Dartos flap coverage of the neourethra following repair for primary hypospadias , reoperative hypospadias and urethrocutaneous fistulas . It is a safe approach

Purpose: Urethrocutaneous fistula and neourethral dehiscence are frequently seen complications of hypospadias surgery requiring reoperation. In this study we report the experience of one surgeon with dartos flap coverage in primary hypospadias, reoperative hypospadias and urethrocutaneous fistulas repair. Methods: A total of 23 patients underwent hypospadias and urethrocutaneous fistulas repair from January 2006 to May 2009. Fourteen patients were operated on for primary hypospadias repair at our institution and 9 patients were admitted for hypospadias complications such as failed hypospadias repair and urethrocutaneous fistula. In all the patients, the dartos flap was dissected and transposed to cover the neourethra. Operative results were recorded. Results: The primary surgical procedure was a one-stage repair in 61% (n = 14); tubularised incised plate (TIP) urethroplasty in 43% (n = 6) and a Mathieu procedure in 57% (n = 8). Urethrocutaneous fistulas complicating the previous initial hypospadias repair were anterior in 33% (n = 2), middle in 33% (n = 2) and proximal in 33% (n = 2). Repair of the fistula was successful on the first attempt in all patients. The reason for redo surgery in 3 patients was complete dehiscence and the patients had distal shaft hypospadias. Conclusion: Dartos flap coverage of the neourethra seems to be an effective method of reducing the fistulous complication rate following primary and secondary hypospadias repair.


Introduction
With an incidence of 1:300, hypospadias is one of the most common genital anomalies in male newborns 1,2.Hypospadias is defined as an anomaly (hypo-or dysplasia) involving the ventral aspect of the penis 2,3 .
The position of the urethral meatus in hypospadias can be glanular, along the penile shaft, scrotal, or perineal 4 .In current practice, hypospadias repairs are performed as outpatient procedures with high success rates 5 .Despite the use of optical magnification, fine suture material and modern techniques, urethrocutaneous fistula or neourethral dehiscence was the most troublesome complication.These problems are the main difficulty in re-operations, because in these cases urethral reconstruction is required, but only a small amount of penile foreskin is available.On the other hand, the vasculature of previously operated tissues may be suboptimal, resulting in further complications 5,6 .In this study we report the experience of one surgeon on dartos flap coverage in primary hypospadias, reoperative hypospadias and urethrocutaneous fistulas repair.

Methods
A total of 23 patients underwent hypospadias and urethrocutaneous fistulas repair from January 2006 to May 2009 at our clinic.Fourteen patients were operated on for primary hypospadias repair at our institution and 9 patients were admitted for hypospadias complications such as failed hypospadias repair and urethrocutaneous fistula (Figure 1).All of the operations were performed by the same surgeon.

Surgical technique for urethrocutaneous fistula repair
All repairs were performed at least 6 months after the original hypospadias repair.A 6F stent was passed into the bladder for post operative urinary diversion.The urethrocutaneous fistula tract is mobilized down to the urethra by sharp dissection after a circumferential incision around the skin opening.Meticulous dissection is important to prevent the formation of a hole in the tract that might invalidate the technique.In all the patients with urethrocutaneous fistula, the repairs were performed using 7-0 polydiaxanone suture material, and the repairs were covered with a second layer of vascularized local tissue flap (dartos).The subcutaneous tissue and skin are then closed using 6-0/7-0 Polydioxanone suture material.
Suprapubic diversion was not used for any of the patients.The catheter within the urethra was secured distally to the glans with the traction suture.The operation was finished by the application of gauze a compression dressing to the penis.The dressings were opened on the fifth and seventh postoperative day.The patients were hospitalized for approximately 2 days postoperatively, sometimes extending to 5-7 days depending on the family's preference.A broad spectrum antibiotic for prophylaxis was given throughout the hospitalization.Catheter was removed after seven days.The patients underwent follow-up examinations the first week, first month, and 6 months after discharge, with more frequent examinations as required.
After general anesthesia, a stay suture was placed through the glans for traction.Then, the penis was degloved and any meatal stenosis or fistula opened widely, to prevent subsequent stricture formation.An artificial erection was carried out for ventral curvature, as a necessary step.Penile curvature correction by dorsal plication, as described by Mingin and Baskin was required in only 1 patient 7 .Also, a tourniquet to the root of the penis was used for hemostasis in all patients.

Surgical technique for Snodgrass and Mathieu urethroplasty
T h e t u b u l a r i z e d i n c i s e d p l a t e urethroplasty (TIPU) was carried out using the technique described by Snodgrass 8 .Parallel incisions separated the glans wings from the urethral plate and the plate was incised in the mid-line.For urethroplasty in Mathieu procedure 9 , a parameatal-based skin flap was created by circumscribing the ventral paraurethral and parameatal penile skin.After complete mobilization and outlining of the urethral plate and skin flap, urethroplasty was completed by onlay of the parameatal skin flap over a 6F urethral catheter with 7-0 Polydioxanone suture in a running subcuticular manner.In all of the patients, double dartos flap from the preputial hood was dissected and transposed to cover the neourethra ventrally and 7-0 Polydioxanone was used for suturing (Figure 2).Then, the subcutaneous tissue and skin are closed using 6-0/7-0 Polydioxanone suture material.
Urethrocutaneous fistulas complicating the previous initial hypospadias repair were anterior in 33% (n = 2), middle in 33% (n = 2) and proximal in 33% (n = 2).Repair of the fistula was successful on the first attempt in all patients.
The reason for redo surgery in 3 patients was complete dehiscence and the patients had distal shaft hypospadias.The previous techniques utilized Mathieu repair in one, Thiersh-Duplay in one and unknown in one.After the primary evaluation, Mathieu procedure was performed for correction of complications related to the previous hypospadias surgery.Uncircumcised in 2 patients, the dartos flap from the preputial hood was dissected and transposed to cover the neourethra ventrally.In the other 1 patient, the repairs were covered with a second layer of vascularized local tissue flap (dartos).These patients were treated successfully with Mathieu repairs.
None of the patients developed meatal stenosis and neourethral caliber and cosmetic appearance were satisfactory in all patients in the follow-up period of this study.

Discussion
Hypospadias surgery is challenging.The fact that there are wide variations in the presentation and extent of malformations as well as tissue characteristics existent makes every hypospadias individual and a proposal of a universal comprehensive algorithm for hypospadias repair difficult.
The "TIPU" technique was first described by Snodgrass 8 following excellent cosmetic results when this technique was used on 16 patients with distal hypospadias without any complications.The technique can be performed for proximal, distal, primary, and secondary hypospadias cases.In the primary cases, a 0%-9% fistula complication rate and 0%-21% meatal stenosis rate have been reported 4 .Parameatal-based flap urethroplasty (the Mathieu procedure) first described by Mathieu 9 is another commonly used standard technique with a complication rate of less than 4% in different series in recent years 10,11 .By this technique, an acceptable meatal caliber could be achieved, and there is no concern about the distal extension of neourethra to prevent meatal stenosis 12 .Urethrocutaneous fistulae after hypospadias surgery have been a serious problem for patients and surgeons since repair was first attempted 13 .In order to prevent fistulas, particularly healthy tissue from different areas is used to cover the neourethra using different techniques.Sozubir and Snodgrass used a dorsal dartos flap that was transposed to the ventral aspect of the penis over a buttonhole technique 2 .Recent reports have revealed that double dartos flap coverage of the neourethra is superior to single flap coverage for the prevention of urethrocutaneous fistula after tubularized incised plate urethroplasty 14 .Further, glanular torsion, a risk with single flap coverage does not happen with double dartos flap coverage.Conventionally, flap coverage has been provided over the entire neourethra 15 .The primary hypospadias cases reported in the present series had distal shaft and mid-penile hypospadias.None of our 14 patients with primary hypospadias operated by TIPU and Mathieu developed an urethrocutaneous fistula.In both techniques, the neourethra was covered with double dorsal dartos flap.We believe that dorsal dartos flap coverage of the neourethra to prevent fistula development may have an important role.Additionally, it is clear that to become more effective in the application of surgical techniques, clinical knowledge and surgical experience is important.
Primary hypospadias repairs are associated with failure rates of 5-20% depending upon the type of procedure performed, location of original meatus and quality of tissue available for the initial repair 16 .The challenges of performing a secondary hypospadias repair include lack of healthy or adequate amount of local tissue with which to create flaps for both replacement and/or coverage of the defective urethra and, resurfacing the penile shaft 17 .The ideal surgical method for complex penile repairs has not been established.Wheeler and Malone 18 and Keramidas and Soutis 19 reported that meatus-based flaps could be used as a salvation operation with high success rates, 83.3% and 100%, respectively.Bar-Yosef et al. 20 reported that they achieved 74% success in their series of 34 patients reoperated using the Mathieu technique.Karabulut et al. 21reported that success rate was 84.2% in the group consisting of 57 patients who were reoperated using the Mathieu technique.We may consider not only the experience acquired by frequent use of the Mathieu technique in our clinic but also fastidiousness in choosing reoperative cases in whom this technique is applicable as the reason for this success.The sensitivity in case selection for this technique is that the urethral plate is narrow, ventral skin is soft and has less scarring, and the skin around the meatus is soft and unscathed 21 , as was in our cases.In this study, two patients with secondary hypospadias were uncircumcised and 1 patient was circumcised.All of the patients with secondary hypospadias were repaired by using the Mathieu technique.In uncircumcised patients, the neourethra was covered with dorsal dartos flap.In one circumcised patient the neourethra was covered by local dartos flap.
Urethrocutaneous fistula is one of the most frequently seen complications of hypospadias surgery requiring reoperation 22 .The incidence of fistula development has varied from 4% to 20% in larger series 23,24 .Factors such as obstruction at the distal part of the new urethra, tissue ischemia, and postoperative infection can lead to urethrocutaneous fistula development after hypospadias surgery.The frequency of fistula formation has decreased as a result of surgeon experience, improvement in operative technique, use of appropriate suture materials and instruments, and coverage of the operation area with well-vascularized tissue 25 .Sunay et al. 25 suggested that the suture lines should not overlap, a second dartos flap should be used between the suture lines, and improved procedures must be performed in the case of the presence of urethral stricture and diverticulum.The principles we pursue during the surgery are as follows: checking the patency of the meatus, dissecting the fistula with its tract up to the base, and the repairs were covered with a second layer of vascularized local tissue flap (dartos).It is clear that to become more effective in the application of surgical techniques, clinical knowledge and surgical experience is important.In our limited study with a small number of patients, we conclude that in experienced hands, the TIPU and Mathieu techniques are valuable single-stage methods, due to its low complication rate as well as its satisfactory functional and cosmetic results in distal and midpenile hypospadias cases.Dorsal dartos flap coverage of the neourethra seems to be an effective method of reducing the fistulous complication rate following TIPU and Mathieu repair for distal and midpenil hypospadias.
Redo hypospadias and urethrocutaneous fistula repairs are challenging and occasionally humbling.Using the Mathieu urethroplasty particularly in uncircumcised patients is a suitable method for treating the re-operative cases.In all patients, an acceptable meatal caliber was achieved.In patients with urethrocutaneous fistula, local dartos flap is critical.From the small number of cases in this study, further studies involving a greater number of reoperative hypospadias patients would be valuable to confirm these results.

Conclusions
Dartos flap coverage of the neourethra seems to be an effective method of reducing the fistulous complication rate following primary and secondary hypospadias repair.