Interventional radiology in renal trauma

Abstract

Injury to the kidney is relatively common in significant abdominal trauma with the majority of injuries being secondary to a blunt rather than penetrating mechanism. Iatrogenic injury is an important additional cause of renal vascular damage. Multidetector computed tomography (CT) is the reference imaging modality in patients with suspected blunt, penetrating or iatrogenic injury. It allows rapid acquisition of images that accurately identify and stage injury to the kidneys and other major organs. This review addresses clinical indications for imaging, injury classification and the subsequent management of renal trauma, focusing on the important role of the interventional radiology team, particularly in stopping life-threatening haemorrhage by transcatheter embolisation techniques.

Keywords

Kidney trauma interventional radiology embolisation computed tomography bleeding

Introduction

Renal injury is relatively common in significant abdominal trauma occurring in up to 10% of cases. The majority of renal injuries are the result of blunt as opposed to penetrating trauma with associated injuries to other organ systems being common. Iatrogenic trauma to kidneys is an additional important group of renal vascular injury to be considered. Multidetector computed tomography (CT) is the imaging modality of choice for grading renal injury whilst allowing pre-existing conditions and associated injuries to be identified. Grading of the injured kidney is most usually done with the American Association for the Surgery of Trauma (AAST) renal injury severity scale. This traditionally provides a framework for guiding management but does not include several important direct and indirect signs of renal injury which if present are readily detected by CT. These findings include perirenal haematoma size and active extravasation of contrast. The majority of injuries are classified as minor injuries. These and increasingly intermediate-grade injuries can be safely managed without intervention or surgery. The challenge to the trauma team is to accurately and rapidly identify those patients with major grade renal injury who require timely treatment by surgery or increasingly interventional radiology (IR). Haemorrhage remains a leading cause of early death in trauma patients and the IR team can offer definitive control of renal vascular bleeding in many cases. The concept of stopping traumatic renal haemorrhage by transcatheter embolisation is not new with small case series using autologous blood clot dating back to the 1970s. Since then there has been a general trend in trauma care towards less invasive management. This, accompanied by significant advances in IR techniques and technology and supported by a growing body of evidence has resulted in a shift away from open surgical management of patients with high-grade renal injury towards transcatheter embolisation even in the face of haemodynamic instability.

Incidence and mechanism of injury

Renal trauma occurs in between 1% and 3% of all trauma cases (Santucci et al., 2004). In significant blunt and penetrating abdominal trauma, the kidney is damaged relatively often, despite some degree of local anatomical protection. It is the most commonly damaged retroperitoneal organ being injured in up to 10% of cases of significant abdominal injury (McAninch and Santucci, 2002). The vast majority of cases (approximately 90%) result from blunt trauma, commonly road traffic accidents and falls, with penetrating injuries, principally from stab and gunshot wounds, being less common (Santucci et al., 2004). This does not include an important subgroup of renal injury caused as a result of medical interventions including renal biopsy, partial nephrectomy and renal access procedures. Iatrogenic injury is a significant cause of renal vascular injury. Injury to other major organs is common in significant blunt and penetrating renal trauma; however, more than 90% of isolated renal injuries are classified as minor and are self-limiting (Santucci et al., 2004).

Clinical features

Haematuria is an important sign of renal injury, being present in up to 95% of cases (McAninch and Santucci, 2002). However, its presence or degree does not necessarily correlate well with injury severity as was first described by Bright et al. (1978) in 1978. Indeed, haematuria may be absent in cases where renal pedicle or pelviureteric junction damage has been sustained. Macroscopic haematuria may be absent, or indeed transient, and performing urine analysis to assess for microscopic haematuria is essential. Accurate identification of the mechanism of injury, evaluation for the presence of associated injuries and dynamic assessment of the haemodynamic status of the patient with significant renal injury is mandatory.

Imaging

Indications

The decision to perform imaging is based on the history including the mechanism of injury, findings at physical examination, the haemodynamic status of the patient and the results of laboratory studies. At our institution, all patients with abdominal trauma who have a significant mechanism of injury or are haemodynamically unstable or have abdominal signs or symptoms or have a reduced level of consciousness will undergo CT imaging. This has reduced the number of cases where application of renal specific criteria for imaging is required. However, indications for renal imaging in blunt trauma include all patients with macroscopic haematuria, microscopic haematuria and shock (systolic BP < 90 mmHg), mechanism of injury known to be associated with renal injury, e.g. rapid deceleration or fall from a height and associated injuries known to be associated with renal injury, e.g. lower rib or lumbar spine transverse process fractures. Note that microscopic haematuria alone is not an absolute indication for imaging as only 0.1–0.5% of haemodynamically stable patients with microscopic haematuria have significant renal tract injuries. All patients sustaining penetrating injury should be imaged, irrespective of the presence or absence of haematuria (Hardeman et al., 1987; Mee et al., 1989; Miller and McAninch, 1995). Indications for imaging in renal trauma are summarised in Table 1.

Table 1.

Specific indications for imaging in renal trauma

Blunt trauma
Macroscopic haematuria
Microscopic haematuria with shock (systolic BP < 90 mmHg)
Significant mechanism of injury
Significant associated injuries
Penetrating trauma
All patients with or without haematuria

Modalities

Multidetector CT examination is the reference standard imaging modality in patients with suspected renal trauma or indeed any significant blunt abdominal trauma (Santucci et al., 2004). Modern scanners, which should ideally be located in close proximity to the trauma resuscitation room, can acquire whole body images in a matter of seconds. This allows minimal interruption to the ongoing resuscitation efforts of the trauma team and underpins a shift away from the concept of the trauma patient being too unstable to undergo CT examination. A recent large multicentre study of 4621 blunt trauma patients demonstrated that the integration of whole body CT into early trauma care significantly increased the probability of survival (Huber-Wagner et al., 2009). The acquired images allow accurate identification and staging of kidney injury, information regarding pre-existing renal disease, assessment of the contralateral kidney and identification of injuries to other organs. This information coupled with the clinical status of the patient allows for timely decision making as to the need for interventional or surgical management.

The examination should be tailored to the injured patient and as such it is not possible to prescribe a universal protocol that suits all cases or institutions. Most scans will be performed as part of an assessment for abdominal trauma, which in the stable patient usually involves acquisition of images in the portal venous phase post-administration of intravenous contrast. This will image the kidneys in the late cortical or early nephrogenic phase, allowing identification of parenchymal injury. In the haemodynamically unstable patient, imaging in the arterial phase is recommended allowing active bleeding to be identified. If there is suspicion of an injury to the collecting system on the initial images (and the patients clinical condition will allow it), a delayed excretory-phase scan can be performed to assess for urinary contrast extravasation.

Other imaging modalities have a very limited role in the initial assessment of the acutely injured kidney. The use of intravenous urography in this setting is largely historical. Ultrasound may be utilised by a member of the trauma team in the resuscitation room as a part, the controversial triage tool Focused Asssessment by Sonography in Trauma which does not involve dedicated assessment of the kidneys. Ultrasound is certainly less sensitive at identifying free retroperitoneal fluid and solid organ injury than CT. Catheter angiography is occasionally used as a first-line diagnostic tool, but is more usually performed as part of a transcatheter embolisation procedure following CT.

Injury classification

Over two decades ago, the AAST organ injury scale for renal trauma was published (Moore et al., 1989). This scheme is an anatomic description of kidney damage which is scaled from one (least severe) to five (most severe). It is outlined in Table 2 and some examples are illustrated in Figure 1. The scale allows the classification of renal injury into categories upon which decisions regarding patient management can be based. Studies have validated its clinical use (Santucci et al., 2001; Kuan et al., 2006; Tasian et al., 2010); however, in the 20 years or so since their publication, the management of renal trauma has significantly changed. As in the management of blunt trauma to other solid organs, there has been a shift towards non-operative management (Santucci and Fischer, 2005). This has in part been driven by significant advances in the quality and acquisition time of CT images, coupled with a surge in transcatheter embolisation techniques and technology. The key features of the AAST organ injury score, principally parenchymal laceration depth and major vessel injury, are readily identified by multidetector CT. However, modern scanners are capable of demonstrating several features of renal injury which are not included in the AAST score. These include active contrast extravasation, perirenal haematoma size and laceration size, and complexity. These findings are important risk factors significant for renal vascular injury associated with the need for urgent intervention to arrest bleeding, increasingly by transcatheter embolisation (Nuss et al., 2009). Other findings indicative of renal vascular injury that may be identified on arterial phase CT imaging include the presence of pseudoaneurysm (PSA) or arteriovenous fistula (AVF). This has led to the proposal to substratify AAST grade 4 injuries into 4a and 4b based on the absence or presence of additional risk factors such as active contrast extravasation, with the former likely to be managed non-operatively and the latter with embolisation or open surgery (Dugi et al., 2010). A further CT finding reported to be associated with the need for transcatheter embolisation is that of discontinuity of Gerota's fascia (Fu et al., 2010).

Figure 1.

(a) A 3D reformatted image from a CT examination of a patient who fell from a height onto his left side. The left kidney is displaced medially by perirenal haematoma. There is extravasation of contrast indicative of active bleeding (arrow). Note the associated fractures of the left 11th and 12th ribs (arrowheads). (b) An axial slice from the CT examination demonstrates significant left perirenal haematoma displacing the left kidney. There is extravasation of contrast indicative of active bleeding (arrow). (c) Selective left renal artery angiogram demonstrates active bleeding from lower pole arterial branch (arrow). (d) Super selective coil embolisation (arrow) and identification of a further area of active bleeding (arrow head) which was also successfully treated by embolisation with coils.

Table 2.

The AAST renal injury severity scale

Grade^a	Type	Description
I	Contusion	Microscopic or gross haematuria; imaging studies normal
	Haematoma	Subcapsular; not expanding with no parenchymal laceration
II	Haematoma	Not expanding perirenal haematoma confined to renal retroperitoneum
	Laceration	<1.0 cm parenchymal depth of renal cortex with no urinary extravasation
III	Laceration	>1.0 cm parenchymal depth of renal cortex with no collecting system ruptures or urinary extravasation
IV	Laceration	Parenchymal laceration extending through the renal cortex, medulla and collecting system
	Vascular	Main renal artery or vein injury with contained haemorrhage
V	Laceration	Completely shattered kidney
	Vascular	Avulsion of renal hilum which devascularises kidney

^aAdvance one grade for bilateral injuries up to grade III. Access online at http://www.aast.org/injury/injury.html.

Management

The vast majority of renal injuries are minor and self-limiting (Santucci et al., 2004). Intermediate-grade injuries are increasingly managed expectantly without IR or surgical intervention. Traditionally, high-grade injuries were treated by open surgery with renal salvage/reconstructive surgery or nephrectomy. In some cases, the decision to proceed to urgent laparotomy may be due to the recognition of coexisting severe injuries to other major organs needing surgical intervention or dictated by limited local access to IR services. The move away from surgical management of isolated high-grade renal injuries has not just been the pull resulting from improved imaging with multidetector CT, better critical care services and advances in IR, but also the poor outcomes following open surgical management. A large proportion of patients undergoing exploratory laparotomy for renal trauma underwent nephrectomy (Wessels et al., 2003), and high morbidity and mortality rates have been reported (Edwards et al., 2009). Nephrectomy in the setting of trauma has also been shown to be associated with a higher incidence of renal failure than other therapeutic modalities (Starnes et al., 2010). Avoidance of iatrogenic nephrectomy is the obvious benefit of non-surgical management of isolated renal injury.

Transcatheter embolisation has been shown to be a safe and effective therapy to control active renal vascular bleeding secondary to blunt and in selected cases penetrating trauma (Dinkel et al., 2002; Bent et al., 2008; Breyer et al., 2008). This is also the experience at our institution where a series of patients have undergone successful embolisation of acute renal haemorrhage following both blunt and penetrating trauma (Figure 1(a)–(d)). More recently, Brewer et al. (2009) reported the safe and effective urgent embolisation of grade 5 renal trauma in haemodynamically unstable patients. Furthermore, intermediate-term follow-up showed no significant adverse events, with no reported complications of refractory hypertension, altered renal function, new urolithiasis, chronic pain, urine leak, AVF or PSA (Stewart et al., 2010). Several studies have evaluated the effects on renal function and morphology of transcatheter embolisation in the setting of trauma, demonstrating preservation of renal function and parenchyma (Chatzioannou et al., 2004), preservation of glomerular filtration rates evaluated by dynamic scintigraphy (Morita et al., 2010) and late functional and morphological improvements in embolised renal units (Mohsen et al., 2007).

The principle role of the IR team in the management of both blunt and penetrating renal traumas is to stop life-threatening haemorrhage. This concept is not new. Renal artery embolisation was first described in 1964 (Edling and Ovenfors, 1964) and small published series of cases using autologous blood clot to successfully arrest traumatic renal haemorrhage date back more than three decades. (Chuang et al., 1975). Since then there have been significant advances in IR equipment, technology and techniques. There is now a wide range of embolic material available in the armamentarium of the IR and the advent of coaxial microcatheter systems allows superselective catheterisation of segmental arteries allowing accurate delivery of embolics. This results in effective arrest of bleeding from renal artery branches whilst preserving nephrons. The challenge to the trauma team is to accurately and rapidly identify those patients whose renal injury would benefit from transcatheter techniques and to ensure timely referral to the IR team.

The IR team should forge strong links with the trauma team and ideally provide a 24-h-a-day service with a rapid response time. At our institution, eight IRs, all offering embolisation for acute bleeding, with the support of dedicated IR radiographers and nurses provide a comprehensive service with a 30-min response time. The IR theatre should ideally be located in close proximity to the CT Scanner and trauma resuscitation room minimising delay. Timely referral is essential to ensure optimal outcome. Delay in time to achieve embolisation has been shown to be an important factor in patient survival in a series of patients undergoing arterial embolisation to control pelvic fracture haemorrhage with development of coagulopathy being cited as an important reason for poor outcome (Agolini et al., 1997). More recently, Howell et al. (2010) reported that in haemodynamically unstable trauma patients undergoing therapeutic catheter-based IR procedures, delay to IR beyond 60 min was independently associated with a twofold increase risk of mortality. Furthermore, for every hour delay, the risk of mortality increased by nearly 50%. Once in the IR theatre, access is obtained to the arterial system usually via the Common Femoral Artery at the groin. CT angiography often negates the need for flush aortic angiography as the source of bleeding has already been identified providing a ‘roadmap’ for the IR to proceed directly to selective catheterisation of the bleeding vessel. Angiography may demonstrate active extravasation of contrast indicative of unrestrained active bleeding, presence of a PSA or AVF. Renal arteries are end arteries and therefore there is no need to consider collateral supply as in other vascular territories such as the gastro- duodenal-pancreatic arcade. Superselective catheterisation minimises ischaemic damage secondary to embolisation. Embolisation is most frequently with coils, however, we have used Gelfoam (spongiostan) or liquid embolics such as glue (N-butyl cyanoacrylate) in selected cases, for example, where the patient has developed a coagulopathy.

An inevitable consequence of the shift away from the management of renal trauma by nephrectomy is the need to be recognised and manage complications related to the injured kidney. The need to perform follow-up imaging in patients with renal trauma is controversial, but it is probably unnecessary for blunt renal injuries of grades I to III (Malcolm et al., 2008). However, complications after renal trauma are reported to occur in between 3% and 33% of cases (Al-Qudah and Santucci, 2006) and can be immediate, early or late. Immediate complications most commonly relate to renal vascular injury as discussed above. Early complications are usually defined as occurring within 4 weeks of trauma and include urinary extravasation and urinoma formation, perinephric collections and secondary haemorrhage often due to PSA or AVF. Extravasation of urine is the most common complication of renal trauma (Matthews et al., 1997). Delayed phase excretory CT imaging may demonstrate active leak of urine from a disrupted collecting system. The majority of these patients can be treated expectantly with only a small proportion requiring intervention. The IR can provide urinary diversion in these cases by performing nephrostomy tube insertion and in selected cases, antegrade ureteric stenting and/or image-guided percutaneous drainage of urinomas. Delayed haemorrhage is a serious complication of renal trauma and most often due to PSA or AVF. When clinically suspected, these are readily identified by CT imaging and can be effectively treated by selective transcatheter embolisation most often with coils or N-butyl cyanoacrylate glue (Miller et al., 2002; Cantasdemir et al., 2003; Yazdi and Moharramzadeh, 2008). Both PSA and AVF can present months or years following injury (Chazen and Miller, 1997). Late complications include hypertension, hydronephrosis and calculus formation. ‘Page kidney’ is a term applied to hypertension secondary to renal compression which in the setting of trauma may be due to perirenal haematoma or urinoma or scarring of the renal capsule. This phenomenon was first described by Page (1939) in 1939 and the first clinical case reported in 1955 by Engel and Page (1955) in a young patient with hypertension cured by removal of a calcified subcapsular haematoma.

Other considerations

Iatrogenic injury

Iatrogenic injury is an important cause of kidney trauma, being the most common cause of significant renal vascular injury (Mohsen et al., 2007; Mavili et al., 2009). This is supported by an analysis of all renal artery embolisations performed at our institution over the past decade. In this series, renal vascular injury requiring percutaneous transcatheter embolisation in the acute setting was three times more common secondary to iatrogenic than a combination of both blunt and penetrating traumas. Renal biopsy was the most common cause of injury (Figure 2(a)–(c)), with partial nephrectomy and renal access procedures being other causes. Figure 3 (a) and (b) demonstrates successful selective embolisation in a patient who became haemodynamically unstable in the immediate post-operative period following partial nephrectomy. Catheter or CT angiography demonstrated active contrast extravasation, PSA, AVF or a combination of these, with PSA being the most common finding. These lesions are safely and effectively treated with transcatheter embolisation with superselective embolisation ensuring minimal damage to the kidney.

Figure 2.

(a) An axial slice from an arterial phase CT examination of a patient with a left Illiac fossa kidney transplant who companied of left-sided abdominal pain following a percutaneous biopsy procedure. It demonstrates a PSA in the anterior part of the transplant kidney (arrow). (b) Selective transplant renal artery angiography confirms the presence of a large PSA (arrow). (c) The right-hand image demonstrates successful selective embolisation. Images courtesy of Dr I McCafferty.

Figure 3.

(a) Selective left renal artery angiogram in a patient with significant hypotension immediately following partial nephrectomy demonstrating active extravasation of contrast from a descending ureteric arterial branch (arrow). (b) Successful superselective coil embolisation of the bleeding artery with excellent preservation of the remaining kidney.

Injury in kidneys with pre-existing abnormalities

Pre-existing renal lesions (PERLs) seem to increase the vulnerability of kidneys in renal trauma (Santucci et al., 2004). They are found in a larger proportion of children suffering renal injury than adults, with one series reporting the existence of PERLs in 36% of children with blunt renal trauma (Onen et al., 2002). Renal lesions predisposing to injuries include hydronephrosis, for example, secondary to pelviureteric junction obstruction or stone, renal cysts, tumours and developmental renal anomalies such as longitudinal renal ectopia (e.g. pelvic kidney) or renal fusion (e.g. horseshoe kidney). These are often undiagnosed at the time of the injury. CT is the optimal examination to evaluate trauma to abnormal kidneys (Rhyner et al., 1984).

Transplant kidneys

Renal transplants are most commonly sited within the pelvis and therefore, like ectopic pelvic kidneys, are potentially more vulnerable to trauma. Iatrogenic injury, frequently secondary to percutaneous biopsy (Figure 2(a)–(c)), is an important cause of transplant renal vascular damage. Early recognition of these injuries, ideally with CT angiography, allows for timely referral for percutaneous embolisation or other transcatheter techniques. Figure 4(a)–(d) demonstrates the successful use of a covered stent-graft to exclude a PSA at the arterial anastomosis of a transplant kidney and serve to illustrate another tool in the armamentarium of the IR.

Figure 4.

(a) An axial image from an arterial phase CT examination of a patient who developed left-sided abdominal pain a month following left renal transplantation. It demonstrates a large left-sided perirenal haematoma (arrows) and abnormality at the arterial anastomosis (arrow head). Note the renal transplant in the right iliac fossa which had failed secondary to rejection. (b) Catheter angiography demonstrates a PSA in the region of the transplant artery anastomosis. (c) The PSA has been successfully excluded by the placement of a covered stent graft. (d) A 3D reconstructed image from follow-up arterial phase CT examination at 1 month demonstrates successful exclusion of the PSA with patency of the transplant renal artery. Images courtesy of Dr P Riley.

Conclusion

Haemorrhage remains a leading cause of early death in trauma patients. As with injury to other solid organs, transcatheter techniques can provide definitive control of acute renal bleeding. To optimise the outcome, this requires rapid identification and staging of renal injury and timely referral to IR. This, in turn, is dependent on the rapid acquisition of CT imaging during trauma resuscitation and close working relationships between the trauma and IR teams.

References

Agolini

Shah

Jaffe

(1997) Arterial embolisation is a rapid and effective technique for controlling pelvic haemorrhage. Journal of Trauma 43(3): 395–399.

Al-Qudah

Santucci

(2006) Complications of renal trauma. Urologic Clinics of North America 33(1): 41–53.

Bent

Lyngkaran

Power

(2008) Urological injuries following trauma. Clinical Radiology 63(12): 1361–1371.

Brewer

Bradley

Daley

(2009) Percutaneous embolisation for the management of grade 5 renal trauma in haemodynamically unstable patients: initial experience. Journal of Urology 181(4): 1737–1741.

Breyer

McAninc

Elliot

(2008) Minimally invasive endovascular techniques to treat acute renal haemorrhage. Journal of Urology 179(6): 2248–2252.

Bright

White

Peters

(1978) Significance of haematuria after trauma. Journal of Urology 120(4): 455–456.

Cantasdemir

Adeleti

Cebi

(2003) Emergency endovascular embolisation of traumatic intrarenal arterial pseudoaneurysms with N-butyl cranoacrylate. Clinical Radiology 58(7): 560–565.

Chatziioannou

Brountzos

Primetis

(2004) Effects of superselective embolisation for renal vascular injuries on renal parenchyma and function. European Journal of Vascular and Endovascular Surgery 28(2): 201–206.

Chazen

Miller

(1997) Intrarenal pseudoaneurysm presenting 15 years after penetrating renal injury. Urology 49(5): 774–776.

10.

Chuang

Reuter

Walter

(1975) Control of renal haemorrhage by selective arterial embolisation. American Journal of Roentgenology, Radium Therapy, and Nuclear Medicine 125(2): 300–306.

11.

Dinkel

Danuser

Triller

(2002) Blunt renal trauma: minimally invasive management with microcatheter embolisation–experience in nine patients. Radiology 223(3): 723–730.

12.

Dugi

Morey

Gupta

(2010) American association for the surgery of trauma grade 4 renal injury substratification into grades 4a (low risk) and 4b (high risk). Journal of Urology 183(2): 592–597.

13.

Edling

Ovenfors

(1964) Interventional embolisation in selective renal angiography: an experimental study in dogs. Acta Radiologica Diagnosis 2: 316–320.

14.

Edwards

Claridge

Forsythe

(2009) The morbidity of trauma nephrectomy. The American Surgeon 75(11): 1112–1117.

15.

Engel

Page

(1955) Hypertension due to renal compression resulting from subcapsular haematoma. Journal of Urology 73(5): 735–739.

16.

Chen

(2010) Evaluation of need for angioembolisation in blunt renal injury: discontinuity of Gerota's fascia has an increased probability of requiring angioembolisation. American Journal of Surgery 199(2): 154–159.

17.

Hardeman

Husmann

Chinn

(1987) Blunt urinary tract trauma; identifying those patients who require radiological diagnostic studies. Journal of Urology 138(1): 99–101.

18.

Howell

Peitzman

Nirula

(2010) Delay to therapeutic interventional radiology postinjury: time is of the essence. Journal of Trauma 68(6): 1296–1300.

19.

Huber-Wagner

Lefering

Qvick

(2009) Effect of whole body CT during trauma resuscitation on survival: a retrospective, multicenter study. Lancet 373(9673): 1455–1461.

20.

Kuan

Wright

Nathens

(2006) American Association for the Surgery of Trauma organ injury severity scale for kidney injuries predicts nephrectomy, dialysis and death in patients with blunt injury and nephrectomy for penetrating injuries. Journal of Trauma 60(2): 351–356.

21.

Malcolm

Derweesh

Mehrazin

(2008) Nonoperative management of blunt renal trauma: is routine early follow up imaging necessary. BMC Urology 8: 11–11.

22.

Matthews

Smith

Spirnak

(1997) Non operative treatment of major blunt renal lacerations with urinary extravasation. Journal of Urology 157(6): 2056–2058.

23.

Mavili

Donmez

Ozcan

(2009) Transarterial bleeding for renal arterial bleeding. Diagnosis Intervention Radiology 15(2): 143–147.

24.

McAninch

Santucci

(2002) Renal and ureteral injuries. In: Gillenwater

Grayhack

Howards

Duckett

(eds) Adult and Paediatric Urology, 4th ed. Philadelphia: Lippincott Williams & Wilkins, 479–499.

25.

Mee

McAninch

Robinson

(1989) Radiographic assessment of renal trauma: a 10-year prospective study of patient selection. Journal of Urology 141(5): 1095–1098.

26.

Miller

Forauer

Faerber

(2002) Successful angioembolisation of renal artery pseudoaneurysms after blunt abdominal trauma. Urology 59(3): 444–444.

27.

Miller

McAninch

(1995) Radiographic assessment of renal trauma: our 15-year experience. Journal of Urology 154(2 pt 1): 352–355.

28.

Mohsen

El-Assmy

El-Diasty

(2007) Long term functional and morphological effects of transcatheter arterial embolisation of traumatic renal vascular injury. BJU International 101(4): 473–477.

29.

Moore

Shackford

Patcher

(1989) Organ injury scaling: spleen, liver and kidney. Journal of Trauma 29(12): 1664–1666.

30.

Morita

Inokuch

Tomoatsu

(2010) Arterial embolisation in patients with grade-4 blunt renal trauma: evaluation of the glomerular filtration rates by dynamic scintigraphy with 99m technetium diethylene triamine pentacetic acid. Scandanavian Journal of Trauma, Resuscitation and Emergency Medicine 18: 11–11.

31.

Nuss

Morey

Jenkins

(2009) Radiographic predictors of need for angiographic embolisation after traumatic renal injury. Journal of Trauma 67(3): 578–582.

32.

Onen

Kaya

Cigdem

(2002) Blunt renal trauma in children with previously undiagnosed pre-existing renal lesions and guidelines for effective initial management of kidney injury. BMC Urology 8: 11–11.

33.

Page

(1939) Production of persistent arterial hypertension by cellophane perinephritis. Journal of the American Medical Association 113(23): 2046–2048.

34.

Rhyner P, Federle MP and Jeffrey RB (1984) CT of trauma to the abnormal kidney. American Journal of Roentgenology 142(4): 747–750.

35.

Santucci

Fischer

(2005) The literature increasingly supports expectant (conservative) management of renal trauma – a systematic review. Journal of Trauma 59(2): 493–503.

36.

Santucci

McAninch

Safir

(2001) Validation of the American association for the surgery of trauma organ injury severity scale for the kidney. Journal of Trauma 50(2): 195–200.

37.

Santucci

Wessells

Bartsch

(2004) Consensus on genitourinary trauma. evaluation and management of renal injuries: consensus statement of the renal trauma subcommittee. BJU International 93(7): 937–954.

38.

Starnes

Demetriades

Hadjizacharia

(2010) Complications following renal trauma. Archives of Surgery 145(4): 377–381.

39.

Stewart

Brewer

Daley

(2010) Intermediate term follow up of patients treated with percutaneous embolisation fro grade 5 blunt renal trauma. Journal of Trauma 69(2): 468–470.

40.

Tasian

Aaronson

McAninch

(2010) Evaluation of renal function after major renal injury: correlation with the American association for the surgery of trauma organ injury scale. Journal of Urology 183(1): 196–200.

41.

Wessels

Suh

Porter

(2003) Renal injury and operative management in the United States: results of a population based study. Journal of Trauma 54(3): 423–430.

42.

Yazdi

Moharramzadeh

(2008) Endovascular treatment of renal arteriovenous fistula following stab wound. Urology Journal 5(2): 129–131.