//Anterior urethral strictures
Anterior urethral strictures2017-04-05T18:51:36+00:00

Anterior urethral strictures

 

Uretra, stenosi uretrale

pdf chirurgia uretrale

Authors:
Enzo Palminteri et Al.

Publication:
BJU INTERNATIONAL

Volume:
92(5):497-505

Centre:
Center for Urethral and Genitalia Reconstructive Surgery, Arezzo, Italy

 

 

The surgical treatment of adult anterior urethral strictures has developed continuously. Recently considerable changes have been introduced, involving the cause of the urethral disease and surgical techniques. The criteria for selecting the reconstructive surgical technique are presented according to the cause and a new classification of urethral strictures. The main surgical procedures are presented and fully illustrated, with an updated and comprehensive review of recent publications.

 

THE AETIOLOGY OF ANTERIOR URETHRAL STRICTURES

The male urethra can be divided into two parts; the posterior urethra, including the membranous and prostatic tracts, and the anterior urethra. The anterior urethra includes the navicularis and penile and bulbar tracts, and is surrounded by the corpus spongiosum soft tissue [1]. Basically, the urethral strictures involving the anterior urethra are caused by: (i) congenital anomalies of the mucosal membrane, usually in the bulbar urethra, with the corpus spongiosum not involved [2]; (ii) traumatic scarring after blunt perineal trauma, in the bulbar urethra, with the spongiosum tissue involved in the scar [2]; (iii) hypospadias failures, which may involve the external urinary meatus or the entire pendulous urethra, and are frequently associated with diverticula, stones, hair, fistula, cosmetic defects and residual penile curvature [3]; (iv) inflammatory disease of the corpus spongiosum, caused by lichen sclerosus (LS) or balanitis xerotica obliterans (BXO) [4,5]. The strictures from LS may involve only the external urinary meatus and the fossa navicularis, or the entire pendulous urethra [3–5]. In some patients the stricture may extend to the bulbar urethra, and there may be a panurethral stricture [3–5]; (v) ischaemia, common in patients after urological endoscopic procedures, after cardiovascular surgery [6–8] or in patients in the resuscitation room with an indwelling catheter in place. This may involve the anterior urethra in different sites.

 

SURGICAL PROCEDURE

There is renewed controversy about the best means of reconstructing the anterior urethra [9]. The popularity of flaps and grafts has varied over time, and in the last few years free grafts are making a resurgence and reducing the use of genital flaps [9]. Current reports provide no clear rationale for selecting a graft rather than a flap urethroplasty, and no prospective comparison of grafts and flaps has ever been carried out, making it difficult to declare a clear winner [9]. The reconstructive urologist must be fully familiar with the use of both flaps and grafts to deal with any condition of the urethra at the time of surgery [9]. Moreover, the use of twostage or mesh-graft urethroplasty may be the only way to restore the urethral lumen in patients with complex urethral stricture disease.
The protocol presented here for the criteria for selecting the surgical procedure is based on current and updated reports, and the present clinical and pathological classification of anterior urethral diseases. Furthermore, it is basically founded on our daily clinical experience, which includes ª 400 urethroplasties over several years.

The surgical procedures for repairing strictures in the fossa navicularis are selected according to the cause of the stricture (Table 1). In patients with hypospadias failure the foreskin is often absent, and the penile skin is tough and scarred; the one-stage buccal mucosa graft meatoplasty [1] offers a good cosmetic final outcome; in patients with LS removing the involved tissues is mandatory and the wide meatotomy or staged buccal mucosa graft meatoplasty is advisable [10]. In young patients with ischaemic urethral disease the one-stage buccal mucosa graft meatoplasty [1], the pedicled flap meatoplasty [1,11] or the De Sy meatoplasty [12] provide the best cosmetic results, and in older patients the Blandy meatoplasty [13] gives a satisfactory result.

The surgical procedures for repairing the penile urethra are also selected according to the cause (Table 1). Penile urethroplasty might be requested in patients with a normal penis (ischaemic urethral stricture) or with an abnormal penis (hypospadias failures or LS). In the former the urethral plate, foreskin, penile skin and dartos fascia are available for urethral reconstruction, and a pedicled flap urethroplasty [1] is the solution of choice worldwide. However, in selected cases in which the corpus spongiosum is not seriously involved a dorsal buccal mucosa graft urethroplasty [14] can be used. In patients with an abnormal penis the urethral plate, foreskin, penile skin and dartos fascia are unavailable for urethral reconstruction, and a staged buccal mucosa graft urethroplasty or mesh-graft urethroplasty is advisable [15]. In patients with LS the use of buccal mucosa as a graft is mandatory, because LS is a skin disease and thus any skin used for the repair can also become diseased [10,16–18].

The surgical procedures for repairing a bulbar urethral stricture are selected according to the length of the stricture (Table 1). In patients with short congenital anomalies of the mucosal membrane endoscopic urethrotomy is the solution of choice. Strictures of 1–2 cm are treated using an endto- end anastomosis [1,19], those of 2–3 cm by augmented anastomotic urethroplasty [1,20] and of >3 cm by an augmented dorsal or ventral onlay graft (skin or buccal mucosa) urethroplasty [21–28]. Finally, in patients with strictures of >6 cm involving both penile and bulbar urethra, or associated with local adverse conditions, a two-stage urethroplasty or mesh graft urethroplasty is mandatory [29,30].

 

SURGICAL TECHNIQUES ONE-STAGE BUCCAL MUCOSA GRAFT MEATOPLASTY

This technique is used in patients with hypospadias failure or ischaemic urethral strictures within the glans (Fig. 1A). The external urinary meatus and the fossa navicularis are fully opened (Fig. 1B). The buccal mucosal graft is sutured to the left side of the opened urethra (Fig. 1C). The graft is rotated over the urethral plate, and sutured to the right side of the urethra (Fig. 1D). The glans is closed over the graft, and a Foley silicone catheter left in place for 1 week (Fig. 1E).

 

PEDICLED FLAP MEATOPLASTY

This technique is used in patients with ischaemic strictures extending beyond the glans (Fig. 2A). The midline longitudinal incision and skin island are outlined on the ventral penile skin (Fig. 2B). The fossa navicularis is fully opened and a longitudinal ventral penile skin island is elevated to the dartos penile fascia (Fig. 2C,D). The left margin of the skin island is sutured to the left urethral margin (Fig. 2E). The skin island is rotated over the urethral plate and sutured to the right urethral margin (Fig. 2F). The glans and the penile skin are closed over the flap and a Foley silicone catheter left in place for 2 weeks (Fig. 2G).

 

DORSAL BUCCAL MUCOSA GRAFT URETHROPLASTY

This technique is suggested for repairing of penile ischaemic urethral strictures only in patients with normal corpus spongiosum tissue. A circumcoronal foreskin incision is made with complete degloving of the penis, the penile urethra exposed, and the strictured tract fully opened by a ventral midline incision (Fig. 3A). The urethral plate is longitudinally incised on the dorsal midline down to the corpora, and the wings of the urethral plate laterally mobilized (Fig. 3B,C). The buccal mucosa graft is sutured and quilted on the bed of the dorsal urethral incision with interrupted 6/0 sutures, and an augmentation of the urethral plate obtained (Fig. 3D). The urethra is closed and tubularized, taking advantage of the mobilized wings of the urethral plate (Fig. 3E). A dartos fascial flap is obtained to cover the urethral suture. The glans and the penile skin are closed, and a Foley silicone catheter left in place for 3 weeks (Fig. 3F).

 

STAGED BUCCAL MUCOSA GRAFT URETHROPLASTY

This technique is suggested for patients with penile strictures from hypospadias failure or LS, in which the urethral plate is removed, because it is unserviceable for an augmentation urethroplasty. In the first stage the urethral plate is removed, the glans fully opened, and the buccal mucosa graft splayed and quilted over the tunica albuginea, and around the urethral stoma. Six months after the first stage, the patient is evaluated for urethral closure (Fig. 4A). A wide strip of the buccal mucosa is obtained (Fig. 4B) and the graft closed and tubularized up to the glans (Fig. 4C). The glans and the penile skin are closed over the new urethra, and a Foley silicone catheter left in place for 2 weeks (Fig. 4D).

 

AUGMENTED ANASTOMOTIC URETHROPLASY

A midline perineo-scrotal incision is made, the bulbocavernous muscles separated, the urethra completely transected at the level of the stricture (Fig. 5A) and the urethral edges freed from the corpora cavernosa (Fig. 5B). The urethral scarred segment is removed, the proximal mucosal edge spatulated and splayed over the corpora cavernosa, and the distal urethra opened dorsally (Fig. 5C). The graft is sutured to the tunica albuginea, its lower margin sutured to the mucosal edge of the urethra, and the distal urethra opened widely along its dorsal surface (Fig. 5D). The left mucosal margin is sutured to the left side of the margin patch (Fig. 5E). The urethra is rotated back to its original position and the right urethral margin sutured to the right side of the graft (Fig. 5F). At the end of the procedure the grafted area is covered entirely by the urethra (Fig. 5F). A Foley silicone 16 F catheter is left in place for 3 weeks.

 

DORSAL ONLAY GRAFT URETHROPLASTY

A midline perineo-scrotal incision is made, the bulbocavernous muscles separated, and the bulbar urethra dissected from the corpora cavernosa (Fig. 6A). The bulbar urethra is rotated of 180 ∞ (Fig. 6B) and the dorsal urethral surface fully opened (Fig. 6C). In patients with a stricture of 4 cm a double circumferential subcoronal incision is made for harvesting a longer preputial skin strip. When local foreskin in
unavailable or the patient does not agree to harvesting from the prepuce, the buccal mucosa graft is preferred to the other types of extragenital free grafts because of its quality. The opened urethra is moved on the right side, and the graft (skin or buccal mucosa) sutured, splayed and quilted over the corpora cavernosa, using 6–0 interrupted sutures (Fig. 6D). The right urethral margin is now sutured on the right side of the patch (Fig. 6E). The urethra is rotated over the graft and the left side of the graft sutured to the left side of the urethra (Fig. 6F). At the end of the procedure the graft is completely covered by the urethra (Fig. 6F). A small suction drainage is left in place for 1 day and the catheter for 3 weeks.

 

DISCUSSION

Selecting the surgical procedure for pendulous urethral reconstruction must respect the status of all the penile tissues and components (foreskin, penile skin, dartos fascia, glans). A penile urethral stricture may be a simple problem in patients with a normal penis, but can be a difficult challenge in those in whom the penis has been damaged by previous surgery (hypospadias failures) or by inflammatory changes (LS).
Penile urethroplasty, whether one- or a twostage, is intrinsically prone to complications, e.g. haematoma or infection, which in turn lead to secondary complications, e.g. fistula, which do not occur in the bulbar or posterior urethra, which is the region most likely to produce alterations in sexual function [16,31,32]. In patients requiring penile urethroplasty the use of buccal mucosa graft avoids the cosmetic disadvantages of using local genital skin, e.g. penile-glans torsion, subcutaneous deformity or chordee [16,18,31]. In patients with LS the use of buccal mucosa as a graft is mandatory, because any local skin used for the repair might also become diseased [2]. We prefer to harvest the buccal mucosal graft from the inner cheek rather than the lip, because the width of the lip limits the size of the graft [25]. Moreover, buccal mucosa from the cheek is thicker and more resistant than that from the lip [25]. The harvesting of buccal mucosa increases the operative duration by ª 1 h [25]. However, two teams can be used, the first exposing and calibrating the stricture tract, while the second harvests the buccal mucosa graft [25]. This approach reduces the risk of infection and may prevent troublesome complications by decreasing the amount of time the patient remains in the lithotomy position [25]. In patients requiring penile urethroplasty the use of free grafts (buccal mucosa or skin) requires no extensive training in tissuetransfer procedures, as the use of a penile flap suggests. At present, it has not been established for which patients the use of the buccal mucosa graft may be successful in penile one-stage urethroplasty, and we are also unsure about the proper anatomical characteristics that the penis should have to ensure ‘graft take’ [9]. The penile spongiosum tissue and dartos fascia do not ensure good vascular and mechanical support to the graft in all patients [16]. What type of vascular support can be used? In which patients does the use of a pedicled flap give a better chance of success rather than a free graft [9,16]? What is the role of urethral plate salvage in reconstructive methods [9,16,33]? Morey [33] suggested that urethral plate replacement may be necessary in a minority of complex, long, severe strictures, and described a new penile urethroplasty using a graft-flap combined procedure. In the near future the accurate selection of patients could answer all these questions, and perhaps the buccal mucosa free graft will become predominant over the penile flap. Recently, the theoretical pathological advantages of buccal mucosa grafts, used as an onlay patch rather than a complete tube, were reported [34]. The great elasticity and utility of the buccal mucosa might engender numerous new surgical techniques, arranging the graft in different ways, using the incision of the urethral plate [35], and its augmentation, as suggested for childhood hypospadias surgery [36]. In the last few years reports seem to support the soundness of the one- or two-stage buccal mucosa graft urethroplasty in the successful repair of penile or bulbar urethral strictures [2,3,10,14,16–18,22–28,33,36]. However, a longer follow-up is mandatory to determine the long-term results and the attrition rate over time, and other potential applications of these surgical techniques. In the bulbar urethra the anastomotic urethroplasty [1,19], the augmented anastomotic urethroplasty [1,20], and the buccal mucosa graft urethroplasty provided excellent results in most patients, with uncomplicated urethral strictures of 3–6 cm. The graft may be used on the ventral [9,28] or dorsal urethral surface [2,3,16,18,21–27], according to the surgeon’s experience and preference. In patients with local adverse conditions or complex urethral strictures, the use of two-stage procedures or mesh-graft urethroplasty is advisable [29,30].

 

CONCLUSIONS

The choices available to the reconstructive urethral surgeon are developing continuously and require familiarity with new concepts and concerns. The successful management of urethral strictures demands attention not only to surgical details but to selecting the procedure [1]. No one technique is appropriate for all situations and the successful surgeon will have a repertoire of methods from which to choose [1]. Certainly, sexual function can be placed at risk by any surgery on the genitalia, and any dissection must avoid interference with the neurovascular supply to the penis; the use of flaps or grafts should not compromise penile length or cause penile chordee, and certainly should not affect penile appearance [1]. Success in urethroplasty surgery is not measured in 1- or 5-year outcomes; we are constantly reminded by late failures that there is no true substitute for a normal urethra [1].

 

TAKE HOME MESSAGES

• The anterior urethra is divided into the navicularis, penile and bulbar tracts.
• Anterior urethral strictures are caused by congenital mucosal anomalies, traumatic scar, hypospadias failure, LS or urethral ischaemia.
• In the navicularis and penile urethra, the surgical technique for urethroplasty is selected according to the cause of the stricture; in the bulbar urethra the surgical technique is selected according to the length of the stricture.
• The urethral plate may be useful for a onestage augmentation urethroplasty, with graft or flap.
• The urethral plate may be removed and replaced by using a staged substitution urethroplasty, with a buccal mucosa graft or mesh graft.

 

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