12 o’clock position.

Figure 1: Midshaft hypospadias

Fig 1  

Cases with severe chordee that needed transection of the urethral plate underwent inlay genital graft using scrotal skin, with onlay island flap urethroplasty performed 6 month later.

A rectangular flap 1cm longer than the length of the urethral plate was harvested from the dorsal inner prepuce, rotated ventrally and anastomosed to the urethral plate using 6.0 polydioxanone running suture over an 8 Fr Silastic Foley catheter (Fig. 2). A vascular pedicle flap was used to cover the suture line. Two lateral incisions were made along the urethral plate with deep dissection into the glanular wings except in cases with very small glans. After glansoplasty the penile shaft skin was closed with a midline suture or with a transverse island skin flap in cases of significant ventral skin deficiency, according to surgeon preferences (Fig. 3).

Figure 2: Inlay flap dissection

Fig 2

Figure 3: Completed onlay island flap urethroplasty

Fig 3

In cases with very small glans, urethroplasty was performed without glansoplasty. The urethra was stented for 7 days post operatively. All patients were operated on a single surgical team. Sandwich dressing was performed in all cases (Fig. 4, 5). The dressing was changed on day 2 post surgery and catheter removed on day 7. Children under 2 years of age had a double nappy whereas older children had a collecting bag. Patients were seen at the time of catheter removal, at 2 week postoperatively and then at 1, 3, 6 and 12 months postoperatively. Regular weekly meatal dilatation was used only in patients with voiding difficulty that had an obvious tendency to stenosis and a narrow stream on visual observation. Yearly follow up was planned by uroflowmetry in toilet trained children. The type of hypospadias, type of ventral curvature repair, complication rate (fistula, wound dehiscence, recurrent ventral curvature, meatal stenosis, diverticulum and urethral stricture), management of complications and number of reoperations were analyzed. Postoperative uroflowmetry pattern in toilet trained patients will be reported in the future. Data were collected and processed using the commercially available software package (SPSS-20 for Windows).

Figure 4: Sandwich dressing

Fig 4

Figure 5: Aspect in the Day 7 postoperatively

Fig 5


Twenty three patients with mean age of 30 months (range 10-60 months) underwent onlay island flap repair (all had a shallow urethral plate 6 mm) 3 had a very small glans and 18 had chordee. Meatus was located in distal shaft in 5 cases, mid shaft in 8, proximal in 6 and penoscrotal in 4 patients. Glansoplasty was performed in all cases, except in the mentioned 3 cases in which 1 cm was left distal to the tip of the glans, which was sutured to the edges of the glanular wings. Chordee was corrected with Nesbit’s dorsal plication in 16 cases. But in 2 cases with severe chordee, the urethral plate was transected first, then underwent inlay genital graft from scrotal skin with onlay island flap urethroplasty performed 6 months later. Following onlay flap repair 3 boys (13%) had fistula (one in distal shaft and two in midshaft). One with distal fistula is under observation, while other 2 cases were repaired surgically without further complications. Meatal stenosis was seen in 2 cases (9%) and underwent meatoplasty. Mean follow up time was 13 months (range 3-20 months). All cases that had glansoplasty have acceptable voiding and satisfactory cosmetic esthetic result and appearance.


The purpose of primary hypospadias repair is to reach both good cosmetic and functional normality. It requires reconstruction of a straight penis, with an acceptable caliber of neourethra in a natural slit-like meatus [3]. In hypospadias repair, there are many different techniques and their modifications. Technique of repair is based on a number of variants such as degree of curvature, site of the meatus, wide of urethral plate and surgeon favorite. In onlay flap repair careful protection of the vasculature of the flap and prevention of overlapping suture lines generate a waterproof closure with minimum risk of postoperative fistula. TIP is a common operation in hypospadias reconstruction, but our experience shows that risk of stricture and fistula is relatively high and requires an acceptable wide urethral plate for urethroplasty. However in Sozubir S et al. [4] study, complications after TIP repair were equivalent to other current techniques wereh cautious in technical details could decrease these complications. They believed that this procedure regularly generated a vertical meatus, and resulted a normal aesthetic. Snodgrass et al. [5] used TIP procedure for distal and proximal hypospadias and the main complication in their patients was fistula. Despite the use of a dartos flap in all cases, fistula occurred in 5% of distal and 19% of proximal repairs. Snodgrass et al. [6] used tubularized incised-plate urethroplasty for hy pospadias reoperation but when it employed in proximal hypospadias, they accounted a complication rate of 33% with 21% incidence of fistula and persistent chordee in some patients. In our study we had 3 boys (13%) with fistula - one in distal shaft and two in midshaft. Results of hypospadias repair vary in different centers. Cheng et al. [7] reported a large multicenter series of patients with both distal and proximal hypospadias who experienced TIP repair with less than 1% occurrence of fistulas. They approximated the corpus spongiosum over the neourethra during proximal repair and protected neouretra with dartos layer and glans wings. In recent study the only parameter for selection of patients was urethral plate diameter less than 6 millimeter and type of hypospadias was not effective factor.

Sarhan et al. [8] in a single-center experience with 500 cases reported TIP procedure as a reli- able technique for management of both distal and proximal hypospadias in both primary and reoperative cases with a small rate of complications but urethral plate diameter was not mentioned. Postoperative meatal/neourethral stenosis after TIP is common so Shimotakahara [9] collected a dorsal inlay graft from the inner prepuce and sutured to midline incision of the urethral plate. In our study 2 cases with severe chordee needed to transect urethral plate who underwent inlay genital graft from scrotal skin and onlay island flap urethroplasty was performed 6 month later and both cases had acceptable results. Although TIP urethroplasty is a choice procedure in distal penile hypospadias for some surgeons, but now some authors prefer to use onlay flap technique, particularly in cases of a small phallus with narrow plate or conical glans, which create tubularization hard [10 ].

In 1987, Elder reported the first one-stage hypospadias repair using an onlay island flap, although the preputial island flap had long been done previously. It permits for repair of distal and midshaft hypospadias [1 ]. Ehab R E et al [11] evaluated the consequences of using a distally folded onlay flap in the repair of distal penile hypospadias in 36 patients, but they had only two urethrocutaneous fistula, and they used onlay flap for distal type but in our study it used for all types except subcoronal. Mamdouh A. et al [12] had a study with forty five boys with similar mid-penile hypospadias deformities which designed comparative study between the TIP and onlay preputial island flap and reported no differences between the two techniques. Braga et al [13] retrospectively analyzed patients with penoscrotal hypospadias, based on surgeon favorite 35 children underwent TIP and 40 performed onlay urethroplasty, and they had complication rates of 60% for TIP and 45% for the onlay flap. Leslie B, et al [14] used tunica vaginalis graft plus onlay preputial island flap in urethral reconstructive surgery in rabbits in one-stage for complex hypospadias with divided urethral plate. Silva EM et al [15] compared three different urethroplasty techniques (onlay, buccal mucosa, Koyanagi type I) in severe hypospadias. The fistula was shown in 15% in onlay group; 32% in the buccal mucosa group, and 19.2% in the Koyanagi cases. Patel R et al [16] explained a technique called the split onlay skin flap, which had fistula in 6 patients. Subramanian R. et al [17] described several surgical techniques in hypospadiasis and their complications.


In our experience with 23 patients, the onlay flap hypospadias repair provided excellent cosmetic and functional results. The overall complication rate as well as the rate of postoperative urethrocutaneous fistula was minimal and is comparable with those reported by others but longer postoperative surveillance is needed.


We would like to thank Ms. Ghavam for typing the manuscript and Ms. Hatefi for helping in re search.


This study was financially supported by the of- fice of the Vice chancellor for Clinical Research of Mofid Children Hospital.




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