Surgery for Urethral Trauma Including Urethral Disruption
TIMOTHY J. TAUSCH
JAY SIMHAN
ALLEN F. MOREY
Early recognition and diagnosis of urethral injuries are crucial to the successful management and prevention of long-term complications. Management of traumatic urethral injuries depends on the location of urethral stenosis. The urethra is divided into anterior (pendulous and bulbar urethra) and posterior (membranous and prostatic urethra) segments, with specific mechanisms of injury for either segment that will ultimately influence therapy and outcomes. Immediate management of anterior and posterior urethral trauma predominantly involves temporizing solutions to divert urine away from the urethral injury, although immediate surgical management of acute anterior urethral trauma may often be appropriate. Many patients with posterior injuries ultimately require formal surgical repair several months following the initial injury.
ANTERIOR URETHRAL INJURIES
The anterior urethra extends distally from the membranous urethra to the urethral meatus (Fig. 40.1). Contrary to the posterior urethra, the anterior urethra is encompassed by the corpus spongiosum, the deep (Buck) fascia, and the superficial (dartos) fascia along its entire length. The penoscrotal junction divides the shorter, proximal bulbar urethra from the longer, distal pendulous urethra. The bulbospongiosus muscle ventrally covers the bulbar urethra and terminates at the penoscrotal junction, prior to the origination of the distal pendulous urethra. The pendulous urethra closely approximates the corpora cavernosa during most of its length, with the lumen of the distal pendulous urethra dilating distally to form the fossa navicularis.
Although susceptible to penetrating trauma (e.g., stab or gunshot wounds), injuries to the anterior urethra most commonly involve blunt compression (“straddle”) injuries, penile fracture with concomitant urethral disruption, iatrogenic trauma (e.g., after Foley catheterization or endoscopic urethral surgery), and constriction rings. Compression of the bulbar urethra against the pubic bone, or a “straddle injury,” is the most commonly encountered anterior urethral injury and occurs after a direct force to the perineum compresses the bulbar urethra against the pubic bone. Alternatively, penile constriction rings can damage the anterior urethra secondary to tissue ischemia, whereas Foley catheterization or endoscopic urethral surgery can damage the bulbar urethra, resulting in contusion or partial urethral disruption. The true extent of iatrogenic injuries, along with trauma from constriction rings,
may not become evident until many years after the original event (1). Although rarely associated with pelvic fractures, anterior urethral injuries may be encountered in approximately 15% of penile fractures (2).
may not become evident until many years after the original event (1). Although rarely associated with pelvic fractures, anterior urethral injuries may be encountered in approximately 15% of penile fractures (2).
Diagnosis
A careful history and physical examination should raise suspicion for anterior urethral injury because these insults may arise immediately or after a substantial period of time. Straddle injuries often present in a delayed fashion with obstructive voiding symptoms and an idiopathic etiology. In a large series of 78 patients with straddle injuries, Park and McAninch (3) reported great variability in the time to presentation, with 40% of patients presenting to the emergency department in an acute setting and 60% of patients presenting 6 months to 10 years after the original injury. Hematuria, penile sleeve hematoma (injury confined to Buck fascia), difficulty voiding, and perineal “butterfly” hematoma (injury penetration of Buck fascia) are common presenting symptoms in the acute setting. In addition to a perineal butterfly hematoma, penetration of Buck fascia can allow the spread of urine and/or blood to the scrotum (dartos fascia), anterior abdominal wall (Colles fascia), and/or thighs (fascia lata).
All patients with a suspected anterior urethral injury should undergo a retrograde urethrogram prior to an attempt at urethral catheter placement. Ideally, the patient should be placed obliquely at a 30- to 45-degree angle with the bottom leg flexed at 90 degrees and the top leg kept straight (Fig. 40.2). In the acute setting, associated pelvic fracture may preclude this position; therefore, a supine retrograde urethrogram may be employed to determine whether the urethral lumen has been disrupted. Flexible cystoscopy may also be used to aid with the diagnosis of urethral trauma, although radiographic imaging is usually sufficient for a diagnosis of urethral trauma.
The retrograde urethrogram should be performed with undiluted water-soluble contrast medium (full-strength [60%] ionic contrast medium). A scout film provides initial information on patient position, the potential presence of a foreign body, as well as any fractures to the bony structures of the pelvis. A 12Fr Foley catheter is then placed into the fossa navicularis, and the balloon is inflated with 3 mL of sterile water to prevent catheter dislodgment during the evaluation. The penis is positioned laterally on slight stretch to provide a more descriptive study, and 20 to 30 mL of contrast is then injected in a retrograde fashion. Dynamic fluoroscopy is ideal; however, in the setting of acute trauma in the emergency department, static radiographs will suffice. Although the anterior urethra can be visualized in its entirety during a retrograde urethrogram, the posterior urethra is typically excluded by reflex contraction of the external sphincter. If a catheter is present at the time of evaluation, a cystogram is recommended to confirm the catheter’s presence in the bladder. After documenting the correct location of the urethral catheter, a pericatheter retrograde urethrogram may additionally be performed to delineate any possible urethral injury.
Anterior urethral injuries are classified into three groups based upon radiographic, clinical, or endoscopic findings. Although contusions may appear normal on retrograde urethrogram, these injuries are best determined with clinical suspicion through cystoscopy in the setting of a “normal” retrograde urethrogram. Alternatively, partial disruptions appear as extravasated urine on retrograde urethrogram with visualization of contrast in the urethra or bladder proximal to the injury. Complete disruptions appear as total extravasation without visualization of contrast in the more proximal urethra or bladder.
Indications for Surgery
Primary surgical repair of acute anterior urethral injuries is recommended in the context of penetrating injury. We also recommend an attempt at anterior urethral repair in the setting of penile fracture. Because these repairs are delicate and potentially time-consuming, any attempt at immediate repair is predicated on the stability of the patient. Injuries to the posterior urethra should be managed in a delayed fashion, without attempt at a formal urethroplasty in the acute setting. Posterior urethral injuries are discussed later in this chapter.
Alternative Therapy
Alternative options to surgical repair involve the temporary diversion of urine through the placement of a urethral or suprapubic catheter. Contusions to the anterior urethra should be managed with a urethral catheter for approximately 2 weeks followed by a voiding cystourethrogram to confirm urethral patency. The patient should be counseled on the possibility of delayed development of a urethral stricture at the site of contusion.
Partial urethral disruptions diagnosed by retrograde urethrogram may be managed via various algorithms. We prefer urinary diversion with formal repair after a minimum of 2 months to allow resolution of inflammation and maturation of scar tissue. Although some experts support one attempt at Foley catheter placement, the possibility of causing a complete urethral disruption during this attempt should be considered.
If urethral placement is unsuccessful, percutaneous suprapubic tube placement should be performed. The preservation of urethral mucosa with partial disruptions may be adequate for re-epithelialization and eventual luminal recanalization; however, we would recommend periodic evaluation with uroflow studies and counseling patients regarding the possibility of future stricture development.
If urethral placement is unsuccessful, percutaneous suprapubic tube placement should be performed. The preservation of urethral mucosa with partial disruptions may be adequate for re-epithelialization and eventual luminal recanalization; however, we would recommend periodic evaluation with uroflow studies and counseling patients regarding the possibility of future stricture development.
Surgical Technique
Open surgical repair is primarily reserved for stable patients after open or penetrating injury to the anterior urethra. The patient is placed in either the supine position or lithotomy position and draped widely to allow exploration of potential concomitant injuries to the penis, testes, perineum, and rectum. Clean wounds need only minimal debridement followed by urethral closure with interrupted or running 5-0 polyglyconate monofilament (polydioxanone) sutures over a 16Fr catheter. Contaminated wounds require thorough irrigation and debridement of devitalized tissues to ensure reapproximation of healthy tissue.
With open or penetrating bulbar urethra injuries, the patient is placed in the lithotomy position with adjustable stirrups, and a vertical perineal incision is performed along the raphe. As expected, only stable patients without injury precluding the lithotomy position should be offered acute surgical intervention. The urethra is exposed after division of Colles fascia and the bulbospongiosus muscle. A perineal retractor (e.g., perineal Bookwalter or Lone Star retractor, Cooper Surgical, Trumbull, Connecticut) is used to assist with perineal dissection. Surgeons should avoid acute repair of long bulbar urethral defects (>2 to 3 cm) because more complex intervention with grafts or flaps will be required. The most important factor promoting a successful outcome is the creation of a tension-free anastomosis; therefore, generous mobilization of the urethra is an important step to ensure adequate urethral length. Once adequate length is achieved, the urethral ends are spatulated (Fig. 40.3). The anastomosis is performed with interrupted 5-0 polyglyconate monofilament suture to create a tension-free, watertight closure. The dorsal surface is closed in one layer with 5-0 interrupted polyglyconate monofilament suture incorporating the urethral mucosa and spongiosal adventitia. Since the ventral bulbar urethra is vascularized by the spongy urethra, we advocate ventral spongiosum closure in two layers: the first, inner layer, closed with interrupted 5-0 polyglyconate monofilament suture and the second, outer layer, with a running 5-0 polyglyconate monofilament suture (Fig. 40.4). No further attempt is made to control bleeding from the spongy urethra during closure, as we believe that the added vascularity from the spongy urethra provides enhanced healing of the anastomosis. We also recommend that a firststage marsupialization of healthy proximal urethra be considered if tension-free closure cannot be achieved or if there is significant wound inflammation or contamination.
FIGURE 40.3 Repair of bulbar urethral injuries. The urethra is mobilized and spatulated in preparation for a tension-free end-to-end anastomosis. |
FIGURE 40.4 Repair of bulbar urethral injuries. Anastomosis is carried out with a single-layer dorsal closure and a two-layer ventral closure using interrupted 5-0 or 6-0 Maxon sutures. |
For most penile urethral injuries, we prefer a longitudinal incision directly over the area of injury. Contrary to bulbar urethral injury, anastomotic repair should not be considered for defects >15 mm, as the risk of penile chordee is higher with penile anastomotic repairs. Instead, we prefer to use buccal mucosa in either an inlay, onlay, or combined approach. We routinely use 16Fr silicone Foley catheters at the time of urethral repair. Suppressive antibiotics are given while the catheter is in place to maintain urine sterility, with a voiding cystourethrogram performed after 2 to 3 weeks. If extravasation is noted, we gently replace the catheter for an additional period of time with repeat imaging at the time of urethral catheter removal.
Outcomes
Complications
The major complications relating to anterior urethral trauma include urethral stricture formation and infection. If untreated, persistent extravasation of infected urine or blood may lead to urethrocutaneous fistula, urethral abscess, or urethral diverticula. Prolonged urine extravasation into the corpus spongiosum may also lead to added spongiofibrosis, resulting in a longer urethral stricture. Consequently, a longer anterior urethral stricture translates to more complex management with a buccal mucosa graft or fasciocutaneous flap.
Patients with resultant urethral strictures are often subjected to endoscopic procedures such as dilations or urethrotomies that frequently need to be repeated. Such interventions can subject patients to pain and complications negatively impacting quality of life. Success of dilations is also low, with most patients eventually requiring definitive urethral repair.
With early urinary diversion, many anterior urethral strictures will never progress and remain amenable to excision. Incontinence and impotence, although common in posterior urethral injuries, are uncommon in anterior urethral injuries. Stricture recurrence is most common in the first 12 months, so close follow-up is required.
Results
Anastomotic urethroplasty can be performed successfully in a high percentage of patients who sustain a bulbar urethra (straddle) injury requiring surgery. The procedure has an overall success rate of approximately 95% when performed in a delayed setting (3). As mentioned previously, patients sustaining open or penetrating injuries associated with minimal inflammation are the best candidates for acute repair; otherwise, urinary diversion with suprapubic tube placement is recommended with formal repair at a later date.
POSTERIOR URETHRAL INJURIES
Posterior Urethral Anatomy
The urethra is divided into anterior and posterior anatomic segments by the urogenital perineal membrane. The posterior urethra consists of the membranous and prostatic urethra and is much shorter than the anterior urethra (Fig. 40.1). Extending from the bladder neck to the apex of the prostate, the prostatic urethra is secured to the pubic bone by the paired puboprostatic ligaments. During cystoscopy, the verumontanum marks the most distal aspect of the prostatic urethra. The bladder neck sphincter is an extension of smooth muscle fibers of the trigone and prostatic urethra cephalad to the verumontanum. The distal sphincter is approximately 2.5 cm long and consists of smooth muscle fibers caudad to the verumontanum, including the rhabdosphincter (slow-twitch skeletal muscle fibers) (4). The distal sphincter is only 3 to 4 mm thick and forms the entire thickness of the membranous urethra (5). In the absence of a functional distal urethral sphincter, the proximal urethral sphincter can maintain urinary continence in select patients; however, the bladder must be compliant and free from periodic elevations of detrusor pressure (e.g., detrusor overactivity).