of Transection and Anastomosis in Bulbar Urethral Reconstruction

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© Springer Nature Switzerland AG 2020
F. E. Martins et al. (eds.)Textbook of Male Genitourethral Reconstructiondoi.org/10.1007/978-3-030-21447-0_15



15. Role of Transection and Anastomosis in Bulbar Urethral Reconstruction



Jason P. Joseph1  , Allen F. Morey2   and Boyd R. Viers1  


(1)
Department of Urology, Mayo Clinic, Rochester, MN, USA

(2)
Department of Urology, University of Texas Southwestern, Dallas, TX, USA

 



 

Jason P. Joseph



 

Allen F. Morey



 

Boyd R. Viers (Corresponding author)



Keywords

Urethral strictureBulbar urethroplastyEPAAnastomotic urethroplasty


15.1 Etiology of Bulbar Urethral Strictures


The incidence of male urethral stricture disease is greatest in the bulbar urethra, comprising at least 47% of all strictures treated [1, 2]. It is therefore important for the reconstructive urologist to become familiar with effective and durable treatment solutions for bulbar urethral stricture disease. We favor the technique of excision and primary end-to-end anastomosis (EPA) whenever possible.


Contemporary series suggest the four most common stricture etiologies include idiopathic (37%), iatrogenic (28%), post-traumatic (15%), and inflammatory (11%), the latter including lichen sclerosis [1, 36]. While idiopathic urethral strictures remain poorly understood, they tend to be found in the bulbar urethra (91%), relatively short (60% ≤ 2 cm), and associated with a remote history of repetitive trauma [3]. These findings suggest that the most common etiology of bulbar urethral stricture disease, idiopathic strictures, may be the eventual consequence of unrecognized urethral injury and activities associated with repetitive subacute perineal trauma such as cycling, motocross, and horseback riding [3, 7]. Fortunately, idiopathic urethral strictures tend to be associated with excellent reconstructive success (>95% five year success) after urethroplasty [4].


Iatrogenic anterior urethral strictures are most commonly associated with previous endoscopic instrumentation, particularly transurethral resection (TUR), and prolonged urethral catheterization [6, 8]. Additional iatrogenic risk factors include prior pelvic radiotherapy and hypospadias surgery. Iatrogenic strictures more frequently occur in the penile urethra, though lesions in the bulbar urethra – specifically the bulbopendulous and bulbomembranous junction – may be amenable to anastomotic urethroplasty [6].


Acute traumatic strictures of the bulbar urethra most often occur following a straddle injury, during which blunt perineal trauma causes compression of the urethra against the pubic symphysis. This leads to some combination of loss of urethral continuity, urine extravasation, and hemorrhage, thereby precipitating inflammation and spongiofibrosis [9]. Patients may present with history of acute perineal trauma, inability to void, and blood at the urethral meatus. Resultant bulbar urethral strictures are commonly focal and obliterative in nature, often with complete transmural spongiofibrosis . These patients have excellent results with delayed primary anastomotic urethroplasty following a period of urethral rest.


15.2 Patient Selection


To optimize success and minimize risk of morbidity, appropriate patient selection is paramount. The technical objectives of anastomotic urethroplasty include complete excision of the diseased segment with formation of a wide spongiosal sparing anastomosis. A 1 cm spatulation of both proximal and distal segments can help facilitate formation of a wide (>26 Fr), oblique anastomosis, thereby reducing the risk of annular retraction and stricture recurrence. When considering the length of the excised segment, as well as the degree of proximal and distal mobilization needed to facilitate a spatulated, tension-free anastomosis, stricture length, location, and degree of spongiofibrosis are the most important considerations.


The penile urethra lacks elasticity, has a paucity of ventral spongiosum, and obtains substantial collateralizing blood supply from perforating vessels along the corpora cavernosa. These characteristics in combination with the often lengthy and multi-focal nature of penile urethral stricture disease limit the use of anastomotic urethroplasty techniques. In highly select men with focal (<1 cm) obliterative strictures of the proximal penile urethra, primary excision, distal bulbar urethra mobilization, and reanastomosis may provide a durable reconstructive solution without a detrimental impact to sexual function [10]. Nonetheless, despite a possible evolving role for EPA in highly selected men with focal penile urethral strictures, this is uncommon in practice, and therefore will not be discussed here in detail.


With adequate mobilization of the bulbar urethra, proximally to the membranous urethra and distally to the penoscrotal junction, a tension-free primary anastomosis can be performed to bridge sizeable defects. Urethral elongation relies upon the natural elasticity bulbar urethra where there is robust, well vascularized, and redundant ventral spongiosum. Importantly, bulbar strictures amenable to EPA depend not only on stricture length but also on the relative location. In general, strictures 2 cm or less are amenable to anastomotic urethroplasty at any location within the bulbar urethra. For lengthier strictures (3–5 cm), extended anastomotic urethroplasty can be performed for defects of the mid to proximal bulbar urethra with excellent outcomes [11]. Further, for men with greater than average stretched penile length (14 cm or greater) and strictures located in the mid to proximal perineum, tension-free extended anastomotic urethroplasty can be effectively performed for strictures exceeding 5 cm (Fig. 15.1) [12]. Conversely, in our analysis of 40 men with distal bulbar strictures and median stricture length of 3.75 cm, 90% of cases required augmentation with substitution techniques (graft or flap) based on the intraoperative determination that a tension-free primary anastomosis could not be achieved [11].

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Fig. 15.1

The proximal bulbar urethra is favorable for extended anastomotic urethroplasty for strictures up to 5 cm; the distal bulbar urethra is unfavorable for extended anastomotic urethroplasty and anastomotic urethroplasty in this location should be limited to strictures <2 cm; VM verumontanum


Despite a well-executed preoperative staging evaluation, the decision to proceed with EPA is finally determined with intraoperative assessment. Patients should be counseled that inability to effectively excise all scar and achieve a tension-free anastomosis may necessitate an augmented reconstruction with substitution techniques to optimize outcomes.


15.3 Preoperative Evaluation


Meticulous preoperative evaluation is necessary to facilitate surgical approach and optimize outcomes after anastomotic urethroplasty. A thorough preoperative evaluation consists of several clinical and radiographic considerations as described below.


15.3.1 History


History should include an assessment of urinary symptoms and sexual function, creating a documented baseline for postoperative comparison and to guide counseling on postoperative expectations. Standardized questionnaires (American Urological Association Symptom Index, International Index of Erectile Function, etc.) are useful to objectively quantify pre and postoperative urinary and sexual function.


While the majority bulbar urethral strictures are idiopathic, it is essential that the surgeon attempts to determine stricture etiology as this will influence candidacy for anastomotic urethroplasty and expected outcomes. Historical elements of significance include any prior perineal or pelvic trauma and relative timing, urinary tract instrumentation including urethral catheterization, and review of prior urologic and non-urologic surgeries, eliciting detail regarding any history of perioperative bladder catheterization or traumatic catheterization. Men with iatrogenic strictures abutting the membranous urethra following BPH surgery must be counseled that any EPA technique may predispose to de novo stress incontinence postoperatively. Additionally, men with inflammatory and radiation induced urethral stricture disease should be counselled on a greater incidence of stricture recurrence relative to those with idiopathic, iatrogenic, or traumatic stricture etiologies [3].


Urologic instrumentation history should be specifically evaluated, with special attention to history (including frequency and timing) of indwelling or intermittent catheterization, urethral dilation, internal urethrotomy, and prior stricture surgeries. Corresponding operative reports should be reviewed if available, as these procedures may have implications on anticipated anatomic relationships, vascular supply, and stricture complexity [13]. It is crucial to determine the timing of most recent urethral instrumentation. We suggest 6–8 weeks of “urethral rest” following any urethral intervention prior to preoperative staging and consideration of urethroplasty [14] in order to accurately characterize the urethral stricture.


Additional risk factors for impaired urethral perfusion should also be elicited, including history of diabetes mellitus, peripheral vascular disease, tobacco use, vasculogenic erectile dysfunction, or prior pelvic radiation. In patients with history of pelvic trauma, details regarding any prior pelvic angioembolization; compromise to even a unilateral internal pudendal artery, which gives rise to the ipsilateral dorsal, cavernous, and bulbar arteries, will have implications on anastomotic perfusion and erectile function postoperatively. Any neurologic disease or prior surgery (spine surgery, abdominoperineal resection, low anterior resection, etc.) placing the patient at risk for voiding and erectile dysfunction, should be noted.


15.3.2 Physical Examination


A focused genitourinary exam is crucial. Examination of the urethral meatus, fossa navicularis, ventral penile shaft, and perineum, both visually and by palpation, should enable documentation of phimosis, lichen sclerosis, prior scars, fistulae, erythema, or palpable induration, the latter frequently correlating with underlying spongiofibrosis. Testicular atrophy and general health of the surrounding genital tissue are a good indication of occult hypogonadism, a process that has been associated with urethral atrophy and decreased vascularity of the male urethra [15, 16]. Evidence and degree of stress urinary incontinence is useful to guide patient expectations postoperatively, direct operative approach (transecting vs non-transecting), and the need for future interventions which may require perineal dissection for male stress incontinence surgery. Chronic urine soilage of the perineum and intertriginous folds can be associated with fungal and/or bacterial infection, which may complicate incisional healing postoperatively. Stretched penile length (SPL) is useful to establish a baseline prior to reconstruction and guide patient selection for extended bulbar anastomotic urethroplasty, which is facilitated by increasing penile length [12].


BMI should be considered, as obesity can pose challenges in achieving adequate surgical exposure, increases the risk of positioning-related neuromuscular complications, and may be associated with increased likelihood of stricture recurrence [17]. Given the high lithotomy position which is required for bulbar urethral exposure, mobility of the bilateral lower extremities, particularly at the hips and knees, and neuromuscular function should be evaluated.


15.3.3 Radiographic and Endoscopic Evaluation


Radiographic and endoscopic evaluation provides the surgeon with an understanding of patient-specific urethral anatomy; this is crucial to appropriately select candidates for anastomotic bulbar urethroplasty. It is necessary to stop all urethral instrumentation for a period of time before surgical reconstruction. In men presenting with indwelling catheters, chronic intermittent self-catheterization, or recent endoscopic instrumentation (dilation, DVIU, etc.), we recommend suprapubic cystostomy or a trial of spontaneous voiding for at least 6–8 weeks to allow for scar maturation and stabilization, before stricture staging and definitive reconstruction [14].


A retrograde urethrogram (RUG) (Fig. 15.2) performed in the oblique position is necessary to define urethral anatomy and characterize stricture length, location, diameter, and density. Voiding cystourethrography (VCUG) is a useful staging adjunct that can often be performed simultaneously with RUG to more accurately characterize the proximal extent of disease [18, 19]. VCUG provides dynamic information regarding bladder capacity, vesicoureteral reflux, cystographic evidence of detrusor dysfunction, and bladder neck competency during both storage and voiding. For non-obliterative lesions, VCUG can be obtained after the bladder is sufficiently filled with contrast in a retrograde fashion. Retrograde passage of a small open-ended ureteral catheter into the bladder for contrast instillation for VCUG has been described, though we caution against this practice due to the theoretical risk of dilating and/or distorting the stricture. Finally, VCUG can be obtained using antegrade contrast instillation in patients with indwelling suprapubic catheters. When feasible, our preference is for combined RUG and VCUG to achieve a thorough, synergistic evaluation of the urethra.

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Fig. 15.2

Retrograde urethrogram demonstrating a focally high-grade 2 cm mid bulbar urethral stricture


Preoperative flexible urethroscopy is a useful tool to assess urethral anatomy , characterize stricture density, and identify any suspicious lesions that warrant biopsy. We reserve preoperative urethroscopy for those men with stricture recurrence following prior urethroplasty and those with rapid stricture recurrence following endoscopic management to rule out malignant transformation. Urethroscopy is useful to characterize the relationship between the stricture and the membranous urethral sphincter in those with prior bladder outlet surgery, as well as those men with prior radiation to assess adjacent urethral integrity and vascularity. In men with indwelling suprapubic catheters, antegrade cystourethroscopy can also be performed. While not routinely used in our practice, ultrasonography and MRI provide accurate stricture staging evaluation and may be useful adjuncts in the identification of associated pathology such as fistulae, diverticulae, abscesses, and false passages [19].


15.4 Presurgical Preparation


Prophylactic guideline specific parenteral antibiotics are administered prior to incision, and in men with positive preoperative urine cultures, targeted antibiotic therapy should be implemented. Men with incomplete bladder emptying, recent instrumentation, or indwelling suprapubic catheters, often have urinary bacterial colonization. In these patients, we prefer to initiate culture directed prophylaxis starting three days before surgery to sterilize the urine. For those men without such risk factors, we do not initiate preoperative antibiotic therapy, as prophylaxis administered the day of surgery is typically sufficient to prevent postoperative infection. Venous thromboembolism prophylaxis includes lower extremity sequential compression devices intraoperatively and early postoperative ambulation.


Positioning should foremost optimize patient safety, but also maximize technical ergonomics and surgeon comfort. Bulbar urethroplasty is best performed in a high lithotomy position , thereby rotating the pubic ring anteriorly and cephalad while providing excellent perineal exposure. This exposure can be further facilitated by with a slight Trendelenberg position. We utilize Yellofin stirrups with careful attention to lower extremity positioning, to reduce the risk of peroneal nerve compression injury. The patient’s buttocks is brought just beyond the end of the operating table to minimize distance between the surgeon and target anatomy, as well as to prevent interference between the operative table and the overlying drape or self-retaining retractor. The arms are secured to armboards with slight abduction and flexion at the elbow, reducing stretch on the brachial plexus. All pressure points are carefully are padded (Fig. 15.3).

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Fig. 15.3

Positioning for transperineal anastomotic bulbar urethroplasty


The risk of positioning-related complications , such as rhabdomyolysis, compartment syndrome, and peroneal neuropraxia, can be minimized by limiting the duration of exaggerated lithotomy positioning; these complications are uncommon when operative duration does not exceed 5 hours [20]. Relative to alternative reconstructive techniques, anastomotic urethroplasty of the bulbar urethra is a time efficient operation with operative times that rarely exceed 4 hours. Nevertheless, we recommend limiting the duration of high and exaggerated lithotomy positioning whenever possible. A low or standard lithotomy position may provide sufficient exposure for more distal bulbar lesions. In our practice during portions of the operation such as wound closure, where high lithotomy is not necessary, we routinely lower the legs into standard or low lithotomy position .


Using electric clippers, all hair is carefully removed from the perineal and genital region. Epidermal abrasions should be avoided as these may be a potential entry point for bacteria, thereby increasing the risk of surgical site infection. Chlorhexidine skin preparation is performed from the umbilicus to the mid-thigh, including the genitalia and perineum. The sterile field includes the suprapubic region to facilitate antegrade access if a suprapubic tube is in place, or in the event that one is needed.


We prefer a systematic approach to draping, which can help aid in surgeon orientation. Sterile blue towels are applied to “square” the field, and most notably the posterior towel is secured with staples immediately anterior to the anal verge, exposing the entirety of the perineum (Fig. 15.4). This allows the surgeon to maintain orientation in a plane of dissection that is parallel to the rectum when approaching the proximal bulbar urethra. On the contrary, more anterior towel placement without complete exposure of the perineum would require the surgeon to proceed in a plane obliquely towards the anterior rectal wall. The perineal drape is next secured to the underlying towels and the perineal skin with additional staples. A lithotomy drape with an integrated under buttocks pouch is an excellent system to effectively manage fluid spillage from the field.

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Fig. 15.4

The perineal drape is secured just anterior to the anal verge as shown, maintaining surgeon orientation during initial transperineal dissection in a plane parallel to the rectum


15.5 Operative Technique


Retrograde endoscopic evaluation with a flexible cystoscope allows for a final evaluation of the anterior urethra, and precise confirmation and localization of the distal aspect of the stricture. Aggressive attempts to negotiate the scope proximal to the stricture are not made, but if the surgeon is able to smoothly negotiate a 17 Fr cystoscope through the stricture without resistance, the procedure should be terminated. For non-obliterative strictures , proximal access is secured by passing a flexible guidewire (0.035 in. diameter) into the bladder. Palpating the wire can expedite initial perineal dissection, particularly in obese patients and reoperative fields. If the stricture is obliterative, intraoperative antegrade urethroscopy can facilitate localization of the proximal non-diseased urethra. We caution against the practice of only securing proximal access after transection for proximal bulbar lesions; in a bloody operative field this can be highly challenging, risking loss of tissue planes and potential adverse outcomes.


The cystoscope is removed and the safety wire is secured out of the field. A vertical midline incision is made sharply along the perineal raphe from the perineoscrotal junction anteriorly, and carried down to approximately 1 cm above the anal verge (Fig. 15.4). For mid to distal strictures where additional distal urethral mobilization may be needed, this incision can be extended anteriorly onto the base of the scrotum. We have abandoned use of the lamba incision for transperineal urethroplasty due to increased risk of postoperative wound complications [21]. The incision is deepened though the subcutaneous tissue with electrocautery, following which a self-retaining retractor is placed. We prefer use of the Lone-Star self-retaining retractor system (Cooper Surgical, Trumbull, CT, USA), and tend to place this promptly. Eight blunt hooks (sharp hooks for reoperative cases) are placed circumferentially, with laterally placed hooks applying excellent lateral traction thereby facilitating efficient electrocautery dissection through Colles fascia and the perineal fat down to the bulbospongiosus muscle. In men with an abundance of perineal or scrotal fat, it can be helpful to dynamically reposition the hooks and utilize small hand-held retractors as the dissection is deepened, maximizing visualization until there is satisfactory exposure. Two four-finger rake retractors are secured to the retractor at the 10 and 2 o’clock positions to elevate the scrotal contents out of the field.


The bulbospongiosus muscle is sharply divided in the midline (Fig. 15.5). Alternatives include lateral mobilization of the muscle, or dissection of the muscle away from the underlying spongiosum and retracting it proximally. We prefer a sharp midline division of the muscle and primary reapproximation during closure as it efficiently facilitates bulbar urethra visualization without evidence to suggest that doing so compromises antegrade ejaculation or causes urinary dribbling. Once the muscle is divided, the blunt hooks are repositioned to retract the muscle away from the underlying corpus spongiosum, as this facilitates further proximal dissection ventrally, including exposure of the proximal bulb and central tendon of the perineum (Fig. 15.6).

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Fig. 15.5

Sharp midline division of the bulbospongiosus muscle


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Fig. 15.6

Blunt hooks for the self-retaining retractor are repositioned, incorporating the divided bulbospongiosus muscle, facilitating exposure of the underlying corpus spongiosum


After complete ventral exposure of the bulbar corpus spongiosum , attention is turned to circumferential mobilization. Our approach is to sharply mobilize the lateral and dorsolateral attachments working from side-to-side, thus isolating the dorsal spongiosal attachments to the ventral corporal bodies. With care taken to avoid inadvertent corporotomy, a right angle is passed dorsally to complete focal circumferential mobilization, and a vessel loop is passed around the urethra. The vessel loop is dynamically retracted by the assistant to create atraumatic counter traction, facilitating ongoing sharp division of the dorsal septum and urethral lengthening proximally and distally (Fig. 15.7).

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Fig. 15.7

Following circumferential exposure distally, a vessel loop facilitates atraumatic retraction during additional proximal bulbar mobilization


The bulbar urethra should be mobilized to the penoscrotal junction within the avascular plane between Buck’s fascia and the tunica spongiosum. During the course of mobilization, should inadvertent corporotomy or entry into the spongiosal tunica occur, these can be primarily repaired with 4-0 polyglactin suture to control bleeding, which might otherwise impair intraoperative visualization or increase the risk of postoperative hematoma. For strictures at or proximal to the mid bulbar urethra, we prefer to place a Beckman-Weitlaner self-retaining retractor to aid with proximal bulbar exposure (Fig. 15.8). The urethral bulb is mobilized proximally, and for all but distal bulbar lesions and select focal mid to proximal lesions, this will entail sharp transection of the central tendon of the perineal body to fully mobilize and advance the bulb.

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Fig. 15.8

A Beckman-Weitlaner self-retaining retractor can be utilized to further aid with proximal bulbar exposure


The paired bulbourethral arteries , branches of the paired internal pudendal arteries, perforate the anterior pelvic floor triangle and enter the base of the bulbar urethra at the 4 and 8 o’clock position. These vital bulbar arteries should be prospectively identified and avoided when possible; this will maximize antegrade anastomotic perfusion, theoretically reducing the risk of ischemic recurrence, particularly in men with impaired urethral vascularity [22]. In men with concurrent stress urinary incontinence requiring staged artificial urinary sphincter, maximizing bulbar urethral perfusion is important to reduce the risk of urethral cuff erosion [23]. Though rarely necessary in our practice, the natural curve of the bulbar urethra, largely generated by the proximal fusion of the corporal bodies superiorly with the bulbar urethra curving in concave fashion below and coursing cephalad towards the bulbomembranous junction, can be straightened by incising and splitting the intercrural septum, affording additional mobilization [24].


After sufficient mobilization of the bulbar urethra is complete, attention is turned to localization of the stricture. Multiple techniques exist for precise identification of the distal aspect of the stricture, including passing a sound via the meatus (soft urethral catheter, or Bougie-à-Boule), as well as flexible urethroscopy. We prefer the latter, and once the distal aspect of the stricture is identified endoscopically, the corresponding location on the ventral bulbar spongiosal tunica is identified and marked with electrocautery. Regardless of the technique chosen, it is important to avoid erring distally, which would otherwise sacrifice healthy urethral length. Likewise, it is crucial to avoid dilating the stricture, which can obscure estimation of the true margins of the diseased segment resulting in incomplete excision, a common cause of stricture recurrence.


Two angled Debakey vascular clamps are next placed across the urethra, flanking the marked location, and a no. 20 blade is used to transect the entire thickness of the corpus spongiosum and urethra within (Fig. 15.9). We find that the vascular clamps not only facilitate stabilization of the urethra during transection, but also provide hemostasis of the proximal spongiosum, thus preserving visualization. Once the urethra is completely transected, the distal vascular clamp is removed, and the safety wire is carefully pulled out of the distal segment, into the field via the urethrotomy, and secured to the drape to maintain proximal access. We place a distal stay suture (3-0 chromic) into the ventral spongiosal tunica, 1–2 cm distal to the transected edge, perpendicular to the lumen, as this greatly aids in atraumatic manipulation of the distal segment. By gently sounding the distal urethral segment with an 18 Fr catheter, the distal scar is defined and excised. Care is taken to resect back to healthy appearing pink mucosa with overlying well vascularized spongiosum . It is important to excise all apparent spongiofibrosis, which often appears pale with grossly poor vascularity. The distal segment is spatulated dorsally, and calibrated to 26 Fr or larger with a Bougie-à-Boule. Additional distal mobilization can be performed at this point, further freeing the dorsolateral spongiosal tunica from the corporal tunica above. Gentle countertraction on the previously placed stay suture with an indwelling 18 Fr catheter can facilitate this portion of the dissection (Fig. 15.10).

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