In the current retrospective study, both AUU and dorsal buccal mucosa only graft were comparable regarding the postoperative outcomes. The overall incidence of recurrent stricture, penile curvature, and ventral sacculation was low with a statistically insignificant difference between the two groups. However, the operative time was statistically significant longer in dorsal graft compared to AAU, and the frequency of post-void dripping was statistically and clinically higher in the AAU group.
The choice of surgical repair for penile urethral stricture depends on stricture etiology, the extent of spongiofibrosis, and the surgeon experience . The repair of penile urethral stricture is more challenging because of the small thickness of corpus spongiousum and consequently lack of support for ventrally placed grafts. Furthermore, excessive mobilization of penile urethra could compromise the critical blood supply for the circumferential arteries.
For penile urethral strictures, the surgical options for urethral reconstruction include buccal mucosa urethroplasty using dorsal onlay or dorsal inlay techniques, fasciocutaneous local skin flap urethroplasty or staged approach in longer and more complex cases. Excision and primary anastomosis can lead to tension and chordee, whereas the risk of sacculation or pseudo-diverticulum formation increases in cases of ventral onlay with pedicled flaps [6, 10].
The causes of penile urethral stricture in our study were iatrogenic trauma in 59%, Idiopathic in 30%, and traumatic in 11%. While in developed countries, LS and failed hypospadias repair are reported to be the most common causes . This could explain the short stricture length in our patients.
Augmented anastomotic urethroplasty is usually employed for longer unequal bulbar urethral strictures that have a segment with dense spongiofibrosis and too narrow residual lumen not suitable for augmentation urethroplasty. It is a combination repair and comprises excision and substitution urethroplasty . In our study, the success rate of the AAU group was 88% in terms of anatomical urethral patency. Three patients (9%) developed mild penile curvature (< 15 degrees), while two patients (6%) developed ventral sacculation.
In 2001, Guralnick and Webster reported a 93% success rate for AAU as shown in their retrospective analysis at a mean 28-month follow-up. However, in their study, they did not state a clear definition for successful repair as they had one patient that did dilatation and one patient underwent visual urethrotomy. 21% of patients noticed some degree of penile shortening however they report that they were "neither measured nor problematic . In 2007, a retrospective analysis done was by Abouassaly and Angermeier, where they reported their results with AAU in 69 patients showing a success rate of 90% in median follow-up period of 34 months. On the other hand, their main complications were UTI and stricture recurrence, with no report of penile curvature. They were using oral mucosa in their surgical repair . In 2008, El-Kassaby and coworkers reported their results in AAU for long bulbar stricture and the overall success rate was 93.7%. They reported an incidence of 40.4% of postoperative dribbling of urine which is similar to the current results (41%). It should be mentioned that they had temporary perioral numbness in most patients . More recently, Hoy and colleagues reported their outcomes in AAU in long bulbar urethral stricture even more than 5 cm. The success rate (no stricture recurrence) was 96.9%, and the main complication was post-void dribbling (41.7%) [20, 21]. The success rate in our study was slightly lower than reported in the literature; however, we should emphasize that all previous studies used AAU for bulbar urethral stricture, which has more limits of mobilization and thick supportive corpus spongiousum. Besides, their sample size was larger.
On the other hand, the success rate of dorsal onlay graft augmentation in our study was 76.7%. The success rate varied widely in the literature. In 1998, the success rate of the dorsal onlay graft urethroplasty using penile skin as a substitute material, with a mean follow-up of 21.5 months, was 92% . In 2001, the success rate, with a mean follow-up of 43 months, was 85% . In 2008, the success rate, with a mean follow-up of 111 months, decreased more to 65.8% . Finally, in 2014, the success rate, with a mean follow-up of 190 months, was 63.6% . The use of buccal mucosa is superior to the penile skin in dorsal onlay graft bulbar urethroplasty. The success rate of buccal mucosa used in 6 patients, showed a 100% success rate at 13.5 months mean follow-up . In 2005, the success rate on 23 cases with 42 months mean follow-up, was 85% . Notably, the success rate of the dorsal only graft in this study was lower than reported in the literature. This could be explained by the dense fibrosis and the markedly reduced lumen in this group (< 6 mm).
Our results showed that AAU could be a reliable procedure to manage ultra-short penile urethral stricture with an obliterated lumen (residual urethral plate width less than 6 mm) that appeared unsuitable for one-stage urethroplasty. The pedicled skin flap was used as a ventral onlay. The pedicled skin flap is a long, hairless, and flexible flap that is suitable for restoring the urethral patency without cosmetic disfigurement. In addition, the operative time of AAU was shorter than of the dorsal onlay buccal mucosa graft. But, the frequency of post-void dripping is high due to the risk of ballooning of the ventral flap caused by the lack of ventral support. This finding was in tandem with other studies .
The limitation of the current study includes; the small sample size as this type of stricture is infrequent and its retrospective nature. It is important to conduct a prospective or cohort study including a larger number of patients with clear inclusion and exclusion criteria to state clear indications and outcomes for the described technique.