Generally, the choice of repair technique seems to be largely influenced by the preference of the surgeon and the subjective assessment of the characteristics of hypospadias. Onlay, tubularized incised plate (TIP) and Duckett urethroplasty are trustworthy for their reproductivity and feasibility, which appear to have less complication rate comparing to other procedures [6, 8, 9]. Since Duckett first described the transverse preputial island flap urethroplasty (TPIF), the surgical procedure for repairing hypospadias has been widely used . However, the disadvantage of the operation is that the learning curve required to grasp this technique is steep, as well as intractable complications [11–14].
In terms of improving surgical fluency, we directly tubularized the prepuce inner plate with the urinary tube as a support before harvesting the pedicle flap. Therefore, the operating step is easier. Meanwhile, estimating the width of the flap could be more intuitive, so as to enable a more appropriate diameter of tubularized flap.
As reported in other literature, urethra-cutaneous fistula and urethral stenosis are the most common complications of TPIF urethroplasty. Respectively, the rate of fistula and stenosis can run up to 66% and 44% [6, 15–16], although the overall complication rate could be as low as 14.6% in proficient hands . In the past years, many authors made well efforts to reduce the developments of complications by modifying the Duckett procedure [8–9, 18].
Unlike Onlay and TIP repair, one of the defining features of Duckett procedure is the need to transect the urethral plate. Urethral plate (UP) is considered as an ideal material for neourethra, due to the fact that it consists of collagen I and III, nerve tissue, and rich blood vessels . Procedures which reserve UP like Onlay repair could give the neourethra a dual blood supply from both UP and the vascular pedicle, lowering the possibility of ischemia of the flap. Therefore, the rate of fistula and urethral strictures can be reduced. However, preserving UP is not an assurance for decreasing complications. In the findings of Snodgrass and Braga, the overall rate of complications for repair of proximal hypospadias with UP preserved was 35–37% [20–21]. On the other hand, Onlay urethroplasty is not preferable in cases with severe penile chordee, while the Duckett urethroplasty does. For patients who have severe penile curvature and dysplastic urethral plate, transection of the urethral plate for fully correcting the curvature is essential and inevitable. For this reason, in our study, urethral plate of all the included patients were transected. However, given that the benefit of abundant blood vessels, we preserve the glans part of UP, making the transection at 0.5 cm below the coronal sulcus for the purpose of increasing the blood supply. Afterwards, a re-fixation of UP was performed.
On the other hand, we modified our steps by using interrupted suturing technique instead of continuous suture when we perform the tubularization of preputial flap, in order to get a lower complication rate. From our perspective, compared with continuous suture, the interrupted suture can minimize the curling of the tubularized flap. Accordingly, the incidence of flap ischemia and necrosis could be reduced. Samir et al conducted a prospective trial to compare the outcome of interrupted suture and continuous suture in hypospadias repair using TIP technique. Their result showed that the interrupted sutures groups was associated with a lower complication rate .
Apart from the procedures noted above, we improved the technique while making the anastomosis between the tubularized flap and original urethral meatus. Owing to the intersection of different tissues, the anastomosis between neourethra and native urethral meatus is with a tendency of stenosis . Bevel incision was sufficient and large enough, and then we make the anastomosis by interrupted sutures, in order to release the tension. If the tension of the proximal tubularized tube was too high, a full-thickness longitudinal section on the dorsal side of the urethral mucosa was performed. In addition, the fascia pedicle of flap was then tacked in place covering the anastomosis and part of the neourethra, which is beneficial to the survival of the flap and could increase the thickness of the tissue coverage.
In addition, we expect that extending the indwelling catheter time can reduce the incidence of urethral stricture. All the urinary catheters of patients in our current study were kept for 14 days before being removed. In this way, we believe it can decrease occurrence of urine extravasation, reduce postoperative inflammation and scar hyperplasia. At the same time, it provides a supporting effect, and prevents the neourethra from being angled and twisted during the fusion process of the newly formed urethra and the surrounding tissues. Consequently, the occurrence of urethral stricture could be reduced.
Fortunately, in this study, the rate of fistula and urethral stricture is 16.5% and 5.3% respectively. The number is significantly lower than the reported rate in a 20-year systematic review , where the Duckett technique demonstrated a fistula rate of 22.4% and a urethral stricture of 12.5%.
Moreover, in terms of recurrent curvature, fortunately, we got a favorable result that no patient was found recurrent penile chordee. Nevertheless, we shall never neglect the importance of long-term follow-up. Vandersteen reported 22 cases of late onset recurrent chordee after hypospadias repair . All the onset of recurrence developed during puberty with the median age at 16 years, which indicates the necessity of focusing on late onset complications. Hence, longer and continuous follow-up is required necessarily, 52.9% of patients had at least one problem that required long-term follow-up . Secondary surgery rates are underreported if follow-up is limited to less than 6 years .
Furthermore, whether choosing single-stage or two-stage urethroplasty for the treatment of proximal hypospadias with severe chordee remains controversial . The two-stage procedure is considered as a method to reduce the difficulty of surgery, in terms of increasing the available prepuce, tissue vascularity and providing a healthier urethral bed for the second stage surgery . Reportedly, it has relatively low risk of complications [6, 27, 29, 30]. However, compared with two-stage urethroplasty, most of the patients can avoid re-operation who undergo a single-stage urethroplasty. In our study, the overall complication rate is 23.3%, thus 76.7% of the patients have benefits over staged procedure, such as lower risk of anesthesia, less cost of treatment, and decreased psychological influence of surgery . Additionally, 22 of 31 patients (71.0%) who had fistula can be treated by a minor surgical repair.
Since this is a retrospective study, a selection bias of surgical methods is inevitable. A prospective study is necessary to be carried out, so that the outcomes ought to be undoubtedly more convincing. Meanwhile, the limitations of this study also include the relatively insufficient follow-up duration, that we are not able to find out the long-term complications like recurrent chordee and sexual intercourse disorders. Moreover, data of uroflowmetry for evaluation of urethral function were not collected in this study. In addition, a comparison group of other repair techniques is essential to help compare and confirm the benefits of our modified technique in the future.
In brief, based on the traditional Duckett technique, we have modified the surgical procedures regarding tubularization of flap, urethral anastomosis, and extension of the indwelling catheter time to improve the surgical fluency and reduce complications. All of the operations were performed by the same experienced doctor who has a stable learning curve of Duckett urethroplasty. In this way, the bias caused by different skill level of different surgeons can be avoided.