INTRODUCTION

The kidney is the most commonly injured solid organ in the genitourinary system and the third most commonly injured organ overall in trauma, following the spleen and liver [1–6]. Renal injuries have been reported in up to 5% of all trauma cases and have been identified in up to 10% of patients with abdominal trauma [3–10]. The relatively low prevalence of renal injuries in trauma can be attributed to its anatomical location; specifically, the kidneys are positioned in the retroperitoneum and held in place by the Gerota fascia. The organs are protected by perinephric fat and the psoas muscles, and are partially covered by the lower ribs and spinal column. This anatomical arrangement minimizes the risk of trauma to the kidneys; nonetheless, the kidneys are still prone to injury in the setting of blunt and penetrating traumas.

In the past several decades, the approach to managing renal trauma has undergone notable transformations, particularly in cases of blunt injury. There has been a shift from surgical to conservative or minimally invasive management, aligning with advances in cross-sectional imaging and the development of interventional radiological techniques [6–10]. This review article explores the current management of renal trauma, with an emphasis on the endovascular treatment of renal injuries.

ETIOLOGY AND EPIDEMIOLOGY

Renal injuries resulting from trauma are broadly categorized into two main types: blunt and penetrating injuries. While the distribution of these mechanisms may vary depending on the demographic served and location of a hospital, renal injuries are most often associated with blunt trauma, accounting for 80% to 90% of cases [4]. Penetrating renal trauma, although less common, may comprise up to 20% of renal trauma cases in certain urban areas [6]. In adults, renal trauma predominantly affects young men, and the primary mechanism for blunt injuries is overwhelmingly attributed to motor vehicle accidents, followed by falls, sports-related incidents, and other less frequent causes [5,11]. Penetrating renal injuries most commonly result from gunshot wounds, followed by stab wounds [11]. Due to its protective anatomic location, isolated renal injuries are relatively infrequent, as shown by an 86% association rate with concomitant injuries in the setting of polytrauma [8,11]. Most cases of renal trauma are of lower-grade and non–life-threatening, and therefore are managed conservatively. Risk factors for high-grade renal trauma include female sex and medical comorbidities, such as peripheral vascular disease, renal insufficiency, and malignancy [10].

Iatrogenic renal injuries are not uncommon in certain practices and can be seen in the setting of percutaneous renal biopsies and partial nephrectomy in oncologic therapy for renal tumors. Although these procedures are associated with low rates of complications, renal hemorrhage is often a feared complication for which renal arteriography and renal artery embolization can be performed with a high success rate and preservation of kidney function [12–15].

CLASSIFICATION

In 1989, Moore et al. [16], as part of the Organ Injury Scaling Committee of the American Association for the Surgery of Trauma (AAST), devised a classification system for spleen, liver, and kidney injuries. This system was revised in 2018, incorporating multidetector computed tomography findings of vascular injuries to better assess organ injury severity and to provide a more standardized management approach [17]. The AAST injury scoring scales are the most widely accepted and used system of classifying traumatic injuries. This system utilizes a scale from 1 to 5, characterizing injuries based on anatomical descriptions that range from the least severe (1) to the most severe (5) [16]. The injury scoring scales play an important role in directing treatment strategies and assist in predicting the prognosis. This system also plays an essential role in effective communication with other physicians and healthcare professionals involved in the care of trauma patients.

There are five grades of injury in renal trauma as defined by AAST (Table 1) [18]. Grade I injury includes subcapsular hematoma or parenchymal contusion without laceration. Grade II injury includes perirenal hematoma confined to the Gerota fascia or laceration less than 1 cm in depth. Grade III injury includes renal parenchymal laceration greater than 1 cm in depth, any renal vascular injury, or active bleeding contained by the Gerota fascia. Grade IV injury includes renal parenchymal laceration extending into the urinary collecting system, renal pelvis laceration, segmental renal vein or artery injury, active bleeding beyond the Gerota fascia into the retroperitoneum or intraperitoneum, or renal infarct due to vessel thrombosis without active bleeding. Grade V injury includes laceration of the main renal artery or vein, a devascularized kidney with active bleeding, or a shattered kidney.

In a classification system devised by the World Society of Emergency Surgery (WSES), renal trauma is categorized into four grades. This system is largely based upon the AAST classification and the patient’s hemodynamic status (Table 2) [19]. WSES grade I injury includes AAST grade I and II renal injuries. WSES grade II injury includes AAST grade III renal injuries or segmental vascular injuries. WSES grade III injury includes AAST grade IV and V renal injuries or any AAST grade with main vessel dissection or occlusion. WSES grade IV injury includes any renal injury with hemodynamic instability.

CLINICAL AND DIAGNOSTIC ASSESSMENT

Initial assessment

The initial evaluation of a trauma patient includes maintaining and establishing a patent airway, ensuring adequate oxygenation and ventilation, and assessing the adequacy of circulation with hemorrhage control, which may be prioritized in certain situations [20]. When evaluating renal trauma, a comprehensive assessment follows with a detailed exploration of the patient's history and details of the injury if able. The mechanism of injury is important because there is a higher risk of renal injury in mechanisms involving acceleration-deceleration, and would prompt further imaging [21,22]. Additionally, the identification of preexisting renal abnormalities is essential, as even a low-velocity impact may increase the risk of renal injury [22,23]. In patients with a solitary kidney or a solitary functioning kidney, a nephrectomy should only be performed when deemed absolutely necessary.

On physical examination, certain signs may indicate renal trauma, including flank or upper abdominal hematoma, a palpable mass, ecchymosis, and rib fractures [22]. Macroscopic hematuria is not a reliable finding in renal trauma patients, as it may be absent in 50% of patients with grade II trauma and in up to 30% of patients with grade IV renal trauma [22,24]. For laboratory testing, obtaining a urine analysis to assess for microscopic hematuria, hematocrit to assess for blood loss, and creatinine to assess baseline renal function is recommended in addition to the usual trauma panel in patients presenting with renal injury. Imaging is warranted if there is a strong suspicion of renal injury based on the physical examination or associated injuries.

Imaging

Hemodynamically stable trauma patients often undergo series of examinations, including Focused Assessment with Sonography for Trauma (FAST). Despite its use to detect intraperitoneal bleeding, FAST has limited use in the evaluation of retroperitoneal hemorrhage. Contrast-enhanced ultrasound, although not widely used, has been suggested for hemodynamically stable patients with negative FAST findings and clinical suspicion for renal injury [19]. Contrast-enhanced computed tomography (CECT) is considered the gold-standard imaging modality for the assessment of hemodynamically stable patients presenting with renal injury in the setting of blunt and penetrating trauma [25]. CT is widely available and aids in determining the grade of renal injury, which, in turn, helps assess the appropriateness of nonoperative management for a stable patient.

Depending on the institution, the preferred imaging protocol for evaluating a suspected renal injury is a multiphase CECT with at least two phases: the arterial and portal venous phases. A postcontrast arterial phase of the abdomen and pelvis is obtained approximately 35 seconds following intravenous contrast injection. The resulting corticomedullary pattern of parenchymal enhancement allows the visualization of arterial injury, but is seldom sensitive for characterizing parenchymal or collecting system injury [17]. The portal venous phase is obtained 70 to 90 seconds after the intravenous contrast injection, resulting in a late corticomedullary or early nephrogenic phase in which there is optimal enhancement of the renal parenchyma, including the medulla. This phase is helpful for assessing solid organ injury and can help determine whether an arterial injury involves active extravasation or a pseudoaneurysm/arteriovenous fistula, as well as enabling the assessment of whether venous injury is present [17]. Additional phases include precontrast and delayed phase imaging, the latter of which is obtained 5 to 10 minutes following intravenous contrast injection. The precontrast phase may help identify acute bleeding or intraparenchymal hematoma, which may become isoattenuating in comparison to the normal renal parenchyma on postcontrast CT [26]. The delayed phase, also known as the excretory or urographic phase, allows optimal enhancement of the renal collecting systems, which may help visualize injury to the collecting system and ureteric injury [22]. Patients without concerning findings on CT, such as contrast extravasation, who are responsive to fluid therapy and blood transfusions, are admitted to the intensive care unit for conservative treatment.

RENAL TRAUMA MANAGEMENT

Operative management

Patients presenting with blunt or penetrating abdominal trauma require prompt assessment and intervention. Priorities for renal trauma management include preventing mortality by controlling hemorrhage, preserving nephrons, and averting complications [22]. Hemorrhage control is important for preventing hypothermia, coagulopathy, and acidosis [27]. While the management approach for traumatic renal injuries has shifted toward nonoperative strategies, it is important to recognize that life-threatening renal bleeding in hemodynamically unstable patients is an absolute indication for surgical exploration [22,28,29]. Hypovolemic shock patients unresponsive to fluid therapy and blood transfusions are immediately transported to the operating room after an initial basic examination. Emergency laparotomy is then performed, with the primary objective of hemorrhage control and salvaging the kidney if feasible. Fortunately, the majority of renal injuries are minor and are successfully managed by conservative treatment [30]. However, extensive kidney damage may be present in 20% to 40% of patients [30]. Therefore, surgery is indicated in only about 5% to 10% of patients and is generally reserved for hemodynamically unstable and select patients with high-grade renal trauma (grade IV and V) [27,31].

Urgent surgical exploration in the management of renal trauma frequently results in nephrectomy, but certain injuries—including small stab wounds to the renal parenchyma or injuries to the renal pelvis—can be closed primarily, while partial nephrectomy may be considered if adequate functional renal parenchyma can be preserved [25,32]. Nephrectomy is to be considered in cases where hemorrhage is attributable to the kidney, but identifying the kidney as the sole source of hemorrhagic shock can be difficult [8]. Currently accepted indications for surgery are avulsion of the renal pelvis, injuries to the vascular pedicle, and continued hemodynamic instability. Surgical options for renal vascular injury include gaining vascular control at the pedicle, followed by wedge resection, partial nephrectomy, and total nephrectomy [27].

Attempts are being made to avoid surgery when possible, as patients with renal trauma are at significant risk of nephrectomy, with rates reported as high as 64% for patients undergoing renal exploration [33]. The retroperitoneal location of the kidneys provides an innate tamponade mechanism to control excess bleeding and urinary extravasation [34]. Therefore, when the Gerota fascia is violated during renal exploration, the hematoma can no longer be contained, resulting in an increased risk of bleeding and nephrectomy. Furthermore, the repair of adjacent structures may be compromised due to uncontained urinary leakage [34].

Nonoperative management

The management of renal trauma traditionally involved surgical intervention as the primary approach. The rationale behind this practice was the concern for controlling bleeding, repairing damaged structures, and ensuring the preservation of renal function. However, over the years, there has been a shift in the management of renal trauma toward a more conservative, nonoperative, and organ-preserving approach [35]. Advances in diagnostic imaging have played a crucial role in the accurate assessment of renal injuries. This has enabled better risk stratification, leading to more tailored and less invasive management strategies. Nonoperative management can be categorized into conservative treatment or angiographic embolization. Conservative treatment is designed to stop hemorrhage caused by trauma through methods such as close observation, bed stabilization, fluid resuscitation, and blood transfusion. Diagnostic angiography with angiographic catheter-directed embolization has proven to be an effective treatment method with high technical and clinical success in appropriately selected patients [36].

For blunt trauma, the respective roles of expectant management, embolization, and surgery may depend on the grade of injury and overall patient status [15,37]. The standard of care for low-grade renal injuries, such as contusions, low-grade lacerations, and capsular hematomas, involves conservative nonoperative management, as these types of injuries are known to heal spontaneously with few complications [27]. The guidelines from the American Urological Association (AUA) and the European Urological Association (EUA) support initial conservative management for patients with lower-grade renal trauma (grades I–III) and even some hemodynamically stable higher grade injuries (grades IV–V). These guidelines aim to preserve renal function and avoid unnecessary interventions [35,38–43]. In two large-scale cohorts, nonoperative management was employed in 83.4% to 94.8% of renal trauma cases, with a failure rate ranging from 2.7% to 5.4%, showing its effectiveness in managing patients with renal injuries [11,44].

While nonoperative treatment is widely accepted as the standard for low-grade traumatic kidney injuries, the approach to high-grade traumatic kidney injuries remains a subject of debate, especially regarding patients who are hemodynamically unstable. Some authors have argued that prompt surgical intervention reduces complications, mortality, and the likelihood of late nephrectomy during follow-up. Conversely, more recent studies have reported successful nonoperative treatment for patients with high-grade blunt kidney injuries. Therefore, the success of nonoperative management in the context of high-grade renal injuries remains an unresolved issue [30,45,46]. A simplified algorithm for the management of patients with suspected renal injuries is shown in Fig. 1.

Several studies have described indications for angiographic embolization in high-grade renal injuries. Disruption of the Gerota fascia results in large, expansile retroperitoneal hematoma and indicates a need for renal angiography with embolization [8]. Perirenal hematoma thickness exceeding 35 to 40 mm also predicts a need for embolization [8,30]. A study by Ha et al. [30] noted that disruption of the Gerota fascia and hypotension were risk factors for the operative management of renal injuries. Active contrast extravasation on CT did not necessarily indicate a need for renal angiography and could be managed conservatively if the amount of extravasation is small and the patient is hemodynamically stable with mild symptoms. Elevated lactate levels were also not indicative of the need for operative management or renal angiography.

Among patients stabilized after high-grade renal injuries, routine reimaging utilizing CT was found to make little difference in management, as 12.5% of patients required intervention based on the repeated CT scan. Selectively reimaging patients with collecting system injuries increased the change in management to 23.1% [47]. Further research is needed to identify clinical factors capable of predicting changes in management after repeated imaging.

Management of penetrating renal trauma

CECT is the modality of choice for evaluating penetrating injuries of the abdomen and should be performed in all hemodynamically stable patients. On physical exam, entry and exit wounds must be assessed in all patients presenting with a penetrating injury. Although penetrating trauma is much less common than blunt injury, penetrating trauma is more likely to result in severe renal injury and is often associated with multiorgan injuries. In hemodynamically stable patients without expanding hematoma, renal salvage has shown to be possible despite multiorgan involvement in cases of penetrating renal trauma [48]. However, penetrating renal trauma does have a higher nephrectomy rate per grade of the injury, a higher rate of multiorgan injuries, and a higher failure rate of angioembolization than blunt renal trauma [48–50].

In the past, penetrating renal trauma was deemed an absolute indication for renal exploration. Currently, increasing evidence supports nonoperative management for hemodynamically stable patients with penetrating renal trauma, and there has been a notable shift towards endovascular repair, similar to what has been observed in the management of blunt renal trauma [51]. A high nonoperative success rate following penetrating trauma may be achievable, as demonstrated in a prospective study by Moolman et al. [52].

ENDOVASCULAR TECHNIQUES

Vascular access and catheters

In select patients for whom angioembolization is indicated, the procedures have been traditionally performed via femoral access. However, this approach is not without complications, including hemorrhage, pseudoaneurysm, arteriovenous fistula formation, and embolism [53]. Furthermore, there may be medical devices within the vicinity, such as pelvic binders, or placed in their femoral vessels as part of their resuscitation, potentially limiting access for endovascular interventions [54]. Although femoral access is the more common approach, radial access is recommended in certain situations, with benefits including improved quality of imaging, versatility for different cases in trauma settings, and improved post-procedure care. It is important to note that when performing renal artery angioembolization via a transradial approach, the left radial artery is generally preferred given the shorter distance, but a right radial approach may be more comfortable for the operator [55].

Under local anesthesia, vascular access is generally obtained via the common femoral artery with an 18- or 19-gauge puncture needle via a modified Seldinger puncture technique. An arterial sheath, ranging from 5F to 6F, is then carefully positioned in the common femoral artery, with the tip placed at the level of the external iliac artery. This positioning enables swift and secure exchange of angiographic catheters for aortography using a 5F Omni Flush (Angiodynamics) or pigtail catheter and selective catheterization of the main renal artery. Diagnostic digital abdominal aortography, typically at a rate of 15 to 20 mL/sec for a total of 30 to 40 mL of contrast, is then performed to identify any aberrant or accessory renal arteries or variants. This is followed by selective renal arteriography, which is directed to the injured kidney based on clinical, imaging, or surgical findings. In the latter case, surgical exploration may precede imaging, particularly in patients who are initially hemodynamically unstable, perhaps due to other intra-abdominal and pelvic injuries.

Angiographic selective catheterization of the renal artery is facilitated by the use of reverse-curve or double-curve catheters, such as Simmons (Merit Medical), SOS Omni (Angiodynamics), and Cobra (Merit Medical) catheters [27,56–58]. Several factors that may pose challenges to catheterization include atherosclerosis, narrowed or tortuous iliac arteries, renal artery stenosis, abdominal aortic aneurysm, or a mass effect from retroperitoneal tumors. Therefore, selecting a catheter that conforms to the vessel anatomy is advisable [59]. All catheter insertion and withdrawal steps are carefully executed over a 0.035-inch (0.09 cm) guidewire to prevent vessel dissection by the catheter tip. Manual contrast injections are performed using 8 to 10 mL of contrast medium, and the images are assessed for vascular pathology [58]. Multiple oblique projections may be needed to identify the take-off of renal arteries. Care must be taken in identifying accessory renal artery branches, as the failure to identify accessory branches may lead to missing active bleeding, resulting in inadequate embolization [56].

Microcatheters smaller than 2.8F can be used to select second- and third-order branches of the renal artery [57]. Superselective catheterization of renal artery branches involves the use of microcatheters either via coaxial or guidewire-controlled techniques, and allows the operator to be as selective as possible so that angioembolization is performed at or near the site of arterial injury. The use of microcatheter embolization in a superselective position significantly reduces the extent of renal infarction and promotes the preservation of renal function, while decreasing the risk of distal recanalization and rebleeding [60,61]. However, in an unstable patient where initial angiography demonstrates multiple areas of contrast extravasation, nonselective embolization may be the necessary option for expedited treatment [61].

Selection of embolic material

The choice of embolization materials for renal trauma is largely dictated by operator preference and the diameter of the target vessel [62]. Many embolic agents, including Gelfoam (Pfizer), polyvinyl alcohol (PVA), N-butyl-2-cyanoacrylate (NBCA), and microcoils, have been successfully used for renal artery embolization in the setting of trauma [63–68].

Gelatin foam, or Gelfoam, is a biodegradable embolic agent used for temporary embolization. It works by mechanically packing into a vessel lumen and promoting clot formation, leading to distal vessel obstruction and thrombus formation [69]. Gelfoam undergoes enzymatic degradation and is therefore avoided in the treatment of arteriovenous malformation because of its temporary embolic effect and risk of recanalization [59]. Given its particulate nature, Gelfoam should also be avoided when an arteriovenous fistula is present due to the risk of pulmonary embolism [70]. Interestingly, Gelfoam has been used in the setting of nonselective transcatheter complete renal embolization in a hemodynamically unstable patient with a grade V renal injury, resulting in vessel recanalization a few weeks post-procedure and enabling the partial preservation of renal function [71]. Although further research is needed to compare this technique with surgical nephrectomy in similar settings, such cases highlight the versatility of Gelfoam as an embolic agent.

PVA serves as a permanent occlusion agent and is commonly used to embolize small-caliber vessels. Its mechanism involves inducing an inflammatory response in the vessel wall, ultimately leading to angionecrosis [72]. While PVA is safe and effective for use in mechanical embolization of vessels, it has certain drawbacks. These include unpredictable embolization behavior and possible blockage of the delivery catheter, which are more commonly seen with noncalibrated particulates, given their heterogeneity in shape and lack of size precision. Calibrated PVA microspheres offer a controllable size distribution, enabling better localized targeted embolization [69,73].

NBCA, more commonly known as “glue,” is a permanent liquid embolic agent that has been utilized since the 1980s but has had limited application compared to particulate agents and coils because of its difficulty of use and higher risk of complications due to its rapid and sometimes unpredictable polymerization [69,74]. An advantage of NBCA is that it can be effectively employed in patients with systemic coagulopathy, as it readily precipitates upon contact with an ionic fluid medium (e.g., blood) and does not depend on the coagulation cascade [75]. The challenge lies in determining the optimal concentration of NBCA needed for targeted embolization, particularly in regions of high flow. Lipiodol (Guerbert) is mixed with NBCA to enhance radiopacity and increase the time it takes to polymerize [69]. Therefore, the composition of the NBCA and Lipiodol mixture determines the speed of polymerization and distance traveled in the target vessel. A high concentration of NBCA is used in high-flow regions and to achieve proximal rapid precipitation. A lower concentration of NBCA allows distal percolation, facilitating downstream embolization [75].

Coils serve as mechanical occlusion devices that are widely utilized in the embolization of bleeding vessels and aneurysms [69]. During embolization, the catheter is carefully positioned within the target vessel, and a delivery system is employed to push the coil through the catheter. The coil is strategically wedged against the vessel lumen or the aneurysm sac, effectively occluding the target primarily due to its mechanical occlusive and low thrombogenic properties [69]. The low thrombogenicity is attributed to the coil’s capacity to mechanically impede blood flow initiating clot formation. This process is contingent on the body’s ability to form blood clots, a factor that may vary across different areas of the coil, between coils, and among patients [69]. Bioactive coatings have been integrated into coils to enhance thrombogenicity. For example, fibered coils are particularly effective in increasing thrombogenicity, which is especially beneficial in patients with hemodynamic instability or hemorrhagic shock. Additional embolic agents such as Gelfoam may be used in conjunction with coils to efficiently occlude the lesion [76].

The main challenges in coil embolization include nontargeted embolization and coil migration. Nontargeted embolization typically results from coil misplacement or a mismatch between the coil and vessel size. Coil migration is typically seen with smaller coils, and although rare, there are reports of migration into the systemic circulation [69]. Extrusion into the parent vessel may be seen with large coils used to embolize aneurysms, which may lead to nontargeted thrombosis. Excessive radial force from an oversized coil can also cause elongation within the sac and potentially result in a ruptured aneurysm [69]. Other limitations are related to post-procedural imaging. These include beam hardening and scatter artifact limiting evaluation on CT, and susceptibility artifact limiting evaluation on magnetic resonance imaging [77]. Despite the challenges, the versatility provided by coils in terms of their size and shape makes them a popular embolic agent in the setting of renal trauma. Additionally, advances in delivery systems and accommodations for microcatheters have made it possible to place the coils in selective targets, increasing the rate of organ salvage and tissue preservation [78].

Success rates

The success rate of angioembolization for the treatment of renal injuries in the setting of blunt trauma ranges from 63% to 100%, with higher rates of failure following embolization observed in higher grade renal injuries [19,70]. In situations necessitating repeated embolization, the success rates parallel those observed in initial embolization, substantiating the justification for repeated interventions when clinically indicated [79]. A study by Hotaling et al. [50] showed that 78% and 83% of patients with grade IV and V injuries, respectively, avoided nephrectomy when treated with embolization, although the initial angioembolization success rate was low and most of the patients required some type of secondary intervention. Therefore, higher grade injuries were associated with an increased risk of initial angioembolization failure, but a repeated procedure has a high chance of preventing nephrectomy in these patients. Lastly, angioembolization results in similar or better renal function, lower complication rates, and a shorter length of stay in the intensive care unit, with equal transfusion requirements and rebleeding rates when compared to surgery [80,81].

Complications

While renal artery embolization is generally regarded as a safe procedure, there are potential complications including access site bleeding, renal infarction, iatrogenic vascular injury, postembolization syndrome, and renal abscess [27,66]. Postembolization syndrome, characterized by mild fever, flank pain, and leukocytosis, represents a recognized complication that can be effectively managed through conservative measures involving anti-inflammatory and analgesic medications [58]. Contrary to earlier findings reporting no correlation with acute kidney injury, a more recent study has identified acute kidney injury as a potential complication following renal artery embolization [82].

Follow-up

For patients with grade I and II renal injuries managed nonoperatively, follow-up imaging can be safely omitted. In cases of grade III to V renal injuries, the need for follow-up imaging is contingent upon the patient’s clinical condition [19]. In patients with higher grade renal injuries (grade IV and V), repeated CECT with delayed excretory phase imaging is recommended within the initial 48 hours following admission, as urinary leaks are missed on initial imaging in 0.2% of all cases and in 1% of high-grade renal injuries [19].

CONCLUSIONS

Renal injuries most commonly occur in association with blunt trauma, and the primary mechanism for blunt injuries is overwhelmingly attributed to motor vehicle accidents. The AAST injury scoring scales are used to determine the severity, guide management, and assist in predicting the prognosis. Although the management of blunt trauma depends on the grade of injury and overall patient status, there is an increasing trend toward a more conservative, nonoperative approach. Additionally, guidelines from the AUA and EUA support the initial conservative management of lower-grade renal trauma in hemodynamically stable patients.

The indications for renal angiography with embolization include disruption of the Gerota fascia, resulting in a large, expansile retroperitoneal hematoma. Active extravascular contrast extravasation on CT is another radiological finding that may necessitate intervention. In appropriately selected patients for whom angioembolization is indicated, superselective embolization is typically recommended for preserving renal function. Various embolic agents are used for renal artery embolization, including temporary and permanent agents. The overall success rate of angioembolization in blunt renal trauma is high in lower-grade injuries, with a relatively low complication rate.

ARTICLE INFORMATION

Conflicts of interest

The authors have no conflicts of interest to declare.

Funding

The authors received no financial support for this study.

Author contributions

Conceptualization: all authors; Investigation: all authors; Methodology: all authors; Project administration: all authors; Visualization: all authors; Writing–original draft: PL; Writing–review & editing: all authors. All authors read and approved the final manuscript.

Data availability

Data sharing is not applicable as no new data were created or analyzed in this study.

Fig. 1.

Simplified algorithm for the management of patients with suspected renal injuries. CECT, contrast-enhanced computed tomography; AAST, American Association for the Surgery of Trauma. ^a)In select hemodynamically stable patients with grade IV and V renal injury, nonoperative management with close monitoring and serial CECT imaging may be an option. ^b)Renal exploration if hemorrhage is attributable to the kidney.

REFERENCES

• 1. Ahmed I, Beckingham I. Liver trauma. Trauma 2007;9:171–80. ArticlePDF
• 2. Gupta P, Dar PM, Gupta S, et al. Analysis and approach to renal trauma: a five-year experience at a level I trauma centre in north India. Chin J Traumatol 2023;Sep 23; [Epub]. https://doi.org/10.1016/j.cjtee.2023.08.004. Article
• 3. Kwon H, Jeon CH, Kim CW. Intervention for urologic trauma. J Korean Soc Radiol 2019;80:667–83. ArticlePDF
• 4. Austin J, Rajkumar G. The diagnosis and management of renal trauma. J Clin Urol 2018;11:70–6. ArticlePDF
• 5. Petrone P, Perez-Calvo J, Brathwaite CE, Islam S, Joseph DK. Traumatic kidney injuries: a systematic review and meta-analysis. Int J Surg 2020;74:13–21. ArticlePubMed
• 6. Veeratterapillay R, Fuge O, Haslam P, Harding C, Thorpe A. Renal trauma. J Clin Urol 2017;10:379–90. ArticlePDF
• 7. Salcedo A, Ordonez CA, Parra MW, et al. Damage control for renal trauma: the more conservative the surgeon, better for the kidney. Colomb Med (Cali) 2021;52:e4094682ArticlePubMedPMCPDF
• 8. Adams CA. Renal trauma: when to embolize? Curr Surg Rep 2016;4:23. ArticlePDF
• 9. Salem MS, Urry RJ, Kong VY, Clarke DL, Bruce J, Laing GL. Traumatic renal injury: five-year experience at a major trauma centre in South Africa. Injury 2020;51:39–44. ArticlePubMed
• 10. Tae BS, Jang HA, Yu J, Oh KJ, Moon KH, Park JY. Epidemiology and management trend of renal trauma: results of a nationwide population-based study. J Korean Med Sci 2022;37:e333. ArticlePubMedPMCPDF
• 11. Voelzke BB, Leddy L. The epidemiology of renal trauma. Transl Androl Urol 2014;3:143–9. PubMedPMC
• 12. Ali H, Murtaza A, Anderton J, Ahmed A. Post renal biopsy complication rate and diagnostic yield comparing hands free (ultrasound-assisted) and ultrasound-guided biopsy techniques of renal allografts and native kidneys. Springerplus 2015;4:491. ArticlePubMedPMCPDF
• 13. Rochon PJ, Hu JH. Renal artery embolization for renal biopsy bleed. Semin Intervent Radiol 2016;33:342–6. ArticlePubMedPMC
• 14. Baumann C, Westphalen K, Fuchs H, Oesterwitz H, Hierholzer J. Interventional management of renal bleeding after partial nephrectomy. Cardiovasc Intervent Radiol 2007;30:828–32. ArticlePubMedPDF
• 15. Loffroy R, Chevallier O, Gehin S, et al. Endovascular management of arterial injuries after blunt or iatrogenic renal trauma. Quant Imaging Med Surg 2017;7:434–42. ArticlePubMedPMC
• 16. Moore EE, Cogbill TH, Malangoni MA, et al. Organ injury scaling. Surg Clin North Am 1995;75:293–303. ArticlePubMed
• 17. Chien LC, Vakil M, Nguyen J, et al. The American Association for the Surgery of Trauma Organ Injury Scale 2018 update for computed tomography-based grading of renal trauma: a primer for the emergency radiologist. Emerg Radiol 2020;27:63–73. ArticlePubMedPDF
• 18. Kozar RA, Crandall M, Shanmuganathan K, et al. Organ injury scaling 2018 update: spleen, liver, and kidney. J Trauma Acute Care Surg 2018;85:1119–22. ArticlePubMed
• 19. Coccolini F, Moore EE, Kluger Y, et al. Kidney and uro-trauma: WSES-AAST guidelines. World J Emerg Surg 2019;14:54. ArticlePubMedPMCPDF
• 20. Ferrada P, Ferrada R, Jacobs L, et al. Prioritizing circulation to improve outcomes for patients with exsanguinating injury: a literature review and techniques to help clinicians achieve bleeding control. J Am Coll Surg 2024;238:129–36. ArticlePubMed
• 21. Schmidlin F, Farshad M, Bidaut L, et al. Biomechanical analysis and clinical treatment of blunt renal trauma. Swiss Surg 1998;237–43. PubMed
• 22. Erlich T, Kitrey ND. Renal trauma: the current best practice. Ther Adv Urol 2018;10:295–303. ArticlePubMedPMCPDF
• 23. Schmidlin FR, Iselin CE, Naimi A, et al. The higher injury risk of abnormal kidneys in blunt renal trauma. Scand J Urol Nephrol 1998;32:388–92. ArticlePubMed
• 24. Shariat SF, Roehrborn CG, Karakiewicz PI, Dhami G, Stage KH. Evidence-based validation of the predictive value of the American Association for the Surgery of Trauma kidney injury scale. J Trauma 2007;62:933–9. ArticlePubMed
• 25. Dayal M, Gamanagatti S, Kumar A. Imaging in renal trauma. World J Radiol 2013;5:275–84. ArticlePubMedPMC
• 26. Alonso RC, Nacenta SB, Martinez PD, Guerrero AS, Fuentes CG. Kidney in danger: CT findings of blunt and penetrating renal trauma. Radiographics 2009;29:2033–53. ArticlePubMed
• 27. Stratil PG, Burdick TR. Visceral trauma: principles of management and role of embolotherapy. Semin Intervent Radiol 2008;25:271–80. ArticlePubMedPMC
• 28. Morey AF, Brandes S, Dugi DD, et al. Urotrauma: AUA guideline. J Urol 2014;192:327–35. ArticlePubMedPMC
• 29. Lynch TH, Martinez-Pineiro L, Plas E, et al. EAU guidelines on urological trauma. Eur Urol 2005;47:1–15. ArticlePubMed
• 30. Ha G, Jang SW, Shin IS, et al. Finding new indicators for operation and angiographic embolization in blunt renal injury patients: a single-center experience over 13 years. Ann Surg Treat Res 2021;101:49–57. ArticlePubMedPMCPDF
• 31. Keihani S, Wang SS, Joyce RP, et al. External validation of a nomogram predicting risk of bleeding control interventions after high-grade renal trauma: the Multi-institutional Genito-Urinary Trauma Study. J Trauma Acute Care Surg 2021;90:249–56. ArticlePubMedPMC
• 32. Shoobridge JJ, Corcoran NM, Martin KA, Koukounaras J, Royce PL, Bultitude MF. Contemporary management of renal trauma. Rev Urol 2011;13:65–72. PubMedPMC
• 33. Wessells H, Suh D, Porter JR, et al. Renal injury and operative management in the United States: results of a population-based study. J Trauma 2003;54:423–30. ArticlePubMed
• 34. Keihani S, Xu Y, Presson AP, et al. Contemporary management of high-grade renal trauma: results from the American Association for the Surgery of Trauma Genitourinary Trauma study. J Trauma Acute Care Surg 2018;84:418–25. ArticlePubMed
• 35. Chen J, Cai W, Li L. Profile of renal artery embolization (RAE) for renal trauma: a comparison of data from two major trauma center. Int Braz J Urol 2020;46:194–202. ArticlePubMedPMC
• 36. Holden A. Abdomen: interventions for solid organ injury. Injury 2008;39:1275–89. ArticlePubMed
• 37. Ramaswamy RS, Darcy MD. Arterial embolization for the treatment of renal masses and traumatic renal injuries. Tech Vasc Interv Radiol 2016;19:203–10. ArticlePubMed
• 38. Lanchon C, Fiard G, Arnoux V, et al. High grade blunt renal trauma: predictors of surgery and long-term outcomes of conservative management. A prospective single center study. J Urol 2016;195:106–11. ArticlePubMed
• 39. Shoobridge JJ, Bultitude MF, Koukounaras J, Martin KE, Royce PL, Corcoran NM. A 9-year experience of renal injury at an Australian level 1 trauma centre. BJU Int 2013;112 Suppl 2:53–60. PubMed
• 40. van der Wilden GM, Velmahos GC, Joseph DK, et al. Successful nonoperative management of the most severe blunt renal injuries: a multicenter study of the research consortium of New England Centers for Trauma. JAMA Surg 2013;148:924–31. ArticlePubMed
• 41. Hotaling JM, Wang J, Sorensen MD, et al. A national study of trauma level designation and renal trauma outcomes. J Urol 2012;187:536–41. ArticlePubMed
• 42. Broghammer JA, Fisher MB, Santucci RA. Conservative management of renal trauma: a review. Urology 2007;70:623–9. ArticlePubMed
• 43. Sartorelli KH, Frumiento C, Rogers FB, Osler TM. Nonoperative management of hepatic, splenic, and renal injuries in adults with multiple injuries. J Trauma 2000;49:56–62. ArticlePubMed
• 44. Bjurlin MA, Fantus RJ, Fantus RJ, Villines D. Comparison of nonoperative and surgical management of renal trauma: can we predict when nonoperative management fails? J Trauma Acute Care Surg 2017;82:356–61. PubMed
• 45. Ahn SR, Seo SH, Lee JH, Park CY. Non-operative management with angioembolization of grade IV and V renal injuries in a hybrid emergency room system. J Trauma Inj 2021;34:191–7. ArticlePDF
• 46. Burns J, Brown M, Assi ZI, Ferguson EJ. Five-year retrospective review of blunt renal injuries at a level I trauma center. Am Surg 2017;83:148–56. ArticlePubMedPDF
• 47. Kim K, Ha G, Jang SW, Jang JY, Bae KS. Determination of the radiologic findings for predicting failure of conservative management with observation for blunt renal injury patients: a single-centre experience over 13 years. Injury 2021;52:2588–93. ArticlePubMed
• 48. Kansas BT, Eddy MJ, Mydlo JH, Uzzo RG. Incidence and management of penetrating renal trauma in patients with multiorgan injury: extended experience at an inner city trauma center. J Urol 2004;172(4 Pt 1):1355–60. ArticlePubMed
• 49. Santucci RA, McAninch JM. Grade IV renal injuries: evaluation, treatment, and outcome. World J Surg 2001;25:1565–72. ArticlePubMedPDF
• 50. Hotaling JM, Sorensen MD, Smith TG, Rivara FP, Wessells H, Voelzke BB. Analysis of diagnostic angiography and angioembolization in the acute management of renal trauma using a national data set. J Urol 2011;185:1316–20. ArticlePubMedPMC
• 51. Colaco M, Navarrete RA, MacDonald SM, Stitzel JD, Terlecki RP. Nationwide procedural trends for renal trauma management. Ann Surg 2019;269:367–9. ArticlePubMed
• 52. Moolman C, Navsaria PH, Lazarus J, Pontin A, Nicol AJ. Nonoperative management of penetrating kidney injuries: a prospective audit. J Urol 2012;188:169–73. ArticlePubMed
• 53. Hetrodt J, Engelbertz C, Gebauer K, et al. Access site related vascular complications following percutaneous cardiovascular procedures. J Cardiovasc Dev Dis 2021;8:136. ArticlePubMedPMC
• 54. Adnan SM, Romagnoli AN, Madurska MJ, Dubose JJ, Scalea TM, Morrison JJ. Safety and efficacy of radial access in trauma in 65 trauma endovascular cases. J Vasc Surg 2020;71:1564–71. ArticlePubMed
• 55. Ruzsa Z, Toth K, Jambrik Z, et al. Transradial access for renal artery intervention. Interv Med Appl Sci 2014;6:97–103. ArticlePubMedPMC
• 56. Farg HM, Elawdy MM, Soliman KA, et al. Predictors of renal angioembolization outcome: a retrospective analysis with 148 patients at a tertiary urology institute. Asian J Urol 2022;9:103–8. ArticlePubMed
• 57. Floridi C, Cacioppa LM, Rossini N, et al. Predictive factors of selective transarterial embolization failure in acute renal bleeding: a single-center experience. Emerg Radiol 2023;30:597–606. ArticlePubMedPDF
• 58. Farg HM, Elawdy M, Soliman KA, et al. Renal arterial embolization: indications, angiographic findings, and outcomes in a series of 170 patients. Curr Urol 2023;17:213–8. ArticlePubMed
• 59. Sauk S, Zuckerman DA. Renal artery embolization. Semin Intervent Radiol 2011;28:396–406. ArticlePubMedPMC
• 60. Sofocleous CT, Hinrichs C, Hubbi B, et al. Angiographic findings and embolotherapy in renal arterial trauma. Cardiovasc Intervent Radiol 2005;28:39–47. ArticlePubMedPDF
• 61. Lopera JE. Embolization in trauma: review of basic principles and techniques. Semin Intervent Radiol 2021;38:18–33. ArticlePubMedPMC
• 62. Liguori G, Rebez G, Larcher A, et al. The role of angioembolization in the management of blunt renal injuries: a systematic review. BMC Urol 2021;21:104. ArticlePubMedPMCPDF
• 63. Brewer ME, Strnad BT, Daley BJ, et al. Percutaneous embolization for the management of grade 5 renal trauma in hemodynamically unstable patients: initial experience. J Urol 2009;181:1737–41. ArticlePubMed
• 64. Stewart AF, Brewer ME, Daley BJ, Klein FA, Kim ED. Intermediate-term follow-up of patients treated with percutaneous embolization for grade 5 blunt renal trauma. J Trauma 2010;69:468–70. ArticlePubMed
• 65. Charbit J, Manzanera J, Millet I, et al. What are the specific computed tomography scan criteria that can predict or exclude the need for renal angioembolization after high-grade renal trauma in a conservative management strategy? J Trauma 2011;70:1219–27. ArticlePubMed
• 66. Vozianov S, Sabadash M, Shulyak A. Experience of renal artery embolization in patients with blunt kidney trauma. Cent European J Urol 2015;68:471–7. PubMedPMC
• 67. Yanagi M, Suzuki Y, Hamasaki T, et al. Early transcatheter arterial embolization for the american association for the surgery of trauma grade 4 blunt renal trauma in two institutions. J Nippon Med Sch 2018;85:204–7. ArticlePubMed
• 68. Desai D, Ong M, Lah K, Clouston J, Pearch B, Gianduzzo T. Outcome of angioembolization for blunt renal trauma in haemodynamically unstable patients: 10-year analysis of Queensland public hospitals. ANZ J Surg 2020;90:1705–9. ArticlePubMedPDF
• 69. Hu J, Albadawi H, Chong BW, et al. Advances in biomaterials and technologies for vascular embolization. Adv Mater 2019;31:e1901071ArticlePubMedPMCPDF
• 70. Smith TA, Eastaway A, Hartt D, Quencer KB. Endovascular embolization in renal trauma: a narrative review. Ann Transl Med 2021;9:1198. ArticlePubMedPMC
• 71. Jairam A, King B, Berman Z, Rivera-Sanfeliz G. Non-permanent transcatheter proximal renal artery embolization for a grade 5 renal injury with delayed recanalization and preserved renal parenchymal enhancement. J Trauma Inj 2021;34:198–202. ArticlePDF
• 72. Sukamto AR, Sembiring YE, Akbar E, Limanto DH. Technical aspect in renal artery embolization in renal tumors: a case series. Int J Surg Case Rep 2022;100:107724. ArticlePubMedPMC
• 73. Sheth RA, Sabir S, Krishnamurthy S, et al. Endovascular embolization by transcatheter delivery of particles: past, present, and future. J Funct Biomater 2017;8:12. ArticlePubMedPMC
• 74. Kim J, Shin JH, Yoon HK, et al. Transcatheter renal artery embolization with N-butyl cyanoacrylate. Acta Radiol 2012;53:415–21. ArticlePubMedPDF
• 75. Tayal M, Nandolia KK, Sharma P, Mittal A, Chauhan U. N-butyl 2-cyanoacrylate (NBCA) in nephron sparing superselective embolization of iatrogenic renovascular injuries: a single centre experience. Cureus 2022;14:e33166ArticlePubMedPMC
• 76. Alwarraky MS, Abdallah MM, Elgharbawy MS. Clinical outcome and safety of selective renal artery embolization using permanent occlusive agents for acute renal bleeding. Egypt J Radiol Nucl Med 2020;51:205. ArticlePDF
• 77. Young S, Rostambeigi N, Golzarian J. The common but complicated tool: review of embolic materials for the interventional radiologist. Semin Intervent Radiol 2021;38:535–41. ArticlePubMedPMC
• 78. Dinkel HP, Danuser H, Triller J. Blunt renal trauma: minimally invasive management with microcatheter embolization: experience in nine patients. Radiology 2002;223:723–30. ArticlePubMed
• 79. Huber J, Pahernik S, Hallscheidt P, et al. Selective transarterial embolization for posttraumatic renal hemorrhage: a second try is worthwhile. J Urol 2011;185:1751–5. ArticlePubMed
• 80. Choudhury S, Ray P, Pal DK. Changing paradigms of management of isolated blunt renal trauma. Trauma 2022;24:36–42. ArticlePDF
• 81. Sarani B, Powell E, Taddeo J, et al. Contemporary comparison of surgical and interventional arteriography management of blunt renal injury. J Vasc Interv Radiol 2011;22:723–8. ArticlePubMed
• 82. Huang JF, Liao CH, Chen SA, et al. The effect of transarterial embolization and nephrectomy on acute kidney injury in patients with blunt renal trauma: an American College of Surgeons Trauma Quality Improvement Program analysis. Injury 2024;55:111188. ArticlePubMed

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