Reconstruction of Strictures of the Bulbar Urethra





The view(s) expressed herein are those of the author(s) and do not reflect the official policy or position of Brooke Army Medical Center, the US Army Medical Department, the US Army Office of the Surgeon General, the Department of the Army, and Department of Defense or the US Government.


Preoperative Preparation and Planning


Bulbar urethral strictures, although common and often debilitating, are almost always amenable to definitive reconstruction, regardless of their length, severity, or prior treatment. The forgiving nature of the bulbar urethra is due to the robust blood supply from multiple bilateral branches of the common penile arteries, which provide vascular inflow for the thick corpus spongiosum at multiple points along its axis, especially the paired bulbar arteries proximally. The redundant vascular supply of the bulbar urethra facilitates the various methods of bulbar urethral reconstruction detailed below.


Preoperative Evaluation


Bulbar urethroplasty is invariably a low-risk operation with negligible blood loss and fluid shifts. Operative time rarely exceeds 3–4 hours. Prior to urethroplasty, a focused medical evaluation should identify medical risks for spinal or general anesthesia (cardiovascular disease, diabetes, renal insufficiency, peripheral vascular disease), history of neurologic disease that might negatively affect detrusor function after successful reconstruction, and history of oral disease/surgery or smokeless tobacco use, especially if oral mucosal grafting is anticipated. Finally, preoperative assessment and documentation of urinary and sexual function is important to provide a baseline for postoperative comparison in the immediate and long term.


Although physical examination will reveal very little about a patient’s bulbar urethral anatomy, a focused physical assessment of the patient can provide valuable information about potential challenges that may affect perioperative risk and subsequent urethroplasty outcome. The fossa navicularis and pendulous urethra should be palpated, noting any areas of palpable urethral/spongiosal induration that correlate well with luminal fibrosis. Stretched penile length (SPL) should be assessed as bulbar excision and primary anastomosis (EPA) is facilitated by longer penile length. The quality and quantity of penile and perineal skin must be assessed, noting any evidence of lichen sclerosis, phimosis, prior surgical scars, or other cutaneous abnormalities. The urethral meatus should be inspected and if stenotic or hypospadiac, carefully calibrated with Bougie-à-Boule sounds ( Fig. 94.1 ). The buccal, lingual, and labial surfaces should be inspected in men in whom substitution urethroplasty is anticipated, especially smokeless tobacco users and those with a history of oral surgery and/or radiation. Body mass index (BMI) should be assessed as obesity can impact surgical exposure of the perineum, increase the risk of positioning-related complications, and may increase the risk of stricture recurrence following urethroplasty. Finally, assessment of bilateral hip and knee mobility is important to ensure the patient can safely tolerate 2–4 hours in the lithotomy position.




FIGURE 94.1


Bougie-à-Boule sounds used for urethral calibration.


Routine laboratory evaluation prior to bulbar urethroplasty is limited. Urinalysis frequently reveals microscopic hematuria and/or pyuria even in the absence of overt urinary tract infection symptoms. Urine culture can help guide choice of perioperative antibiotics, but preoperative urinary sterilization is challenging (because of poor bladder emptying and chronic indwelling urinary catheters) and thus not mandatory. When bacteriuria is present, culture-specific antibiotics on the day of surgery will prevent postoperative infections in the majority of men.


Men younger than 60 years do not require routine hematologic studies unless significant medical comorbidities exist. For men older than 60 years or for those with a history of medical comorbidities, a complete blood count, renal function panel, and coagulation profile is prudent. Blood transfusion is virtually never needed after bulbar urethroplasty and thus a preoperative blood type and antibody screen is needed only in the case of significant preoperative anemia (hematocrit <30%).


High-quality retrograde urethrography (RUG) is a critically important component of the preoperative evaluation of urethral stricture patients. A well-performed RUG will accurately delineate the length, location, and severity of the stricture ( Fig. 94.2 ). This information then allows the surgeon to determine what reconstruction technique(s) may be required and appropriately counsel the patient on the likelihood of surgical success and the potential for postoperative complications. Helpful adjuncts to RUG include antegrade/retrograde cystourethrography ( Fig. 94.3 ), flexible urethroscopy, and sonourethrography; many of these adjunctive maneuvers can be conducted at the beginning of the case in the operating theater.




FIGURE 94.2


Retrograde urethrogram demonstrating a focally severe, 3-cm midbulbar stricture.



FIGURE 94.3


Antegrade/retrograde cystourethrography showing an obliterative stricture in the proximal bulbar urethra.


Surgical Planning


As discussed above, a well-performed RUG will delineate the length, location, and severity of most bulbar strictures. While a certain amount of intraoperative flexibility is necessary, a thoughtfully crafted preoperative plan (based on the preoperative evaluation) can maximize the chances of a smooth operation and long-term success. In general, EPA should be performed whenever possible, because of its technical simplicity and superior efficacy, while avoiding graft donor site morbidity. EPA can be applied to longer bulbar strictures when the distal aspect of the stricture is in the lower half of the perineum and in men who have either a longer than average penis (SPL >14 cm) or who would prefer a negligible risk of penile shortening/chordee compared with the increased risk of recurrent stricture associated with substitution urethroplasty.


When substitution urethroplasty is necessary, bulbar strictures can be excised, incised, or both; grafts can be then applied in either the dorsal, ventral, or overlapping dorsal + ventral location(s). This diverse repertoire of technical options speaks to both the heterogeneity of bulbar strictures and the lack of consensus regarding superiority of any individual technique. Nevertheless, logical principles can guide the surgeon during the preoperative (and intraoperative) decision-making process. First, obliterative urethral segments are not amenable to onlay reconstruction and therefore must be excised. Second, a healthy recipient site is necessary to support any graft. The robust corpus spongiosum of the central and proximal bulb is well suited for ventral onlay while dorsal onlay is often preferred in the distal bulb where the spongiosum is of narrower caliber. Third, an ample urethral plate is an important foundation for successful onlay repair. Therefore, segments of severely narrowed/diseased urethral plate (<5 mm width) should be excised (when short) and/or incised and augmented dorsally prior to overlapping ventral graft placement. An algorithmic illustration of these principles is shown in Fig. 94.4 .




FIGURE 94.4


Algorithm for surgical decision making during bulbar urethroplasty. RUG, retrograde urethrogram; EPA, excision and primary anastomosis; VOBMG, ventral onlay buccal mucosal graft; DOBMG, dorsal onlay buccal mucosal graft; AAU, augmented anastomotic urethroplasty; BMG, buccal mucosal graft.


Even the most meticulous preoperative plan can be disrupted by unexpected intraoperative findings. All preoperative patient counseling sessions and informed consent documents should obtain appropriate information about the various graft (oral mucosa and skin based) and flap harvest procedures, even if the need for substitution urethroplasty is unlikely. Similarly, the instruments needed for graft harvest should be readily available should the unanticipated need for a graft arise intraoperatively. Rarely, perineal exploration and stricture incision will reveal urethral epithelial lesions suspicious for carcinoma. In such cases, immediate pathologic analysis (via frozen section) should be performed to exclude malignancy before any definitive reconstruction attempts are made.


Diligent preoperative preparation and intraoperative adaptation will maximize surgical efficiency and thus decrease operative time and lessen the risk of positioning and anesthetic-related complications. Operating room efficiency can be further improved by using a “two-team” approach to substitution urethroplasty where one team harvests the oral graft while the second team simultaneously performs the urethral dissection. When two teams are not available, use of adjustable boot-type stirrups will allow the lower extremities to “rest” in a low position during graft harvest, and then be easily elevated to improve exposure during the perineal dissection and bulbar reconstruction.




Patient Positioning and Surgical Incision


Careful attention to patient positioning will maximize patient safety during bulbar urethroplasty. The upper extremities are gently secured to arm boards in a supinated, partially abducted position. The lower extremities are carefully positioned in adjustable boot-type stirrups, which are raised or lowered as needed for access to the urethra.


Positioning-related complications such as neuropraxia and compartment syndrome are related to the length of time and degree of leg elevation, and thus are usually preventable. Procedures at higher risk include those with lengthy, synchronous, proximal, and/or reoperative bulbar urethral strictures. A low lithotomy position is adequate for the distal bulb; stirrups are raised only as needed for perineal access. The classic exaggerated lithotomy position is not typically needed for bulbar urethroplasty and should be avoided when possible to avoid lower extremity complications.


Another important consideration when positioning the patient for bulbar urethroplasty is surgeon ergonomics and comfort. The patient’s buttocks are positioned even with (or slightly overhanging) the lower end of the surgical table. This brings the operative field closer to the surgeon and eliminates interference of the lower end of the bed with drape placement and retractor positioning. Sitting stools improve surgeon stamina during lengthy cases but mandate that the bed be positioned in a manner so the base does not interfere with the base of the stools or the surgeons’ knees.


Proper placement of surgical drapes is helpful to maintain orientation during perineal exposure. After standard skin preparation, a folded sterile towel is stapled immediately anterior to the anal verge, thus exposing the entire perineum enabling proximal perineal dissection if needed. A perineal drape with pouch is then secured to both the towel and perineal skin, thus creating a channel for all fluid and blood to fall into the pouch ( Fig. 94.5 ). Placement immediately over the anus isolates the anus from the sterile field while marking the posterior limit of the skin incision and perineal dissection. If the towel is placed further anteriorly on the perineum, proximal bulbar dissection proceeds toward the rectum. Conversely, the dissection is parallel to the rectum when begun from the proper, more posterior starting point ( Fig. 94.6 ). Anteriorly, the sterile field extends to the umbilicus in the event suprapubic access is needed.




FIGURE 94.5


The posterior limit of the sterile field extends to a towel secured immediately anterior to the anus ( red circle ).



FIGURE 94.6


When the perineal drape ( blue line ) is placed immediately over the anus, proximal bulbar dissection ( green arrow ) proceeds parallel to the rectum.


Before any incision is made, gentle calibration or endoscopy of the urethra should be performed if it has not been so previously by the surgeon himself/herself as urethrography films can occasionally be misleading, outdated, or of poor quality. We pass a flexible cystoscope at the beginning of every case to guide the location of the incision and assess for unrecognized synchronous strictures. If a scope can be passed without difficulty into the bladder, the procedure is aborted. Antegrade flexible cystourethroscopy is especially helpful for evaluating the proximal bulb in cases having obliterative strictures. In patients having bulbomembranous strictures and no preliminary suprapubic tube, a flexible guidewire is placed into the bladder to enable proximal urethral control, which can otherwise be challenging in a bloody operative field.


An 8–10-cm midline perineal skin incision from the perineoscrotal junction to just above the anal verge will provide excellent exposure to the proximal and midbulbar urethra. The distal bulb can be accessed by extending the incision into the scrotum or invaginating the penis out through the perineal incision ( Fig. 94.7 ). An inverted-Y (lambda) incision does not improve bulbar exposure, is more complex to close, and may be associated with a higher risk of postoperative wound complications.




FIGURE 94.7


Invaginating the penis out through the perineal incision provides panurethral exposure without the need for penile or scrotal skin incision(s).


After midline skin incision, Colles fascia is incised with electrocautery and the perineal fat is dissected in the midline to the level of the bulbospongiosus muscle. A self-retaining retractor (Lone-star, perineal Bookwalter, etc.) is placed to retract the fat (which can be abundant in obese men) and expose the muscle; for obese patients, firm fixation of the retractor is critical in providing scrotal elevation, which enables adequate urethral exposure. Extensive extramuscular dissection is unnecessary and risks damage to the perineal/posterior scrotal neurovascular bundles that lie on the anterolateral surface of the bulbospongiosus muscle. Once exposed, the bulbospongiosus muscle is either divided in the midline, retracted posteriorly, or rolled laterally. We prefer midline sharp division of the muscle ( Fig. 94.8 ) as it provides the best exposure, is quick and easy to perform, and has not been shown to cause urinary dribbling or decreased ejaculatory force. Once divided, the retractor is repositioned to include and fully retract the muscle, thus allowing ventral dissection and exposure of the corpus spongiosum from the central tendon of the perineum to the upper limit of the skin incision ( Fig. 94.9 ). This initial exposure facilitates performance of any of the bulbar urethroplasty techniques detailed below.


Jan 2, 2020 | Posted by in UROLOGY | Comments Off on Reconstruction of Strictures of the Bulbar Urethra
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