There are many management options for patients with urethral stricture disease. Regarding strictures of the bulbar urethra, ideal management strategies remain controversial. This article reviews important anatomic principles for surgeons to consider when repairing bulbar urethral strictures. Specific presenting features of a bulbar urethral stricture that can serve as a guide for the optimal surgical approach are described. Patient characteristics that are important and may have an impact on the outcome of repair are discussed. The optimal repair of a bulbar urethral stricture should be guided by anatomic principles and scientific evidence, leaving room for individualized therapy and surgeon preference.
Key points
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Oral mucosa is the most common and versatile substitution material available today for urethral repair.
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The success rate of excision primary anastomosis has been reported to be excellent (can exceed 90%). It should be considered the optimal treatment of short bulbar urethral strictures.
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If the stricture length, cause, and/or patient characteristics necessitate substitution urethroplasty, the surgeon can choose from a variety of techniques for a bulbar urethral stricture.
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Patients should be surgically managed based on their individual circumstances. Surgeons should choose a familiar surgical approach that is based on a patient’s clinical characteristics.
Introduction
It is difficult to make best clinical practice recommendations on the management of urethral stricture disease. There is a lack of evidence to allow definitive recommendations regarding which circumstances to perform a particular urethroplasty technique. The management of bulbar urethral stricture disease remains a source of controversy and depends on the characteristics of the urethral stricture as well as patient characteristics and surgeon preference. Among bulbar urethral strictures, a buccal graft can be used or the urethra can be excised and primarily reanastomosed. These 2 options do not exist in the penile urethra, because excision and primary anastomosis of the urethra is contraindicated. As such, the aim of this review is to describe the various surgical techniques of bulbar urethral stricture surgery with associated outcomes and complications, with emphasis on individualized therapy.
Excision and primary reanastomosis (EPA) of a bulbar urethral stricture is the simplest surgical option; however, certain urethral strictures and patient characteristics demand the use of a graft or flap substitution. Several different grafts have been described, including penile skin, scrotal skin, extragenital skin, bladder mucosa, colonic mucosa and buccal mucosa. Initially, skin grafts or flaps were used for substitution bulbar urethroplasty; however, buccal mucosa grafts (BMGs) have since replaced skin grafts. The oral mucosa graft urethroplasty was first described by the Russian surgeon Kirill Sapezhko in 1890. Approximately 50 years later buccal mucosa was described for urethral repair, and another 40 years passed before this technique could be found in the literature again. Nowadays it is the most common graft used in urethral reconstruction.
A recent multi-institutional study on 466 patients found higher complication and restricture rates with skin flaps versus BMG for long strictures. The preference for buccal mucosa is due to its ease of harvest, reliable take, and few donor site complications; hence, it can be considered the gold standard for substitution urethroplasty. The BMG has a dense capillary network in the submucosa. Through imbibition and inosculation from the graft bed, BMGs are incorporated into the surrounding tissue. Because the BMG initially depends on nutrients and revascularization from the surrounding tissue, it is important to provide a healthy and vascularized recipient site for successful graft take.
Introduction
It is difficult to make best clinical practice recommendations on the management of urethral stricture disease. There is a lack of evidence to allow definitive recommendations regarding which circumstances to perform a particular urethroplasty technique. The management of bulbar urethral stricture disease remains a source of controversy and depends on the characteristics of the urethral stricture as well as patient characteristics and surgeon preference. Among bulbar urethral strictures, a buccal graft can be used or the urethra can be excised and primarily reanastomosed. These 2 options do not exist in the penile urethra, because excision and primary anastomosis of the urethra is contraindicated. As such, the aim of this review is to describe the various surgical techniques of bulbar urethral stricture surgery with associated outcomes and complications, with emphasis on individualized therapy.
Excision and primary reanastomosis (EPA) of a bulbar urethral stricture is the simplest surgical option; however, certain urethral strictures and patient characteristics demand the use of a graft or flap substitution. Several different grafts have been described, including penile skin, scrotal skin, extragenital skin, bladder mucosa, colonic mucosa and buccal mucosa. Initially, skin grafts or flaps were used for substitution bulbar urethroplasty; however, buccal mucosa grafts (BMGs) have since replaced skin grafts. The oral mucosa graft urethroplasty was first described by the Russian surgeon Kirill Sapezhko in 1890. Approximately 50 years later buccal mucosa was described for urethral repair, and another 40 years passed before this technique could be found in the literature again. Nowadays it is the most common graft used in urethral reconstruction.
A recent multi-institutional study on 466 patients found higher complication and restricture rates with skin flaps versus BMG for long strictures. The preference for buccal mucosa is due to its ease of harvest, reliable take, and few donor site complications; hence, it can be considered the gold standard for substitution urethroplasty. The BMG has a dense capillary network in the submucosa. Through imbibition and inosculation from the graft bed, BMGs are incorporated into the surrounding tissue. Because the BMG initially depends on nutrients and revascularization from the surrounding tissue, it is important to provide a healthy and vascularized recipient site for successful graft take.
Anatomic considerations
To make appropriate reconstructive decisions, it is mandatory to understand the anatomy of the bulbar urethra that is positioned between the distal penile urethra and more proximal membranous urethra. The bulbar urethra is part of the anterior urethra and is surrounded by vascularized corpus spongiosum that is covered ventrally by the bulbospongiosus muscle. At the bulbar urethra, the lumen is located dorsally and not centrally, rendering the corpus spongiosum thick on the ventral surface and thin on the dorsal surface ( Fig. 1 ). The corpus spongiosum serves as a vascularized mechanical support for substitution grafts, especially with ventral grafting. The spongiosum may not be sufficient for mechanical support, which can lead to sacculation if a ventral graft is used.
The internal pudendal artery is the primary source of blood supply to the penis. The internal pudendal artery branches to the inferior rectal, posterior scrotal, and penile arteries. The penile artery subsequently branches into the dorsal, bulbar, and cavernosal arteries ( Fig. 2 ). The bulbar urethra travels in the deep perineal space to supply the corpus spongiosum and urethra. The bulbar artery connects to the dorsal penile artery at the glans penis, allowing the urethra to get antegrade and retrograde blood supply. The dorsal penile artery runs along the dorsum of the penis and supplies the penile skin, fascia, and glans penis. As the dorsal artery travels distally along the penis, circumflex arteries periodically branch off laterally to supply the corpus spongiosum. The cavernosal artery is an end artery that supplies the corpus cavernosum. It is critical to understand the implications of penile dissection and urethral mobilization. If the urethra is mobilized off the corpora cavernosa (as with a dorsal onlay BMG urethroplasty or after urethral mobilization for EPA urethroplasty), the circumflex arterial supply can be impaired. Likewise, transection of the bulbar urethra and spongiosum (as with an EPA or augmented urethroplasty) can result in loss of antegrade blood flow to the urethra distal to the transection. Fortunately, retrograde blood flow from the dorsal penile artery and circumflex blood vessels can provide arterial blood supply. Excessive mobilization of the penile urethra, a hypospadiac deformity, and distal spongiofibrosis compromise the retrograde flow derived from the distal collaterals and may impair graft take or lead to stricture recurrence secondary to ischemia.
Several techniques have been described to preserve optimal blood supply. Jordan and colleagues have proposed a vessel-sparing approach to EPA urethral reconstruction to preserve the best vascularity. They preserved the bulbar arteries by dissecting them off the urethra ventrally and left the ventral corpus spongiosum intact ( Fig. 3 ). Even though they could not show superior outcomes concerning stricture patency, they were able to demonstrate that preservation of the blood supply was possible and may be considered as the preferred technique for patients with compromised vascularity and/or who might need adjuvant urethral surgery in the future (ie, artificial urinary sphincter).
Kulkarni and colleagues described the successful results of a 1-sided dorsal onlay graft technique, avoiding extensive, circumferential dissection of the urethra. It is a modification to the traditional dorsal onlay technique that involves a circumferential mobilization of the bulbar urethra. As a modification of this technique, they proposed to dissect only on 1 side of the urethra, preserving the lateral circumflex blood supply, central tendon of the perineum, and the bulbospongiosus muscle. The bulbospongiosus muscle can be split vertically when the stricture involves the bulbar urethra. The dorsal urethral dissection is carried out just past the dorsal midline, to make the dorsal urethrotomy and to quilt the buccal graft to the tunica albuginea overlying the corpora cavernosa. The Heineke-Mikulicz repair was described as an alternative to an EPA for very short strictures of less than or equal to 1 cm, with a wide caliber and minimal fibrosis. The urethra is not transected as with a traditional EPA, but a longitudinal stricturotomy is made and closed transversely, keeping the retrograde blood flow intact.
Innervation of the bulbar urethra and bulbospongiosus muscle is also important for surgical outcomes. Previous research has revealed that branches of the perineal nerve do extend into the bulbospongiosus muscle. Therefore, impaired nerve function from a bulbar urethroplasty with the standard approach of transection of the bulbospongiosus muscle potentially explains the loss of the bulbar contractions needed for efficient semen emission and could lead to postvoid dribbling. A bulbospongiosus muscle-sparing approach for the bulbar urethroplasty has been described, leaving the lateral muscle attachments and central tendon intact and thereby preserving the perineal nerves. None of the patients in a comparative study of the impact of bulbospongiosus muscle-sparing surgery to transection of this muscle reported a decreased force of semen emission, and none complained of postvoid dribbling. With division of the bulbospongiosus muscle, the investigators reported sluggish ejaculation in 20% and postvoid dribbling in 50%. A randomized study of the effect of bulbospongiosus muscle transection versus preservation during bulbar urethroplasty was subsequently performed in an attempt to replicate these findings. The investigators did not note an impact on ejaculatory function or postvoid dribbling. This study was small and may have had limited power to assess a difference. Further study is needed to assess if bulbospongiosus muscle-sparing surgery provides benefit to any particular patient populations.
Bulbar urethral stricture characteristics
Anatomic considerations are the cornerstone for all surgical interventions; however, the presenting features of the stricture and patient characteristics play an important role in surgical decision making.
Stricture Length
Not all bulbar urethral strictures are the same and much of the treatment decision depends on length and etiology. Stricture length is one of the characteristics that has a great impact on reconstruction choice. Previously, short strictures of 1 cm were considered amenable to an EPA, whereas strictures longer than 1 cm were traditionally treated with substitution urethroplasty. The rationale was to avoid tension on the anastomosis leading to stricture recurrence and possible penile curvature and shortening. With passage of time, the accepted limits to EPA urethroplasty have expanded. Morey and McAninch proposed a stricture length of 2.5 cm to be considered for EPA, and thereafter several studies have reported acceptable outcomes with excision of isolated bulbar strictures up to 4.5 cm.
It is theorized that more proximal bulbar urethral strictures can be excised in longer lengths without jeopardizing the antegrade blood flow to the most distally transected portion of the urethra; however, there is a limit to the length of urethra that can be safely transected, because unintended consequences can occur. Tension on the reanastomosed urethra after EPA repair can lead to penile curvature after excessive urethral excision. When performing an EPA, the entire stricture needs to be excised, leaving only healthy urethra for planned reanastomosis ( Fig. 4 ). A tension-free anastomosis can usually be achieved, and urethral mobilization to the penoscrotal junction can be used to enable a tension-free anastomosis. Only rarely is it necessary to split the corporal bodies to achieve tension-free urethral continuity. Using these techniques, EPA repair can be highly successful with a low complication rate. The Société Internationale d’Urologie with the International Consultation on Urological Diseases published a literature review on primary anastomosis anterior urethroplasty and reported a success rate of 93.8% and a negligible effect on sexual function.
Although EPA urethroplasty has the highest success rate for bulbar strictures, substitution urethroplasty with buccal mucosa has a considerably high success rate as well, approximately 85% to 90%. In contrast to EPA repair, substitution urethroplasty has a steady failure rate that increases over the years. Previous reports examining long-term success at 5-year, 10-year, and 15-year periods noted restricture results that were 12%, 13%, and 14% for anastomotic repairs and 21%, 31%, and 58% for substitution urethroplasty, respectively.
When the urethral stricture is too long for an EPA repair, the options then include stricture incision with substitution graft onlay (ventral, dorsal or lateral), graft inlay (Asopa or Palminteri), or an excision with an augmented roof strip ( Figs. 5–8 ). Before the introduction of the dorsal onlay technique by Barbagli in 1996, bulbar strictures were traditionally repaired with a ventral stricturotomy and graft onlay (see Fig. 5 ). The dorsal onlay has gained widespread acceptance with suggested benefits of less bleeding from the thinner dorsal spongiosum and more stable fixation of the graft to the corpora cavernosa, providing a nourishing graft bed, the potential for proximal and distal extension of the urethrotomy, and theoretically limited sacculation (see Fig. 6 ). Nevertheless, the ventral onlay should be considered for proximal bulbar strictures when there is limited spongiofibrosis, because the ventral approach can provide better exposure. Additionally, when dealing with radiation-induced strictures or particularly high-risk patients with long strictures, a ventral BMG maybe the best choice, because it can be supported by a gracilis muscle flap, giving the BMG a healthy graft bed. The lateral onlay was described in 2005 and theorized that it may be useful for patients who would have significant bleeding with the ventral approach or for patients whose erectile function may be adversely affected by dorsal dissection (see Fig. 7 ). The lateral approach has only been described in a handful of patients and is used infrequently, likely because of a lack of advantage over the other onlay techniques.
Related posts:
Management of Urethral Strictures
Definition of Successful Treatment and Optimal Follow-up after Urethral Reconstruction for Urethral Stricture Disease
Cost-effective Strategies for the Management and Treatment of Urethral Stricture Disease
Management of Panurethral Stricture
Treatment of Radiation-Induced Urethral Strictures
Effect of Lichen Sclerosis on Success of Urethroplasty
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