Etiology and Management

Injury to the kidneys is the most common genitourinary trauma encountered, accounting for 24% of traumatic abdominal solid organ injuries. Due to their retroperitoneal location, the kidneys are fixed only by the renal pelvis and vasculature, rendering them susceptible to deceleration injuries. Contrast-enhanced computed tomography (CT) scanning, with delayed images, remains the most common method for evaluating both vascular and collecting system trauma.

Although operative exploration was the traditional method of treatment, the paradigm has shifted to nonoperative management. Emergent surgery often results in nephrectomy, and with advances in imaging, monitoring, and endovascular techniques, most injured kidneys can now be effectively preserved. The current American Urological Association guidelines on urotrauma now advocate for noninvasive management of any patient with a renal injury who is hemodynamically stable, and compulsory intervention (either endovascular or surgical) in unstable patients with poor response to resuscitation.

Complications

A common problem following renal trauma is persistent urinary extravasation, which can result in urinoma, perinephric infection, or even renal loss. Systemic antibiotics and close observation result in resolution in many patients. In patients with a persistent urine leak on repeat imaging (48 hours later), or with complications such as enlarging urinoma, fever, pain, ileus, fistula, or infection, urinary drainage with an internalized ureteral stent should be performed. Drainage helps to avoid further complications, such as perinephric abscess.

Occasionally, patients may present with a delayed hemorrhage several weeks following the initial trauma, and the immediate treatment is bed rest and hydration. If the bleeding persists, then endovascular arteriography can usually localize the vessel, which can then be controlled with embolization. Rarely hypertension can be encountered, resulting from stimulation of the renin-angiotensin axis from renal ischemia due to renal artery stenosis (Goldblatt kidney), compression of the parenchyma by hematoma or urinoma (Page kidney), or arteriovenous fistula.

Etiology and Management

Because of its anatomic location in the retroperitoneum protected by the vertebrae and musculature, the ureter is less susceptible to traumatic forces. For this reason, ureteral injury is present in less than 4% of all penetrating and less than 1% of all blunt trauma cases.

In cases where ureteral injury is suspected, intravenous contrast-enhanced axial imaging with delayed films is recommended, or direct visualization during laparotomy if no preoperative imaging is available. In stable patients, lacerations can be primarily repaired, and contusions can be stented or resected and repaired, depending on the nature and severity of the injury. Either a stent or percutaneous nephrostomy (if a stent cannot be placed) can divert the urine from a partial or delayed presentation of a ureteral injury, with a definitive repair at a later date when the patient has recovered from the acute trauma.

Complications

If unrecognized, significant complications can arise, making a prompt, accurate diagnosis imperative in managing these patients. A missed and persistent ureteral urine leak can lead to urinoma formation ( Fig. 15.1 ), abscess, ureteral stricture, fistula, and potentially the loss of an entire ipsilateral kidney. Patients with missed ureteral injuries can suffer increased nephrectomy rates and prolonged hospital stays.

Delayed recognition of a ureteral injury following colon surgery. The patient presented with fevers and concern of pelvic abcess. A CT urogram demonstrates (A) proximal left hydronephrosis (arrow), (B) urinary ascites with layering contrast within ascites fluid (arrows), (C) extravasation into the urinoma from the site of ureteral injury (arrow), and (D) a phlegmon surrounding the uteral extravasation (arrow).

(Figure provided by Samir Taneja.)

Etiology and Management

As the bladder is anatomically located deep in the bony pelvis, it is relatively protected from external traumatic forces. Significant blunt forces, such as rapid decelerations, falls, or crushes, can rupture the bladder, as well as penetrating injuries such as bone shards, projectiles, or surgical iatrogeny. Because of the forces necessary to compromise the bladder inside of the bony pelvis, concomitant injuries are common (80–94%), and mortality rates can be high, usually from nonurologic causes.

Diagnosis can be made when clinically suspected, such as when conscious patients have suprapubic or abdominal pain and inability to void following the inciting event. Associated injuries or altered mental status can mask the symptoms; therefore when the mechanism suggests a potential bladder injury, evaluation should be undertaken. Gross hematuria upon catheter placement is typically the first indication and is nearly universally present. Difficult catheter placement or blood at the meatus can indicate a concomitant urethral injury, and a retrograde urethrogram should be performed in these cases.

Bladder ruptures are best evaluated with a cystogram with drainage films. Alternatively, axial imaging with contrast instilled in the bladder can be utilized in stable patients. In uncomplicated patients, extraperitoneal bladder ruptures should be managed conservatively with urethral drainage alone, typically for 14 days following injury, which can be removed when a cystogram confirms no leak of contrast. If a patient is complex, with other injuries that necessitate laparotomy or orthopedic intervention, once stable the patient should undergo immediate repair of extraperitoneal injuries, as complications rates are lower.

Intraperitoneal ruptures should be managed by immediate operative repair, as these injuries are unlikely to heal with conservative management and are often more severe than suggested in imaging studies. Careful inspection of the ureters and evaluation for clear efflux can evaluate for ureteral injury, with repair or stenting as indicated. A urethral catheter is again left and bladder integrity confirmed via cystogram prior to removal to ensure proper healing.

Complications

When promptly diagnosed and appropriately managed, complications following bladder injuries are minimized. Delayed or missed diagnoses can result in significant morbidity, as in patients with devastating complex pelvic trauma. If missed, patients can develop acidosis, azotemia, infection with fever and sepsis, acute renal failure, peritoneal signs, ileus, urine ascites, and even respiratory compromise from abdominal compartment syndrome. In complex genitourinary or concomitant colorectal injuries, incontinence, fistulas, or strictures can develop, necessitating difficult and complex reconstructive surgery.

Diagnosis

Because of the typical association of PFUI with more serious concomitant injuries, above all else resuscitation and stabilization of the patient is paramount. When the mechanism of injury portends a possible PFUI, the triad of blood at the meatus, inability to urinate, and a palpably full bladder may indicate a urethral disruption. Because these classic signs or others (a “high-riding” prostate or perineal hematoma) may be clinically absent, a PFUI is often first suspected when a urethral catheter cannot be placed into the bladder. When a PFUI is suspected, an immediate retrograde urethrogram can aid in the diagnosis.

Management

Debate continues regarding whether primary endoscopic realignment (PER) or suprapubic tube (SPT) diversion (with delayed posterior urethroplasty) is better for acute management of PFUI. There is no consensus among experts, with varying literature regarding the impact of each on eventual incontinence, impotence, and urethral stricture rates. The obvious benefit of primary alignment is the potentially lower stricture rate of 56% versus the 97% seen with suprapubic catheter placement alone; however, a more recent series reported that PER is only successful in 21% (4/19) of patients. Additionally, a recent report of a large series showed that strictures that form after realignment can be shorter and therefore potentially easier to treat when undergoing urethroplasty, though this too remains controversial.

While PER and SPT placement are currently both acceptable for the acute management of PFUI, placement of an SPT, with definitive and durable treatment via posterior urethroplasty 2 months postinjury, can avoid a prolonged and complicated clinical course to establishing urethral patency. Additionally, in the setting of a severely injured or unstable patient, one should perform percutaneous SPT placement as the more expeditious procedure. This allows for stabilization and treatment of concomitant injuries, and the posterior urethroplasty can be performed electively in a controlled setting.

Complications

At the time of repair, complete excision of the fibrotic scar tissue is absolutely imperative, with outcomes directly related to complete scar removal ( Fig. 15.2 ). After a posterior urethroplasty, 5–15% of patients can experience recurrent stenosis at the anastomosis. However, as the majority of the fibrotic scar tissue has been excised, endoscopic treatment (with a direct vision internal urethrotomy) has proven successful in managing these patients.

During the posterior urethroplasty for a PFUI, complete excision of the fibrous scar (A) that results from hematoma resorption is imperative to a successful outcome, allowing for precise mucosal apposition of healthy urothelium (B).

Erectile dysfunction (ED) commonly results following pelvic fractures, with an average rate of about 50%, and reported as high as 82%. Similar to PFUI itself, the incidence of ED is related to the nature of the pelvic ring disruption itself. The precise etiology of post-PFUI ED is unclear, but theoretically could include cavernosal nerve injury, arterial insufficiency, venous leak, and direct corporal injury, although in most cases the cause of ED is likely multifactorial. The varying rates and causative mechanisms have relied mainly on individual study methods, rendering a meaningful conclusion impossible. Anatomically, the proximity of the erectile nerves and vessels to the mechanism of injury leads one to conclude that damage to either or both may be responsible. Additionally, neurogenic ED has been reported to improve with time, suggesting that neuropraxia rather than complete disruption may be a cause.

Urinary incontinence is surprisingly rare following PFUI (<4%), with redundancy of continence mechanisms helping to preserve continence in the vast majority of patients following PFUI. Both the bladder neck and urethral sphincter help to prevent involuntary urine leakage; following PFUI the urethral sphincter may be damaged, but only when the bladder neck is also injured will the patient be incontinent. More recently, urodynamic data have shown that a significant proportion of patients will also have identifiable rhabdosphincter function following repair. In patients with persistent incontinence, placement of an artificial urinary sphincter is recommended.

Diagnosis

A careful history and physical examination should raise suspicion for anterior urethral injury, as 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 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’s fascia), difficulty voiding, and perineal “butterfly” hematoma (injury penetration of Buck’s fascia) are common presenting symptoms in the acute setting. In addition to a perineal “butterfly” hematoma, penetration of Buck’s 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). In patients with a suspected anterior urethral injury, a retrograde urethrogram should be performed. Flexible cystoscopy may also be utilized to aid with the diagnosis of urethral trauma, although radiographic imaging is usually sufficient for a diagnosis of urethral trauma.

Management

Anterior urethral injuries are classified into three groups based upon radiographic, clinical, or endoscopic findings. Though 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.

Contusions to the anterior urethra should be managed with a urethral catheter for approximately 2 weeks followed by a voiding cystourethrogram (VCUG) 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. Urinary diversion (via SPT) with formal repair after a minimum of 2 months allows 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 catheter 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, this requires periodic evaluation with uroflow studies and counseling regarding the possibility of future stricture development.

In patients with a complete disruption, either immediate or delayed repair can be considered, depending on any concomitant injuries or surgeon experience. In straddle injuries of a lesser degree, primary anterior urethral alignment alone has shown promising results with respect to stricture rate and ED. In patients with low-velocity gunshot wounds, primary repair is recommended, as catheter placement alone results in far worse stricture rate. Limited debridement of the corpus spongiosum should be performed in these cases, as the robust corporal blood supply allows for spontaneous healing of most contused areas. In high-velocity gunshot wounds, SPT diversion and delayed repair should be undertaken, as the degree of tissue damage is greater in these patients.

Complications

As the risk of ED and incontinence are much lower in anterior compared to posterior urethral injuries, 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 necessitates more complex management with a buccal mucosa graft (BMG) 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. The success rate of dilations is also low, with most patients eventually requiring definitive urethral repair.

In patients with recurrent strictures following urethroplasty, direct visualization and incision of the urethra (DVIU) may be considered for singular bulbar stenoses that are < 1 cm and recur > 6 months following the initial procedure. In this setting, success rates of 9–52% can be achieved; however, longer, multiple, penile, or distal strictures do not respond to repeat dilation/incision. In patients with long (>3 cm), complex, or multifocal recurrent strictures, substitution urethroplasty with either buccal mucosa grafting or penile skin flaps is necessary ( Fig. 15.4 ). However, typically, patients who fail urethroplasty suffer from a focal, short-segment stricture, which can be effectively treated with anastomotic techniques, with excellent success rates of up to 93%.

Retrograde urethrogram (A) of a patient with a pendulous stricture following a transurethral procedure. After failing previous attempts at dilation, an Orandi penile skin flap was mobilized (B) and used as a substitution for the scarred segment (C).

In order to optimize success of urethroplasty, several aspects need to be considered. Above all, complete excision of all scar tissue must be assured. In the reoperative setting, it is common to find that the stenosis extends proximally to virgin tissue planes, indicating inadequate proximal dissection during the initial procedure. In order to best achieve complete scar excision, precise control of the proximal urethral lumen can be facilitated by preoperative guidewire placement or antegrade instrumentation via a SPT tract (when available). The distal-most extent of the scar is easily identified with urethroscopy and visualization or palpation of the scope at the site of the stricture.

After the urothelial scar is excised, the surrounding fibrotic tissue must also be removed. Often, scalpel dissection is required as scissors may not be effective in cutting the dense fibrosis encasing the urethra. For these reasons, excisional techniques may be superior to nontransecting methods, as scar tissue is more developed in the reoperative setting.