Hypospadias is one of the most common congenital malformations of the male genitourinary system, with a reported global incidence of 0.6–34.2 per 10,000 live births (1). Hypospadias is characterized by the ectopic urethral opening being displaced along the ventral side of the penis, the only cure for which is surgery. Correction of proximal hypospadias remains a surgical challenge, which is mainly attributable to the characteristics of proximal hypospadias including a more proximal meatus, severe ventral curvature (Figure 1), and the need to transect the urethral plate during the operation (2). Although many techniques have been described to resolve this common issue, including 1-stage repair and the 2-stage repair, there is currently no definitive evidence to confirm the superiority of any technique over the others (3). Nonetheless, some studies have confirmed that 2-stage repair is a better option for proximal hypospadias with severe ventral curvature (4, 5), and a recent survey study indicated that younger surgeons prefer 2-stage techniques in treating patients with proximal hypospadias (6). Therefore, pursuing the optimal 2-stage repair that can achieve the most satisfactory functional and cosmetic outcomes for proximal hypospadias may be a valuable endeavor. Bracka repair, first described in 1995 by Bracka, is a prominent 2-stage repair that uses grafts (7). This technique has been improved over time, and recent studies have confirmed its association with an ideal success rate, especially in proximal hypospadias with severe ventral curvature (8, 9). Staged transverse preputial island flap urethroplasty (STPIF), first reported by Chen et al., is a newly adapted method using flaps based on the traditional transverse preputial island flap (TPIF) (10). STPIF has been shown to reduce the difficulty of surgery and the complication rate in proximal hypospadias treatment (11). Thus, both Bracka repair and STPIF are noteworthy 2-stage methods, and both have achieved encouraging results in the cure of hypospadias using grafts and flaps, respectively. However, to the best of our knowledge, no study has compared these 2 methods in treating proximal hypospadias. STPIF has been the option for 2-stage urethroplasty for treating proximal hypospadias in Tianjin Children's Hospital since 2017, providing us with adequate clinical data to conduct a retrospective study to compare the outcomes of Bracka repair and those of STPIF for proximal hypospadias with severe ventral curvature.

With the progress of technology and the accumulation of clinical experience, pediatric urologists have made great advances in the management of hypospadias; nevertheless, it is worth noting that most of these have been made in the management of distal hypospadias (3). A recently published review frankly points out that the incidence of postoperative complications in proximal hypospadias is higher than that assumed (13). Proximal hypospadias not only involves the posterior ectopic meatus but is also often accompanied by a smaller glans, more defective penile skin, and more severe ventral curvature; all these factors make the surgery for proximal hypospadias a challenging task. However, the results of many studies have indicated that staged repair may provide hope for tackling this problem. Christopher et al. retrospectively reviewed 167 consecutive boys undergoing repair for proximal hypospadias and found that the high complication rates in proximal hypospadias were mainly attributed to 1-stage repair (14). Other analogous studies also reported that the 2-stage repair of proximal hypospadias achieved better results compared to 1-stage repair (15, 16). Based on these findings, persisting in discussing and comparing various staged methods to pursue the optimal approach is critical for patients with proximal hypospadias. Since first being described in 1995, Bracka repair has been well received as a staged repair for proximal hypospadias (2). This method makes full use of the graft's advantages and, for example, can provide good fixation of the neourethra to the corpora, thereby solving the issue of diverticulum caused by the flap technique in 1-stage repair (7). STPIF is a relatively new method that improves upon TPIF, which was first described by Duckett in 1980 (17). TPIF had been an efficacious 1-stage method for treating proximal hypospadias with severe ventral curvature, but as time went on, problems with this once revolutionary technology emerged, for instance, a high incidence of anastomotic stenosis and the requirement of considerable clinical experience (5). To fully exploit the advantages and bypass the disadvantages of TPIF, STPIF was described by Chen et al. in 2016 (10). Leaving the ectopic urethral orifice as a fistula for the next stage of surgery to improve the effect of urethroplasty is a significant concept for hypospadias repair. Duplay recommended 3 steps or stages of repair in the 19th century. First, excision of chordee, second, neourethra tube reconstruction, third, anastomosis of the neourethra to the proximal native urethra (18). STPIF retains the original hypospadiac meatus and neourethra created by tubed flaps after the first stage, giving the neourethra a more stable environment to mature. For one, because urine is excreted through the ectopic meatus, it avoids the adverse effects of metabolic substances in urine on wound healing; for another, it diminishes the impact of the pressure of urine flow on the neourethra. Consequently, STPIF could reduce the occurrence of complications that tend to occur in TPIF, such as urinary fistula and urethral stricture (10). As the core of a variety of techniques, flaps and grafts were compared and discussed in proximal hypospadias by Powell et al. in 2000 (19). However, since the 2-stage technology was not mature at that time, the study only focused on the 1-stage repair to compare flaps and grafts. In view of the above, it is clinically significant to compare the clinical presentation of these 2 methods in the treatment of proximal hypospadias since they represent the significant usage of grafts and flaps in 2-stage repair for proximal hypospadias. To the best of our knowledge, no previous study has made such a comparison.

Severe ventral curvature often appears in proximal hypospadias, and it is usually handled as the first step of surgery. Mild-to-moderate ventral curvature could be corrected after degloving the penile skin and removing the ventral fibrous band, but severe ventral curvature needs further treatment. The current consensus suggests that urethral plate transection supplemented with dorsal plication is an effective means for treating severe ventral curvature in proximal hypospadias (20). Snodgrass introduced a method using transverse ventral corporotomies (21). He indicated that slitting 3 parallel lines with 4-mm intervals on the curved area is effective for correcting the obstinate curvature. This conclusion informs our practice, in this study, transverse corporotomies was performed in 37 patients (59.7%) in Group A and 34 patients (61.8%) in Group B, no recurrence of ventral curvature was found in our study.

Urethrocutaneous fistula, which is related to many factors such as a lack of blood supply, inadequate urinary diversion, and a low-quality waterproof layer, is the most common complication after hypospadias repair (22). In the present study, fistula was seen in 8.1% of patients in Group A and 7.2% of those in Group B. Other authors have reported an incidence of fistula from 3.4% to 21% with Bracka repair (4, 8, 23–25), and the reported incidence of fistula following STPIF ranges from 4.2% to 7.8% (5, 10, 11, 26). It appears that the incidence of fistula is more variable in Bracka repair than in STPIF. However, we believe that these figures do not imply that the STPIF is a more stable method, as fewer studies have been conducted on STPIF than on Bracka repair. The longer a technique has been in existence, the greater the variability in success rates reported in the literature. This is because as increasing numbers of surgeons use this technology, individual ability and experience become important variable that cannot be ignored. In our study, 2 different types of surgery were performed by the same surgeon, and we observed almost the same incidence of fistula in both groups.

Postoperative urethral stricture is also still among the most complex conditions to treat in hypospadias (27). In our study, 1 patient in each group experienced stricture. The overall stricture rate of Group A (1.6%) was lower than the 7% reported in Bracka's paper (7). However, considering that most of the strictures were of late onset in Bracka's study, and his patients included salvage cases, our results may only represent the short-term effect of patients after their first surgery. After all, our duration of follow-up was shorter and we excluded patients who had undergone a failed operation. The stricture rate of Group B was 1.8%, which is close to the 2.4% reported by Chen et al. (10). Lin et al. reported that no urethral stricture occurred in any of the patients who had undergone STPIF in their study, and they attributed this result to the prolonged dwelling time of the urinary catheter (3 weeks) (11). However, considering that the difference in the incidence of stricture is not significant, and taking care of pediatric patients with the urinary catheter is a challenge for parents, more research is needed to confirm the benefit of prolonging the indwelling time of urinary catheter.

Glans dehiscence often results in a deformed glanular meatus and may lead to spraying upon urination. The proximal meatal location is closely linked to this complication (28). In our study, 1 patient with glans dehiscence was observed in Group A, and no cases of glans dehiscence were observed in Group B, but the incidence was not statistically significant. We believe that the 2 methods treated the glans equally, leading to the approximately identical outcomes. The glans construction in STPIF for our study did not adopt the channel technology described by Chen et al. (10); rather, the glans was slit as in Bracka repair; according to Snodgrass' (29), severing the glans more extensively could reduce the risk of glans dehiscence.

Hypospadias repair is the main cause of the acquired diverticulum in children. This complication often occurs due to poorly supported tissue or distal stricture (30). The incidence of the diverticulum was higher in Group B in the present study. Diverticulum occurred in 3.6% of patients in Group B, and there were no cases of diverticulum in Group A. We speculate that this may be attributable to the unique characteristics of tubularization technology. Although STPIF mitigates the impact of the high pressure of urine flow on the distal neourethra and provides the neourethra sufficient time to form a more stable connection with the corpora, the final reconstructed urethra is still composed of flaps. The strength offered by the combination of the corpus cavernosum penis and tube made by flaps is inevitably weaker than that achieved by grafts. The latter is generally tightly stitched onto the corpus cavernosum penis after being fully unfolded, which enables a larger contact area and firmer connection. However, since the difference in rate did not reach statistical significance, we believe that studies with a larger sample size are needed to clarify whether there is a difference in diverticulum rate between the 2 methods.

Since modern surgical techniques have reduced the complication rate, cosmetic outcome has gradually risen in prominence as a concern in hypospadias repair (31). To date, there are no standardized algorithms for the evaluation of cosmetic outcome after hypospadias repair (32). We selected PPPS as the evaluation tool in our study since it is concise and has been shown to have a positive concordance (12). In order to be as objective as possible, we asked patients' parents, the surgeon, and a surgical peer to evaluate the cosmetic outcome of each patient. After statistical calculation, the results of meatus and glans items did not show a consistent trend. However, scores of shaft skin and general appearance were higher in Group A than in Group B, and the trend was consistent among the 3 parties. We consider these differences might be due to the technical characteristics of the 2 methods. In STPIF repair, flaps needed to be transferred to the ventral side of the penis to construct the neourethra. The tension of any twist could cause asymmetry in the appearance of the skin. As for Bracka repair, part of the neourethra was constructed in stage I. The second stage was equivalent to repairing the mild hypospadias without ventral curvature, and the new urethral plate was smooth and wide, which provided the ideal and sufficient material for urethroplasty. To sum up, it might be easier for creating the desired appearance in Bracka repair. Although the Bracka procedure might achieve a better appearance in the aggregate according to scores, the differences were not significantly different. We believe that additional research from multiple perspectives is needed to comprehensively compare the cosmetic outcomes between these 2 methods, as the evaluation of appearance is highly subjective.

As mentioned above, the surgical treatment effect was similar between the Bracka repair and STPIF. There was no statistical evidence to confirm that either technique is more appropriate than the other for proximal hypospadias with severe ventral curvature in the present study. Despite the lack of statistical difference in safety between the 2 methods, we believe each has unique advantages. Bracka repair has a wider scope of application since the source of grafts is not limited to the foreskin. A recent retrospective study compared the treatment results of Bracka repair using preputial vs. buccal grafts in 220 patients with proximal hypospadias; the authors found that the functional results were nearly the same, and the cosmetic results were even better in the buccal mucosa group (24). Mitsukawa et al. reported that they performed a modified Bracka repair using oral mucosal grafts for 6 severe proximal hypospadias cases, and satisfactory results were obtained in all the patients (33). Therefore, when a patient does not have ample foreskin, or if his penile skin has multiple scarred areas due to a previous operation, Bracka repair is undoubtedly a better choice. Moreover, Bracka repair may yield a better appearance according to our results. However, only a small portion of the neourethra was shaped in the first stage of the Bracka repair, and major defects were left after the first operation. According to our clinical experience, many parents may consequently endure a considerable psychological burden during the interval between the 2 operations. As for STPIF, the main surgical procedure is completed in the first stage, the penis could possess an acceptable appearance after the first operation, and the second stage is equivalent to a fistula repair. These factors would enable parents to maintain a more positive mindset while waiting for the second surgery. For the sake of diminishing the trauma experienced by the children, parents also may be more willing to accept STPIF.

The major limitation of this study is that it was conducted retrospectively. The grouping of patients was not completely random. Hence, the surgeon's individual preference might have led to statistical bias. As the duration of follow-up was relatively short, certain long-term complications might have been missed. A prospective study with a longer follow-up duration will provide more powerful evidence for the comparation of these 2 methods.

Our research provides a clinical reference for pediatric surgeons to select the most appropriate method for proximal hypospadias with severe ventral curvature. Our future research will concentrate on comparing the long-term results between Bracka repair and STPIF. We also believe that voiding function and psychological health, among other factors, should be included in subsequent research to more comprehensively evaluate both methods.

Both Bracka repair and STPIF are reliable staged surgical options for treating proximal hypospadias with severe ventral curvature, as both could achieve a satisfactory success rate. The incidence of residual ventral curvature, urethrocutaneous fistula, urethral stricture, diverticulum, and glans dehiscence was similar between the 2 methods in this study. Although the cosmetic outcomes of Bracka appeared to be better, the difference was not statistically significant. Pediatric surgeons should consider more factors other than safety, including patient's specific conditions, parents’ inclination, and personal experience, to make the best choice between the 2 methods.