Refinements in Surgery for Complications of Hypospadias
I am providing a commentary by Hunter Wessels on â€˜Refinements in Surgery for Complications of Hypospadiasâ€™. I am sure this will be useful in increasing our knowledge.
I hope our pundits will shed more light on this with their experience
With warm Regards,
Refinements in Surgery for Complications of Hypospadias
Stricture and fistula after childhood hypospadias repair can play out over decades and represent one of the most challenging problems for reconstructive urologists. The original surgical technique is from a different era, creating uncertainty as to the presence or absence of the urethral plate, how skin tubes were created, and whether grafts or flaps were used. Underpinning these questions are fundamental challenges: uncertain vascularization of rearranged tissue; deficiency of shaft skin; persistence of chordee; a meatus that may be difficult to recreate; lack of Spongiosal support for reconstruction; the risk or presence of fistula; Lichen Sclerosus; and the challenges of graft take.
In 2021, two studies were published,1,2 which provide refinements and an alternative to the most commonly used and most successful approach to hypospadias complications; namely, staged urethroplasty.
The advent and dissemination of staged urethroplasty arose out of the need to create a reliable situation out of an unreliable one. Often the urethra that is strictured or fistulized is removed because it is poorly vascularized and created from unpredictable skin. By laying down oral mucosa grafts onto the tunica albuginea, or occasionally the dartos, one can establish a high probability that the urethral plate will become pliable, will have a reliable blood supply, and can be tubularized without undue tension. In a summary of urethroplasty options and outcomes for hypospadias-associated urethral strictures in adults, Saavedra and Rourke demonstrate that the vast majority of patients with a previous hypospadias repair and a long penile urethral stricture undergo a staged procedure with oral mucosa.3 Only the occasional patient can be offered a single-stage procedure with either oral mucosa or a flap. Thus, the questions that most of us face is whether we 1) need to do the staged procedure, and 2) how can we improve its outcomes.
Usually with a stricture there is little choice but to proceed with staged urethroplasty due to the length and severity of the narrowing. However, Shaw and associates describe the novel use of the Asopa technique in case of penile Urethrocutaneous fistula repair with stricture after hypospadias.2 Importantly, although fistula is one reason to use the Asopa technique, this could equally be applied to strictures. The important point with this procedure is that 1) there must be enough of a urethral lumen so that when the urethra is split and lateralized there is still adequate tissue to close ventrally, and 2) that the urethral lumen and tube is sufficiently mobile so it can be lateralized dorsally. In particular, if there is an existent urethral plate from the original hypospadias, with elements of corpus spongiosum, those lateralize effectively. Similarly, a skin tube created from local or pedicled skin flaps will generally split dorsally and lateralize. In contrast, the urethra reconstructed entirely from Buccal Mucosa that has been previously fixed to the tunica albuginea may not lateralize well enough to accommodate the dorsal inlay graft, which is the core of an Asopa repair.
In their limited series, Shaw et al avoided the more extensive staged reconstruction of a strictured fistula while trying to solve the problem of the unreliable local skin flaps, which are the typical approach to an Urethrocutaneous fistula after hypospadias. The default position of proceeding to a staged urethroplasty and removing the strictured fistulised urethra may still be necessary and should be in the armamentarium of the surgeon proceeding down this pathway, particularly if the fistulae are large or long.
Azuma, Horiguchi, and colleagues provided an approach to enhance the success of staged oral mucosa graft urethroplasty.3 Acknowledging that narrowing at the proximal urethrostomy created during first-stage urethroplasty is a problem and challenge that often requires additional grafting (â€˜stage 1.5â€™), the authors propose a triangular extension of the Buccal Mucosa in the first stage in order to create a â€œhinge flapâ€ to be used in the second stage. The principle of the hinge flap is not new. However, the use of the oral mucosa free graft in stage 1 to create hairless healthy tissue to be used as a hinge flap is novel in the area of urethral reconstruction. This is particularly appropriate for failed hypospadias strictures, where there again is limited local skin that has reliable blood supply and is hairless. By extending the graft a centimetre proximal and distal to the urethrostomies (for a mid-penile urethral stricture) or the proximal urethrostomy (for a stricture that extends all the way to the meatus), the surgeon invests some additional oral mucosa to mitigate against potential stomal stenosis, which could become problematic at stage 2.
Using the hinge flaps, the authors were able to avoid an intermediate-stage procedure requiring additional Buccal Mucosa, which had been required in 20% of their patients in an historical control group.
These two papers2,3 provide very specific solutions for advanced problems; namely, a Urethrocutaneous fistula in the context of a penile urethral stricture after hypospadias reconstruction on the one hand, and stomal stenosis at the proximal (or distal) urethrostomy after first-stage urethroplasty using oral mucosa grafts on the other. One could imagine expanding the use of these approaches. The Asopa technique for penile Urethrocutaneous fistula may be applied to a broader range of urethral strictures after hypospadias surgery. This will require larger case series and careful consideration of the quality and viability of the remnant urethra preserved for the ventral closure. Incorporating the triangular extension onto every oral mucosa graft used in staged urethroplasty will over treat, but conversely may help prevent some of the long-term stricture recurrences which we see years and decades after staged reconstructions. The mainstay of urethral complications of hypospadias surgery remains the staged urethroplasty with oral mucosa grafts. These refinements may reduce the need for such extensive staged procedures in selected individuals and complement and improve the success of the workhorse of reconstructive urologists currently for the remaining majority of patients.
2. https://onlinelibrary.wiley.com/doi/epdf/10.1111/iju.14582 (PDF available)