The combined tissue transfer is an option for severe urethral stricture or congenital penile anomalies. The concepts mainly consist in a graft dorsally fixed on the penis covered by a pedicled penile skin flap.
To the glans and fossa navicularis
The management of strictures affecting the distal penile urethra, including external meatus and fossa navicularis (FN), has long constituted a difficult task for both general and reconstructive urologists. The therapeutic goal for surgical reconstruction of these strictures is two-fold: (1) to create a patent distal urethra; and, simultaneously; (2) to yield an aesthetically pleasing outcome. The implementation of a standard reconstructive procedure for strictures of the distal penile urethra is usually compromised by three important obstacles: (1) these strictures are difficult to evaluate by imaging studies; (2) they are difficult to diagnose; and (3) they are difficult to treat. As with most urologic reconstructive procedures, the evaluation of both operative and patient-reported outcomes by randomized trials is mostly inexistant. Therefore, data favoring one technique over another are, to a certain extent, based on and obtained from prospectively gathered, but retrospectively delineated, observational series. In this review, the evolution and treatment of distal penile urethral strictures are discussed with a special focus on tissue transfer, in either isolated or combined fashion.
The selection of the most appropriate technique to reconstruct distal urethral strictures depends significantly on stricture etiology. In turn, the most frequent causes of these strictures have altered dramatically in the last 30 years. In the past, infectious urethritis, such as sexually transmitted diseases, was predominant. However, contemporary series in the industrialized world report iatrogenic etiologies, such as traumatic urethral catheterizations or transurethral procedures, and LS[16-18]. Distal and FN strictures correspond to 18% of all strictures of the anterior urethra[17].
Several therapeutic options may be useful to create urethral patency and simultaneously preserve satisfactory penile cosmesis. Due to the challenges imposed by these two functional issues, an algorithmic approach has been recommended. In short strictures that are limited to the external meatus only, a simple meatotomy, or urethral dilatation, may be the procedure of choice. However, these options require repeated intervention in the short term and are often considered palliative. Therefore, because they are considered palliative, they should be attempted only once. Endoscopic urethrotomy using a cold knife or laser has not produced efficacious results in a consistent fashion[19-20]. However, most distal strictures tend to extend proximally. Endoscopic urethrotomy for distal urethral strictures was associated with notably lower efficacy compared to bulbar urethra (16% vs. 42%)[19]. Although very popular due to their simplicity and minimally invasiveness, both urethral dilatation and endoscopic urethrotomy are linked to high failure rates, thereby leading to recurrent interventions, and therefore should not be recommended in complex distal urethral strictures.
Traditionally, open distal urethroplasty has been reserved for the longest strictures that involve the external meatus and FN, or for recurrent or obliterative cases. Reconstructive approaches have included grafts, flaps, or combined use of both, including several variations in technique. A single-stage penile skin flap procedure can often be utilized for these strictures if not due to LS. If previous penile flap surgery has been attempted or in the presence of LS, a staged reconstruction with oral mucosa grafting (as dorsal onlay or inlay) is more advisable, as using skin in these cases is associated with high recurrence rates[21-22]. Multiple flap procedures have been reported for the surgical reconstruction of distal strictures of the penile urethra.
Flaps
Flap urethroplasty for distal penile strictures was first described more than 50 years ago. Originally, tubularized or advancement flaps were the local penile flaps described, and these were tormented by severe problems, such as flap necrosis, flap contraction, penile ventral curvature, penile rotation, or deformities of the external meatus. In 1987, Jordan introduced the ventral transverse fasciocutaneous island flap[23]. This cutaneous island flap is based and lifted on a broad pedicle of dartos fascia and is designed transversally on the ventral skin of the penis. In this technique, a well-vascularized fasciocutaneous distal transverse ventral skin flap is prepared and sutured to the ventral urethra [Figure 1]. Glans wings are raised and reapproximated over the flap. Only minimal advancement of the flap is needed, making the final cosmetic appearance highly gratifying. Long-term stricture free rates after this technique were 83% with a mean follow-up of 10.3 years[22]. In 1998, Armenakas and McAninch reported a modification of the previous technique to mitigate potential complications of glans dehiscence that utilized a similar ventral transverse skin flap but with preservation of the glans and elevation of the glans off the urethra [Figure 2][24]. The authors reported a stricture-free rate of 94% at a mean follow-up of 43 months. Globally, patients were very pleased with the cosmetic outcome. McAninch and Morey[25] also adapted this concept to complex, long urethral strictures extending from the FN to the proximal penile urethra. Based on a modification of the original technique, they utilized a circumferential penile fasciocutaneous flap for long anterior urethral strictures spanning up to 15 cm. They initially reported 79% successful results. Asserting that the total length of FN stricture disease is a predictor for restricture, Virasoro et al.[22] stratified FN strictures into two groups, those < 2.5 cm and those > 2.5 cm, finding a statistical difference in terms of restricture in the longer stricture cohort The use of local genital cutaneous flaps was strongly discouraged in the presence of LS, which was associated with a 50% higher risk of restricture at the flap location in their series.
Grafts
Grafting procedures for distal penile strictures are deemed more flexible than flap procedures. Grafts can be employed in inflammatory strictures, especially LS that discourages the use of penoscrotal cutaneous flaps. Venn and Mundy[26] compared the results between a single-stage penile skin flap urethroplasty and a traditional staged graft (posterior auricular skin or oral mucosa) urethroplasty in patients with LS. Patients treated with skin flap urethroplasty had a 100% recurrence rate at a mean follow-up of five years compared to 8.3% recurrence of those who had a graft. These findings led them to infer that genital skin that is affected by LS must be avoided in urethral reconstruction. Depasquale et al.[21] also published a 90% long-term restricture rate in LS patients who underwent staged urethral reconstruction with genital skin grafting as opposed to 0% recurrence in those who received an OMG. In 1998, Naudé[27] initiated the concept of endoscopic graft urethroplasty. A few modifications were published later[28-29]. Unfortunately, these procedures did not gain popularity due to intrinsic technical complexity and problems with surgical reconstruction of distal penile strictures. The main advantage of this concept of intraurethral urethroplasty over open procedures is to avoid skin incisions and glans elevation with spatulation. Open procedures are intrinsically associated with cosmetic and functional complications, including infection, dehiscence, and fistula. In 2008, Seth et al.[29] reported a hybrid technique of intraurethral approach to distal urethral stricture combining a transurethral graft placement with a ventral subcoronal incision to promote better scar removal and proximal graft anastomosis. At a mean follow-up of 38 months, an 84% success rate was reported. In 2016, Nikolavsky et al.[30] published a new transurethral surgical technique for the reconstruction of distal penile strictures employing OMG with promising outcomes [Figures 3 and 4]. They developed this innovative and elegant reconstructive concept to avoid the drawbacks, technical complexities, and weaknesses of the previous procedures used in this urethral segment. Other advantages include avoidance of an external skin incision, preservation of the glans penis, and use of oral mucosa for grafting, thus providing both very good functional and cosmetic outcomes. This surgical technique is mainly advised for men with distal strictures due to LS, where only OMGs are recommended. At an initial follow-up of 12 months, a 93% stricture free rate was reported.
Combined graft and flap urethroplasty
In 2011, Gelman and Sohn published a surgical technique characterized by the combined use of a dorsal onlay graft with a ventral onlay flap for a subgroup of patients with obliterated distal strictures due to ischemia, who had already failed reconstructive attempts, or with a history of hypospadias in childhood[31]. The technique was considered a combination of fasciocutaneous flap designed by Jordan with OMG. This surgical procedure is very useful in men with highly compromised urethral plates due to ischemia and dense scar formation caused by earlier surgical attempts and when a staged procedure is not favored [Figure 5]. The authors achieved a 100% success rate in a cohort of 12 patients at a 39-month follow-up. The authors concluded that this is a better approach to handling these complex strictures. A success rate of 92% was confirmed by urethroscopy four months after reconstruction with a subsequent mean follow-up of 39 months. Based on previous experiences, Djordjevic et al.[32] also used a technique that combined a dorsal longitudinal island skin flap and OMG to form a neourethra in patients with severe hypospadias. The main goal was to correct all defects in a single-stage reconstruction. They recommended this combined reconstructive approach as a good and highly successful option for neourethral reconstruction with satisfactory results in the most severe forms of hypospadias. In 2001, Morey[33] published his first experience with a similar procedure.
Staged techniques
The best application of these techniques is in men who have failed hypospadias surgical attempts, with a deficient or densely fibrotic urethral plate, or in the presence of LS. These techniques are usually regarded as more adaptable compared to flap procedures and are especially favored in the presence of LS. In 1995, Bracka initiated a modern era of staged urethral reconstruction by describing a versatile approach to difficult anterior urethral reconstructions[34]. In his procedure, the diseased urethra is completely removed, and the urethral plate is covered by an onlay graft of oral mucosa.
To the penile urethra and bulbar urethra
Dorsal graft with ventral penile skin flap
In 2001, Morey introduced the principle of augmentation urethroplasty combining OMG and penile cutaneous flap. He reported salvage of the urethral plate using a dorsal OMG combined with a flap of ventral penile skin in men with complex strictures involving the penile urethra[33]. In the initial use of this new procedure (with mean follow-up to 2.1 years), all four patients voided well and needed no further intervention. Similarly, Erickson et al.[35] described a single-stage procedure in 14 men with anterior urethral strictures using this combination of dorsal onlay OMG with a ventral fasciocutaneous flap.
The average length of the urethral strictures in his patient population was 9.75 cm with 12 (12/14; 85%) strictures found in the penobulbar segment. At a median follow-up of 2.5 years, the authors published an overall urethral patency rate of 78% (11/14 patients), although two of these patients (14%) needed an additional intraluminal maneuver to attain a fairly good urethral caliber. Individuals with longer strictures seemed to have a higher risk of restricture (12.8 cm vs. 8.7 cm). A similar experience was reported by Gelman and Sohn when applying this combination of dorsal oral graft with a ventral penile fasciocutaneous flap in distal obliterative strictures[31]. Although stricture length was not specified by the authors, various sizes of OMGs were employed (range, 2-6.5 cm) with all strictures detected in the penile urethra. All 12 patients had good urethral patency on three-month postoperative follow-up cystoscopy and all voided well at a mean 39-month follow-up.
Dorsal graft with ventral penile skin flap in proximal hypospadias surgery
Surgical reconstruction of proximal hypospadias implies rectifying different basic elements of the hypospadias complex to optimize long-term success, both functionally and cosmetically. These elements include ventral penile chordee, proximal implantation of the urethral meatus, ventral skin shortage, atypical glans morphological appearance, abnormal division of the corpus spongiosum, penile rotation, and penoscrotal transposition [Figure 6]. In some cases, there is not enough foreskin or penile skin tissue for surgery, so the choice of the technique will depend on the surgeon’s preference. Staged repairs aim at the initial rectification of ventral chordee with the fashioning of a new urethral plate using preputial/penile skin flap or OMG and followed by urethral reconstruction in the next stage[34-36]. A recently described technique by Djordjevic et al.[32] used the combination of a longitudinal dorsal island skin flap and OMG [Figure 7]. They employed this surgical procedure in children with hypospadias. Seventeen patients, aged less than two years old, received this single-stage operation for severe hypospadias (13 penoscrotal and 4 scrotal). This technique involved a combination of a dorsal OMG with a ventrally applied dorsal island penile cutaneous flap. Functional and cosmetic success was achieved in 14 patients (82%) at a mean follow-up of 25 months. Complications occurred in the remaining three patients, specifically urethral fistulation and distal urethral stricture (18%)[32].
Double graft
A double-faced dorsal plus ventral onlay urethroplasty described by Palminteri et al.[37] was applied in nearly obliterative strictures where an isolated graft would be clearly insufficient to achieve adequate lumen caliber without urethral transection. The strictured segment was opened on the ventral aspect, followed by a midline incision of the exposed dorsal urethral plate and then followed by dorsal and ventral augmentation using two OMGs[38]. In cases where a severe penile curvature was present, Djordjevic et al.[39,40] started to repair the chordee by ventral tunica albuginea incision and grafting. In patients with a penile length less than 2.5 cm, preoperative topical hormonal therapy was instituted for a period of three weeks.
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