About The Hypospadias Surgery

Hypospadias surgery is continuously evolving, implying that no single technique is considered perfect and applicable in all cases without complication. (70 – 73) The use of interposition flaps is well documented in the literature. Those harvested from the prepuce are the triangular soft tissue flaps (74) and Belman flaps.(75) Penile skin based flap is Smith D flap,(70) whereas Buck’s fascial flap is harvested from penile shaft. Corpus spongiosum either from the normal native urethra as a turnover perimeatal flap or from the diverging spongiosa has also been used. Either a scrotal dartos flap from the scrotum (76,77)or a TVF (78) from the testis can also be used.

Snodgrass (79) described additional coverage of neourethra by vascularized subcutaneous tissue dissected from dorsal prepucial and shaft skin. This dissection requires skill and there are chances that vascularity of the skin cover may get compromised resulting in subsequent dermal necrosis. Duckett (80) has ascribed it to hypovascularity of the overlying skin when dartos is separated from skin. Although there are various options for soft tissue coverage, the ideal one is still not found. Dartos based flaps have the advantage that they are available locally and do not require another incision or extension of the incision.

Snow et al.,(81) in 1995, were the first to report the use of tunica vaginalis as interposition graft. The fistula rate reported was 9%. Similar results have also been reported by Shankar et al. (82) and Handoo.(83) It is a dependable soft tissue cover for redo cases and posterior hypospadias surgery.(84) In his recent experience, Snodgrass could reduce the fistula rate to 0% with the use of TVF.(85).

In our study, four cases in group A had developed urethrocutaneous fistula. two out of which were associated with meatal stenosis, that lead to the fistula formation. One have wound dehiscence and marginal necrosis that exposed the neourethra and caused the fistula formation. Using dartos may result in shortage of skin or skin necrosis from damage to the intrinsic blood supply to the outer skin. Since TVF does not depend on the skin, the ventral skin cover is compromised in fewer cases.

Seven fistulas occurred in group B but five healed by conservative means, two required reoperations for closure. In two of them, it was possibly related to development of meatal stenosis in one case leading to large sized fistula and in one case wound dehiscence had occurred that resuled in large sized fistula formation. The difference in the fistula rates in the two groups is not statistically significant possibly because of the small sample size.

Chatterjee et al. (86) have prospectively compared the two techniques of neourethral coverage after a TIP procedure. They have concluded that TIP with TVF could be an alternative to other techniques in a primary case of hypospadias. However, it was a multi-institutional study inviting surgeon variations. In their study, the fistula rate for cases with TVF and dartos flap were 0% and 15–20%, respectively. Dhua et al (87)have reported in 2012 that fistula formation rate was 0% with TVF waterproofing and fistula rate for dartos flap was 12%. In our series we have effective fistula formation with TVF is 8.33% and with dartos is 16.67% which is in the tune with with other studies.A study conducted by Das et al (88) in 2017 have reported fistula formation rate with TVF repair was 22% and with dartos coverage was 52%.Wound dehiscence and marginal necrosis were found with same rate in both groups but surgery was required for the same in dartos repair.More importantly, we have seen three cases of superficial skin necrosis following dartos flap. It did cause anxiety and distress to the families and invited more hospital visits. Hence, we consider that dartos flap had significant morbidity because of this inconsequential complication. Total breakdown of repair is also known after this operation.

In every case of hypospadias has an imprint of the meatus and the ventral glansplasty. We have to design our operation based on this imprint. In such difficult cases, the TVF serves a good purpose by providing a thin but nicely vascularized tissue underneath the glans. This prevents tight glans closure, achieves good cosmesis and decreases fistula formation.