Overview of traumatic upper genitourinary tract injuries in adults

INTRODUCTION — The upper genitourinary (GU) tract consists of the kidneys (parenchyma, collecting system) and ureters. The kidneys are the most commonly injured GU organ. While ureteral injury is very rare, when it occurs, it is usually associated with other severe injuries. Younger males (mean age approximately 30 years) are predominantly affected.

The management of GU tract injuries requires clinical knowledge pertaining to each GU organ to avoid unwanted outcomes (eg, loss of renal function, urinary incontinence, difficulty voiding) and secondary psychosocial stressors. Coordination of care among general/trauma surgeons, urologists, orthopedic surgeons, and other services is essential to improve overall outcomes.

An overview of the evaluation and management of upper genitourinary tract injuries will be reviewed here. Management of individual upper GU organ injuries is reviewed separately. (See "Management of blunt and penetrating renal trauma" and "Overview of traumatic and iatrogenic ureteral injury".)

A review of lower GU tract injuries is provided separately. (See "Overview of traumatic lower genitourinary tract injury".)

MECHANISM AND ASSOCIATED INJURIES — Injury to the genitourinary system is overall uncommon, with an estimated incidence of <1 percent [1]. The upper genitourinary tract consists of the kidneys and ureters (figure 1 and figure 2). While renal injuries are more commonly due to blunt trauma, most ureteral injuries are due to penetrating trauma.

●Kidneys – The kidneys (figure 3) are well protected in the retroperitoneum. Significant force is required to injure the kidney, and such forces frequently result in injuries to surrounding viscera. (See "Blunt genitourinary trauma: Initial evaluation and management", section on 'Anatomy, physiology, and mechanism'.)

●Ureters – The ureters (figure 3) are also well protected within the retroperitoneum. As a result of its close anatomic associations, penetrating ureteral injury is highly associated with concomitant injuries, most commonly to the bowel [2]. (See "Overview of traumatic and iatrogenic ureteral injury", section on 'Mechanism of injury'.)

TRAUMA EVALUATION — We perform initial resuscitation, diagnostic evaluation, and management of the trauma patient with blunt or penetrating trauma based upon protocols from the Advanced Trauma Life Support (ATLS) program, established by the American College of Surgeons Committee on Trauma. The initial resuscitation and evaluation of the patient with blunt or penetrating abdominal or thoracic trauma is discussed in detail elsewhere.

●(See "Initial evaluation and management of blunt abdominal trauma in adults".)

●(See "Initial evaluation and management of abdominal gunshot wounds in adults".)

●(See "Initial evaluation and management of abdominal stab wounds in adults".)

●(See "Initial evaluation and management of blunt thoracic trauma in adults".)

The initial evaluation of the abdominal trauma patient commonly uses focused assessment with sonography in trauma (FAST exam) and computed tomography (CT) scan of the abdomen and pelvis. The FAST exam is useful in hemodynamically unstable patients to identify the immediate need for abdominal exploration. While the exam is useful in the emergency room to evaluate for hemoperitoneum, important renal injuries can be missed [3], and it does not identify ureteral injury.

CLINICAL FEATURES AND DIAGNOSIS — The primary and secondary survey should identify individuals with findings suggestive of upper genitourinary (GU) tract injury. (See "Blunt genitourinary trauma: Initial evaluation and management" and "Penetrating trauma of the upper and lower genitourinary tract: Initial evaluation and management".)

For trauma patients with indications for immediate laparotomy (eg, hemodynamically unstable), the diagnosis of upper GU tract injury will often be made during exploration. For others, radiographic imaging is recommended in those with appropriate clinical features (eg, blunt abdominal trauma and gross hematuria, deceleration injury, penetrating trajectory) to confirm and grade the injury [4-6]. Knowledge of entry/exit wounds following penetrating abdominal trauma is important to guide regions of the body that require imaging. (See "Management of blunt and penetrating renal trauma", section on 'Diagnosis' and "Overview of traumatic and iatrogenic ureteral injury", section on 'Diagnosis'.)

The diagnosis of injury to the kidneys or ureters in hemodynamically stable patients relies on GU tract imaging, typically using contrast-enhanced computed tomography (CT) scan of the abdomen/pelvis (ie, CT pyelography, CT urography). It is important to note that the protocols for these studies differ from the typical contrast-enhanced study obtained for abdominal trauma. The appropriate performance of CT pyelography and CT urography is discussed separately. (See "Overview of traumatic and iatrogenic ureteral injury", section on 'CT urography' and "Management of blunt and penetrating renal trauma", section on 'CT pyelography'.)

The most relevant clinical and typical diagnostic imaging findings are summarized as follows:

●Renal injury – An appropriate mechanism of injury (eg, rapid deceleration injury, direct blow to the back or flank), hemodynamic instability, and presence of hematuria should increase suspicion for significant renal trauma. Physical exam findings such as flank ecchymosis should alert treating providers to possible renal injury. The degree of hematuria cannot predict the severity of renal injury, highlighting the need for kidney imaging [7,8]. Findings on CT scan indicative of renal injury include subcapsular hematoma, perirenal hematoma, renal pelvis rupture, parenchymal laceration with or without collecting system injury, intravenous contrast extravasation from the renal artery or vein, or nonvisualization of a portion of or the entire kidney. (See "Management of blunt and penetrating renal trauma", section on 'Clinical features' and "Management of blunt and penetrating renal trauma", section on 'CT pyelography'.)

●Ureteral injury – Flank pain, hematuria, and/or flank ecchymosis or posterior rib or spine fractures should increase suspicion for ureteral injury [9]. Hematuria is an unreliable finding following ureteric trauma. There are no signs that are pathognomonic for ureteral injury. Some patients will not have any external signs to suggest a ureter injury. As such, a high index of suspicion (eg, deceleration injury) is necessary to identify the presence of ureteral injuries. Findings on CT that suggest ureteral injury include nonvisualization of the ureter, contrast extravasation from the ureter, ipsilateral hydronephrosis, and poor renal excretion localized to one side. (See "Overview of traumatic and iatrogenic ureteral injury", section on 'Clinical presentations'.)

When new symptoms of fever, flank pain, sepsis, or ileus occur following initial trauma stabilization, clinicians should be mindful to assess for a potential missed upper GU tract injury, particularly ureteral injury, which is difficult to diagnose.

Injury grading — The American Association for the Surgery of Trauma (AAST) grading system is the most commonly used injury grading system for renal trauma [10].

●Kidney – The AAST renal injury grading scale is used routinely in the evaluation of renal trauma and is useful for predicting outcomes (table 1 and figure 4) [11-13]. A study from the National Trauma Data Bank (NTDB) showed that most renal injuries were low grade (73 percent) [10]. (See "Management of blunt and penetrating renal trauma", section on 'Imaging findings and renal injury grading'.)

●Ureter – The AAST grading system for ureteral injury (table 2) is rarely reported in the medical literature. Most surgeons distinguish ureteral injuries based upon location of ureteral injury (upper, mid, lower), mechanism of injury (blunt versus penetrating), and severity of injury (partial versus complete transection) as these categories guide the type of surgical management necessary for repair. (See "Overview of traumatic and iatrogenic ureteral injury", section on 'Ureter injury grading'.)

Differential diagnosis — Following trauma, upper GU tract injury needs to be distinguished from lower GU tract injury (ie, bladder, urethra), particularly since both are associated with hematuria. Often the mechanism of injury or penetrating injury tract will aid with increasing or decreasing suspicion of one over the other. Imaging studies will identify the origin of the injury, though at times both the upper and lower GU tract may be injured, more likely in association with pelvic fracture. (See "Overview of traumatic lower genitourinary tract injury".)

APPROACH TO MANAGEMENT — The approach to managing upper genitourinary (GU) injuries is based upon trauma mechanism, the clinical status of the patient, and the nature and severity of GU injuries identified on initial imaging studies, as well as the type and severity of associated injuries, which may require laparotomy (algorithm 1). (See "Overview of the diagnosis and initial management of traumatic retroperitoneal injury".)

Hemodynamically unstable — For patients who are hemodynamically unstable or have other indications for laparotomy, exploration may identify the presence of a retroperitoneal hematoma. Whether to open the retroperitoneum (zone II) and explore the kidney depends upon the mechanism of injury (blunt, penetrating), whether the hematoma is expanding, and the presence and severity of other injuries (algorithm 1).

Damage control surgery for the upper GU organs and the management of retroperitoneal hematoma are discussed briefly below and in more detail separately. (See 'Damage control surgery' below and "Overview of the diagnosis and initial management of traumatic retroperitoneal injury", section on 'When to explore retroperitoneal hematoma'.)

Damage control surgery — During damage control surgery, an attempt should always be made to preserve the kidney. When the trauma service is the primary service, there should be a low threshold to consult urology for assistance for exploration of the upper GU tract when the clinical situation does not dictate nephrectomy as the only surgical option, since the urology service is more experienced with renal-preserving surgery.

Prior to renal exploration and possible nephrectomy, if indicated, the use of a one-shot intravenous pyelogram (IVP) in the operating room is controversial. The primary role of a one-shot IVP is to identify a normal contralateral kidney before renal exploration and possible nephrectomy. IVP has been recommended in the setting of hemodynamic instability when immediate laparotomy precludes preoperative computed tomography (CT) imaging. When chosen, this study can be performed in the operating room; however, doing so can delay treatment. To perform this study, 2 mL/kg of renal contrast medium is given intravenously with a one-shot anteroposterior radiograph performed 10 minutes later (ie, urogram). Intraoperative IVP is not a sensitive test for urologic injury [14]. The clarity of the exam can be affected by massive fluid resuscitation, peripheral edema, and/or significant hypotension. In addition, when not performed on a routine basis, the test can be cumbersome and time consuming. As such, most trauma surgeons have abandoned this study, and it is becoming less used by urologists as well. As an alternative method to confirm a functioning contralateral kidney, we prefer to quickly evaluate the flow to the uninjured kidney by manual palpation of the contralateral renal pedicle to ensure a strong renal artery pulse.

For patients taken to the operating room under emergency circumstances without imaging studies, and for whom the retroperitoneum was not explored, subsequent postoperative CT scan may be indicated to reduce the incidence of missed injuries [15,16]. (See "Overview of inpatient management of the adult trauma patient", section on 'Consider other potential injuries' and "Management of blunt and penetrating renal trauma", section on 'Subsequent/repeat imaging'.)

Exploration of zone II injury — During laparotomy for hemodynamically unstable patients with associated injuries, exploration of zone II injuries is managed as follows (see 'Damage control surgery' above and "Overview of the diagnosis and initial management of traumatic retroperitoneal injury", section on 'When to explore retroperitoneal hematoma'):

●Blunt renal injury – Do not explore a contained, nonexpanding hematoma (zone II). Explore only an expanding hematoma or one that has failed alternative methods of hemorrhage control (angioembolization). Conservative management of nonexpanding renal hematoma is the same for blunt renal injury identified intraoperatively in the setting of concomitant trauma as for injury identified on imaging studies in hemodynamically stable patients [17-19]. (See 'Conservative care' below and "Management of blunt and penetrating renal trauma", section on 'Renal exploration'.)

●Penetrating renal injury – Selectively explore the kidney for active hemorrhage or an expanding hematoma. Exploration is warranted if the ureters are in proximity to the penetrating trajectory.

Nonselective renal exploration increases the risk for subsequent nephrectomy [20]. In an analysis of the National Trauma Data Bank, nephrectomy was the most common surgical procedure performed on the injured kidney in the first 24 hours following hospital admission, typically following an operation for concomitant abdominal injuries (86 percent). Interestingly, nephrectomy was performed for any grade of renal injury (approximately 25 percent penetrating and approximately 60 percent blunt low-to-intermediate American Association for the Surgery of Trauma [AAST] grade I to III renal injuries) (table 1), emphasizing the avoidance of renal exploration whenever possible [20].

Ureteral exploration — During exploratory laparotomy in the hemodynamically unstable patient, direct inspection of the ureters is the most sensitive method to assess the ureters when injury is suspected, particularly in those who had no, or inadequate, preoperative imaging. The use of intravenous dyes such as methylene blue or indigo carmine can be used at the time of direct inspection to assess for dye leakage along the ureter. Direct injection of the dye into the ureter is another method. Retrograde pyelography may be performed in equivocal cases, when possible.

In cases of ureteral injury noted in patients with hemodynamic instability due to severe concomitant injuries, the ureter can be ligated with subsequent urinary drainage. (See "Overview of traumatic and iatrogenic ureteral injury", section on 'Ligation of traumatic injury'.)

For patients with gunshot wounds, the blast effect may result in delayed tissue ischemia and necrosis. Thus, adequate debridement and reconstruction is recommended at the time of laparotomy, depending on the extent of ureteral tissue involvement. (See "Overview of traumatic and iatrogenic ureteral injury", section on 'Treatment'.)

Hemodynamically stable — For hemodynamically stable patients who do not require abdominal exploration for other reasons, conservative management of renal injuries is successful for the majority who are candidates. Conservative management is considered the standard of care for patients with blunt renal injury who are hemodynamically stable (algorithm 1). Conservative management of penetrating renal injury (typically low grade; AAST I, II, III) can be considered for selected patients (see 'Conservative care' below and "Management of blunt and penetrating renal trauma", section on 'Nonoperative management'):

Ureteral injuries generally will require some form of treatment, either via minimally invasive or open reconstructive techniques. (See "Overview of traumatic and iatrogenic ureteral injury", section on 'Treatment'.)

CONSERVATIVE CARE — Conservative management of upper genitourinary (GU) trauma includes supportive care, serial clinical evaluation, and laboratory monitoring, and may include a variety of minimally invasive techniques, such as angioembolization for renal parenchymal bleeding, or tube drainage procedures for urine leak.

The location of in-hospital care of patients with renal injury can vary across institutions. At our institution, trauma patients are admitted to the surgical intensive care unit (ICU), where vital signs and clinical examinations can be monitored on an hourly basis. Serial laboratory studies (hematocrit levels) are monitored every six to eight hours initially and decreased in frequency as the patient's overall condition stabilizes.

Repeat contrast-enhanced computed tomography (CT) imaging with 10-minute delays at 48 to 72 hours is recommended for patients with high-grade renal injuries or worsening clinical signs [21]. Clinical signs during the period of observation that suggest a missed upper GU tract injury include progressively worsening flank pain, fever, persistent blood loss, abdominal distention, ileus, or hemodynamic instability. When indicated, surgical intervention should be undertaken expeditiously to minimize morbidity and mortality. (See "Management of blunt and penetrating renal trauma", section on 'Subsequent/repeat imaging' and "Management of blunt and penetrating renal trauma", section on 'Renal exploration' and "Overview of traumatic and iatrogenic ureteral injury", section on 'Treatment'.)

Other imaging studies that may be used during the course of managing upper GU tract injuries include angiography, retrograde pyelography, and radionuclide scintigraphy.

●Arteriography – Catheter-based angiography is used to identify potential sources for persistent bleeding during conservative management of renal injury. If a source is identified, angioembolization can be used as a minimally invasive strategy to avoid the need for open surgery. (See "Management of blunt and penetrating renal trauma", section on 'Angioembolization'.)

●Retrograde pyelography – If there is a suspicion for a collecting system or ureteral injury that is not definitively proven by CT scan (initial or repeat), then cystoscopy with a retrograde pyelogram can aid the evaluation. Depending on the location and severity of the injury, endoscopic placement of a ureteral stent or other tube drainage can be performed. (See "Management of blunt and penetrating renal trauma", section on 'Subsequent/repeat imaging' and "Overview of traumatic and iatrogenic ureteral injury", section on 'Missed injury/delayed presentation'.)

●Although radionuclide scintigraphy is not recommended for acute management of renal trauma, it can be useful for evaluating residual renal function following nonoperative management of high-grade renal injuries or following renal-preserving operative management. (See "Management of blunt and penetrating renal trauma", section on 'Follow-up care'.)

EXPLORATION AND REPAIR — Renal exploration may be necessary during trauma laparotomy or during a period of observation, in spite of advances in conservative management of renal injuries. The indications for renal exploration and the repair of renal parenchymal, collecting system, and renovascular injuries are discussed separately. (See "Management of blunt and penetrating renal trauma", section on 'Renal exploration'.)

Ureteral injuries will generally require some form of treatment, either using minimally invasive or open reconstructive techniques, the timing of which depends on the location and severity of the injury and the overall clinical status of the patient. Urine drainage and delay of definitive management may be necessary, particularly in the setting of severe concomitant injuries. (See "Overview of traumatic and iatrogenic ureteral injury", section on 'Treatment'.)

MORBIDITY AND MORTALITY — Mortality is rarely directly related to the upper genitourinary (GU) tract injury but has a reported rate of 0 to 2 percent [22-24]. Mortality increases with higher-grade injuries, which are attributed to the typically severe associated injuries [22].

In a review of penetrating torso injuries in the National Trauma Data Bank, 15.5 percent had an injury to the urinary tract. Among these patients, 63 percent had traumatic injury to the kidneys, 28 percent had injury to the bladder and urethra, and 11 percent had injury to the ureter [25]. Patients with gunshot wound and injury to the urinary tract had a higher incidence of severe acute kidney injury (AKI) and dialysis compared with patients with no injury to the urinary tract. Mortality among the entire cohort of patients with penetrating torso injury was significantly higher for patients requiring dialysis compared with AKI not requiring dialysis or no AKI (28.4 versus 20 or 8.8 percent, respectively).

Complications related to upper GU tract injury and repair are reviewed separately. (See "Management of blunt and penetrating renal trauma", section on 'Complications' and "Overview of traumatic and iatrogenic ureteral injury", section on 'Complications'.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Genitourinary tract trauma in adults" and "Society guideline links: Thoracic and lumbar spine injury in adults".)

SUMMARY AND RECOMMENDATIONS

●Upper genitourinary injury – Injury to the genitourinary (GU) tract is overall uncommon. The kidneys are the most commonly injured GU organ. Ureteral trauma is very rare. Younger males are predominantly affected, and, while renal injuries are more commonly due to blunt trauma, most ureteral injuries are due to penetrating injury. (See 'Introduction' above.)

●Clinical features and diagnosis – Upper GU tract injury is suggested by an appropriate mechanism of injury and clinical signs (flank pain, gross hematuria, micro hematuria). The degree of hematuria does not predict the severity of renal injury. When new symptoms of fever, flank pain, sepsis, or ileus occur following initial trauma stabilization, clinicians should be mindful to assess for a potential missed upper GU tract injury, particularly ureteral injury, which is difficult to diagnose. (See 'Trauma evaluation' above and 'Clinical features and diagnosis' above.)

●Diagnosis – A diagnosis of renal or ureteral injury in hemodynamically stable patients relies on GU tract imaging, typically using contrast-enhanced CT scan of the abdomen/pelvis with immediate and delayed imaging phases (ie, CT pyelography, CT urography). Protocols for these studies differ from the typical contrast-enhanced study obtained for abdominal trauma. (See 'Clinical features and diagnosis' above.)

●Approach to management – The initial approach to the trauma patient depends upon the clinical status of the patient, as well as the type and severity of injuries. (See 'Approach to management' above.)

•Conservative management – Hemodynamically stable patients with blunt renal trauma (all grades) (figure 4) are managed conservatively (algorithm 1), which includes supportive care and serial evaluation and may include angioembolization for renal parenchymal bleeding, or tube drainage procedures for collecting system injuries. Conservative management of penetrating renal injury (typically low grade; American Association for the Surgery of Trauma [AAST] I, II, III) can be considered for selected patients. During a period of conservative care, surgical exploration may be necessary if bleeding continues or urinary extravasation worsens. (See 'Conservative care' above.)

•Surgical management – Whether to open the retroperitoneum and explore the kidney and ureters in hemodynamically unstable patients is based on the mechanism of injury (blunt, penetrating), whether the hematoma is expanding, and the presence and severity of other injuries (algorithm 1). Every effort should be made to salvage the kidneys. Prior to considering nephrectomy, we manually palpate the contralateral kidney to confirm its viability. There should be a low threshold to consult urology for assistance with renal exploration. Nephrectomy may be required despite efforts to salvage the kidney. (See 'Exploration and repair' above.)

-Blunt renal injury – For blunt renal injury, only an expanding perinephric hematoma or one that has failed alternative methods of hemorrhage control (eg, angioembolization) should be opened and explored. Surgical exploration is associated with high rates of kidney loss. Nonexpanding renal hematoma identified intraoperatively is managed conservatively.

-Penetrating renal injury – For penetrating renal injury, the kidneys should generally be explored if there is concern for injury (eg, active hemorrhage, expanding hematoma).

-Collecting system injury – Although parenchymal collecting system injuries often resolve spontaneously, injuries to the renal pelvis, and ureteropelvic junction generally require some form of treatment using minimally invasive (stenting, tube drainage) or open reconstructive techniques (immediate or delayed).

-Ureteral injury – Most ureteral injuries occur in the setting of concomitant injuries that often require exploratory laparotomy. Direct inspection of the ureters is the most sensitive method to assess for ureteral injury. Immediate repair is preferred, if possible, but drainage and delay of definitive management may be necessary, particularly in the setting of severe concomitant injuries.