Classic TIP urethroplasty is considered the surgical method of choice for treatment for distal penile hypospadias because of its simplicity and favorable outcomes [6]. Distributed outcomes from patients who had undergone C-TIP urethroplasty for primary hypospadias repair has been outlined, and the mean overall complication rate was 10.8% (range, 0–33.3%), with a mean rate of UCF of 5.7% (range, 0–21.2%), a mean rate of meatal stenosis of 4.7% (range, 0–19.0%) and a mean rate of dehiscence of 1.3% (range, 0–4.2%) [3].
Lopes et al., 2001 reported that the new dorsal urethral plate area could regenerate through normal epithelium, which is called re-epithelialization. They found that epithelial cells could move into the dorsal epithelial defect on postoperative day 2, and the re-epithelialization process was completed by postoperative day 5. These effects are thought to be helped by stenting the urethra in order to allow the urothelium to grow on a wider surface [7]. A urethral plate incision enables a urethral tubularization, but in cases with narrow urethral plate and shallow urethral groove, a scar tissue may form within the incised plate without epithelium, which can increase flow resistance and prompt to proximal fistula formation [8].
Intraoperative grafting of the raw surface of the UP was thought to prevent stricture by offering immediate coverage of the UP, stopping the granulation phase and the contraction [9]. In 2000, Kolon and Gonzales reported the technique of one-stage dorsal inlay inner preputial graft. The workgroup performed this technique in 32 patients, and at 21 months of follow-up, none of the patients had neourethral stricture, meatal stenosis, UCF, or urethral diverticulum. The authors reported that this technique creates a vertical slit-like neourethral meatus and it was effective in reducing the risk of meatal or neourethral complications in cases of a hypospadiac penis with a flat or narrow glans [4]. In 2018, Abbas and Pippi salle supposed that a ratio of the urethra before and after incision of < 0.5 indicates that a significant component of the neourethra will be composed by raw tissue, and therefore the neourethra is vulnerable to stenosis, thus should be grafted [10].
Several studies reported on the efficacy of the G-TIP technique. Asanuma and colleagues studied dorsal inlay graft urethroplasty in 28 patients; 19 distal penile, six proximal penile, and six were penoscrotal [11]. Mouravas et al., and Gupta et al., recruited primary cases of hypospadias ranging from glanular to proximal and operated on them using G-TIP procedure [12, 13]. Shuzhu et al., studied 508 cases of primary distal penile hypospadias, with the cases with poor UP were designated for the G-TIP technique (either inner preputial graft or buccal mucosa) and the cases with good UP were designated for the C-TIP repair [6]. Helmy et al., included 60 patients of primary distal hypospadias in a comparative study between C-TIP and G-TIP techniques with comparable preoperative data as regard to patients’ age, meatus location, UP length and width and depth, and glans width [14].
In the current study, we analyzed the results of G-TIP versus C-TIP in 107 cases of primary distal hypospadias with comparable success rates and cosmesis. However, the operative time with statistically longer in the G-TIP (91.4 ± 6.2 vs. 85.2 ± 6.3 min (p < 0.001). This was congruent with the findings of Asanuma et al. study, where the operative time was 200 min including an additional time needed for the dorsal inlay graft of approximately 40 min [11]. Similarly, Helmy et al. study reported longer operative time in the G-TIP (106 ± 12 min) compared with the C-TIP (79 ± 9 min) (p = 0.005) [14].
In the current study, meatal stenosis was not reported in the G-TIP group and occurred in two cases (3.7%) of C-TIP, one of these was associated with UCF. In Mouravas et al. study, 17.4% of the cases in the C-TIP developed meatal stenosis compared with no cases in the G-TIP group [12]. Similarly, Gupta et al. reported no cases with meatal stenosis in their study [13]. Moreover, Shuzhu et al., reported 3% (6/198) meatal stenosis in the C-TIP group compared with 4.4% (7/160) in the G-TIP group [6], and Helmy and colleagues reported 3.3% meatal stenosis in C-TIP group compared with no cases in G-TIP group [14]. However, most of the studies did not show statistically significant difference between the G-TIP and C-TIP in terms of meatal stenosis, yet the results showed potentially better results in favor of the G-TIP.
In this study, ten cases of UCF occurred (3 in the G-TIP and 7 in the C-TIP) early in the postoperative course at 2 weeks. Regular urethral dilatation was done for all cases for one month where spontaneous healing occurred in all cases of G-TIP and three cases of C-TIP. In the studies by Schuzhu et al. and Mouravas et al., UCFs were developed 3.1% and 4.16% in the G-TIP compared with 3% and 8.7% in the C-TIP group [6, 12].
In terms of the glans dehiscence, the current study reported two cases of glans dehiscence (3.7%) developed in the G-TIP group compared with no cases in the C-TIP group. These were corrected using C-TIP urethroplasty after 6 months of the primary repair. Other studies reported glans dehiscence as well where two cases (6.7%) of partial glans dehiscence were reported in G-TIP group of Helmy et al. study [14], and 4.16% versus 4.35% developed glans dehiscence were reported in the G-TIP and C-TIP groups of Mouravas et al. study [12].
This study included three cases (5.5%) of distal penile hypospadias with mild chordee who underwent G-TIP repair with excellent overall results except for residual minimal to mild postoperative chordee. In Gupta et al. study, seven cases (2.6%) developed residual postoperative chordee and they explained this by the hypothesis that the graft uptake might have been associated with development of hypergranulation and possible vertical graft contracture which may have been a contributory factor for the development of residual chordee in long inlay grafts as the study included both distal and proximal cases [13].
In terms of the cosmetic outcomes, the HOSE score in the present study was comparable between the G-TIP and the C-TIP. These results were comparable to Shuzhu et al., study where HOSE score was 14.34 for C-TIP group with a success rate of 93.9% (180/198) compared with a HOSE score of 14.25 for G-TIP with a success rate of 92.5% (148/160) [6]. Despite being statistically insignificant, results of this study showed potentially better clinical results in favor of the G-TIP. We refer this to the skin graft that provides epithelialized urethral plate from the beginning, and this might contribute to decreasing the fibrosis reaction which occurs after dorsal incision of the urethral plate in the classic repair.
One limitation that must be acknowledged in this study is the relatively short follow-up compared to other series. However, most of the complications of hypospadias develop early postoperatively. Furthermore, we did not track blood loss for our patients intraoperatively because it is usually minimal, but none of the cases experienced noticeable bleeding.