Anterior Urethral Stricture Disease

HUNTER WESSELLS

Urethral strictures have plagued men since antiquity, with descriptions in Indian literature dating as far back as 1000 BC. (1). The presentation of urethral stricture disease differs based on geographical, population, patient, and environmental factors, including prevalence of sexually transmitted infections, occupation of the workforce, and sophistication of health care systems (2). Despite etiologic variation, strategies to care for men with anterior urethral strictures depend less on pathophysiologic mechanism and more on accurate determination of the anatomic characteristics of the stricture including its location, length, luminal diameter, and previous treatment. The concept of a reconstructive ladder, in which progressively more invasive interventions are applied one after the other (3), has been supplanted by an individualized approach in which the best treatment for the stricture is delivered based on anatomic characteristics and probability of recurrence after treatment. Urethral stricture remains the province of surgeons, although innovations in stent technology and regenerative medicine (4,5) may one day allow treatment by minimally invasive proceduralists. Until that time, the care of patients with stricture disease requires a comprehensive and technically complex series of strategies to address the problems of poor tissue vascularization, prior irradiation, and spongiofibrosis; comorbid medical conditions; deficiencies in genital skin; and the unfortunate effects of repeated dilations or urethrotomies applied when success is unlikely (3).

This chapter summarizes the author’s approach to the evaluation and treatment of anterior urethral stricture disease, with a focus on management across a spectrum of stricture complexity. The reader is encouraged to review the in-depth treatment of the subject in the International Consultation on Urethral Strictures (6) convened and published under the joint sponsorship of the Societe Internationale d’Urologie and the International Consultation on Urological Disease.

EPIDEMIOLOGY AND PATHOPHYSIOLOGY

Anterior urethral strictures are uncommon, accounting for approximately $200 million in direct medical costs per year (2). The average use rate for outpatient visits for stricture disease was approximately 274 visits per 100,000 U.S. population (range 200 to 1,200). Rate of utilization varies by healthcare context, age, ethnicity and other factors: reports among Veterans, Medicare beneficiaries, and the younger commercially insured population differ considerably (2,7,8). Although uncommon, treatment is costly, with strictures being responsible for incremental cost of treatment equaling $6,759 per patient. Additional economic impact of stricture disease derives from the fact that 25% of patients will miss work because of treatment (2).

The etiology of contemporary urethral stricture disease can largely be divided into traumatic, iatrogenic, inflammatory, and idiopathic (9). Pathophysiology will vary by age. Younger men will be more likely to have anterior urethral strictures due to straddle injury or complications from hypospadias surgery, whereas older patients will more likely suffer as a result of prior transurethral instrumentation. Of note, treatment for gonococcal urethritis with penicillin-based antimicrobial agents has effectively eradicated the complex debilitating bulbar urethral strictures previously associated with this disease. However, the emergence of multiply resistant strains of Neisseria gonorrhoeae may lead to resurgence in these cases worldwide. Lichen sclerosis (also known as balanitis xerotica obliterans) represents a particularly challenging cause of stricture disease with involvement of genital skin, progression to panurethral disease, and association with comorbidities such as obesity, which complicate treatment and surgery (10).

EVALUATION OF URETHRAL STRICTURE DISEASE

A careful history and physical examination allow the urologist to develop a reasonable understanding of the cause and possible complicating factors of an anterior urethral stricture. Urinary symptoms are the most common cause for presentation, with a reduction in the force of the urinary stream being characteristic. Both obstructive and irritative voiding occurs as a result of stricture disease, and thus questionnaires such as the American Urological Association (AUA) Symptom Index (11), which document these symptoms, have been used in characterizing and quantifying the severity of symptoms. However, these patientreported outcome measures were not developed to identify the most relevant symptoms in men with stricture disease and do not necessarily address other domains of importance such as penile curvature, ejaculatory dysfunction, urinary incontinence, bother and impact, or responsiveness to treatment. Development of new instruments is an important need for the field (12,13).

Elements of the past history relevant to the cause of stricture and success of urethroplasty include presence of comorbid conditions such as obesity, diabetes mellitus, or severe peripheral vascular disease. A detailed surgical history is essential because of the potential for a stricture to develop as a result of endoscopic surgical manipulation such as transurethral resection of the prostate (14); abdominal perineal resection; and obvious etiologies such as previous urethroplasty, previous hypospadias surgery, or traumatic injuries to the penis or
urethra. The personal and social history should be probed for evidence of cigarette smoking, which may significantly impair wound healing (15); long-distance bicycle riding or other sports leading to straddle injury; and risk factors for sexually transmitted infections. A complete review of systems is necessary to identify potentially significant conditions requiring assessment prior to surgery and anesthesia.

The physical examination focuses on the abdominal and genital region. Examination should assess potential bladder distention, presence of previous suprapubic cystostomy, hernia, and other abdominal scars. The phallus should be examined to determine whether the patient has been circumcised, or whether there is sufficient redundant shaft skin to allow creation of a penile skin flap, either circumferentially, based on the distal shaft skin, or longitudinally, based on a ventral skin island. The urethral meatus should be examined for stenosis and the surrounding skin of the glans for signs of lichen sclerosis. A shiny pallor of the glans and/or prepuce is characteristic. The corpus spongiosum should be palpated along its length to identify areas of intense stricture, abscess, or constriction. The scrotum and its contents should be examined. Hair distribution on both the penile shaft and the scrotum should be recorded when skin flaps are considered. Although scrotal skin flaps are no longer commonly used for urethral reconstruction, laser hair removal or other forms of epilation allow scrotal skin to be used in selected circumstances. Perineal and rectal examinations complete the pertinent regions of interest.

Laboratory studies are used selectively to identify associated urologic conditions including urinary tract infection and renal insufficiency. A urinalysis with microscopic evaluation will detect hematuria, pyuria, and bacteriuria. Because urethral strictures frequently cause microscopic hematuria, complete workup is not generally pursued unless persistent. Serum creatinine is not indicated unless signs of poor bladder emptying suggest a risk for renal deterioration.

Noninvasive urodynamic studies are a valuable adjunct to the assessment of urinary symptoms. Uroflowmetry provides a quantitative estimate of the degree of obstruction, which along with postvoid residual urine volume provides a gauge of the severity of urethral narrowing and efficiency of voiding. More formal pressure flow urodynamic studies are only indicated for the evaluation of complex cases. When concomitant prostatic obstruction and urethral narrowing are found, video urodynamics may successfully distinguish the anatomic point of obstruction.

Radiographic Studies

Contrast studies of the urethra are the cornerstone of appropriate and individualized management. The combination of retrograde urethrogram and voiding cystourethrogram allows appropriate delineation of the anterior urethra, accurate assessment of the length of the stricture and narrowing of the urethra, as well as the dynamic understanding of urethral caliber and function above the point of obstruction. Techniques for retrograde and voiding urethrography are beyond the scope of this chapter (16). However, several points require elaboration. A retrograde urethrogram is performed by positioning the patient obliquely at 45 degrees with the bottom leg flexed at the knee and the top leg kept straight.

FIGURE 39.1 A: Retrograde urethrogram showing apparently short bulbar stricture. B: Intraoperative sonourethrogram showing corresponding length and narrowness of stricture demonstrating a 1.21-cm long stricture.

A 12Fr Foley catheter, Brodney clamp, or catheter-tipped syringe is introduced into the fossa navicularis, the penis is placed on gentle traction and 20 mL undiluted water soluble contrast material is injected. Retrograde urethrogram can underestimate the length of bulbar urethral strictures, potentially due to inadequate rotation or stretch of the penis (Fig. 39.1). The penis must be adequately stretched so that the pendulous portion of the penile urethra and the penoscrotal junction are appropriately visualized (Fig. 39.2). Voiding cystourethrography requires that the bladder be filled by retrograde instillation of contrast (Fig. 39.3), which may be challenging if the stricture is very stenotic or the external sphincter is tightly contracted.

Ultrasonography represents an adjunct to fluoroscopic modalities to assess anterior urethral strictures (17). Usually performed intraoperatively, the technique can clarify stricture length when upstream imaging is not possible on voiding cystourethrogram (VCUG), or when rotation of the patient impedes accurate measurement of the length of the stricture (see Fig. 39.1B). Additionally, estimation of the inner diameter of the urethral lumen can aid in deciding whether to perform excision and anastomosis of a portion of a longer stricture as part of augmented anastomotic urethroplasty (vide infra).

Endoscopic Studies

Cystoscopic evaluation of urethral stricture disease has a limited role in the diagnostic protocol. It serves an important initial evaluation of men with suspected urethral stricture disease,
identifying the distalmost portion of the stricture. However, it cannot determine the length of the stricture nor assess the urethra proximal to the stricture. Further endoscopic evaluation is best reserved for several scenarios. An example is a stricture that cannot be fully visualized due to lack of retrograde filling of the urethra by obliteration or sphincteric spasm during the study. Specialized endoscopes such as a pediatric cystoscope or 8Fr ureteroscope can be used to examine strictures under these circumstances. Another indication is a rare case in which physical examination or other factors raise the suspicion of urethral cancer.

FIGURE 39.2 Retrograde urethrogram showing short stricture of penile urethra well visualized because of adequate rotation and stretch of urethra.

FIGURE 39.3 VCUG showing long penile urethral stricture. Note prostatic urethra narrowed because of concomitant benign prostatic hyperplasia.

RECONSTRUCTIVE PRINCIPLES

Urethral reconstructive surgeons need to maintain an array of skills to allow transition from simple to more complex reconstructive strategies during the course of a surgical case. An apparently simple stricture will occasionally require more complex care than anticipated prior to surgery. For example, preoperative imaging of a bulbar stricture may underestimate its length, so that an initial anastomotic approach must be supplanted by free graft substitution urethroplasty, based on intraoperative findings, patient anatomy, and other factors. Similarly, a straightforward 3- or 4-cm bulbar urethral stricture, normally treated with ventral or dorsal onlay substitution urethroplasty, may in fact require staged approaches or additional grafts or skin flaps. Thus, it is only appropriate to embark on urethroplasty if one can offer the patient all necessary options and bring all appropriate techniques to the surgical procedure.

The key techniques include endoscopic incision; anastomotic techniques; dorsal and ventral substitution; free graft donor options including full thickness and split thickness skin, oral mucosa, and bladder epithelium; skin flap urethroplasty from penile or scrotal skin; local tissue rearrangement in the form of advancement flaps (YV-plasty, Z-plasty); and flaps for defect coverage such as gracilis muscle or smaller flaps such as dartos and tunica vaginalis.

Internal Urethrotomy

Internal urethrotomy is an important technique for the reconstructive urologist, based on the principle of healing by secondary intention described by Davis for ureteral strictures (18). Sachse (19) applied the concept to urethrotomy, using a cold knife to precisely incise the urethral epithelium under direct vision. Although few strictures are cured with direct vision internal urethrotomy (DVIU), recurrent strictures after urethroplasty can often be effectively treated by DVIU. In cases involving a prior flap or graft, or prior hypospadias surgery, techniques have been modified to create multiple shallower radial incisions (20).

Anastomotic Techniques

Excision and reanastomosis is an essential tool for anterior and posterior urethral reconstruction. Knowledge of the anatomy of the corpus spongiosum (Fig. 39.4) is essential to safely take advantage of the antegrade and retrograde blood supply provided by the bulbourethral and dorsal arteries, respectively (21). The ability to mobilize the urethra, excise portions of it, and reapproximate underlies successful primary anastomosis as well as a variety of augmented approaches (22) in which excision of a portion of the stricture, and reanastomosis, is combined with tissue transfer using a graft or flap (23). In addition to preservation of the longitudinal intrinsic blood supply of the corpus spongiosum, anastomotic urethroplasty requires assessment of the appropriate degree of tension that may be placed on the anastomosis. A rule of thumb in the bulbar urethra is that strictures 1 to 2 cm in length can be bridged with excision and primary anastomosis (EPA). This assumes that the remaining urethra is normal, compliant, and able to undergo elongation to bridge a gap. In cases of proximal bulbar
strictures, the uninvolved urethra, if completely normal, may be capable of significant elongation beyond 2 cm (24). The ability to reduce the gap between the ends of the urethra is dictated in part by the location of the gap. In the more proximal bulbar urethra, division of the corporal bodies is a maneuver to reduce the distance between the two ends for tension-free anastomotic urethroplasty. With longer strictures associated with spongiofibrosis of significant portions of the urethra, the behavior of the remaining urethra under stretch may be different. It may not be possible to bridge a 2-cm defect. Thus, augmented anastomotic approaches typically involve excision of shorter portions of the urethra. Likewise, in the penile urethra, the elasticity of the urethra is significantly less, and only short defects can be bridged with EPA.

FIGURE 39.4 Blood supply of penis and urethra. (Reprinted with permission from Jordan GH, McCammon KA. Surgery of the penis and urethra. In: Wein AJ, ed. Campbell-Walsh Urology, 10th ed. Philadelphia: Saunders/Elsevier, 2011. Copyright © 2011 Elsevier Health Science Books.)

Free Grafts

Free grafts have been used for reconstruction of complex anterior urethral strictures since the 1960s (25). Full-thickness skin grafts from the prepuce or penile shaft fare well in substitution urethroplasty, although early indications for severe complex strictures exceeded the limits of the technique. The evolution of stricture etiology away from gonococcal infection, with its severe spongiofibrosis, to less complex strictures supports the greater use of free grafts. No prospective study has definitively shown inferiority of full-thickness genital skin to oral mucosa, although a recent meta-analysis found higher odds of recurrence with penile skin (26). Nevertheless, the ease of harvesting, suppleness of the oral tissues, intrinsic acceptance of the moist environment, lesser donor site morbidity, and other factors accelerated the adoption of buccal mucosa as the preferred free graft for substitution urethroplasty. Use of bladder epithelium and full-thickness skin should be considered for specific cases in which pathology of the oral mucosa, paucity of donor sites within the oral cavity, or other factors make oral mucosa unavailable. With any free graft, donor site morbidity and characteristics of the graft must be taken into account in a surgical plan. For example, defatting a full-thickness skin graft is straightforward: Shiny undersurface of the dermis allows for simple and rapid defatting. In contrast, the buccal mucosa harvesting as reported in the literature invites greater variation in technique, for example, relating to the depth of defatting that occurs (27). Such factors may affect outcomes of graft take. Lastly, bladder mucosa has a very thin lamina propria and is extremely pliant, making it unsuitable for meatal reconstruction or staged procedures with exteriorization of the neourethra. Full-thickness skin from the genitalia is relatively thin yet nevertheless does not suffer from substantial contraction. In contrast, split-thickness skin grafts will contract more significantly, limiting their application in all but the most severe and complex reconstructive scenarios.

Skin Flaps

Vascularized skin flaps, once a workhorse of anterior urethroplasty, have become less prevalent due to the increased adoption of buccal mucosa free graft urethroplasty, rise in prevalence of strictures related lichen sclerosis, and lack of sufficient genital skin in many circumcised men. Nevertheless, the island skin-flap approach to urethroplasty remains important, particularly in reoperative cases with extensive spongiofibrosis and poor graft fed characteristics (Fig. 39.5), such as postirradiation, posttraumatic, or postinfectious scenarios (28). Whether a circumferential distal penile flap (e.g., circular fasciocutaneous flap) or a longitudinal ventral flap, the principles are similar. A paddle of skin, which will not contract, is marked out on stretch, so that the exact dimensions of the flap are cut and used during the surgery. Preservation of the pedicle and its blood supply is based on the tunica dartos, either through random vascularity or a specific pedicle. Adequate mobilization of the pedicle is required to transfer the tissue into the appropriate recipient site, whereas preservation of the intrinsic blood supply of the overlying shaft skin prevents necrosis or complications of the donor site. Circular distal flaps (29), whether harvested from the prepuce (uncircumcised) or the distal shaft skin (circumcised), allow up to 15 cm length of skin to be transferred and create a pedicle which can reach all the way into the perineum for the very most proximal bulbar, membranous, and prostatic strictures.

FIGURE 39.5 Retrograde urethrogram showing severe stricture within metallic stent in the proximal bulbar urethra of a previously radiated patient. The stricture was treated with stent removal and skin flap urethroplasty.

FIGURE 39.6 Algorithm for the management of anterior urethral stricture. DVIU, direct vision internal urethrotomy; EPA, excision and primary anastomosis; RUG, retrograde urethrogram; VCUG, voiding cystourethrogram.

Flaps for Coverage

In cases of primary urethroplasty, adjacent tissue such as the tunica dartos or bulbospongiosus muscle can provide for graft vascularization and protection against urethrocutaneous fistulization. However, with reoperative surgery, staged surgery, or other cases in which the graft bed is compromised, the urethra lacks coverage options locally. Due to space constraints on the penile shaft, less bulky coverage flaps such as tunica dartos or tunica vaginalis are required. A potential obstacle to the use of dartos is previous hypospadias surgery. The rearrangement of skin and underlying dartos presents particular technical challenges to mobilization, although these can be successfully navigated (29). For such patients, rearrangement of the tunica vaginalis of the scrotum to bring it up alongside the penile urethra may be the best option (30). In contrast, the perineum can accommodate placement of a gracilis muscle flap in cases of extreme tissue deficit or postradiation cavities.

PREOPERATIVE AND INTRAOPERATIVE DECISION MAKING

Patient and stricture characteristics dictate the surgical approach necessary to achieve the desired outcome for an individual patient. Except in cases of strictures complicated by urinary retention and/or urethral obliteration, the decision to proceed with urethroplasty versus another approach to a specific urethral stricture is heavily driven by patient expectations and goals. In young men, one may recommend definitive procedures to achieve complete resolution of urinary symptoms, whereas in elderly or debilitated patients, strictures are more likely to be managed in an expectant or “custodial” manner. In all cases, the individual patient goals and circumstances will necessarily be considered.

A brief algorithm for the treatment for urethra strictures is shown in Figure 39.6. For a first-time bulbar stricture less than 1 cm in length, a cost-effectiveness perspective indicates that a single attempt at DVIU is usually recommended prior to urethroplasty (31). The success rates for dilation or internal urethrotomy for short bulbar strictures ranges from 30% to 80% (see summary in Wright et al. [31]) and our approach is, under most circumstances, to proceed with DVIU. Exceptions include individuals in whom a prior straddle injury, and its associated full-thickness spongiosal fibrosis, makes the probability of success with DVIU much lower (Fig. 39.7).

FIGURE 39.7 Short very narrow stricture after straddle injury not suitable for DVIU.

FIGURE 39.8. A and B: Penile urethral stricture due to instrumentation (same as Fig. 39.2) causing chordee treated in this case with skin flap urethroplasty (and penile plication for curvature). C: Arrow shows pedicle of flap rotating around base of penis. Dorsal onlay substitution with free graft could also be considered.

Bulbar urethral strictures between 1 and 2 cm in length are optimally treated with EPA, yielding success rates >95% (31). DVIU for a 2-cm bulbar stricture is very unlikely to yield a successful outcome and theoretically can change the stricture from one amenable to EPA, with overwhelmingly successful outcomes, to a longer stricture requiring substitution. Thus, these individuals should proceed to urethroplasty except under exceptional circumstances. A variety of centers have advocated for alternative surgical approaches to these short strictures, such as “nontransecting bulbar urethroplasty” based on the rationale that the odds of erectile dysfunction after EPA is higher than after substitution urethroplasty (32,33). These reports, however, do not contain sufficient evidence to counterbalance the success of EPA and the generally accepted low rate of erectile dysfunction after urethroplasty, which was 1% in a recent meta-analysis (34).

Only gold members can continue reading. Log In or Register to continue